diff --git a/cara/apps/calculator/static/js/form.js b/cara/apps/calculator/static/js/form.js
index cddbde05..c512c380 100644
--- a/cara/apps/calculator/static/js/form.js
+++ b/cara/apps/calculator/static/js/form.js
@@ -400,9 +400,9 @@ function validateFinishTime(obj) {
   var startTime = parseValToNumber(startObj.value);
   var finishTime = parseValToNumber(finishObj.value);
   if (startTime > finishTime) {
-    $(obj).addClass("red_border finish_time_error");
-    $(obj).next('span').remove();
-    insertSpanAfter(obj, "Finish time must be after start");
+    $(finishObj).addClass("red_border finish_time_error");
+    $(finishObj).next('span').remove();
+    insertSpanAfter(finishObj, "Finish time must be after start");
     return false;
   }
   else {