diff --git a/backend/controllers/tournamentController.js b/backend/controllers/tournamentController.js
index dd383232..6d363789 100644
--- a/backend/controllers/tournamentController.js
+++ b/backend/controllers/tournamentController.js
@@ -64,8 +64,9 @@ export const getInternalTournamentStats = async (req, res) => {
     const { authcode: token } = req.headers;
     const { clubId } = req.params;
     const months = req.query.months;
+    const ageClassKeys = req.query.ageClassKeys;
     try {
-        const data = await tournamentService.getInternalTournamentPlayerStats(token, clubId, months);
+        const data = await tournamentService.getInternalTournamentPlayerStats(token, clubId, months, ageClassKeys);
         res.status(200).json(data);
     } catch (error) {
         console.error(error);
diff --git a/backend/services/internalTournamentStatsService.js b/backend/services/internalTournamentStatsService.js
index 183cd5f4..d79973ff 100644
--- a/backend/services/internalTournamentStatsService.js
+++ b/backend/services/internalTournamentStatsService.js
@@ -81,6 +81,35 @@ export function groupPercentFromRankings(rankings, nInGroup) {
   return map;
 }
 
+/** Schlüssel für Gruppen/Spiele ohne zugeordnete Klasse (classId null) */
+export const NO_CLASS_AGE_KEY = 'ak|__noclass__';
+
+/**
+ * Stabiler Filter-Schlüssel aus einer Einzel-Klasse (Geburtsjahre + Geschlecht).
+ * @param {object} classRow – TournamentClass-Plain
+ * @returns {string|null} null bei Doppel
+ */
+export function ageClassFilterKey(classRow) {
+  if (!classRow || classRow.isDoubles) return null;
+  const min = classRow.minBirthYear ?? classRow.min_birth_year ?? null;
+  const max = classRow.maxBirthYear ?? classRow.max_birth_year ?? null;
+  const g = classRow.gender ?? '';
+  return `ak|${min ?? ''}|${max ?? ''}|${g}`;
+}
+
+/**
+ * @param {number|null|undefined} classIdNum
+ * @param {Array<object>} classes
+ * @returns {string|null} null wenn unbekannte ID oder Doppel-Klasse
+ */
+export function ageKeyForClassSlice(classIdNum, classes) {
+  if (classIdNum == null || classIdNum === undefined) return NO_CLASS_AGE_KEY;
+  const c = (classes || []).find((x) => Number(x.id) === Number(classIdNum));
+  if (!c) return null;
+  if (c.isDoubles) return null;
+  return ageClassFilterKey(c);
+}
+
 /**
  * @param {object} opts
  * @param {Array} opts.groups – Aus getGroupsWithParticipants (participants: flache Objekte mit id, position, isExternal, …)
@@ -88,6 +117,7 @@ export function groupPercentFromRankings(rankings, nInGroup) {
  * @param {Array<{ id: number, isDoubles?: boolean }>} opts.classes
  * @param {Map<number, number>} opts.tmToMemberId – Turnier-Mitglied-ID -> Vereins-Mitglied-ID
  * @param {Map<number, { firstName: string, lastName: string }>} [opts.tmToName] – optional Namen
+ * @param {Set<string>|null} [opts.allowedAgeKeys] – nur diese Altersklassen-Schlüssel werten; null = alle
  * @returns {Map<number, { points: number, firstName: string, lastName: string }>} Vereins-Mitglied-ID -> Aggregation
  */
 export function computeInternalSinglesStatsForTournament({
@@ -96,6 +126,7 @@ export function computeInternalSinglesStatsForTournament({
   classes,
   tmToMemberId,
   tmToName,
+  allowedAgeKeys = null,
 }) {
   const doublesClassIds = new Set(
     (classes || []).filter((c) => c.isDoubles).map((c) => Number(c.id))
@@ -137,6 +168,14 @@ export function computeInternalSinglesStatsForTournament({
     const classIdNum = classKey === 'null' ? null : Number(classKey);
     if (classIdNum != null && doublesClassIds.has(classIdNum)) continue;
 
+    const sliceAgeKey = ageKeyForClassSlice(classIdNum, classes);
+    if (sliceAgeKey == null) continue;
+
+    if (allowedAgeKeys != null) {
+      if (allowedAgeKeys.size === 0) continue;
+      if (!allowedAgeKeys.has(sliceAgeKey)) continue;
+    }
+
     const classGroups = (groups || []).filter((g) => {
