diff --git a/docs/js/upgrade.js b/docs/js/upgrade.js
index 173d3f9..b01cf9d 100644
--- a/docs/js/upgrade.js
+++ b/docs/js/upgrade.js
@@ -42,7 +42,7 @@ for (let upgrade of upgrades) {
 
         price = upgrade.price * (1.02 ** counts[upgrade.exec]);
 
-        nothingness -= upgrade.price;
+        nothingness -= price;
         upgrade.price *= 1.02;
         updateText(button, price, upgrade.name, cc);