diff --git a/src/core/core.tooltip.js b/src/core/core.tooltip.js
index 6eb6b3a557a..589d4292b1a 100755
--- a/src/core/core.tooltip.js
+++ b/src/core/core.tooltip.js
@@ -117,8 +117,10 @@ module.exports = function(Chart) {
 		var x = 0,
 			y = 0;
 		for (i = 0; i < xPositions.length; ++i) {
-			x += xPositions[i];
-			y += yPositions[i];
+			if (xPositions[ i ]) {
+				x += xPositions[i];
+				y += yPositions[i];
+			}
 		}
 
 		return {