       const gc = g.classId != null ? Number(g.classId) : null;
       const key = gc != null ? String(gc) : 'null';
@@ -219,4 +258,7 @@ export default {
   groupPercentFromRankings,
   computeInternalSinglesStatsForTournament,
   parseWinnerFromMatch,
+  ageClassFilterKey,
+  ageKeyForClassSlice,
+  NO_CLASS_AGE_KEY,
 };
diff --git a/backend/services/tournamentService.js b/backend/services/tournamentService.js
index fe4bb634..4f8d2284 100644
--- a/backend/services/tournamentService.js
+++ b/backend/services/tournamentService.js
@@ -15,7 +15,30 @@ import { Op, literal } from 'sequelize';
 
 
 import { devLog } from '../utils/logger.js';
-import { computeInternalSinglesStatsForTournament } from './internalTournamentStatsService.js';
+import {
+  computeInternalSinglesStatsForTournament,
+  ageClassFilterKey,
+  NO_CLASS_AGE_KEY,
+} from './internalTournamentStatsService.js';
+
+/** @param {unknown} val Query ageClassKeys: fehlend = alle; leer = keine; sonst kommagetrennte Schlüssel */
+function parseInternalStatsAgeClassKeys(val) {
+  if (val === undefined || val === null) return null;
+  if (Array.isArray(val)) {
+    const out = [];
+    for (const v of val) {
+      String(v)
+        .split(',')
+        .map((s) => s.trim())
+        .filter(Boolean)
+        .forEach((k) => out.push(k));
+    }
+    return out;
+  }
+  const s = String(val).trim();
+  if (s === '') return [];
+  return s.split(',').map((x) => x.trim()).filter(Boolean);
+}
 
 function normalizeJsonConfig(value, label = 'config') {
     if (value == null) return {};
@@ -4283,7 +4306,7 @@ Ve    // 2. Neues Turnier anlegen
     /**
      * Ranglisten für interne Einzel-Turniere (Punkte nach Gruppenplatz + K.-o.) über einen Zeitraum.
      */
-    async getInternalTournamentPlayerStats(userToken, clubId, months = 12) {
+    async getInternalTournamentPlayerStats(userToken, clubId, months = 12, ageClassKeysQuery = null) {
         await checkAccess(userToken, clubId);
         const m = Number(months);
         const monthsNum = [3, 6, 12].includes(m) ? m : 12;
@@ -4303,14 +4326,65 @@ Ve    // 2. Neues Turnier anlegen
         });
         const list = JSON.parse(JSON.stringify(tournaments));
 
+        const ageClassOptionsByKey = new Map();
+
         const memberAgg = new Map();
 
+        const rawKeys = parseInternalStatsAgeClassKeys(ageClassKeysQuery);
+
         for (const t of list) {
             const classes = await this.getTournamentClasses(userToken, clubId, t.id);
             const classesJson = classes.map((c) => (c.toJSON ? c.toJSON() : c));
             const groups = await this.getGroupsWithParticipants(userToken, clubId, t.id);
             const matches = await this.getTournamentMatches(userToken, clubId, t.id);
 
+            for (const c of classesJson) {
+                if (c.isDoubles) continue;
+                const k = ageClassFilterKey(c);
+                if (!k) continue;
+                if (!ageClassOptionsByKey.has(k)) {
+                    ageClassOptionsByKey.set(k, {
+                        key: k,
+                        name: c.name || '',
+                        minBirthYear: c.minBirthYear ?? c.min_birth_year ?? null,
+                        maxBirthYear: c.maxBirthYear ?? c.max_birth_year ?? null,
+                        gender: c.gender ?? null,
+                        isNoClass: false,
+                    });
+                }
+            }
+            let hasNoClassSlice = false;
+            for (const g of groups || []) {
+                if (g.classId == null || g.classId === undefined) {
+                    hasNoClassSlice = true;
+                    break;
+                }
+            }
+            if (!hasNoClassSlice) {
+                for (const ma of matches || []) {
+                    if (ma.round === 'group') continue;
+                    if (ma.classId == null || ma.classId === undefined) {
+                        hasNoClassSlice = true;
