diff --git a/app/controllers/contests_controller.rb b/app/controllers/contests_controller.rb
index 55014fe..d71f010 100644
--- a/app/controllers/contests_controller.rb
+++ b/app/controllers/contests_controller.rb
@@ -3,7 +3,7 @@ class ContestsController < ApplicationController
   include ContestantsConcern
 
   before_action :set_contest, only: %i[ destroy show ]
-  before_action :set_settings_contest, only: %i[ settings_general_edit settings_general_update settings_public_edit settings_public_update settings_onsite_edit settings_onsite_update settings_online_edit settings_online_update settings_categories_edit ]
+  before_action :set_settings_contest, only: %i[ stopwatch stopwatch_continue stopwatch_pause stopwatch_reset stopwatch_start settings_general_edit settings_general_update settings_public_edit settings_public_update settings_onsite_edit settings_onsite_update settings_online_edit settings_online_update settings_categories_edit ]
   before_action :offline_setup, only: %i[ offline_new offline_create offline_edit offline_update offline_completed ]
   skip_before_action :require_authentication, only: %i[ scoreboard offline_new offline_create offline_edit offline_update offline_completed ]
 
@@ -80,6 +80,47 @@ class ContestsController < ApplicationController
     end
   end
 
+  def stopwatch
+    authorize @contest
+  end
+
+  def stopwatch_continue
+    authorize @contest
+
+    pause_duration = Time.now() - @contest.pause_time
+    @contest.start_time = @contest.start_time + pause_duration
+    @contest.pause_time = nil
+    @contest.save
+    redirect_to "/contests/#{@contest.id}/stopwatch"
+  end
+
+  def stopwatch_pause
+    authorize @contest
+    authorize @contest
+
+    @contest.pause_time = Time.now()
+    @contest.save
+    redirect_to "/contests/#{@contest.id}/stopwatch"
+  end
+
+  def stopwatch_reset
+    authorize @contest
+
+    @contest.start_time = nil
+    @contest.pause_time = nil
+    @contest.save
+    redirect_to "/contests/#{@contest.id}/stopwatch"
+  end
+
+  def stopwatch_start
+    authorize @contest
+
+    @contest.start_time = Time.now()
+    @contest.pause_time = nil
+    @contest.save
+    redirect_to "/contests/#{@contest.id}/stopwatch"
+  end
+
   def new
     authorize :contest
 
@@ -241,7 +282,7 @@ class ContestsController < ApplicationController
   end
 
   def settings_public_params
-    params.expect(contest: [ :public, :ranking_mode ])
+    params.expect(contest: [ :public, :ranking_mode, :show_stopwatch ])
   end
 
   def settings_onsite_params
diff --git a/app/models/contest.rb b/app/models/contest.rb
index 7a60dbd..1b4ded9 100644
--- a/app/models/contest.rb
+++ b/app/models/contest.rb
@@ -10,9 +10,12 @@
 #  lang               :string           default("en")
 #  name               :string
 #  offline_form       :boolean          default(FALSE)
+#  pause_time         :datetime
 #  public             :boolean          default(FALSE)
 #  ranking_mode       :string
+#  show_stopwatch     :boolean
 #  slug               :string
+#  start_time         :datetime
 #  team               :boolean          default(FALSE)
 #  created_at         :datetime         not null
 #  updated_at         :datetime         not null
diff --git a/app/policies/contest_policy.rb b/app/policies/contest_policy.rb
index d26a6cb..d153826 100644
--- a/app/policies/contest_policy.rb
+++ b/app/policies/contest_policy.rb
@@ -75,6 +75,26 @@ class ContestPolicy < ApplicationPolicy
     edit?
   end
 
