Comparison

Interval Timer vs HIIT Interval Timer | Cero

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Interval Timer

Organize your running and high-intensity interval training sessions with ease. Quickly set up custom time intervals for running, walking, warm-ups, and cool-downs. Receive voice and vibration notifications for interval changes, and enjoy background music playback.

Highlights
  • Intuitive design
  • Customizable time intervals
  • Warm-up and cool-down timers
  • Voice and vibration notifications
  • Background music support
  • Foreground/background operation
Features
Read full description

Interval Run is a running interval timer for iPhone and Apple Watch. Create run/walk intervals, sprint sessions, and HIIT workouts in seconds. Train with voice announcements and haptic cues, control workouts from Apple Watch, save sessions to Apple Health, and track your workout history. Choose from 25+ ready-made running workouts or build your own. Follow intervals from the Lock Screen and Dynamic Island, and focus on your run. 25+ READY-MADE RUNNING WORKOUTS • Explore run/walk workouts, running intervals, sprints, hill repeats, tempo runs, fartlek sessions, ladders, pyramids, and more • Find workouts for speed, endurance, recovery, and different training goals • Start any workout immediately or customize it to match your training • Save your favorites to My Workouts for quick access BUILD YOUR OWN INTERVAL WORKOUT • Create simple run/walk intervals or advanced multi-step workouts • Add warm-up, running, walking, recovery, rest, and cool-down sections • Set a custom duration for every step • Repeat intervals and complete workout blocks • Add custom cues to guide you through each workout step • Build sprint, HIIT, cardio, and structured running sessions • Save multiple workouts and reuse them anytime • Preview the complete workout before you start VOICE & HAPTIC INTERVAL CUES • Hear clear voice announcements at every interval transition • Feel haptic cues when it’s time to run, walk, recover, or rest • Keep your workout active while your iPhone is locked or the app is in the background • Follow your current interval from the Lock Screen and Dynamic Island with Live Activities • Listen to music, podcasts, or audiobooks while you train RUN WITH APPLE WATCH • Sync workouts to Apple Watch • Start, pause, and control workouts directly from your wrist • Run phone-free with your workouts ready on Apple Watch • Follow interval progress without repeatedly checking your phone • Track heart rate, distance, and active energy during your workout • Get haptic interval cues directly on your Watch • Save completed workouts to Apple Health TRACK YOUR TRAINING • Browse completed workouts in calendar and history views • Review workout duration, intervals, distance, and active energy • Look back at your running and interval training over time • Share your workout results • Export and restore backups of your workout data MADE FOR RUNNERS WHO TRAIN WITH INTERVALS Whether you’re starting with beginner run/walk intervals, adding speed work to your weekly training, preparing for a 5K or another race, or creating a challenging HIIT session, Interval Run keeps every interval clear from start to finish. Use it as a simple run/walk timer, a running interval timer for speed training, an Apple Watch interval timer for phone-free workouts, or a flexible workout builder for more advanced structured sessions. From beginner run/walk workouts to sprints, tempo runs, hill repeats, fartlek training, and custom multi-step sessions, Interval Run adapts to the way you train. Start with one of 25+ ready-made workouts or create your own. Interval Run handles the timing so you can focus on your training. Some features shown, including the full workout library, advanced workout creation, multiple saved workouts, and full workout history, require Interval Run Pro. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

HIIT Interval Timer | Cero

This interval timer app enhances various workouts like HIIT, Tabata, and yoga with intuitive design and customizable timer modes. Create and save custom intervals, track calorie expenditure, and sync settings across devices, including Apple Watch.

Highlights
  • Customizable interval timers
  • Simple and advanced timer modes
  • Create and save multiple workout settings
  • Apple Watch compatibility with heart monitor
  • Automatic calorie tracking to Apple Health
  • Cross-device sync
Features
Read full description

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/

Screenshots

Interval Timer4 screens
HIIT Interval Timer | Cero4 screens

Verdict

The call

The clearest difference is review sentiment: HIIT Interval Timer | Cero at 75% against Interval Timer's 21%. HIIT Interval Timer | Cero also leads on update cadence (every 3 days vs every 3 months) and rating (4.7 vs 4.5). Interval Timer's advantage is ads (none vs shown). On price, ratings volume, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Interval Timer sells 3 in-app purchases, starting at $2.99 per month and HIIT Interval Timer | Cero sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

HIIT Interval Timer | Cero holds the better App Store score, 4.7 against 4.5. Both are backed by a comparable volume of ratings — 534 and 435 respectively. Written reviews point the same way: 21% of Interval Timer's written reviews are positive against 75% of HIIT Interval Timer | Cero's.

