diff --git a/toolkit/content/widgets/scrollbox.xml b/toolkit/content/widgets/scrollbox.xml
index 46182d0ae61..e9b605d0f9f 100644
--- a/toolkit/content/widgets/scrollbox.xml
+++ b/toolkit/content/widgets/scrollbox.xml
@@ -248,7 +248,7 @@
         handleEvent: function scrollAnim_handleEvent(event) {
           const timePassed = event.timeStamp - this.startTime;
           const pos = timePassed >= this.duration ? 1 :
-                      1 - Math.pow(1 - timePassed / this.duration, 2);
+                      1 - Math.pow(1 - timePassed / this.duration, 4);
 
           this.scrollbox.scrollPosition = this.startPos + (this.distance * pos);