diff --git a/frontend/src/app/features/calculator/calculator-page.component.html b/frontend/src/app/features/calculator/calculator-page.component.html
index 72b1ed3..07b1912 100644
--- a/frontend/src/app/features/calculator/calculator-page.component.html
+++ b/frontend/src/app/features/calculator/calculator-page.component.html
@@ -3,7 +3,7 @@
   <p class="subtitle">{{ 'CALC.SUBTITLE' | translate }}</p>
 
   @if (error()) {
-    <app-alert type="error">{{ 'CALC.ERROR_GENERIC' | translate }}</app-alert>
+    <app-alert type="error">{{ errorKey() | translate }}</app-alert>
   }
 </div>
 
diff --git a/frontend/src/app/features/calculator/calculator-page.component.ts b/frontend/src/app/features/calculator/calculator-page.component.ts
index a997649..9bef380 100644
--- a/frontend/src/app/features/calculator/calculator-page.component.ts
+++ b/frontend/src/app/features/calculator/calculator-page.component.ts
@@ -27,6 +27,7 @@ export class CalculatorPageComponent implements OnInit {
   uploadProgress = signal(0);
   result = signal<QuoteResult | null>(null);
   error = signal<boolean>(false);
+  errorKey = signal<string>('CALC.ERROR_GENERIC');
   
   orderSuccess = signal(false);
   
@@ -64,6 +65,14 @@ export class CalculatorPageComponent implements OnInit {
           next: (data) => {
               // 1. Map to Result
               const result = this.estimator.mapSessionToQuoteResult(data);
+              if (this.isInvalidQuote(result)) {
+                  this.setQuoteError('CALC.ERROR_ZERO_PRICE');
+                  this.loading.set(false);
+                  return;
+              }
+
+              this.error.set(false);
+              this.errorKey.set('CALC.ERROR_GENERIC');
               this.result.set(result);
               this.step.set('quote');
               
@@ -79,7 +88,7 @@ export class CalculatorPageComponent implements OnInit {
           },
           error: (err) => {
               console.error('Failed to load session', err);
-              this.error.set(true);
+              this.setQuoteError('CALC.ERROR_GENERIC');
               this.loading.set(false);
           }
       });
@@ -146,6 +155,7 @@ export class CalculatorPageComponent implements OnInit {
     this.loading.set(true);
     this.uploadProgress.set(0);
     this.error.set(false);
+    this.errorKey.set('CALC.ERROR_GENERIC');
     this.result.set(null);
     this.orderSuccess.set(false);
 
@@ -163,6 +173,14 @@ export class CalculatorPageComponent implements OnInit {
         } else {
             // It's the result
             const res = event as QuoteResult;
+            if (this.isInvalidQuote(res)) {
+                this.setQuoteError('CALC.ERROR_ZERO_PRICE');
+                this.loading.set(false);
+                return;
+            }
+
+            this.error.set(false);
+            this.errorKey.set('CALC.ERROR_GENERIC');
             this.result.set(res);
             this.loading.set(false);
             this.uploadProgress.set(100);
@@ -180,7 +198,7 @@ export class CalculatorPageComponent implements OnInit {
         }
       },
       error: () => {
-        this.error.set(true);
+        this.setQuoteError('CALC.ERROR_GENERIC');
         this.loading.set(false);
       }
     });
@@ -216,10 +234,19 @@ export class CalculatorPageComponent implements OnInit {
               next: () => {
                   // 3. Fetch the updated session totals from the backend
                   this.estimator.getQuoteSession(currentSessionId).subscribe({
-                      next: (sessionData) => {
+                  next: (sessionData) => {
                           const newResult = this.estimator.mapSessionToQuoteResult(sessionData);
                           // Preserve notes
                           newResult.notes = this.result()?.notes;
+
+                          if (this.isInvalidQuote(newResult)) {
+                              this.setQuoteError('CALC.ERROR_ZERO_PRICE');
+                              this.loading.set(false);
+                              return;
+                          }
+
+                          this.error.set(false);
+                          this.errorKey.set('CALC.ERROR_GENERIC');
                           this.result.set(newResult);
                           this.loading.set(false);
                       },
@@ -282,4 +309,14 @@ export class CalculatorPageComponent implements OnInit {
 
