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21 Second Interval Timer

Start a free 21 seconds interval timer online for workouts, circuits, study blocks, stretching, recovery, and timed routines.

Work and rest routine

Ready

0:21

Round 1 of 10

Phase

Work

Round

1/10

Total

7:30

Build your interval

Set your work time, rest time, and rounds. Use settings to choose the alert sound.

0:21 / 00:15 x 10

Work time

active phase

Minutes Seconds

Rest time

break phase

Minutes Seconds

Rounds

work intervals

Total Rest after

Your progress

Saved on this device.

Completed

0

Rounds

0

Work time

0m

Last done

Never

Interval Timer Pages

Open a ready-made interval timer for the exact work length you need. Each page starts with the selected work time and still lets you adjust rest, rounds, sounds, and restart options.

Second interval timers

10 Second Interval Timer 11 Second Interval Timer 12 Second Interval Timer 13 Second Interval Timer 14 Second Interval Timer 15 Second Interval Timer 16 Second Interval Timer 17 Second Interval Timer 18 Second Interval Timer 19 Second Interval Timer 20 Second Interval Timer 21 Second Interval Timer 22 Second Interval Timer 23 Second Interval Timer 24 Second Interval Timer 25 Second Interval Timer 26 Second Interval Timer 27 Second Interval Timer 28 Second Interval Timer 29 Second Interval Timer 30 Second Interval Timer 31 Second Interval Timer 32 Second Interval Timer 33 Second Interval Timer 34 Second Interval Timer 35 Second Interval Timer 36 Second Interval Timer 37 Second Interval Timer 38 Second Interval Timer 39 Second Interval Timer 40 Second Interval Timer 41 Second Interval Timer 42 Second Interval Timer 43 Second Interval Timer 44 Second Interval Timer 45 Second Interval Timer 46 Second Interval Timer 47 Second Interval Timer 48 Second Interval Timer 49 Second Interval Timer 50 Second Interval Timer 51 Second Interval Timer 52 Second Interval Timer 53 Second Interval Timer 54 Second Interval Timer 55 Second Interval Timer 56 Second Interval Timer 57 Second Interval Timer 58 Second Interval Timer 59 Second Interval Timer 60 Second Interval Timer

Minute interval timers

1 Minute Interval Timer 2 Minute Interval Timer 3 Minute Interval Timer 4 Minute Interval Timer 5 Minute Interval Timer 6 Minute Interval Timer 7 Minute Interval Timer 8 Minute Interval Timer 9 Minute Interval Timer 10 Minute Interval Timer 11 Minute Interval Timer 12 Minute Interval Timer 13 Minute Interval Timer 14 Minute Interval Timer 15 Minute Interval Timer 16 Minute Interval Timer 17 Minute Interval Timer 18 Minute Interval Timer 19 Minute Interval Timer 20 Minute Interval Timer 21 Minute Interval Timer 22 Minute Interval Timer 23 Minute Interval Timer 24 Minute Interval Timer 25 Minute Interval Timer 26 Minute Interval Timer 27 Minute Interval Timer 28 Minute Interval Timer 29 Minute Interval Timer 30 Minute Interval Timer 31 Minute Interval Timer 32 Minute Interval Timer 33 Minute Interval Timer 34 Minute Interval Timer 35 Minute Interval Timer 36 Minute Interval Timer 37 Minute Interval Timer 38 Minute Interval Timer 39 Minute Interval Timer 40 Minute Interval Timer 41 Minute Interval Timer 42 Minute Interval Timer 43 Minute Interval Timer 44 Minute Interval Timer 45 Minute Interval Timer 46 Minute Interval Timer 47 Minute Interval Timer 48 Minute Interval Timer 49 Minute Interval Timer 50 Minute Interval Timer 51 Minute Interval Timer 52 Minute Interval Timer 53 Minute Interval Timer 54 Minute Interval Timer 55 Minute Interval Timer 56 Minute Interval Timer 57 Minute Interval Timer 58 Minute Interval Timer 59 Minute Interval Timer 60 Minute Interval Timer

21 Second Interval Timer

21 Second Interval Timer

This 21 seconds interval timer gives you a clean work-and-rest setup without building the duration from scratch. Open the page, adjust the rest time or rounds if needed, and start a steady routine from your browser.

21 Second Exercise Timer

A 21 seconds exercise timer works well for quick drills, warmups, mobility work, conditioning sets, classroom activities, and short practice rounds. The display keeps the active interval easy to read while the sound alert marks each switch.

21 Sec Workout Timer

Use this 21 sec workout timer when you want a simple interval page for training, focus sessions, or any routine that needs timed work blocks with optional rest between rounds.

Timer Interval for 21 seconds

The timer interval page starts with a 21 seconds work period, then lets you control rest, rounds, restart, and completion tracking. It is built for quick use on desktop or mobile without extra setup.