diff --git a/addons/account/models/account_payment_term.py b/addons/account/models/account_payment_term.py
index 5fcbfdbd60e..3dccc01e8ee 100644
--- a/addons/account/models/account_payment_term.py
+++ b/addons/account/models/account_payment_term.py
@@ -263,7 +263,7 @@ class AccountPaymentTermLine(models.Model):
 
     def _get_due_date(self, date_ref):
         self.ensure_one()
-        due_date = fields.Date.from_string(date_ref)
+        due_date = fields.Date.from_string(date_ref) or fields.Date.today()
         if self.delay_type == 'days_after_end_of_month':
             return date_utils.end_of(due_date, 'month') + relativedelta(days=self.nb_days)
         elif self.delay_type == 'days_after_end_of_next_month':