diff --git a/frontend/app.js b/frontend/app.js
index cc7790b..26896f8 100644
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -3282,6 +3282,11 @@ function wireDeliveryLineEvents(line) {
     }
 
     if (packCountInput) {
+        // Prevent accidental value changes when users scroll while focused.
+        packCountInput.addEventListener('wheel', (event) => {
+            event.preventDefault();
+        }, { passive: false });
+
         packCountInput.addEventListener('input', () => {
             updateDeliveryLineQuantityDisplay(line);
         });