COMPARE APPS
Cero vs Seconds
Two flexible interval timers for iPhone, iPad and Apple Watch: how they differ on what’s free, price, ads and languages
CeroFlawless Studio
SecondsRunloopA side-by-side by the makers of Cero, from both apps’ US App Store listings.
Choose Cero if you want
- Every feature free, with no timer locked after one run
- Rest that lasts until your heart rate drops (Adaptive HR)
- Open intervals that end when you tap Done, for rounds for time
- Gym Display on a TV, widgets and Siri
- The app in one of 31 languages
Side by side
| Cero | Seconds | |
|---|---|---|
| Free version | Every feature; 2 saved timers, with ads | Every feature; each timer locks after one run, except your newest |
| Apple Watch app | Yes | Yes |
| iPad app | Yes | Yes |
| Saves workouts to Apple Health | Yes | Yes |
| Languages | 31 | 10 |
| Account needed | No | No |
What’s free
Seconds is free to download with every feature, but each timer locks after you run it once; since version 26 you can keep running your newest timer, and creating a new one replaces it. Running the others again takes an in-app unlock or the paid Seconds Pro. Cero’s free version has every timer, template and feature with no run limit, and saves 2 timers. Cero Pro adds unlimited saved timers and removes ads, for $2.99 a month, with a free week for eligible new subscribers, or $14.99 once. See what’s free and what Pro adds.
Building a workout
Seconds starts from HIIT, Tabata or circuit templates or from scratch, with sets, rounds and intervals of different lengths. Cero has a simple timer for work, rest, sets, warm-up and cool down, and an advanced timer for up to 200 intervals, each timed or open, with templates for Tabata, EMOM, Work / Rest, rounds for time and run + station.
Apple Watch and heart rate
Both run on Apple Watch: Seconds needs watchOS 26, Cero watchOS 10. Cero runs your saved workouts from the wrist with heart rate, has a standalone countdown and stopwatch, and its Adaptive HR can extend rest until you reach your target heart rate, with Apple Watch or a Bluetooth heart-rate monitor. Both save workouts to Apple Health.
Devices and languages
Seconds runs on iPhone, iPad, Mac and Apple Watch and needs iOS 18; it’s in 10 languages. Cero runs on iPhone, iPad, Mac and Apple Watch from iOS 16, in 31 languages, including Arabic, Hebrew, Hindi, Korean and Polish.
Questions
Is Cero a good alternative to Seconds?
Yes, if you want every feature without paying and without timers locking after one run. Cero also adds rest by heart rate, Gym Display and open intervals, in 31 languages.
Is Seconds free?
Seconds is free to download with every feature, but each timer locks after one run, except your newest. Running the others again takes an in-app unlock or the paid Seconds Pro.
What’s the difference between Seconds and Seconds Pro?
They’re the same app: Seconds is free with a one-time unlock, and Seconds Pro is paid up front. A purchase in one doesn’t carry over to the other.
Can I move my timers from Seconds to Cero?
Not directly: Cero doesn’t import Seconds’ timers. Set them up again in Cero’s advanced timer; Cero can then share them by file or QR code.
Seconds, Timer Plus, SmartWOD, Interval Timer and Tabata Stopwatch Pro are trademarks of their owners. Cero isn’t affiliated with, sponsored or endorsed by any of them; their names and icons appear only to identify the apps compared.
YOUR NEXT SESSION STARTS HERE
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Cero is free to download for iPhone, iPad and Apple Watch.
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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.