diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 1f11b98b9b7..ca1b2cecdb1 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -228,7 +228,7 @@ class SaleOrder(models.Model):
         """
         for order in self:
             dates_list = []
-            confirm_date = fields.Datetime.from_string(order.confirmation_date if order.state == 'sale' else fields.Datetime.now())
+            confirm_date = fields.Datetime.from_string((order.confirmation_date or order.write_date) if order.state == 'sale' else fields.Datetime.now())
             for line in order.order_line.filtered(lambda x: x.state != 'cancel' and not x._is_delivery()):
                 dt = confirm_date + timedelta(days=line.customer_lead or 0.0)
                 dates_list.append(dt)
diff --git a/addons/sale_stock/models/sale_order.py b/addons/sale_stock/models/sale_order.py
index cef8abf9137..9d84752dd24 100644
--- a/addons/sale_stock/models/sale_order.py
+++ b/addons/sale_stock/models/sale_order.py
@@ -48,7 +48,7 @@ class SaleOrder(models.Model):
         super(SaleOrder, self)._compute_expected_date()
         for order in self:
             dates_list = []
-            confirm_date = fields.Datetime.from_string(order.confirmation_date if order.state == 'sale' else fields.Datetime.now())
+            confirm_date = fields.Datetime.from_string((order.confirmation_date or order.write_date) if order.state == 'sale' else fields.Datetime.now())
             for line in order.order_line.filtered(lambda x: x.state != 'cancel' and not x._is_delivery()):
                 dt = confirm_date + timedelta(days=line.customer_lead or 0.0)
                 dates_list.append(dt)