diff --git a/lib/spriteBackgroundImages.js b/lib/spriteBackgroundImages.js
index 556846a..1177832 100644
--- a/lib/spriteBackgroundImages.js
+++ b/lib/spriteBackgroundImages.js
@@ -91,7 +91,7 @@ function maxPaddingDimensions(...paddings) {
   const result = [0, 0, 0, 0];
   for (const padding of paddings) {
     if (padding) {
-      for (var i = 0; i < 4; i += 1) {
+      for (let i = 0; i < 4; i += 1) {
         result[i] = Math.max(result[i], padding[i]);
       }
     }