Interval Timer | Cero

Flawless Studio LLC · Health & Fitness

4.7 435 ratings Free

Independent analytics for this App Store listing. AppTracker is not affiliated with Flawless Studio LLC.

Chart standing · US

Not currently charting in this storefront.

What changed · US

Listing changes AppTracker has observed for this app in this storefront — new versions, price moves, rating shifts, and store copy.

Oct 12, 2026
Promotional text Removed
Oct 12, 2026
New version 4.2.2 → 4.3.0

Cero for Apple Watch, rebuilt from the ground up. • A redesigned Watch app that's faster and easier to read mid-workout • Workouts run as Apple Watch workout sessions with live heart rate and save to Health • Follow and control a Watch workout from your iPhone with a Live Activity • New complications and a Smart Stack widget show the current interval and time left • Quick timer, countdown and stopwatch redesigned for the wrist, with Always On support • Your timers and appearance sync from your iPhone

Oct 10, 2026
New version 4.2.1 → 4.2.2
Sep 28, 2026
New version 4.2.0 → 4.2.1
Sep 25, 2026
New version 4.1.3 → 4.2.0
Sep 21, 2026
New version 4.1.2 → 4.1.3
Sep 18, 2026
New version 4.1.1 → 4.1.2
Sep 17, 2026
New version 4.0.1 → 4.1.1
Sep 15, 2026
New version 4.0.0 → 4.0.1
Sep 14, 2026
Promotional text “Build better interval sessions with Adaptive HR, timer music, Live Activities, widgets, Gym Display, Apple Watch tools and automatic iCloud backups.”
Sep 14, 2026
New version 3.7.3 → 4.0.0

Ratings breakdown · US

The star breakdown behind this app's rating in this storefront.

5★ 85% 368
4★ 8% 36
3★ 4% 17
2★ 1% 6
1★ 2% 8

Screenshots

About

Build an interval workout around the way you train. Cero is a flexible interval timer for HIIT, Tabata, circuit training, WODs and HYROX preparation. Set up a quick work/rest timer or program each interval in detail. Distinct colors, large controls and reliable cues keep you focused on the session instead of the clock. BUILD YOUR SESSION • Set work, recovery, sets, warm-up and cool-down. • Create advanced workouts with custom intervals, colors, icons and intensity levels. • Save, duplicate and reorder timers. • Share timers by file or QR code. • Review completed sessions in workout history. STAY IN THE WORKOUT • Follow compatible sessions with Live Activities and Dynamic Island. • Start saved or recent timers from Home Screen widgets. • Use Siri and Shortcuts to start, pause, resume and stop a timer. • Put Gym Display on a larger screen or mirrored TV. • Choose a default song or assign music to individual intervals. • Customize sounds, voice cues, vibrations and background alerts. TRAIN BY HEART RATE Adaptive HR can extend recovery until you reach your target heart rate, then guide hard efforts with low and high alerts. Pair a Bluetooth heart-rate monitor with iPhone or train with heart-rate data from Apple Watch. COUNTDOWN AND STOPWATCH The built-in countdown and lap stopwatch cover warm-ups, station changes, rest periods and race-day practice. Stopwatch sessions continue after you close and reopen the app. ON APPLE WATCH Run saved workouts from your wrist, follow heart rate and use the standalone countdown and stopwatch. Cero can save completed workouts and estimated calories to Apple Health. Automatic iCloud backups help protect saved timers and custom intervals. Useful for HIIT, Tabata, circuits, EMOM-style workouts, boxing rounds, strength and conditioning, indoor cycling, running intervals and hybrid race preparation. Feedback and suggestions: hi@flawless.studio Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

What's new · 4.3.0

Cero for Apple Watch, rebuilt from the ground up. • A redesigned Watch app that's faster and easier to read mid-workout • Workouts run as Apple Watch workout sessions with live heart rate and save to Health • Follow and control a Watch workout from your iPhone with a Live Activity • New complications and a Smart Stack widget show the current interval and time left • Quick timer, countdown and stopwatch redesigned for the wrist, with Always On support • Your timers and appearance sync from your iPhone

Details

ReleasedJul 2017
UpdatedJun 2025
Version4.3.0
Size38 MB
RequiresiOS 12.0 or later
Age rating4+
LanguagesArabic, Chinese, Danish, English, Finnish, French, German, Hindi, Indonesian, Italian, Japanese, Korean, Malay, Norwegian Bokmål, Portuguese, Russian, Spanish, Swedish, Thai
PriceFree
Categories Health & FitnessSports
Bundle IDco.bullcode.HIIT