diff --git a/backend/services/falukantService.js b/backend/services/falukantService.js
index 4166b35..52a5fc9 100644
--- a/backend/services/falukantService.js
+++ b/backend/services/falukantService.js
@@ -3793,6 +3793,37 @@ class FalukantService extends BaseService {
         return Math.round(cfg.min + (cfg.max - cfg.min) * p);
     }
 
+    /** Resolve character id for education: self = user's character, children/director = studentId */
+    async _resolveLearningCharacterId(hashedUserId, student, studentId) {
+        if (student === 'self') {
+            const user = await getFalukantUserOrFail(hashedUserId);
+            const char = await FalukantCharacter.findOne({ where: { userId: user.id }, attributes: ['id'] });
+            return char?.id ?? null;
+        }
+        return studentId ?? null;
+    }
+
+    async getKnowledgeSingle(hashedUserId, student, studentId, productId) {
+        const characterId = await this._resolveLearningCharacterId(hashedUserId, student, studentId);
+        if (!characterId) throw new Error('Character not found');
+        const row = await Knowledge.findOne({
+            where: { characterId, productId },
+            attributes: ['knowledge']
+        });
+        return { knowledge: row?.knowledge ?? 0 };
+    }
+
+    async getKnowledgeForAll(hashedUserId, student, studentId) {
+        const characterId = await this._resolveLearningCharacterId(hashedUserId, student, studentId);
+        if (!characterId) throw new Error('Character not found');
+        const [products, knowledges] = await Promise.all([
+            ProductType.findAll({ attributes: ['id'] }),
+            Knowledge.findAll({ where: { characterId }, attributes: ['productId', 'knowledge'] })
+        ]);
+        const knowledgeMap = new Map((knowledges || []).map(k => [k.productId, k.knowledge ?? 0]));
+        return products.map(p => ({ productId: p.id, knowledge: knowledgeMap.get(p.id) ?? 0 }));
+    }
+
     async sendToSchool(hashedUserId, item, student, studentId) {
         const falukantUser = await getFalukantUserOrFail(hashedUserId);
 
@@ -3812,11 +3843,14 @@ class FalukantService extends BaseService {
         let percent;
         if (item === 'all') {
             const all = await this.getKnowledgeForAll(hashedUserId, student, studentId);
-            const sum = all.reduce((s, k) => s + k.knowledge, 0);
-            percent = sum / all.length;
+            if (!all.length) percent = 0;
+            else {
+                const sum = all.reduce((s, k) => s + (k.knowledge || 0), 0);
+                percent = sum / all.length;
+            }
         } else {
             const single = await this.getKnowledgeSingle(hashedUserId, student, studentId, item);
-            percent = single.knowledge;
+            percent = single.knowledge ?? 0;
         }
 
         // 4) Kosten berechnen