diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 73708e13e51..8fb42672d1e 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -1505,6 +1505,11 @@ class SaleOrderLine(models.Model):
                     price_subtotal = line.price_reduce * line.qty_delivered
                 else:
                     price_subtotal = line.price_reduce * line.product_uom_qty
+                if len(line.tax_id.filtered(lambda tax: tax.price_include)) > 0:
+                    # As included taxes are not excluded from the computed subtotal, `compute_all()` method
+                    # has to be called to retrieve the subtotal without them.
+                    # `price_reduce_taxexcl` cannot be used as it is computed from `price_subtotal` field. (see upper Note)
+                    price_subtotal = line.tax_id.compute_all(price_subtotal)['total_excluded']
 
                 amount_to_invoice = price_subtotal - line.untaxed_amount_invoiced
             line.untaxed_amount_to_invoice = amount_to_invoice