diff --git a/erpnext/controllers/buying_controller.py b/erpnext/controllers/buying_controller.py
index f28de3b..8d5a042 100644
--- a/erpnext/controllers/buying_controller.py
+++ b/erpnext/controllers/buying_controller.py
@@ -300,7 +300,7 @@
 						raise_error_if_no_rate=False,
 					)
 
-					rate = flt(outgoing_rate * d.conversion_factor, d.precision("rate"))
+					rate = flt(outgoing_rate * (d.conversion_factor or 1), d.precision("rate"))
 				else:
 					rate = frappe.db.get_value(ref_doctype, d.get(frappe.scrub(ref_doctype)), "rate")