diff --git a/erpnext/stock/doctype/serial_and_batch_bundle/serial_and_batch_bundle.py b/erpnext/stock/doctype/serial_and_batch_bundle/serial_and_batch_bundle.py
index abdbeb4..3c824fd 100644
--- a/erpnext/stock/doctype/serial_and_batch_bundle/serial_and_batch_bundle.py
+++ b/erpnext/stock/doctype/serial_and_batch_bundle/serial_and_batch_bundle.py
@@ -1018,7 +1018,7 @@
 		doc.append(
 			"entries",
 			{
-				"qty": d.get("qty") * (1 if doc.type_of_transaction == "Inward" else -1),
+				"qty": (d.get("qty") or 1.0) * (1 if doc.type_of_transaction == "Inward" else -1),
 				"warehouse": warehouse or d.get("warehouse"),
 				"batch_no": d.get("batch_no"),
 				"serial_no": d.get("serial_no"),