+                        break;
+                    }
+                }
+            }
+            if (hasNoClassSlice && !ageClassOptionsByKey.has(NO_CLASS_AGE_KEY)) {
+                ageClassOptionsByKey.set(NO_CLASS_AGE_KEY, {
+                    key: NO_CLASS_AGE_KEY,
+                    name: '',
+                    minBirthYear: null,
+                    maxBirthYear: null,
+                    gender: null,
+                    isNoClass: true,
+                });
+            }
+
+            let allowedAgeKeys = null;
+            if (rawKeys !== null) {
+                allowedAgeKeys = new Set(rawKeys);
+            }
+
             const tmIds = new Set();
             for (const g of groups || []) {
                 for (const p of g.participants || []) {
@@ -4347,6 +4421,7 @@ Ve    // 2. Neues Turnier anlegen
                 classes: classesJson,
                 tmToMemberId,
                 tmToName,
+                allowedAgeKeys,
             });
 
             for (const [mid, row] of memberTotals) {
@@ -4383,10 +4458,19 @@ Ve    // 2. Neues Turnier anlegen
             b.averagePoints - a.averagePoints || (a.lastName || '').localeCompare(b.lastName || '', 'de')
         );
 
+        const ageClassOptions = [...ageClassOptionsByKey.values()].sort((a, b) => {
+            if (a.isNoClass && !b.isNoClass) return 1;
+            if (!a.isNoClass && b.isNoClass) return -1;
+            const an = (a.name || '').localeCompare(b.name || '', 'de');
+            if (an !== 0) return an;
+            return (a.key || '').localeCompare(b.key || '', 'de');
+        });
+
         return {
             months: monthsNum,
             fromDate: fromStr,
             tournamentCount: list.length,
+            ageClassOptions,
             absoluteRanking,
             averageRanking,
         };
diff --git a/frontend/src/components/tournament/InternalTournamentStats.vue b/frontend/src/components/tournament/InternalTournamentStats.vue
index c501957c..68c239f2 100644
--- a/frontend/src/components/tournament/InternalTournamentStats.vue
+++ b/frontend/src/components/tournament/InternalTournamentStats.vue
@@ -23,7 +23,7 @@
         </button>
         <label class="period-label">
           <span>{{ $t('tournaments.internalStatsPeriod') }}</span>
-          <select v-model="months" @change="load" :disabled="loading">
+          <select v-model="months" @change="onMonthsChange" :disabled="loading">
             <option :value="12">{{ $t('tournaments.internalStatsLast12Months') }}</option>
             <option :value="6">{{ $t('tournaments.internalStatsLast6Months') }}</option>
             <option :value="3">{{ $t('tournaments.internalStatsLast3Months') }}</option>
@@ -35,6 +35,29 @@
       </p>
       <p class="stats-explain">{{ $t('tournaments.internalStatsPointsExplain') }}</p>
 
+      <fieldset v-if="sortedAgeOptions.length > 1" class="age-filter">
+        <legend class="age-filter-legend">{{ $t('tournaments.internalStatsAgeFilter') }}</legend>
+        <div class="age-filter-actions">
+          <button type="button" class="age-filter-link" @click="selectAllAgeKeys" :disabled="loading">
+            {{ $t('tournaments.internalStatsAgeSelectAll') }}
+          </button>
+          <button type="button" class="age-filter-link" @click="selectNoAgeKeys" :disabled="loading">
+            {{ $t('tournaments.internalStatsAgeSelectNone') }}
+          </button>
+        </div>
+        <div class="age-filter-checkboxes">
+          <label v-for="opt in sortedAgeOptions" :key="opt.key" class="age-filter-item">
+            <input
+              type="checkbox"
+              :checked="selectedAgeKeys.includes(opt.key)"
+              :disabled="loading"
+              @change="onAgeCheckboxChange(opt.key, $event.target.checked)"
+            />
+            <span>{{ formatAgeOption(opt) }}</span>
+          </label>
+        </div>
