diff --git a/addons/website_forum/models/forum.py b/addons/website_forum/models/forum.py
index a04531745bd..efeda981118 100644
--- a/addons/website_forum/models/forum.py
+++ b/addons/website_forum/models/forum.py
@@ -163,8 +163,11 @@ class Post(models.Model):
     @api.one
     @api.depends('vote_count', 'forum_id.relevancy_post_vote', 'forum_id.relevancy_time_decay')
     def _compute_relevancy(self):
-        days = (datetime.today() - datetime.strptime(self.create_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)).days
-        self.relevancy = math.copysign(1, self.vote_count) * (abs(self.vote_count - 1) ** self.forum_id.relevancy_post_vote / (days + 2) ** self.forum_id.relevancy_time_decay)
+        if self.create_date:
+            days = (datetime.today() - datetime.strptime(self.create_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)).days
+            self.relevancy = math.copysign(1, self.vote_count) * (abs(self.vote_count - 1) ** self.forum_id.relevancy_post_vote / (days + 2) ** self.forum_id.relevancy_time_decay)
+        else:
+            self.relevancy = 0
 
     # vote
     vote_ids = fields.One2many('forum.post.vote', 'post_id', string='Votes')