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For training

The interval timer that runs your whole workout.

Chain HIIT, Tabata, EMOM and circuit intervals — each with its own work and rest — into one routine that auto-advances. Loud, clear audio cues mean you never stop mid-rep to tap your phone.

Download Free on iPhone

Free · Pro unlock $4.99 · No account needed

ChainFlow running a workout interval showing a large Work countdown

Not just another Tabata timer

Fixed 20/10 timers are fine until your workout isn't 20/10. ChainFlow lets every interval be a different length, so one app builds a proper circuit: 40s push-ups, 60s rest, 30s burpees, 90s plank — chained and looping automatically.

01

Build the circuit

Add each exercise with its own setup, work and rest. Toggle loop to repeat the whole chain.

02

Train hands-free

Distinct beeps signal work and rest. A Live Activity shows the current interval on your lock screen.

03

Reuse your routines

Save leg day, HIIT and warm-up as separate chains and launch any of them in a tap.

Popular workout formats

FormatPatternBest for
Tabata20s work / 10s rest × 8Fat-burn finishers
HIIT circuit40s work / 20s rest × 6 movesFull-body conditioning
EMOMEvery minute on the minute × 10Strength + cardio
Boxing rounds3m round / 1m rest × 5Bag & sparring work

Questions

Can I build a custom interval workout?

Yes. Chain intervals of any length, each with its own work and rest, then loop the whole thing. HIIT, Tabata, EMOM, circuits and mixed routines are all just chains.

Does it work with the screen locked?

Yes. Audio cues play on every transition even when locked or in your pocket, and the current interval shows on your lock screen.

Good for CrossFit and boxing?

Definitely — variable interval lengths handle WODs and timed rounds with rest, not just fixed cycles.

Is it free?

Free to download and use. A one-time $4.99 Pro unlock adds unlimited saved routines and cloud sync.

Also great for

Build your next workout in a minute

Free on the App Store. Chain your circuit and press play.

Download ChainFlow