+      </fieldset>
+
       <div v-if="loading" class="stats-loading">{{ $t('common.loading') }}</div>
       <div v-else-if="error" class="stats-error">{{ error }}</div>
       <div v-else class="stats-grid">
@@ -108,9 +131,13 @@ export default {
       dialogPosition: { x: 80, y: 80 },
       stats: {
         tournamentCount: 0,
+        ageClassOptions: [],
         absoluteRanking: [],
         averageRanking: [],
       },
+      selectedAgeKeys: [],
+      ageFilterInitialized: false,
+      pendingResetAgeSelection: false,
     };
   },
   computed: {
@@ -124,9 +151,21 @@ export default {
         (!this.stats.absoluteRanking?.length && !this.stats.averageRanking?.length)
       );
     },
+    sortedAgeOptions() {
+      const list = [...(this.stats.ageClassOptions || [])];
+      list.sort((a, b) =>
+        this.formatAgeOption(a).localeCompare(this.formatAgeOption(b), 'de', {
+          sensitivity: 'base',
+        }),
+      );
+      return list;
+    },
   },
   watch: {
     clubId() {
+      this.ageFilterInitialized = false;
+      this.selectedAgeKeys = [];
+      this.pendingResetAgeSelection = false;
       if (this.modelValue) this.load();
     },
     modelValue(open) {
@@ -154,6 +193,74 @@ export default {
             : 'internalStatsLast3Months';
       return this.$t(`tournaments.${key}`);
     },
+    buildStatsParams() {
+      const params = { months: this.months };
+      if (this.pendingResetAgeSelection) return params;
+      const opts = this.stats.ageClassOptions || [];
+      const allKeys = opts.map((o) => o.key);
+      if (allKeys.length === 0) return params;
+      if (this.selectedAgeKeys.length === 0) {
+        params.ageClassKeys = '';
+      } else if (this.selectedAgeKeys.length < allKeys.length) {
+        params.ageClassKeys = this.selectedAgeKeys.join(',');
+      }
+      return params;
+    },
+    onMonthsChange() {
+      this.pendingResetAgeSelection = true;
+      this.load();
+    },
+    onAgeCheckboxChange(key, checked) {
+      if (checked) {
+        if (!this.selectedAgeKeys.includes(key)) {
+          this.selectedAgeKeys = [...this.selectedAgeKeys, key];
+        }
+      } else {
+        this.selectedAgeKeys = this.selectedAgeKeys.filter((k) => k !== key);
+      }
+      this.load();
+    },
+    selectAllAgeKeys() {
+      this.selectedAgeKeys = (this.stats.ageClassOptions || []).map((o) => o.key);
+      this.load();
+    },
+    selectNoAgeKeys() {
+      this.selectedAgeKeys = [];
+      this.load();
+    },
+    formatAgeOption(opt) {
+      if (!opt) return '';
+      if (opt.isNoClass) return this.$t('tournaments.internalStatsAgeNoClass');
+      const bits = [];
+      if (opt.name) bits.push(opt.name);
+      const min = opt.minBirthYear;
+      const max = opt.maxBirthYear;
+      if (min != null && max != null) bits.push(`${min}–${max}`);
+      else if (max != null) bits.push(`≤ ${max}`);
+      else if (min != null) bits.push(`≥ ${min}`);
+      if (opt.gender === 'male') bits.push(this.$t('members.genderMale'));
+      else if (opt.gender === 'female') bits.push(this.$t('members.genderFemale'));
+      else if (opt.gender === 'mixed') bits.push(this.$t('tournaments.genderMixed'));
+      return bits.join(' · ');
+    },
+    ageFilterPdfLine() {
+      const opts = this.stats.ageClassOptions || [];
+      if (opts.length <= 1) return '';
+      const allKeys = opts.map((o) => o.key);
+      if (this.selectedAgeKeys.length === allKeys.length) {
+        return this.$t('tournaments.internalStatsAgeFilterAll');
+      }
+      if (this.selectedAgeKeys.length === 0) {
+        return this.$t('tournaments.internalStatsAgeFilterNone');
+      }
+      const labels = this.selectedAgeKeys
+        .map((k) => {
+          const o = opts.find((x) => x.key === k);
+          return o ? this.formatAgeOption(o) : k;
+        })
+        .join('; ');
