diff --git a/frappe/core/doctype/event/event.py b/frappe/core/doctype/event/event.py
index 9f3afbc64f..a68e4d6dad 100644
--- a/frappe/core/doctype/event/event.py
+++ b/frappe/core/doctype/event/event.py
@@ -14,6 +14,11 @@ class Event(Document):
 	def validate(self):
 		if self.starts_on and self.ends_on and self.starts_on > self.ends_on:
 			frappe.msgprint(frappe._("Event end must be after start"), raise_exception=True)
+
+		if self.starts_on == self.ends_on:
+			# this scenario doesn't make sense i.e. it starts and ends at the same second!
+			self.ends_on = None
+
 		if self.starts_on and self.ends_on and int(date_diff(self.ends_on.split(" ")[0], self.starts_on.split(" ")[0])) > 0 \
 			and self.repeat_on == "Every Day":
 			frappe.msgprint(frappe._("Every day events should finish on the same day."), raise_exception=True)
diff --git a/frappe/public/js/frappe/views/calendar.js b/frappe/public/js/frappe/views/calendar.js
index 97b7b8007a..29f8c9d0e1 100644
--- a/frappe/public/js/frappe/views/calendar.js
+++ b/frappe/public/js/frappe/views/calendar.js
@@ -207,7 +207,7 @@ frappe.views.Calendar = Class.extend({
 		if(this.field_map.end) {
 			if (args[this.field_map.allDay]) {
 				args[this.field_map.end] = frappe.datetime.get_datetime_as_string(event.start);
-			} else {
+			} else if (event.end) {
 				args[this.field_map.end] = frappe.datetime.get_datetime_as_string(event.end);
 			}
 		}
diff --git a/frappe/widgets/calendar.py b/frappe/widgets/calendar.py
index 8cc8c27a3c..17ce524217 100644
--- a/frappe/widgets/calendar.py
+++ b/frappe/widgets/calendar.py
@@ -13,6 +13,6 @@ def update_event(args, field_map):
 	field_map = frappe._dict(json.loads(field_map))
 	w = frappe.get_doc(args.doctype, args.name)
 	w.set(field_map.start, args[field_map.start])
-	w.set(field_map.end, args[field_map.end])
+	w.set(field_map.end, args.get(field_map.end))
 	w.save()