40-Second Timer

Forty seconds is the work half of the most common HIIT pairing, 40 on and 20 off. It is long enough that the last ten seconds genuinely hurt, which is the point, and short enough that form does not fall apart before the rest arrives. It is also the length most coaches use for a hard plank hold or the rest between heavy sets.

00:00

Hours Minutes Seconds

Alarm sound Volume

Tip: press Space to start or pause, R to reset, F for full screen.

In short

This page opens at 0:40 and targets a forty-second work interval. Press Start for a full-screen countdown with pause, alarm and loop controls.

Is a 40-Second Timer the Right Length?

Best for: HIIT work rounds, plank holds and rest between heavy lifts.

Choose another length for: skill work or anything you need to think about while doing it.

Use the interval timer if you want the 40-on/20-off pattern to repeat on its own instead of restarting it by hand.

One forty-second work interval

Stage	Time	What to do
Prepare	8 seconds	Set up completely before you start, because forty seconds leaves no room to adjust.
Main block	24 seconds	Hold the effort steady rather than sprinting the first ten seconds and fading.
Finish	8 seconds	Take the rest immediately at the beep, before you decide you do not need it.

How to Set a Timer for 40 Seconds

Starting this countdown takes one click. The clock is already set to 0:40. Here is the full flow, including pausing, looping and full screen.

Open the presetThe countdown already shows 40 seconds (0:40), so no duration entry is needed.
Use it for a forty-second work intervalSet up completely before you start, because forty seconds leaves no room to adjust.
Follow the finish cueTake the rest immediately at the beep, before you decide you do not need it.

Duration and Clock Conversion

This duration spans 40 seconds in total.

That's under a minute - A short, precise countdown.

However you measure it, the 40-second countdown tracks the same span and reaches zero at the scheduled finish time. Alarm sound requires the page to remain open and the browser to permit audio.

Seconds	40
Minutes	0.6667
Hours	0.0111
Clock (h:mm:ss)	0:00:40

Using this for training?

Interval Training Timer Guide for HIIT Workouts

Set up interval timers for HIIT, Tabata, EMOM and circuits. Learn the work/rest formats and how to loop a timer so your rounds run hands-free.

Read the guide →

Related Second Timers

5 Seconds 10 Seconds 15 Seconds 20 Seconds 30 Seconds 45 Seconds

View all second timers →

Questions About This Duration

What is a 40-second timer best used for?

It is a strong fit for HIIT work rounds, plank holds and rest between heavy lifts. Use the interval timer if you want the 40-on/20-off pattern to repeat on its own instead of restarting it by hand.

Is 40 seconds the right timer length for every task?

No. It is less suitable for skill work or anything you need to think about while doing it. Match the timer to the task rather than choosing a duration only because it is familiar.

What timer should I use instead of 40 seconds?

Use the interval timer if you want the 40-on/20-off pattern to repeat on its own instead of restarting it by hand.

How is the remaining time calculated?

The countdown is driven by your device clock, so its display recalculates the remaining time whenever the browser is able to update. When the page is hidden the browser may slow the on-screen updates, but the finish time is calculated from the real clock. Background alarm sound is not guaranteed.

Need this countdown on another page? Create an embeddable timer with your preferred title, theme and size.