diff --git a/addons/point_of_sale/models/pos_session.py b/addons/point_of_sale/models/pos_session.py
index 39a3c84518b..0c767e2db2b 100644
--- a/addons/point_of_sale/models/pos_session.py
+++ b/addons/point_of_sale/models/pos_session.py
@@ -2030,8 +2030,8 @@ class PosSession(models.Model):
     def get_total_discount(self):
         amount = 0
         for line in self.env['pos.order.line'].search([('order_id', 'in', self.order_ids.ids), ('discount', '>', 0)]):
-            original_price = line.price_subtotal_incl / (1 - line.discount / 100)
-            amount += original_price * line.discount / 100
+            original_price = line.tax_ids.compute_all(line.price_unit, line.currency_id, line.qty, product=line.product_id, partner=line.order_id.partner_id)['total_included']
+            amount += original_price - line.price_subtotal_incl
 
         return amount