diff --git a/src/lib/quantity-format.ts b/src/lib/quantity-format.ts
index 6346dab..653ed6f 100644
--- a/src/lib/quantity-format.ts
+++ b/src/lib/quantity-format.ts
@@ -1,7 +1,7 @@
 export function formatQuantity(q: number | null): string {
   if (q === null || q === undefined) return '';
-  const rounded = Math.round(q);
-  if (Math.abs(q - rounded) < 0.01) return String(rounded);
-  // auf max. 2 Nachkommastellen, trailing Nullen raus
-  return q.toFixed(2).replace(/\.?0+$/, '');
+  return q.toLocaleString('de-DE', {
+    maximumFractionDigits: 2,
+    useGrouping: false
+  });
 }
diff --git a/tests/unit/quantity-format.test.ts b/tests/unit/quantity-format.test.ts
index a631b06..498fc6f 100644
--- a/tests/unit/quantity-format.test.ts
+++ b/tests/unit/quantity-format.test.ts
@@ -16,10 +16,10 @@ describe('formatQuantity', () => {
   });
 
   it('renders fractional with up to 2 decimals, trailing zeros trimmed', () => {
-    expect(formatQuantity(0.5)).toBe('0.5');
-    expect(formatQuantity(0.333333)).toBe('0.33');
-    expect(formatQuantity(1.1)).toBe('1.1');
-    expect(formatQuantity(1.1)).toBe('1.1');
+    expect(formatQuantity(0.5)).toBe('0,5');
+    expect(formatQuantity(0.333333)).toBe('0,33');
+    expect(formatQuantity(1.1)).toBe('1,1');
+    expect(formatQuantity(1.1)).toBe('1,1');
   });
 
   it('handles zero', () => {