diff --git a/erpnext/manufacturing/doctype/production_order/production_order.py b/erpnext/manufacturing/doctype/production_order/production_order.py
index 158c4433d5..2f2c40ef2d 100644
--- a/erpnext/manufacturing/doctype/production_order/production_order.py
+++ b/erpnext/manufacturing/doctype/production_order/production_order.py
@@ -318,7 +318,7 @@ class ProductionOrder(Document):
 
 				from_time, to_time = self.get_start_end_time(timesheet, d.name)
 
-				if date_diff(from_time, original_start_time) > plan_days:
+				if date_diff(from_time, original_start_time) > cint(plan_days):
 					frappe.throw(_("Unable to find Time Slot in the next {0} days for Operation {1}").format(plan_days, d.operation))
 					break