+  def stopwatch?
+    edit?
+  end
+
+  def stopwatch_continue?
+    edit?
+  end
+
+  def stopwatch_pause?
+    edit?
+  end
+
+  def stopwatch_reset?
+    edit?
+  end
+
+  def stopwatch_start?
+    edit?
+  end
+
   def finalize_import?
     owner_or_admin
   end
diff --git a/app/views/application/_contest_nav.html.slim b/app/views/application/_contest_nav.html.slim
index b442ced..1f6ce80 100644
--- a/app/views/application/_contest_nav.html.slim
+++ b/app/views/application/_contest_nav.html.slim
@@ -7,6 +7,9 @@
       li.nav-item
         a.nav-link class=active_page(contest_puzzles_path(@contest)) href=contest_puzzles_path(@contest)
           = t("puzzles.plural").capitalize
+      li.nav-item
+        a.nav-link class=active_page("/contests/#{@contest.id}/stopwatch") href="/contests/#{@contest.id}/stopwatch"
+          = t("contests.nav.stopwatch").capitalize
       li.nav-item
         a.nav-link class=active_page(contest_messages_path(@contest)) href=contest_messages_path(@contest)
           = t("messages.plural").capitalize
diff --git a/app/views/contests/_scoreboard_desktop_marathon.html.slim b/app/views/contests/_scoreboard_desktop_marathon.html.slim
index e9dcdfe..3233ec2 100644
--- a/app/views/contests/_scoreboard_desktop_marathon.html.slim
+++ b/app/views/contests/_scoreboard_desktop_marathon.html.slim
@@ -8,6 +8,9 @@
         thead
           tr
             th
+              - if @contest.show_stopwatch
+                .stopwatch id="display-time" style="font-size: 60px; font-weight: 400;"
+                = render "stopwatch_js"
             th
             th
             th
diff --git a/app/views/contests/_scoreboard_desktop_single.html.slim b/app/views/contests/_scoreboard_desktop_single.html.slim
index 95b3b76..31addcb 100644
--- a/app/views/contests/_scoreboard_desktop_single.html.slim
+++ b/app/views/contests/_scoreboard_desktop_single.html.slim
@@ -1,5 +1,5 @@
 .row
-  .mt-3.col-6.d-flex.flex-column style="height: calc(100vh - 250px)"
+  .mt-3.col-6.d-flex.flex-column style="height: calc(100vh - 310px)"
     .d-flex.flex-column style="overflow-y: auto"
       table.table.table-striped.table-hover
         thead
diff --git a/app/views/contests/_scoreboard_mobile_single.html.slim b/app/views/contests/_scoreboard_mobile_single.html.slim
index 047721b..947661a 100644
--- a/app/views/contests/_scoreboard_mobile_single.html.slim
+++ b/app/views/contests/_scoreboard_mobile_single.html.slim
@@ -3,14 +3,14 @@ css:
 
 .row
   - if @puzzles.size > 0
-    .d-flex.flex-column.justify-content-center.mb-5
+    .d-flex.flex-column.justify-content-center.mb-2
       = image_tag(@puzzles[0].image, style: "max-height: 200px; object-fit: contain") if @puzzles[0].image.attached?
       .mt-2.fs-6 style="text-align: center"
         => "#{@puzzles[0].name} -"
         = "#{@puzzles[0].brand} #{@puzzles[0].pieces}p"
 
 .row
-  .mt-3.d-flex.flex-column style="height: calc(100vh - 250px)"
+  .mt-3.d-flex.flex-column
     .d-flex.flex-column style="overflow-y: auto"
       table.table.table-striped.table-hover
         thead
diff --git a/app/views/contests/_stopwatch_js.html.slim b/app/views/contests/_stopwatch_js.html.slim
new file mode 100644
index 0000000..3eb181b
--- /dev/null
+++ b/app/views/contests/_stopwatch_js.html.slim
@@ -0,0 +1,22 @@
+javascript:
+  startTime = #{@contest.start_time.present? ? @contest.start_time.to_i : "null"};
+  pauseTime = #{@contest.pause_time.present? ? @contest.pause_time.to_i : "null"};
+  function updateTime() {
+    const displayTimeEl = document.getElementById('display-time');
+    if (displayTimeEl) {
+      if (startTime) {
+        let s = Math.floor((Date.now() - 1000 * startTime) / 1000);
+        if (pauseTime) s = Math.floor(pauseTime - startTime);
+        let ss = s % 60;
+        let mm = Math.floor(s / 60) % 60;
+        let hh = Math.floor(s / 3600);
+        displayTimeEl.innerHTML = `${hh < 10 ? `0${hh}` : hh}:${mm < 10 ? `0${mm}` : mm}:${ss < 10 ? `0${ss}` : ss}`;
+        setTimeout(updateTime, 1000);
+      } else {
+        displayTimeEl.innerHTML = '00:00:00';
+      }
+    } else {
+      setTimeout(updateTime, 20);
+    }
+  }
+  setTimeout(updateTime, 1);
\ No newline at end of file
diff --git a/app/views/contests/scoreboard.html.slim b/app/views/contests/scoreboard.html.slim
index c4c3f40..4da4c33 100644
--- a/app/views/contests/scoreboard.html.slim
+++ b/app/views/contests/scoreboard.html.slim
@@ -3,12 +3,16 @@ css:
     .mobile-single { display: block !important; }
     .desktop-single { display: none; }
     #scoreboard-switches { display: none; }
+    .stopwatch { font-size: 50px !important; }
   }
 
