diff --git a/lib/ai/formula_screen.dart b/lib/ai/formula_screen.dart
index f7bb727..c5034ed 100644
--- a/lib/ai/formula_screen.dart
+++ b/lib/ai/formula_screen.dart
@@ -168,6 +168,7 @@ class _FormulaScreenState extends State<FormulaScreen> {
                 setState(() {
                   _selectedOutputUnit = unit;
                 });
+                _evaluateFormula();
               },
             ),
           ],