diff --git a/sass/bootstrap-select.scss b/sass/bootstrap-select.scss
index 0c5e5cc87..8b7ffc515 100644
--- a/sass/bootstrap-select.scss
+++ b/sass/bootstrap-select.scss
@@ -23,7 +23,7 @@
 
 @function fade($color, $amnt) {
   @if $amnt > 1 {
-    $amnt: $amnt / 100; // convert to percentage if int
+    $amnt: calc($amnt / 100); // convert to percentage if int
   }
   @return rgba($color, $amnt);
 }