diff --git a/erpnext/manufacturing/doctype/job_card/job_card.js b/erpnext/manufacturing/doctype/job_card/job_card.js
index a19d11adf5d..073446e91ca 100644
--- a/erpnext/manufacturing/doctype/job_card/job_card.js
+++ b/erpnext/manufacturing/doctype/job_card/job_card.js
@@ -251,6 +251,7 @@ frappe.ui.form.on("Job Card", {
 				change() {
 					const dialog = frm.job_completion_dialog;
 					dialog.set_value("completed_qty", dialog.get_value("for_quantity"));
+					dialog.set_value("pending_qty", 0);
 					dialog.set_value("process_loss_qty", 0);
 				},
 			},
@@ -262,8 +263,21 @@ frappe.ui.form.on("Job Card", {
 				default: pending_qty,
 				change() {
 					const dialog = frm.job_completion_dialog;
-					const remaining = dialog.get_value("for_quantity") - dialog.get_value("completed_qty");
-					if (remaining > 0 && remaining != dialog.get_value("pending_qty")) {
+					const remaining =
+						dialog.get_value("for_quantity") -
+						dialog.get_value("completed_qty") -
+						dialog.get_value("process_loss_qty");
+
+					if (remaining < 0) {
+						const max_completed_qty =
+							flt(dialog.get_value("for_quantity")) - flt(dialog.get_value("process_loss_qty"));
+						dialog.set_value("completed_qty", max_completed_qty);
+						frappe.throw(
+							__("Completed Quantity cannot be greater than {0}", [max_completed_qty])
+						);
+					}
+
+					if (remaining != dialog.get_value("pending_qty")) {
 						dialog.set_value("pending_qty", remaining);
 					}
 				},
@@ -279,7 +293,18 @@ frappe.ui.form.on("Job Card", {
 						dialog.get_value("for_quantity") -
 						dialog.get_value("completed_qty") -
 						dialog.get_value("pending_qty");
-					if (process_loss_qty >= 0 && process_loss_qty != dialog.get_value("process_loss_qty")) {
+
+					if (process_loss_qty < 0) {
+						dialog.set_value("pending_qty", 0);
+						frappe.throw(
+							__("Pending Quantity cannot be greater than {0}", [
+								flt(dialog.get_value("for_quantity")) -
+									flt(dialog.get_value("completed_qty")),
+							])
+						);
+					}
+
+					if (process_loss_qty != dialog.get_value("process_loss_qty")) {
 						dialog.set_value("process_loss_qty", process_loss_qty);
 					}
 				},
@@ -294,7 +319,18 @@ frappe.ui.form.on("Job Card", {
 						dialog.get_value("for_quantity") -
 						dialog.get_value("completed_qty") -
 						dialog.get_value("process_loss_qty");
-					if (remaining >= 0 && remaining != dialog.get_value("pending_qty")) {
+
+					if (remaining < 0) {
+						dialog.set_value("process_loss_qty", 0);
+						frappe.throw(
+							__("Process Loss Quantity cannot be greater than {0}", [
+								flt(dialog.get_value("for_quantity")) -
+									flt(dialog.get_value("completed_qty")),
+							])
+						);
+					}
+
+					if (remaining != dialog.get_value("pending_qty")) {
 						dialog.set_value("pending_qty", remaining);
 					}
 				},
diff --git a/erpnext/manufacturing/doctype/job_card/job_card.py b/erpnext/manufacturing/doctype/job_card/job_card.py
index a06529d0699..069dcdb7299 100644
--- a/erpnext/manufacturing/doctype/job_card/job_card.py
+++ b/erpnext/manufacturing/doctype/job_card/job_card.py
@@ -895,22 +895,21 @@ class JobCard(Document):
 					)
 
 		precision = self.precision("total_completed_qty")
-		total_completed_qty = flt(
+		accounted_qty = flt(
 			flt(self.total_completed_qty, precision)
 			+ flt(self.process_loss_qty, precision)
 			+ flt(self.pending_qty, precision)
 		)
 
