diff --git a/src/ScrollBar.tsx b/src/ScrollBar.tsx
index dcfe1e1..d8f90a7 100644
--- a/src/ScrollBar.tsx
+++ b/src/ScrollBar.tsx
@@ -142,7 +142,8 @@ const ScrollBar = React.forwardRef<ScrollBarRef, ScrollBarProps>((props, ref) =>
         } = stateRef.current;
         raf.cancel(moveRafId);
 
-        const scale = containerSize / scrollbarRef.current.getBoundingClientRect().height;
+        const rect = scrollbarRef.current.getBoundingClientRect();
+        const scale = containerSize / (horizontal ? rect.width : rect.height);
 
         if (stateDragging) {
           const offset = (getPageXY(e, horizontal) - statePageY) * scale;
@@ -193,7 +194,7 @@ const ScrollBar = React.forwardRef<ScrollBarRef, ScrollBarProps>((props, ref) =>
 
   React.useEffect(() => {
     delayHidden();
-     return () => {
+    return () => {
       clearTimeout(visibleTimeoutRef.current);
     };
   }, [scrollOffset]);
diff --git a/tests/scrollWidth.test.tsx b/tests/scrollWidth.test.tsx
index b1f8fd1..79a141c 100644
--- a/tests/scrollWidth.test.tsx
+++ b/tests/scrollWidth.test.tsx
@@ -37,7 +37,7 @@ describe('List.scrollWidth', () => {
       },
       clientHeight: {
         get() {
-          return holderWidth;
+          return holderHeight;
         },
       },
       getBoundingClientRect() {