diff --git a/src/components/cost-estimator/step-3-project-stage.tsx b/src/components/cost-estimator/step-3-project-stage.tsx
index 179f1ef..fa0f335 100644
--- a/src/components/cost-estimator/step-3-project-stage.tsx
+++ b/src/components/cost-estimator/step-3-project-stage.tsx
@@ -25,12 +25,13 @@ const stageLabels = [
     "70%", // 70
     "80%", // 80
     "90%", // 90
-    "100%", // 100
 ];
 
 const calculateHours = (projectStage: number): number => {
-    // Scale hours from 50 down to 0 as projectStage goes from 0 to 100.
-    return Math.round(((100 - projectStage) / 100) * 50);
+    // 0% -> 50 hours
+    // 90% -> 5 hours
+    // Linear interpolation: H(p) = 50 - (45/90) * p = 50 - 0.5 * p
+    return 50 - (0.5 * projectStage);
 };
 
 export function Step3ProjectStage({ onNext, onBack, onUpdateData, formData }: Step3Props) {
@@ -61,13 +62,13 @@ export function Step3ProjectStage({ onNext, onBack, onUpdateData, formData }: St
         <Slider
           defaultValue={value}
           onValueChange={handleSliderChange}
-          max={100}
+          max={90}
           step={10}
           className="w-full"
         />
         <div className="flex justify-between text-xs text-muted-foreground mt-2">
             <span>0%</span>
-            <span>100%</span>
+            <span>90%</span>
         </div>
       </div>
       <div className="mt-16 flex w-full items-center justify-between">