+      return `${this.$t('tournaments.internalStatsAgeFilter')}: ${labels}`;
+    },
     exportPdf() {
       const t = this.$t;
       const margin = 14;
@@ -178,6 +285,12 @@ export default {
       );
       y += 6;
 
+      const ageLine = this.ageFilterPdfLine();
+      if (ageLine) {
+        pdf.text(ageLine, margin, y);
+        y += 5;
+      }
+
       const explain = t('tournaments.internalStatsPointsExplain');
       const explainLines = pdf.splitTextToSize(explain, pageW - margin * 2);
       pdf.setFontSize(8);
@@ -283,12 +396,26 @@ export default {
       this.error = null;
       try {
         const res = await apiClient.get(`/tournament/internal-stats/${this.clubId}`, {
-          params: { months: this.months },
+          params: this.buildStatsParams(),
         });
         this.stats = res.data || {};
+        const opts = this.stats.ageClassOptions || [];
+        if (this.pendingResetAgeSelection) {
+          this.selectedAgeKeys = opts.map((o) => o.key);
+          this.pendingResetAgeSelection = false;
+          this.ageFilterInitialized = true;
+        } else if (!this.ageFilterInitialized && opts.length) {
+          this.selectedAgeKeys = opts.map((o) => o.key);
+          this.ageFilterInitialized = true;
+        }
       } catch (e) {
         this.error = e?.response?.data?.error || e.message || 'Error';
-        this.stats = { tournamentCount: 0, absoluteRanking: [], averageRanking: [] };
+        this.stats = {
+          tournamentCount: 0,
+          ageClassOptions: [],
+          absoluteRanking: [],
+          averageRanking: [],
+        };
       } finally {
         this.loading = false;
       }
@@ -360,6 +487,69 @@ export default {
   line-height: 1.45;
 }
 
+.age-filter {
+  margin: 0 0 1rem;
+  padding: 0.65rem 0.75rem;
+  border: 1px solid var(--border-color, #e5e7eb);
+  border-radius: 8px;
+  background: #fafafa;
+}
+
+.age-filter-legend {
+  padding: 0 0.35rem;
+  font-size: 0.9rem;
+  font-weight: 600;
+  color: #374151;
+}
+
+.age-filter-actions {
+  display: flex;
+  gap: 0.75rem;
+  margin-bottom: 0.5rem;
+}
+
+.age-filter-link {
+  background: none;
+  border: none;
+  padding: 0;
+  font-size: 0.85rem;
+  font-weight: 600;
+  color: var(--primary-color, #2563eb);
+  cursor: pointer;
+  text-decoration: underline;
+}
+
+.age-filter-link:hover:not(:disabled) {
+  color: var(--primary-hover, #1d4ed8);
+}
+
+.age-filter-link:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+}
+
+.age-filter-checkboxes {
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+  max-height: 11rem;
+  overflow-y: auto;
+}
+
+.age-filter-item {
+  display: flex;
+  align-items: flex-start;
+  gap: 0.45rem;
+  font-size: 0.88rem;
+  line-height: 1.35;
+  cursor: pointer;
+}
+
+.age-filter-item input {
+  margin-top: 0.2rem;
+  flex-shrink: 0;
+}
+
 .stats-grid {
   display: grid;
   grid-template-columns: 1fr 1fr;
diff --git a/frontend/src/i18n/locales/de-CH.json b/frontend/src/i18n/locales/de-CH.json
index 6383fcde..2dbfa844 100644
--- a/frontend/src/i18n/locales/de-CH.json
+++ b/frontend/src/i18n/locales/de-CH.json
@@ -178,6 +178,12 @@
     "internalStatsTitle": "Statistik interne Turniere (Einzel)",
     "internalStatsOpenButton": "Turnierstatistik (Einzel)",
     "internalStatsExportPdf": "Als PDF exportieren",
+    "internalStatsAgeFilter": "Altersklassen (Einzel)",
+    "internalStatsAgeNoClass": "Ohni Klassäzuordnig",
+    "internalStatsAgeSelectAll": "Alli",
+    "internalStatsAgeSelectNone": "Keini",
+    "internalStatsAgeFilterAll": "Alli Altersklassä",
+    "internalStatsAgeFilterNone": "Kei Altersklass usgwählt",
     "internalStatsPeriod": "Ziitruum",
     "internalStatsLast12Months": "Letscht 12 Mönet",
     "internalStatsLast6Months": "Letscht 6 Mönet",
diff --git a/frontend/src/i18n/locales/de-extended.json b/frontend/src/i18n/locales/de-extended.json
index 4e13c431..6ae0ea48 100644
--- a/frontend/src/i18n/locales/de-extended.json
