diff --git a/app/views/session_timeout/_ping.js.erb b/app/views/session_timeout/_ping.js.erb
index c20f737ae97..0c93da338a5 100644
--- a/app/views/session_timeout/_ping.js.erb
+++ b/app/views/session_timeout/_ping.js.erb
@@ -1,3 +1,9 @@
+var frequency = <%= frequency %> * 1000;
+var warning = <%= warning %> * 1000;
+var start = <%= start %> * 1000;
+var warning_info = "<%= j render('session_timeout/warning') %>";
+
+
 function ping() {
   var request = new XMLHttpRequest();
   request.open('GET', '/active', true);
@@ -10,7 +16,7 @@ function ping() {
   };
 
   request.send();
-  setTimeout(ping, (<%= frequency %> * 1000));
+  setTimeout(ping, frequency);
 }
 
 
@@ -19,12 +25,13 @@ function success(data) {
       cntnr = document.getElementById('session-timeout-cntnr');
 
   var time_timeout = new Date(data.timeout).getTime(),
-      time_cutoff = new Date().getTime() + <%= warning %> * 1000,
+      time_cutoff = new Date().getTime() + warning,
       show_warning = time_timeout < time_cutoff;
 
-  var warning_info = "<%= j render('session_timeout/warning') %>";
-
-  if (show_warning & !el) cntnr.insertAdjacentHTML('afterbegin', warning_info);
+  if (show_warning & !el) {
+    cntnr.insertAdjacentHTML('afterbegin', warning_info);
+    initTimer(warning);
+  }
   if (!show_warning & el) el.remove();
   if (data.live == false) {
     window.onbeforeunload = null;
@@ -34,4 +41,30 @@ function success(data) {
 }
 
 
-setTimeout(ping, (<%= start %> * 1000));
+function initTimer(duration) {
+  var ctdn = document.getElementById('ctdn');
+  var time_left = duration;
+  var interval = 1000;
+
+  var format = function(ms) {
+    var s = ms / 1000;
+    var min = parseInt(s / 60, 10);
+    var sec = parseInt(s % 60, 10);
+
+    return (min == 0 ? '' :
+      min + ' minute' + (min !== 1 ? 's' : '') + ' and ') +
+      sec + ' second' + (sec !== 1 ? 's' : '');
+  }
+
+  function tick() {
+    ctdn.innerHTML = format(time_left);
+    if (time_left <= 0) return;
+    time_left -= interval;
+    setTimeout(tick, interval);
+  }
+
+  tick();
+}
+
+
+setTimeout(ping, start);
diff --git a/app/views/session_timeout/_warning.html.slim b/app/views/session_timeout/_warning.html.slim
index e27d824db5f..4a88ba7bcd5 100644
--- a/app/views/session_timeout/_warning.html.slim
+++ b/app/views/session_timeout/_warning.html.slim
@@ -4,7 +4,6 @@
       .mx-auto.p4.cntnr-skinny.border-box.bg-white.rounded.relative
         = image_tag(asset_url('clock.svg'), class: 'modal-ico')
         h3.mt0.mb2 = t('headings.session_timeout_warning')
-        p.mb3 = t('session_timeout_warning',
-                  time_left_in_session: time_left_in_session)
+        p.mb3 == t('session_timeout_warning', time_left_in_session: time_left_in_session)
         = link_to t('forms.buttons.continue_browsing'),
           request.original_url, class: 'btn btn-primary'
diff --git a/config/locales/en.yml b/config/locales/en.yml
index d9ca7509bfd..de6215b76de 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -125,8 +125,8 @@ en:
   session_timedout: >
     For your security, you’ve been logged out due to inactivity. Please log in again.
   session_timeout_warning: >-
-    You’ll be logged out of your account in %{time_left_in_session} due to
-    inactivity. If you’d like to remain logged in, please click the button below.
+    You’ll be logged out of your account in <span id="ctdn">%{time_left_in_session}</span>
+    due to inactivity. If you’d like to remain logged in, please click the button below.
 
   titles:
     confirmations:
diff --git a/spec/features/users/sign_in_spec.rb b/spec/features/users/sign_in_spec.rb
index 76b701799c8..a18a13ce0b0 100644
--- a/spec/features/users/sign_in_spec.rb
+++ b/spec/features/users/sign_in_spec.rb
@@ -82,14 +82,10 @@
     end
 
     scenario 'user sees warning before session times out' do
-      def warning_content
-        t('session_timeout_warning', time_left_in_session: time_left_in_session)
-      end
-
       sign_in_and_2fa_user
       visit root_path
 
-      expect(page).to have_css('#session-timeout-msg', text: warning_content)
+      expect(page).to have_css('#session-timeout-msg')
 
       request_headers = page.driver.network_traffic.flat_map(&:headers).uniq