Comparison

HIIT Interval Timer | Cero vs Hi Timer

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

Head to head
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/

About

Hi Timer

Create and customize your own interval workouts with this intuitive timer app. Features include quick start templates, advanced customization, voice cues, and background operation. Seamlessly integrate with your music and save workouts to Apple Health.

Highlights
  • Customizable interval workouts
  • Quick start templates (Tabata)
  • Drag & drop interface
  • Voice and sound cues
  • Background operation
  • Music integration
  • HealthKit integration
Features
Read full description

Hi Timer, Your Personal Interval Training Companion Hi Timer makes it effortless to create and customise your own interval workouts. Whether you’re jumping into a quick Tabata session or building advanced routines like Circuits and Combinations, Hi Timer gives you the tools to stay on track and motivated. Hi Timer is designed to be simple enough for quick sessions, yet powerful enough to handle the most complex training routines. With its intuitive drag-and-drop interface, powerful customization options, and seamless background performance, Hi Timer helps you focus on your workout, not your phone. Featuring: - Quick Start Templates – Get moving right away with popular HIIT formats like Tabata. - Advanced Customisation – Build Circuits, Combinations, or fully custom routines with unlimited flexibility. - Drag & Drop Simplicity – Reorder intervals and sub-timers with ease. - Voice & Sound Cues – Interval names read aloud via text-to-speech, so you never need to glance at your screen. - Works in the Background – Keep your timer running with the screen locked or while using other apps. - Music Integration – Play your own tracks from Apple Music, your library, or other apps alongside your workout. - Smart Sounds – Choose start sounds, halfway alerts, and custom audio cues for every interval. - Cloud Sync & Sharing – Access your timers across devices or share them instantly with friends via a simple link. - HealthKit Integration – Save your completed workouts to Apple Health. This app is for timing only and does not provide medical or fitness advice. Consult a licensed healthcare professional before beginning any exercise program. This app contains optional in-app purchases that grant full access to unlimited timers and workouts, and the ability to share timers between devices. You may be offered a free trial for the Premium subscription. After the free trial period, if offered, the subscription automatically renews with the price and duration given above unless it is cancelled at least 24 hours before the end of the current period. Payment will be charged to your Apple ID account at the confirmation of purchase. Your account will be charged for renewal within 24 hours prior to the end of the current period. You can manage and cancel your subscriptions by going to your account settings on the App Store after purchase. Any unused portion of a free trial period, if offered, will be forfeited when the user purchases a subscription to that publication, where applicable. Removing the app doesn’t automatically cancel the subscription. Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

HIIT Interval Timer | Cero4 screens
Hi Timer4 screens

Verdict

The call

The clearest difference is ads: Hi Timer at none against HIIT Interval Timer | Cero's shown. Hi Timer also leads on review sentiment (100% vs 75%) and rating (5.0 vs 4.7). HIIT Interval Timer | Cero's advantage is update cadence (every 3 days vs every 3 weeks) and ratings volume (435 vs 1). On price, in-app purchases, monetization model and device support 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. HIIT Interval Timer | Cero sells 1 one-off in-app purchase and Hi Timer sells 3 in-app purchases, starting at $0.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Hi Timer holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: HIIT Interval Timer | Cero has 435 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 75% of HIIT Interval Timer | Cero's written reviews are positive against 100% of Hi Timer's.

UpkeepUpdate frequency

HIIT Interval Timer | Cero ships an update every 3 days, Hi Timer every 3 weeks. The most recent releases landed on September 25, 2026 and September 15, 2026 respectively.

Scorecard5 real differences · 5 level
HIIT Interval Timer | Cero versus Hi Timer: the parameters behind the verdict, then further details
ParameterHIIT Interval Timer | CeroHi Timer
PriceFreeFree
Rating4.7 (435 ratings)5.0 (1 ratings) — better
Positive reviews74.6% of reviews100.0% of reviews — better
Number of ratings435 — better1
Update frequencyEvery 3 days — betterEvery 3 weeks
AdsYesNo — better
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, Apple WatchiPhone, iPad, iPod
Requires iOS16.015.0 — better
Further details — not scored
Size42 MB17 MB
Age rating4+17+
DeveloperFlawless Studio LLCSophie Payne

Customer experience

HIIT Interval Timer | Cero

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

Hi Timer

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

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

Hi Timer

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

HIIT Interval Timer | Cero

One-time1
  • Cero Pro$3.99
3 purchases

Hi Timer

Subscriptions2
  • Hi Timer Premium Monthly$0.991 Month
  • Hi Timer Premium Yearly7 Days trial$3.991 Year
One-time1
  • HiTimer Forever$6.99

Questions

Is HIIT Interval Timer | Cero free?
HIIT Interval Timer | Cero is free to download, with in-app purchases available.
Is Hi Timer free?
Hi Timer is free to download, with in-app purchases available.
Which has better reviews, HIIT Interval Timer | Cero or Hi Timer?
Hi Timer is rated higher. HIIT Interval Timer | Cero averages 4.7 out of 5 from 435 ratings, while Hi Timer averages 5.0 from 1 ratings.
Do HIIT Interval Timer | Cero or Hi Timer have ads?
HIIT Interval Timer | Cero shows ads; Hi Timer does not.
Which is updated more often, HIIT Interval Timer | Cero or Hi Timer?
HIIT Interval Timer | Cero ships an update every 3 days, and Hi Timer every 3 weeks. Most recently, HIIT Interval Timer | Cero was updated on September 25, 2026 and Hi Timer on September 15, 2026.

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