     this.router.navigate(['/contact']);
   }
+
+  private isInvalidQuote(result: QuoteResult): boolean {
+    return !Number.isFinite(result.totalPrice) || result.totalPrice <= 0;
+  }
+
+  private setQuoteError(key: string): void {
+    this.errorKey.set(key);
+    this.error.set(true);
+    this.result.set(null);
+  }
 }
diff --git a/frontend/src/assets/i18n/de.json b/frontend/src/assets/i18n/de.json
index b1af8bc..89a4a4d 100644
--- a/frontend/src/assets/i18n/de.json
+++ b/frontend/src/assets/i18n/de.json
@@ -90,7 +90,8 @@
     "PROCESSING": "Verarbeitung...",
     "NOTES_PLACEHOLDER": "Spezifische Anweisungen...",
     "SETUP_NOTE": "* Beinhaltet {{cost}} als Einrichtungskosten",
-    "SHIPPING_NOTE": "** Versandkosten ausgeschlossen, werden im nächsten Schritt berechnet"
+    "SHIPPING_NOTE": "** Versandkosten ausgeschlossen, werden im nächsten Schritt berechnet",
+    "ERROR_ZERO_PRICE": "Etwas ist schiefgelaufen. Versuche ein anderes Format oder kontaktiere uns."
   },
   "SHOP": {
     "TITLE": "Technische Lösungen",
diff --git a/frontend/src/assets/i18n/en.json b/frontend/src/assets/i18n/en.json
index cb443ef..9d7f4e1 100644
--- a/frontend/src/assets/i18n/en.json
+++ b/frontend/src/assets/i18n/en.json
@@ -90,7 +90,8 @@
     "PROCESSING": "Processing...",
     "NOTES_PLACEHOLDER": "Specific instructions...",
     "SETUP_NOTE": "* Includes {{cost}} as setup cost",
-    "SHIPPING_NOTE": "** Shipping costs excluded, calculated at the next step"
+    "SHIPPING_NOTE": "** Shipping costs excluded, calculated at the next step",
+    "ERROR_ZERO_PRICE": "Something went wrong. Try another format or contact us."
   },
   "SHOP": {
     "TITLE": "Technical solutions",
diff --git a/frontend/src/assets/i18n/fr.json b/frontend/src/assets/i18n/fr.json
index 1dcf7f7..00dffc8 100644
--- a/frontend/src/assets/i18n/fr.json
+++ b/frontend/src/assets/i18n/fr.json
@@ -115,7 +115,8 @@
     "REMOVE_FILE": "Supprimer le fichier",
     "FALLBACK_MATERIAL": "PLA (fallback)",
     "FALLBACK_QUALITY_STANDARD": "Standard",
-    "ERR_FILE_TOO_LARGE": "Certains fichiers dépassent la limite de 200MB et n'ont pas été ajoutés."
+    "ERR_FILE_TOO_LARGE": "Certains fichiers dépassent la limite de 200MB et n'ont pas été ajoutés.",
+    "ERROR_ZERO_PRICE": "Quelque chose s'est mal passé. Essayez un autre format ou contactez-nous."
   },
   "QUOTE": {
     "PROCEED_ORDER": "Procéder à la commande",
diff --git a/frontend/src/assets/i18n/it.json b/frontend/src/assets/i18n/it.json
index 5e89136..b17a3b5 100644
--- a/frontend/src/assets/i18n/it.json
+++ b/frontend/src/assets/i18n/it.json
@@ -115,7 +115,8 @@
     "REMOVE_FILE": "Rimuovi file",
     "FALLBACK_MATERIAL": "PLA (fallback)",
     "FALLBACK_QUALITY_STANDARD": "Standard",
-    "ERR_FILE_TOO_LARGE": "Alcuni file superano il limite di 200MB e non sono stati aggiunti."
+    "ERR_FILE_TOO_LARGE": "Alcuni file superano il limite di 200MB e non sono stati aggiunti.",
+    "ERROR_ZERO_PRICE": "Qualcosa è andato storto. Prova con un altro formato oppure contattaci."
   },
   "QUOTE": {
     "PROCEED_ORDER": "Procedi con l'ordine",