 - if @contest.puzzles.size < 2
   = render "selectors"
 
   turbo-frame id="scoreboard"
+    - if @contest.show_stopwatch
+      .stopwatch id="display-time" style="font-size: 60px; font-weight: 400; margin-bottom: 0; text-align: center;"
+      = render "stopwatch_js"
     a.btn.btn-primary href="" id="refresh-button" style="display: none;"
     .mobile-single style="display: none;"
       = render "scoreboard_mobile_single"
diff --git a/app/views/contests/settings_public_edit.html.slim b/app/views/contests/settings_public_edit.html.slim
index fa89bb9..522ef6f 100644
--- a/app/views/contests/settings_public_edit.html.slim
+++ b/app/views/contests/settings_public_edit.html.slim
@@ -6,6 +6,11 @@
       .form-check.form-switch
         = form.check_box :public, class: "form-check-input"
         = form.label :public
+  .row.mt-2
+    .col
+      .form-check.form-switch
+        = form.check_box :show_stopwatch, class: "form-check-input"
+        = form.label :show_stopwatch
   .row.mt-3
     .col
       .form-floating
diff --git a/app/views/contests/stopwatch.html.slim b/app/views/contests/stopwatch.html.slim
new file mode 100644
index 0000000..347b566
--- /dev/null
+++ b/app/views/contests/stopwatch.html.slim
@@ -0,0 +1,16 @@
+.row
+  .col
+    .alert.alert-primary
+      = t("contests.stopwatch.info")
+h1.mt-3 id="display-time" style="font-size: 80px;"
+= render "stopwatch_js"
+.row.mt-3
+  .col.d-flex
+    - if !@contest.start_time.present?
+      = button_to t("helpers.buttons.stopwatch_start"), "/contests/#{@contest.id}/stopwatch_start", method: :post, class: "btn btn-primary"
+    - if @contest.pause_time.present?
+      = button_to t("helpers.buttons.stopwatch_continue"), "/contests/#{@contest.id}/stopwatch_continue", method: :post, class: "btn btn-primary"
+    - if @contest.start_time.present? && !@contest.pause_time.present?
+      = button_to t("helpers.buttons.stopwatch_pause"), "/contests/#{@contest.id}/stopwatch_pause", method: :post, class: "btn btn-primary"
+    - if @contest.start_time.present?
+      = button_to t("helpers.buttons.stopwatch_reset"), "/contests/#{@contest.id}/stopwatch_reset", method: :post, class: "ms-3 btn btn-warning"
\ No newline at end of file
diff --git a/config/locales/en.yml b/config/locales/en.yml
index cfe2a22..a77e229 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -65,6 +65,7 @@ en:
         offline_form_warning: Only for single-puzzle contests
         public: Enable the public scoreboard
         ranking_mode: Ranking mode (public scoreboard & CSV exports)
+        show_stopwatch: Display the stopwatch
         team: Team contest
         team_description: For UI display purposes mainly
         allow_registration: Allow registration
@@ -206,12 +207,13 @@ en:
       onsite: Onsite contests
       public: Public scoreboard
       settings: Settings
+      stopwatch: Stopwatch
     new:
       notice: Contest added
       title: New jigsaw puzzle contest
     scoreboard:
       all_categories: All categories
-      auto_refresh: Auto refresh
+      auto_refresh: Auto refresh (30s)
       hide_offline: Hide offline participants
       refresh: Activate auto-refresh (every 5s)
       title: "%{name}"
@@ -225,6 +227,8 @@ en:
       offline_form_disabled: The offline form is disabled
       public_scoreboard_disabled: The public scoreboard is disabled
       url_copied: URL copied to the clipboard
+    stopwatch:
+      info: This stopwatch is used for display in the public scoreboard, when allowed in the settings
   contestants:
     convert_csv:
       title: Import participants
@@ -287,6 +291,10 @@ en:
       sign_in: Sign in
       save: Save
       start: Click here to start your participation
+      stopwatch_continue: Continue
+      stopwatch_pause: Pause
+      stopwatch_reset: Reset
+      stopwatch_start: Start
       update: Save modifications
     field: Field
     none: No field selected
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 04604b3..513c335 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -36,6 +36,7 @@ fr:
         offline_form_warning: Activable uniquement pour les concours avec un seul puzzle
         public: Activer le classement public
         ranking_mode: Mode de classement (classement public & exports CSV)
+        show_stopwatch: Afficher le chronomètre
         team: Concours par équipes
         team_description: Principalement pour des raisons d'affichage
         allow_registration: Autoriser l'inscription via l'interface
@@ -177,12 +178,13 @@ fr:
       onsite: Concours en présentiel
       public: Classement public
       settings: Paramètres
