diff --git a/app/models/issue.rb b/app/models/issue.rb
index d04f5bd..e6851e4 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1364,7 +1364,8 @@ class Issue < ActiveRecord::Base
           if average == 0
             average = 1
           end
-          done = p.leaves.sum("COALESCE(estimated_hours, #{average}) * (CASE WHEN is_closed = #{connection.quoted_true} THEN 100 ELSE COALESCE(done_ratio, 0) END)", :joins => :status).to_f
+          done = p.leaves.sum("COALESCE(CASE WHEN estimated_hours > 0 THEN estimated_hours ELSE NULL END, #{average}) " +
+			"* (CASE WHEN is_closed = #{connection.quoted_true} THEN 100 ELSE COALESCE(done_ratio, 0) END)", :joins => :status).to_f
           progress = done / (average * leaves_count)
           p.done_ratio = progress.round
         end