diff --git a/erpnext/controllers/taxes_and_totals.py b/erpnext/controllers/taxes_and_totals.py
index 45ed338..0355c26 100644
--- a/erpnext/controllers/taxes_and_totals.py
+++ b/erpnext/controllers/taxes_and_totals.py
@@ -404,10 +404,10 @@
 			self.doc.total_advance = flt(total_allocated_amount, self.doc.precision("total_advance"))
 
 			if self.doc.party_account_currency == self.doc.currency:
-				invoice_total = flt(self.doc.grand_total - self.doc.write_off_amount, 
+				invoice_total = flt(self.doc.grand_total - flt(self.doc.write_off_amount), 
 					self.doc.precision("grand_total"))
 			else:
-				base_write_off_amount = flt(self.doc.write_off_amount * self.doc.conversion_rate, 
+				base_write_off_amount = flt(flt(self.doc.write_off_amount) * self.doc.conversion_rate, 
 					self.doc.precision("base_write_off_amount"))
 				invoice_total = flt(self.doc.grand_total * self.doc.conversion_rate, 
 					self.doc.precision("grand_total")) - base_write_off_amount