Comparison

Interval Timer for HIIT | Cero vs Gustav Workout Timer

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

Head to head
About

Interval Timer for HIIT | Cero

Create custom interval workouts for HIIT, Tabata, and circuit training. This app offers detailed programming with custom intervals, colors, and icons. Stay focused with large controls, clear cues, and optional heart rate training.

Highlights
  • Customizable interval programming
  • Heart rate training integration
  • Live Activities and Dynamic Island support
  • Siri and Shortcuts integration
  • Workout history and calorie tracking
  • Apple Watch app
  • Shareable timers
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

Gustav Workout Timer

This app helps you manage your workout intervals for various training types like HIIT, circuits, and strength. It offers customizable timers, built-in options, and personalized interval naming for a focused and comfortable training experience.

Highlights
  • Customizable intervals up to 10 minutes
  • Ready-made built-in timers
  • Save custom timers to Favourites
  • Custom interval naming
  • New sound and audio cue options
  • Haptic feedback for interval changes
  • Modern Liquid Glass design
Features
Read full description

Gustav Workout Timer – your interval timer for HIIT, Tabata, CrossFit, circuit training, and all workout types. Fast, clean, and more convenient than ever. Perfect for HIIT workouts, cardio training, strength training, yoga, and circuit training – all your interval exercise needs. What you'll find in the app: - Customizable intervals: set up to 10 intervals with durations up to 10 minutes, including countdown before your first interval starts. - Built-in timers: pre-made workout timers ready to use instantly without setup. - Favorites: save your custom timers and easily share them with your team. - Personal naming: name each interval according to your workout. - New sounds + audio alerts: choose what signals the end of each interval. - Haptic feedback: gentle haptic response so you stay informed without looking at the screen. - Liquid Glass design: modern, clean aesthetic with new transitions and depth. - New animations: smoother and more engaging workout experience. - Various backgrounds: choose from preset backgrounds or use your own. - Improved user experience: more intuitive keyboard handling, better portrait mode display, and additional optimizations. Whether you're pushing hard through short intervals or going at a steady pace, this app helps you keep the rhythm and focus on your technique.

Screenshots

Interval Timer for HIIT | Cero4 screens
Gustav Workout Timer4 screens

Verdict

The call

The clearest difference is rating: Interval Timer for HIIT | Cero at 4.7 against Gustav Workout Timer's 4.1. Interval Timer for HIIT | Cero also leads on update cadence (every 3 days vs monthly) and ratings volume (441 vs 8). Gustav Workout Timer's advantage is in-app purchases (none vs 2) and ads (none vs shown). On price, device support and iOS requirement 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 for HIIT | Cero sells 2 in-app purchases, starting at $2.99 per month. Gustav Workout Timer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Interval Timer for HIIT | Cero holds the better App Store score, 4.7 against 4.1. That said, the two scores are not equally well evidenced: Interval Timer for HIIT | Cero has 441 ratings behind it against 8, so its average is the more settled of the two. Written reviews complicate that: 75% of Interval Timer for HIIT | Cero's written reviews are positive against 100% of Gustav Workout Timer's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Interval Timer for HIIT | Cero ships an update every 3 days, Gustav Workout Timer monthly. The most recent releases landed on November 13, 2026 and November 12, 2026 respectively.

Scorecard7 real differences · 3 level
Interval Timer for HIIT | Cero versus Gustav Workout Timer: the parameters behind the verdict, then further details
ParameterInterval Timer for HIIT | CeroGustav Workout Timer
PriceFreeFree
Rating4.7 (441 ratings) — better4.1 (8 ratings)
Positive reviews74.6% of reviews100.0% of reviews — better
Number of ratings441 — better8
Update frequencyEvery 3 days — betterMonthly
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, Apple Watch — betteriPhone, iPad
Requires iOS18.018.0
Further details — not scored
Size59 MB31 MB
Age rating4+4+
DeveloperFlawless Studio LLCDalibor Janecek

Customer experience

Interval Timer for HIIT | Cero

All ratings441 ratings
Positive93.0%
Neutral3.9%
Negative3.2%
Written reviews59 reviews
Positive74.6%
Neutral10.2%
Negative15.3%

Gustav Workout Timer

All ratings8 ratings
Positive87.5%
Neutral0.0%
Negative12.5%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Interval Timer for HIIT | 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

Gustav Workout Timer

Not enough reviews yet to summarise bugs or requests.

In-app purchases

2 purchases

Interval Timer for HIIT | Cero

Subscriptions1
  • Cero Pro Monthly7 Days trial$2.991 Month
One-time1
  • Cero Pro$14.99
None

Gustav Workout Timer

No in-app purchases

Questions

Is Interval Timer for HIIT | Cero free?
Interval Timer for HIIT | Cero is free to download, with in-app purchases available.
Is Gustav Workout Timer free?
Gustav Workout Timer is free to download, with no in-app purchases.
Which has better reviews, Interval Timer for HIIT | Cero or Gustav Workout Timer?
Interval Timer for HIIT | Cero is rated higher. Interval Timer for HIIT | Cero averages 4.7 out of 5 from 441 ratings, while Gustav Workout Timer averages 4.1 from 8 ratings.
Do Interval Timer for HIIT | Cero or Gustav Workout Timer have ads?
Interval Timer for HIIT | Cero shows ads; Gustav Workout Timer does not.
Which is updated more often, Interval Timer for HIIT | Cero or Gustav Workout Timer?
Interval Timer for HIIT | Cero ships an update every 3 days, and Gustav Workout Timer monthly. Most recently, Interval Timer for HIIT | Cero was updated on November 13, 2026 and Gustav Workout Timer on November 12, 2026.

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