+++ b/frontend/src/i18n/locales/de-extended.json
@@ -409,6 +409,12 @@
     "internalStatsTitle": "Statistik interne Turniere (Einzel)",
     "internalStatsOpenButton": "Turnierstatistik (Einzel)",
     "internalStatsExportPdf": "Als PDF exportieren",
+    "internalStatsAgeFilter": "Altersklassen (Einzel)",
+    "internalStatsAgeNoClass": "Ohne Klassenzuordnung",
+    "internalStatsAgeSelectAll": "Alle",
+    "internalStatsAgeSelectNone": "Keine",
+    "internalStatsAgeFilterAll": "Alle Altersklassen",
+    "internalStatsAgeFilterNone": "Keine Altersklasse ausgewählt",
     "internalStatsPeriod": "Zeitraum",
     "internalStatsLast12Months": "Letzte 12 Monate",
     "internalStatsLast6Months": "Letzte 6 Monate",
diff --git a/frontend/src/i18n/locales/de.json b/frontend/src/i18n/locales/de.json
index aae6eb40..01814fae 100644
--- a/frontend/src/i18n/locales/de.json
+++ b/frontend/src/i18n/locales/de.json
@@ -701,6 +701,12 @@
     "internalStatsTitle": "Statistik interne Turniere (Einzel)",
     "internalStatsOpenButton": "Turnierstatistik (Einzel)",
     "internalStatsExportPdf": "Als PDF exportieren",
+    "internalStatsAgeFilter": "Altersklassen (Einzel)",
+    "internalStatsAgeNoClass": "Ohne Klassenzuordnung",
+    "internalStatsAgeSelectAll": "Alle",
+    "internalStatsAgeSelectNone": "Keine",
+    "internalStatsAgeFilterAll": "Alle Altersklassen",
+    "internalStatsAgeFilterNone": "Keine Altersklasse ausgewählt",
     "internalStatsPeriod": "Zeitraum",
     "internalStatsLast12Months": "Letzte 12 Monate",
     "internalStatsLast6Months": "Letzte 6 Monate",
diff --git a/frontend/src/i18n/locales/en-AU.json b/frontend/src/i18n/locales/en-AU.json
index 9c77a838..6ed7037a 100644
--- a/frontend/src/i18n/locales/en-AU.json
+++ b/frontend/src/i18n/locales/en-AU.json
@@ -178,6 +178,12 @@
     "internalStatsTitle": "Internal tournaments statistics (singles)",
     "internalStatsOpenButton": "Tournament statistics (singles)",
     "internalStatsExportPdf": "Export as PDF",
+    "internalStatsAgeFilter": "Age classes (singles)",
+    "internalStatsAgeNoClass": "No class assigned",
+    "internalStatsAgeSelectAll": "All",
+    "internalStatsAgeSelectNone": "None",
+    "internalStatsAgeFilterAll": "All age classes",
+    "internalStatsAgeFilterNone": "No age class selected",
     "internalStatsPeriod": "Period",
     "internalStatsLast12Months": "Last 12 months",
     "internalStatsLast6Months": "Last 6 months",
diff --git a/frontend/src/i18n/locales/en-GB.json b/frontend/src/i18n/locales/en-GB.json
index 8ba1bfc1..25ad63ed 100644
--- a/frontend/src/i18n/locales/en-GB.json
+++ b/frontend/src/i18n/locales/en-GB.json
@@ -359,6 +359,12 @@
     "internalStatsTitle": "Internal tournaments statistics (singles)",
     "internalStatsOpenButton": "Tournament statistics (singles)",
     "internalStatsExportPdf": "Export as PDF",
+    "internalStatsAgeFilter": "Age classes (singles)",
+    "internalStatsAgeNoClass": "No class assigned",
+    "internalStatsAgeSelectAll": "All",
+    "internalStatsAgeSelectNone": "None",
+    "internalStatsAgeFilterAll": "All age classes",
+    "internalStatsAgeFilterNone": "No age class selected",
     "internalStatsPeriod": "Period",
     "internalStatsLast12Months": "Last 12 months",
     "internalStatsLast6Months": "Last 6 months",
diff --git a/frontend/src/i18n/locales/en-US.json b/frontend/src/i18n/locales/en-US.json
index a0fad8cc..fb72b71d 100644
--- a/frontend/src/i18n/locales/en-US.json
+++ b/frontend/src/i18n/locales/en-US.json
@@ -178,6 +178,12 @@
     "internalStatsTitle": "Internal tournaments statistics (singles)",
     "internalStatsOpenButton": "Tournament statistics (singles)",
     "internalStatsExportPdf": "Export as PDF",
+    "internalStatsAgeFilter": "Age classes (singles)",
+    "internalStatsAgeNoClass": "No class assigned",
+    "internalStatsAgeSelectAll": "All",
+    "internalStatsAgeSelectNone": "None",
