15 Minute Countdown — Free Online Tool

What this one is for

Exactly 900 seconds
Visible from the back row
Runs in a background tab

A quarter of an hour, shown big: break times, warm-ups, exam sections and quiz rounds. Exactly nine hundred seconds from start to alarm. It opens at 15:00; change that with the chips under the dial.

Worth knowing

Exactly 900 seconds, displayed large enough for a back row.
Suits exam sections, quiz rounds and warm-ups.
Runs accurately in a background tab if you need the screen for slides.

Getting the most from the 15 minute countdown

Put it where the room can see itFull screen with F, or share the tab in a call. Everyone working to the same visible number removes the awkwardness.
Say what happens at zeroA countdown without a stated consequence is decoration. Announce it before you start.
Extend it openly if you mustThe plus one minute button adds time without resetting, so the room can see exactly what changed.

Related timers

Questions people ask

Is a 15 minute countdown the same as a 15 minute timer?

Functionally yes. Countdown usually implies the time is displayed for a group, while a timer more often runs for one person. This page is set up for the display case.

Does it keep time if I switch tabs?

Yes. It reads the system clock rather than counting frames, so a background tab or a locked screen will not make it drift.

Can I show the 15 minute countdown on a projector?

Yes. Open it on the presenting screen and press F for edge-to-edge digits at high contrast.

Does the 15 minute countdown work offline?

After your first visit, yes. The page is cached by your browser, so it opens and runs without a connection.