FREE TOOLS
Free workout tools
Online timers and calculators that run in your browser, free, with nothing to sign up for
Every tool here runs in your browser: nothing is sent anywhere or stored, and there’s nothing to install. When you want the same timers with your screen locked, on your Apple Watch or with your own music, they’re all in the Cero app.
| Tool | What it’s for |
|---|---|
| Online interval timer | Any work, rest and rounds |
| Tabata timer | 20 seconds on, 10 off, 8 rounds |
| Boxing timer | Rounds and rest for boxing, MMA and Muay Thai |
| EMOM timer | A beep at the top of every minute |
| Max heart rate calculator | Your estimated maximum and interval targets |
| Heart rate zone calculator | Your five training zones |
| Workout time calculator | How long an interval workout takes |
- Free toolOnline interval timerSet work, rest and rounds, press Start and follow the beeps. Free, in your browser
- Free toolOnline Tabata timer20 seconds on, 10 seconds off, 8 rounds, with a beep at every change, free in your browser
- Free toolOnline boxing round timerRounds and rest for boxing, MMA and Muay Thai, with a warning before every bell, free in your browser
- Free toolOnline EMOM timerA beep at the top of every minute, or every 2 or 3, free in your browser
- Free calculatorMax heart rate calculatorYour estimated maximum heart rate, with targets for hard intervals and for recovery
- Free calculatorHeart rate zone calculatorYour five training zones, from your age alone or with your resting and maximum heart rate
- Free calculatorWorkout time calculatorHow long your interval workout takes, from the warm-up to the cool down
YOUR NEXT SESSION STARTS HERE
Bring the effort.
We’ll keep the time.
Cero is free to download for iPhone, iPad and Apple Watch.
Download Cero
Cero is a timer, not a medical device. If you’re new to hard exercise, are pregnant or have a health condition, check with your doctor first, and stop if you feel unwell.