diff --git a/supplier_calendar/models/res_partner.py b/supplier_calendar/models/res_partner.py
index 1255e51f4f1..50d30723f13 100644
--- a/supplier_calendar/models/res_partner.py
+++ b/supplier_calendar/models/res_partner.py
@@ -31,6 +31,8 @@ def supplier_plan_days(self, date_from, delta):
         :return: datetime: resulting date.
         """
         self.ensure_one()
+        if isinstance(delta, float):
+            delta = round(delta)
         if not isinstance(date_from, datetime):
             date_from = fields.Datetime.to_datetime(date_from)
         if delta == 0: