diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index e18c69b7a3d..803b48dd88a 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -354,6 +354,10 @@ module API
       expose :web_url do |issue, options|
         Gitlab::UrlBuilder.build(issue)
       end
+
+      expose :time_stats, using: 'API::Entities::IssuableTimeStats' do |issue|
+        issue
+      end
     end
 
     class Issue < IssueBasic
@@ -383,10 +387,22 @@ module API
     end
 
     class IssuableTimeStats < Grape::Entity
+      format_with(:time_tracking_formatter) do |time_spent|
+        Gitlab::TimeTrackingFormatter.output(time_spent)
+      end
+
       expose :time_estimate
       expose :total_time_spent
       expose :human_time_estimate
-      expose :human_total_time_spent
+
+      with_options(format_with: :time_tracking_formatter) do
+        expose :total_time_spent, as: :human_total_time_spent
+      end
+
+      def total_time_spent
+        # Avoids an N+1 query since timelogs are preloaded
+        object.timelogs.map(&:time_spent).sum
+      end
     end
 
     class ExternalIssue < Grape::Entity
@@ -436,6 +452,10 @@ module API
       expose :web_url do |merge_request, options|
         Gitlab::UrlBuilder.build(merge_request)
       end
+
+      expose :time_stats, using: 'API::Entities::IssuableTimeStats' do |merge_request|
+        merge_request
+      end
     end
 
     class MergeRequest < MergeRequestBasic
diff --git a/lib/api/issues.rb b/lib/api/issues.rb
index 64a425eb96e..c30e430ae85 100644
--- a/lib/api/issues.rb
+++ b/lib/api/issues.rb
@@ -15,7 +15,7 @@ module API
         args[:label_name] = args.delete(:labels)
 
         issues = IssuesFinder.new(current_user, args).execute
-          .preload(:assignees, :labels, :notes)
+          .preload(:assignees, :labels, :notes, :timelogs)
 
         issues.reorder(args[:order_by] => args[:sort])
       end
@@ -68,9 +68,11 @@ module API
       get do
         issues = find_issues
 
-        options = { with: Entities::IssueBasic,
-                    current_user: current_user }
-        options[:issuable_metadata] = issuable_meta_data(issues, 'Issue')
+        options = {
+          with: Entities::IssueBasic,
+          current_user: current_user,
+          issuable_metadata: issuable_meta_data(issues, 'Issue')
+        }
 
         present paginate(issues), options
       end
@@ -93,9 +95,11 @@ module API
 
         issues = find_issues(group_id: group.id)
 
-        options = { with: Entities::IssueBasic,
-                    current_user: current_user }
-        options[:issuable_metadata] = issuable_meta_data(issues, 'Issue')
+        options = {
+          with: Entities::IssueBasic,
+          current_user: current_user,
+          issuable_metadata: issuable_meta_data(issues, 'Issue')
+        }
 
         present paginate(issues), options
       end
@@ -120,10 +124,12 @@ module API
 
         issues = find_issues(project_id: project.id)
 
-        options = { with: Entities::IssueBasic,
-                    current_user: current_user,
-                    project: user_project }
-        options[:issuable_metadata] = issuable_meta_data(issues, 'Issue')
+        options = {
+          with: Entities::IssueBasic,
+          current_user: current_user,
+          project: user_project,
+          issuable_metadata: issuable_meta_data(issues, 'Issue')
+        }
 
         present paginate(issues), options
       end
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 8810d4e441d..a3284afb745 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -21,7 +21,7 @@ module API
         return merge_requests if args[:view] == 'simple'
 
         merge_requests
-          .preload(:notes, :author, :assignee, :milestone, :merge_request_diff, :labels)
+          .preload(:notes, :author, :assignee, :milestone, :merge_request_diff, :labels, :timelogs)
       end
 
       params :merge_requests_params do