UpkeepUpdate frequency

Interval Timer ships an update every 3 months, HIIT Interval Timer | Cero every 3 days. The most recent releases landed on October 14, 2026 and October 12, 2026 respectively.

Scorecard5 real differences · 5 level
Interval Timer versus HIIT Interval Timer | Cero: the parameters behind the verdict, then further details
ParameterInterval TimerHIIT Interval Timer | Cero
PriceFreeFree
Rating4.5 (534 ratings)4.7 (435 ratings) — better
Positive reviews21.1% of reviews74.6% of reviews — better
Number of ratings534 — better435
Update frequencyEvery 3 monthsEvery 3 days — better
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, Apple WatchiPhone, iPad, Apple Watch
Requires iOS26.016.0 — better
Further details — not scored
Size16 MB43 MB
Age rating4+4+
DeveloperRoma SosnovskyFlawless Studio LLC

Customer experience

Interval Timer

All ratings534 ratings
Positive86.7%
Neutral3.4%
Negative9.9%
Written reviews95 reviews
Positive21.1%
Neutral8.4%
Negative70.5%

HIIT Interval Timer | Cero

All ratings435 ratings
Positive92.9%
Neutral3.9%
Negative3.2%
Written reviews59 reviews
Positive74.6%
Neutral10.2%
Negative15.3%

User reviews

Interval Timer

From 534 App Store ratings

What we love

  • 🚀 Simple and easy to use
  • 👍 Customizable intervals
  • 🚀 Straightforward app
  • 👍 Works as advertised
  • 👍 Great for getting back into running

Room to improve

  • 🔇 No audio prompts when screen is locked
  • 🔋 High battery consumption
  • 🔒 Limited free version
  • 🐛 Inconsistent performance
  • 🔇 Voice prompts not loud enough

HIIT Interval Timer | Cero

From 435 App Store ratings

What we love

  • 👍 Simple and straightforward
  • 👍 Very practical and customizable
  • 👍 Great for HIIT and Tabata
  • 👍 Clear design and easy to use
  • 👍 Good value, no subscription

Room to improve

  • 🔋 Drains battery
  • 🎶 Music playback interrupted
  • ⚠️ Ads interrupt timers
  • 🔊 Weak or non-functional sound/haptics
  • 🔄 Forced updates

Bugs and requests

Interval Timer

Reported bugs

4 issues
  • Timer resets or freezes during workout
  • Prompts not working when phone is locked or in pocket
  • Unexpected interval changes or duration changes
  • Compatibility issues with music playback

Requested features

6 requests
  • Option to pause/resume timer
  • Larger time remaining display
  • Apple Watch app
  • Ability to play audio prompts even with screen off
  • More interval options (run/walk/jog)
Show 1 more
  • Congratulatory audio cue at the end

HIIT Interval Timer | Cero

Reported bugs

4 issues
  • App runs in background draining battery
  • Rotation broke after update
  • Apple workout app overrides Cero app on Apple Watch
  • Interval signals too weak or not working

Requested features

5 requests
  • Ability to group timers
  • Option to add warm-up and cool-down features
  • Ability to type numbers for time adjustment
  • Timer sounds through headphones or interrupting music
  • Ability to change exercise names

In-app purchases

3 purchases

Interval Timer

Subscriptions2
  • Interval Run Pro Monthly$2.991 Month
  • Interval Run Pro Annual7 Days trial$19.991 Year
One-time1
  • Full Version$2.99
2 purchases

HIIT Interval Timer | Cero

Subscriptions1
  • Cero Pro Monthly7 Days trial$2.991 Month
One-time1
  • Cero Pro$14.99

Questions

Is Interval Timer free?
Interval Timer is free to download, with in-app purchases available.
Is HIIT Interval Timer | Cero free?
HIIT Interval Timer | Cero is free to download, with in-app purchases available.
Which has better reviews, Interval Timer or HIIT Interval Timer | Cero?
HIIT Interval Timer | Cero is rated higher. Interval Timer averages 4.5 out of 5 from 534 ratings, while HIIT Interval Timer | Cero averages 4.7 from 435 ratings.
Do Interval Timer or HIIT Interval Timer | Cero have ads?
HIIT Interval Timer | Cero shows ads; Interval Timer does not.
Which is updated more often, Interval Timer or HIIT Interval Timer | Cero?
Interval Timer ships an update every 3 months, and HIIT Interval Timer | Cero every 3 days. Most recently, Interval Timer was updated on October 14, 2026 and HIIT Interval Timer | Cero on October 12, 2026.

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