diff --git a/erpnext/accounts/doctype/payment_request/payment_request.py b/erpnext/accounts/doctype/payment_request/payment_request.py
index bd4cc4d..0c46191 100644
--- a/erpnext/accounts/doctype/payment_request/payment_request.py
+++ b/erpnext/accounts/doctype/payment_request/payment_request.py
@@ -211,7 +211,7 @@
 		grand_total = flt(ref_doc.grand_total) - flt(ref_doc.advance_paid)
 		
 	if dt == "Sales Invoice":
-		grand_total = flt(ref_doc.outstanding_amount)
+		grand_total = flt(ref_doc.grand_total)
 		
 	if grand_total > 0 :
 		return grand_total