+      stopwatch: Chronomètre
     new:
       notice: Concours ajouté
       title: Nouveau concours
     scoreboard:
       all_categories: Toutes les catégories
-      auto_refresh: Auto-rafraichissement
+      auto_refresh: Auto-rafraichissement (30s)
       hide_offline: Cacher les participant.e.s hors-ligne
       refresh: Activer le rafraichissement automatique de la page (toutes les 5s)
       title: "%{name}"
@@ -196,6 +198,8 @@ fr:
       offline_form_disabled: Le formulaire hors-ligne n'est pas activé
       public_scoreboard_disabled: Le classement public n'est pas activé
       url_copied: L’URL a été copiée dans le presse-papier
+    stopwatch:
+      info: Ce chronomètre est utilisé pour être affiché dans le classement public, quand autorisé dans les paramètres
   contestants:
     convert_csv:
       title: Importer des participant.e.s
@@ -258,6 +262,10 @@ fr:
       sign_in: Se connecter
       save: Modifier
       start: Clique ici pour démarrer ta participation
+      stopwatch_continue: Reprendre
+      stopwatch_pause: Pause
+      stopwatch_reset: Ré-initialiser
+      stopwatch_start: Démarrer
       update: Enregistrer les modifications
     field: Champ
     none: Aucun champ sélectionné
diff --git a/config/routes.rb b/config/routes.rb
index dc23263..c4e5267 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -18,6 +18,11 @@ Rails.application.routes.draw do
     get "settings/online", to: "contests#settings_online_edit"
     patch "settings/online", to: "contests#settings_online_update"
     get "settings/categories", to: "contests#settings_categories_edit"
+    get "stopwatch", to: "contests#stopwatch"
+    post "stopwatch_continue", to: "contests#stopwatch_continue"
+    post "stopwatch_pause", to: "contests#stopwatch_pause"
+    post "stopwatch_reset", to: "contests#stopwatch_reset"
+    post "stopwatch_start", to: "contests#stopwatch_start"
     resources :categories, only: [ :create, :destroy ]
     resources :completions
     resources :contestants
diff --git a/db/migrate/20251209073711_add_start_time_to_contest.rb b/db/migrate/20251209073711_add_start_time_to_contest.rb
new file mode 100644
index 0000000..f0626d1
--- /dev/null
+++ b/db/migrate/20251209073711_add_start_time_to_contest.rb
@@ -0,0 +1,5 @@
+class AddStartTimeToContest < ActiveRecord::Migration[8.0]
+  def change
+    add_column :contests, :start_time, :datetime
+  end
+end
diff --git a/db/migrate/20251209075739_add_pause_time_to_contest.rb b/db/migrate/20251209075739_add_pause_time_to_contest.rb
new file mode 100644
index 0000000..24f7654
--- /dev/null
+++ b/db/migrate/20251209075739_add_pause_time_to_contest.rb
@@ -0,0 +1,5 @@
+class AddPauseTimeToContest < ActiveRecord::Migration[8.0]
+  def change
+    add_column :contests, :pause_time, :datetime
+  end
+end
diff --git a/db/migrate/20251209081941_add_show_stopwatch_to_contest.rb b/db/migrate/20251209081941_add_show_stopwatch_to_contest.rb
new file mode 100644
index 0000000..cd077de
--- /dev/null
+++ b/db/migrate/20251209081941_add_show_stopwatch_to_contest.rb
@@ -0,0 +1,5 @@
+class AddShowStopwatchToContest < ActiveRecord::Migration[8.0]
+  def change
+    add_column :contests, :show_stopwatch, :boolean
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 563fa05..2e8690b 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_12_04_100550) do
+ActiveRecord::Schema[8.0].define(version: 2025_12_09_081941) do
   create_table "active_storage_attachments", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -103,6 +103,9 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_04_100550) do
     t.string "duration"
     t.integer "duration_seconds"
     t.string "code"
+    t.datetime "start_time"
+    t.datetime "pause_time"
+    t.boolean "show_stopwatch"
     t.index ["slug"], name: "index_contests_on_slug", unique: true
     t.index ["user_id"], name: "index_contests_on_user_id"
   end
diff --git a/spec/factories/contests.rb b/spec/factories/contests.rb
index b4c254c..7460ea5 100644
--- a/spec/factories/contests.rb
+++ b/spec/factories/contests.rb
@@ -10,9 +10,12 @@
 #  lang               :string           default("en")
 #  name               :string
 #  offline_form       :boolean          default(FALSE)
+#  pause_time         :datetime
 #  public             :boolean          default(FALSE)
 #  ranking_mode       :string
+#  show_stopwatch     :boolean
 #  slug               :string
+#  start_time         :datetime
 #  team               :boolean          default(FALSE)
 #  created_at         :datetime         not null
 #  updated_at         :datetime         not null