diff --git a/elements.less b/elements.less
index 5a9ee1a..be6a52c 100644
--- a/elements.less
+++ b/elements.less
@@ -75,7 +75,7 @@
   -webkit-opacity: @opacity;
   opacity: @opacity;
   @opperc: @opacity * 100;
-  -ms-filter: ~"progid:DXImageTransform.Microsoft.Alpha(opacity=@{percent})";
+  -ms-filter: ~"progid:DXImageTransform.Microsoft.Alpha(opacity=@{opperc})";
   filter: ~"alpha(opacity=@{opperc})";
 }
 .transition-duration(@duration: 0.2s) {