Choose a mode and duration
How to use the Interval Timer
Timing your rest between sets accurately has a big impact on training quality. Resting by feel usually means resting too long — while resting too little means you can’t handle enough weight on the next set. This tool is a countdown timer for the rest durations recommended by the Interval Calculator.
How to use this tool
Pick a preset (30 seconds to 3 minutes) or enter a custom duration, then press Start. The remaining time also appears in the browser-tab title, so you can see progress even from another tab. A beep sounds when the timer finishes.
About the Pomodoro mode
The Pomodoro Technique is a time-management method that repeats 25 minutes of focused work plus a 5-minute break, with a longer break (15 minutes) every 4 rounds. It is widely used for studying and desk work. Switch modes and the timer cycles through work and breaks automatically.
Tips
For heavy strength training, rest 3–5 minutes between sets; for hypertrophy, 60–120 seconds is typical (see the Interval Calculator). Starting the timer the moment you finish a set keeps your whole session consistent. You can also track your workouts with the Joy Next World Gym App (in development).
Where an interval timer earns its place
Time-structured training comes in several forms, each with its own settings. The best known are Tabata (20 seconds work, 10 seconds rest, eight rounds — four minutes total), EMOM (every minute on the minute: complete a set number of reps at the top of each minute and rest for what remains) and AMRAP (as many rounds as possible in a fixed window). All exist to hand timekeeping to something other than your own judgement, which is what stops rest quietly stretching.
Fixed rest makes your log comparable
If rest between sets drifts with mood, the same weight for the same reps is not actually the same training stimulus — longer rest raises reps, shorter rest lowers them. Fixing it with a timer lets you tell whether a change in your log reflects your body or just your rest periods. For target rest times, see the rest interval calculator.
If the screen keeps going dark
Mobile browsers dim the display after a period without input. The reliable fix is to lengthen the auto-lock timeout in your device settings before training. Note also that this timer runs in the browser, so switching to another app can affect its accuracy.
Glossary & FAQ
What is an interval timer?+
The optimal rest length differs by goal (strength, hypertrophy, endurance), so timing it precisely rather than by feel is recommended. See the Interval Calculator for goal-based recommendations.
What is the Pomodoro Technique?+
Every 4 rounds you take a longer 15–30 minute break. The Pomodoro mode here cycles 25 min → 5 min → … → a 15-minute break after the 4th round, automatically.
I can’t hear the beep. What should I do?+
Browsers also block audio until you interact with the page at least once. As long as you press the Start button first, the beep normally plays.
Does the timer keep running when the screen is off?+
If you need precise timing, keep the screen on, or use your device’s clock app alongside.
Is anything I enter sent anywhere?+
・Schoenfeld BJ, et al. (2016). Longer Interset Rest Periods Enhance Muscle Strength and Hypertrophy in Resistance-Trained Men. Journal of Strength and Conditioning Research, 30(7), 1805–1812.
・de Salles BF, et al. (2009). Rest interval between sets in strength training. Sports Medicine, 39(9), 765–777.
・Cirillo, F. (2018). The Pomodoro Technique. Currency.
Timer accuracy depends on your browser and device (power-saving settings, background behavior). For uses that require precise timing, such as competition or medical settings, use dedicated equipment. Always train within your physical limits.
Track Your Workouts in the AppIn development
Log weights, reps and menus — the Joy Next World Gym App is currently in development and free to try.