diff --git a/src/onTap.js b/src/onTap.js
index edef3bf..cd41eca 100644
--- a/src/onTap.js
+++ b/src/onTap.js
@@ -1,4 +1,4 @@
-import {noop} from './utils.js';
+import {hypotenuse, noop} from './utils.js';
 
 const MODULE = 'onTap';
 
@@ -123,8 +123,10 @@ export default class OnTap {
 		this.state.lastY = event.offsetY;
 
 		if (event.touches.length > 1) {
+			this.state.scaleStart = hypotenuse(touches[0].pageX - touches[1].pageX, touches[0].pageY - touches[1].pageY);
 			this.state.pinching = true;
-			this.state.scaleStart = Math.sqrt(Math.pow(touches[0].pageX - touches[1].pageX, 2) + Math.pow(touches[0].pageY - touches[1].pageY, 2));
+			this.state.lastPinch = 1;
+
 			clearTimeout(this.state.pressTO);
 		}
 
@@ -240,12 +242,12 @@ export default class OnTap {
 
 			event.scale = event.scale ? event.scale :
 				touches.length < 2 ? 1 :
-				Math.sqrt(Math.pow(touches[0].pageX - touches[1].pageX, 2) + Math.pow(touches[0].pageY - touches[1].pageY, 2)) / this.state.scaleStart;
+				hypotenuse(touches[0].pageX - touches[1].pageX, touches[0].pageY - touches[1].pageY) / this.state.scaleStart;
 
 			Object.assign(event, {
 				offsetX: touches.reduce((memo, touch) => memo + touch.pageX, 0) / touches.length,
 				offsetY: touches.reduce((memo, touch) => memo + touch.pageY, 0) / touches.length,
-				scaleStep: event.scale / (this.state.lastPinch || 1),
+				scaleStep: event.scale / this.state.lastPinch,
 				mobile: true,
 			});