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Cero vs the iPhone Clock app

The built-in timer counts down once. Here’s what an interval timer adds for workouts

Side by side

The Clock app in iOS 27, from Apple’s iPhone User Guide, and Cero 4.4, checked on 29 October 2026.
Clock appCero
Work and rest, one after the otherNoYes
Sets or roundsNo: tap Repeat each timeUp to 100
Warm-up and cool downNoYes
Different intervals in one workoutNoUp to 200
A cue at each changeOne sound when it endsSound, voice or vibration
Voice cuesNoYes, in 31 languages
Saved workoutsRecent and preset lengthsSaved timers, shared as a file or QR code
Workout history and Apple HealthNoYes
Rest by heart rateNoAdaptive HR
Timer on a TVNoGym Display

Moving from the Clock app

If you’ve been tapping Repeat after every round, set the same lengths in a simple timer: high intensity for work, low intensity for rest, and the number of sets. Cero then runs the whole workout without a tap. Step by step in how to set an interval timer on iPhone.

Questions

Can the iPhone Clock app do intervals?

Not by itself. Its timer counts down one length of time; when it ends you can tap Repeat to run the same length again, but it won’t alternate work and rest or count sets.

Can I run several timers at once on iPhone?

Yes. Since iOS 17, the Clock app runs several timers at the same time, each with its own label. They run side by side, though, not one after another as intervals do.

Is there a free interval timer for iPhone?

Yes. Cero is free to download and every feature is free; Cero Pro adds unlimited saved timers and removes ads.

Can Siri start an interval timer?

Yes, with Cero on iOS 17 or later: say “Start a timer in Cero”. See how to start a timer with Siri or the Action Button.

iPhone, iPad, Apple Watch, Siri and the Dynamic Island are trademarks of Apple Inc. Cero isn’t affiliated with, sponsored or endorsed by Apple.

YOUR NEXT SESSION STARTS HERE

Bring the effort.
We’ll keep the time.

Cero is free to download for iPhone, iPad and Apple Watch.

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Cero’s simple timer on iPhone 18 Pro, with the green wave about half full during a high-intensity interval

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.