+    "internalStatsAgeFilterAll": "All age classes",
+    "internalStatsAgeFilterNone": "No age class selected",
     "internalStatsPeriod": "Period",
     "internalStatsLast12Months": "Last 12 months",
     "internalStatsLast6Months": "Last 6 months",
diff --git a/frontend/src/i18n/locales/es.json b/frontend/src/i18n/locales/es.json
index 8cc2683b..a3f289ba 100644
--- a/frontend/src/i18n/locales/es.json
+++ b/frontend/src/i18n/locales/es.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Estadísticas de torneos internos (individual)",
     "internalStatsOpenButton": "Estadísticas de torneos (individual)",
     "internalStatsExportPdf": "Exportar como PDF",
+    "internalStatsAgeFilter": "Categorías de edad (individual)",
+    "internalStatsAgeNoClass": "Sin clase asignada",
+    "internalStatsAgeSelectAll": "Todas",
+    "internalStatsAgeSelectNone": "Ninguna",
+    "internalStatsAgeFilterAll": "Todas las categorías",
+    "internalStatsAgeFilterNone": "Ninguna categoría seleccionada",
     "internalStatsPeriod": "Periodo",
     "internalStatsLast12Months": "Últimos 12 meses",
     "internalStatsLast6Months": "Últimos 6 meses",
diff --git a/frontend/src/i18n/locales/fil.json b/frontend/src/i18n/locales/fil.json
index 4979cf0b..86949cb0 100644
--- a/frontend/src/i18n/locales/fil.json
+++ b/frontend/src/i18n/locales/fil.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Estadistika ng internal na paligsahan (singles)",
     "internalStatsOpenButton": "Buksan ang estadistika (singles)",
     "internalStatsExportPdf": "I-export bilang PDF",
+    "internalStatsAgeFilter": "Mga pangkat ng edad (singles)",
+    "internalStatsAgeNoClass": "Walang klase",
+    "internalStatsAgeSelectAll": "Lahat",
+    "internalStatsAgeSelectNone": "Wala",
+    "internalStatsAgeFilterAll": "Lahat ng pangkat ng edad",
+    "internalStatsAgeFilterNone": "Walang napiling pangkat ng edad",
     "internalStatsPeriod": "Saklaw",
     "internalStatsLast12Months": "Huling 12 buwan",
     "internalStatsLast6Months": "Huling 6 na buwan",
diff --git a/frontend/src/i18n/locales/fr.json b/frontend/src/i18n/locales/fr.json
index 4ff2c955..fbba35a4 100644
--- a/frontend/src/i18n/locales/fr.json
+++ b/frontend/src/i18n/locales/fr.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Statistiques des tournois internes (simple)",
     "internalStatsOpenButton": "Statistiques (simple)",
     "internalStatsExportPdf": "Exporter en PDF",
+    "internalStatsAgeFilter": "Catégories d’âge (simple)",
+    "internalStatsAgeNoClass": "Sans classe assignée",
+    "internalStatsAgeSelectAll": "Tout",
+    "internalStatsAgeSelectNone": "Aucune",
+    "internalStatsAgeFilterAll": "Toutes les catégories",
+    "internalStatsAgeFilterNone": "Aucune catégorie sélectionnée",
     "internalStatsPeriod": "Période",
     "internalStatsLast12Months": "12 derniers mois",
     "internalStatsLast6Months": "6 derniers mois",
diff --git a/frontend/src/i18n/locales/it.json b/frontend/src/i18n/locales/it.json
index f8a0ccf3..ed0dd6cc 100644
--- a/frontend/src/i18n/locales/it.json
+++ b/frontend/src/i18n/locales/it.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Statistiche tornei interni (singolo)",
     "internalStatsOpenButton": "Statistiche tornei (singolo)",
     "internalStatsExportPdf": "Esporta PDF",
+    "internalStatsAgeFilter": "Categorie di età (singolo)",
+    "internalStatsAgeNoClass": "Senza classe assegnata",
+    "internalStatsAgeSelectAll": "Tutte",
+    "internalStatsAgeSelectNone": "Nessuna",
+    "internalStatsAgeFilterAll": "Tutte le categorie",
+    "internalStatsAgeFilterNone": "Nessuna categoria selezionata",
     "internalStatsPeriod": "Periodo",
     "internalStatsLast12Months": "Ultimi 12 mesi",
     "internalStatsLast6Months": "Ultimi 6 mesi",
diff --git a/frontend/src/i18n/locales/ja.json b/frontend/src/i18n/locales/ja.json
index ff9148e2..cd8531ac 100644