-		if self.for_quantity and flt(total_completed_qty, precision) != flt(self.for_quantity, precision):
-			total_completed_qty_label = bold(_("Total Completed Qty"))
-			qty_to_manufacture = bold(_("Qty to Manufacture"))
-
+		if self.for_quantity and flt(accounted_qty, precision) != flt(self.for_quantity, precision):
 			frappe.throw(
-				_("The {0} ({1}) must be equal to {2} ({3})").format(
-					total_completed_qty_label,
-					bold(flt(total_completed_qty, precision)),
-					qty_to_manufacture,
-					bold(self.for_quantity),
+				_(
+					"Total Completed Qty ({0}), Process Loss Qty ({1}) and Pending Qty ({2}) must add up to the Qty to Manufacture ({3})."
+				).format(
+					bold(flt(self.total_completed_qty, precision)),
+					bold(flt(self.process_loss_qty, precision)),
+					bold(flt(self.pending_qty, precision)),
+					bold(flt(self.for_quantity, precision)),
 				)
 			)
 
@@ -1605,6 +1604,8 @@ class JobCard(Document):
 		if flt(kwargs.pending_qty) and flt(kwargs.pending_qty) > self.for_quantity:
 			frappe.throw(_("Pending quantity cannot be greater than the for quantity."))
 
+		self.validate_completion_qty_split(kwargs)
+
 		self.pending_qty = flt(kwargs.pending_qty)
 		self.process_loss_qty = flt(kwargs.process_loss_qty)
 
@@ -1633,6 +1634,31 @@ class JobCard(Document):
 				_("Job Card {0} has been completed").format(get_link_to_form("Job Card", self.name))
 			)
 
+	def validate_completion_qty_split(self, kwargs):
+		if not flt(kwargs.for_quantity):
+			return
+
+		precision = self.precision("total_completed_qty")
+		accounted_qty = flt(
+			flt(kwargs.qty, precision)
+			+ flt(kwargs.pending_qty, precision)
+			+ flt(kwargs.process_loss_qty, precision)
+		)
+
+		if flt(accounted_qty, precision) == flt(kwargs.for_quantity, precision):
+			return
+
+		frappe.throw(
+			_(
+				"Completed Quantity ({0}), Pending Quantity ({1}) and Process Loss Quantity ({2}) must add up to the Qty to Manufacture ({3})."
+			).format(
+				bold(flt(kwargs.qty, precision)),
+				bold(flt(kwargs.pending_qty, precision)),
+				bold(flt(kwargs.process_loss_qty, precision)),
+				bold(flt(kwargs.for_quantity, precision)),
+			)
+		)
+
 	@frappe.whitelist()
 	def make_stock_entry_for_semi_fg_item(self, auto_submit: bool = False):
 		def get_consumed_process_loss():
diff --git a/erpnext/manufacturing/doctype/job_card/test_job_card.py b/erpnext/manufacturing/doctype/job_card/test_job_card.py
index 934c33decd5..55b2a848469 100644
--- a/erpnext/manufacturing/doctype/job_card/test_job_card.py
+++ b/erpnext/manufacturing/doctype/job_card/test_job_card.py
@@ -2114,6 +2114,26 @@ class TestJobCard(ERPNextTestSuite):
 		self.assertEqual(s.additional_costs[2].amount, 480)
 		self.assertEqual(s.additional_costs[3].amount, 480)
 
+	def test_completion_qty_split_must_add_up(self):
+		jc = frappe.new_doc("Job Card")
+		jc.for_quantity = 5
+
+		jc.validate_completion_qty_split(
+			frappe._dict(for_quantity=5, qty=3, pending_qty=2, process_loss_qty=0)
+		)
+
+		self.assertRaises(
+			frappe.ValidationError,
+			jc.validate_completion_qty_split,
+			frappe._dict(for_quantity=3, qty=3, pending_qty=2, process_loss_qty=0),
+		)
+
+		self.assertRaises(
+			frappe.ValidationError,
+			jc.validate_completion_qty_split,
+			frappe._dict(for_quantity=1, qty=0.3334, pending_qty=0.3334, process_loss_qty=0.3334),
+		)
+
 
 def create_bom_with_multiple_operations():
 	"Create a BOM with multiple operations and Material Transfer against Job Card"