--- a/frontend/src/i18n/locales/ja.json
+++ b/frontend/src/i18n/locales/ja.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "内部大会の統計（シングルス）",
     "internalStatsOpenButton": "統計を表示（シングルス）",
     "internalStatsExportPdf": "PDFで出力",
+    "internalStatsAgeFilter": "年齢クラス（シングルス）",
+    "internalStatsAgeNoClass": "クラス未設定",
+    "internalStatsAgeSelectAll": "すべて",
+    "internalStatsAgeSelectNone": "なし",
+    "internalStatsAgeFilterAll": "すべての年齢クラス",
+    "internalStatsAgeFilterNone": "年齢クラス未選択",
     "internalStatsPeriod": "期間",
     "internalStatsLast12Months": "過去12か月",
     "internalStatsLast6Months": "過去6か月",
diff --git a/frontend/src/i18n/locales/pl.json b/frontend/src/i18n/locales/pl.json
index c2c3416d..63df21ad 100644
--- a/frontend/src/i18n/locales/pl.json
+++ b/frontend/src/i18n/locales/pl.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Statystyki turniejów wewnętrznych (singel)",
     "internalStatsOpenButton": "Statystyki turniejów (singel)",
     "internalStatsExportPdf": "Eksportuj do PDF",
+    "internalStatsAgeFilter": "Klasy wiekowe (singel)",
+    "internalStatsAgeNoClass": "Bez przypisania do klasy",
+    "internalStatsAgeSelectAll": "Wszystkie",
+    "internalStatsAgeSelectNone": "Żadna",
+    "internalStatsAgeFilterAll": "Wszystkie klasy wiekowe",
+    "internalStatsAgeFilterNone": "Nie wybrano klasy wiekowej",
     "internalStatsPeriod": "Okres",
     "internalStatsLast12Months": "Ostatnie 12 miesięcy",
     "internalStatsLast6Months": "Ostatnie 6 miesięcy",
diff --git a/frontend/src/i18n/locales/th.json b/frontend/src/i18n/locales/th.json
index a917ab5e..2bf146bb 100644
--- a/frontend/src/i18n/locales/th.json
+++ b/frontend/src/i18n/locales/th.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "สถิติการแข่งขันภายใน (เดี่ยว)",
     "internalStatsOpenButton": "เปิดสถิติ (เดี่ยว)",
     "internalStatsExportPdf": "ส่งออก PDF",
+    "internalStatsAgeFilter": "รุ่นอายุ (เดี่ยว)",
+    "internalStatsAgeNoClass": "ไม่มีคลาส",
+    "internalStatsAgeSelectAll": "ทั้งหมด",
+    "internalStatsAgeSelectNone": "ไม่มี",
+    "internalStatsAgeFilterAll": "ทุกรุ่นอายุ",
+    "internalStatsAgeFilterNone": "ไม่ได้เลือกรุ่นอายุ",
     "internalStatsPeriod": "ช่วงเวลา",
     "internalStatsLast12Months": "12 เดือนล่าสุด",
     "internalStatsLast6Months": "6 เดือนล่าสุด",
diff --git a/frontend/src/i18n/locales/tl.json b/frontend/src/i18n/locales/tl.json
index bf1c71e7..49ba5ea1 100644
--- a/frontend/src/i18n/locales/tl.json
+++ b/frontend/src/i18n/locales/tl.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "Istatistika ng internal na tournament (singles)",
     "internalStatsOpenButton": "Buksan ang istatistika (singles)",
     "internalStatsExportPdf": "I-export bilang PDF",
+    "internalStatsAgeFilter": "Mga pangkat ng edad (singles)",
+    "internalStatsAgeNoClass": "Walang klase",
+    "internalStatsAgeSelectAll": "Lahat",
+    "internalStatsAgeSelectNone": "Wala",
+    "internalStatsAgeFilterAll": "Lahat ng pangkat ng edad",
+    "internalStatsAgeFilterNone": "Walang napiling pangkat ng edad",
     "internalStatsPeriod": "Saklaw",
     "internalStatsLast12Months": "Huling 12 buwan",
     "internalStatsLast6Months": "Huling 6 na buwan",
diff --git a/frontend/src/i18n/locales/zh.json b/frontend/src/i18n/locales/zh.json
index 1db6a592..a3c95788 100644
--- a/frontend/src/i18n/locales/zh.json
+++ b/frontend/src/i18n/locales/zh.json
@@ -177,6 +177,12 @@
     "internalStatsTitle": "内部锦标赛统计（单打）",
     "internalStatsOpenButton": "打开单打统计数据",
     "internalStatsExportPdf": "导出 PDF",
+    "internalStatsAgeFilter": "年龄组（单打）",
+    "internalStatsAgeNoClass": "未分配级别",
+    "internalStatsAgeSelectAll": "全选",
+    "internalStatsAgeSelectNone": "全不选",
+    "internalStatsAgeFilterAll": "全部年龄组",
+    "internalStatsAgeFilterNone": "未选择年龄组",
     "internalStatsPeriod": "时间范围",
     "internalStatsLast12Months": "过去 12 个月",
     "internalStatsLast6Months": "过去 6 个月",