Comparison

Interval Timer for HIIT | Cero vs Sudd

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

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

Sudd

Features
Read full description

Sudd is not a meditation app. It does not ask you to journal. It does not track your productivity. It is protected time for thinking, no notifications, no agenda, nothing asking for your attention. You open the app, choose how long you want, and let your mind work in silence. With each session, your bonsai grows. Nine stages of development, accumulated from the real time you spend thinking. It is not a motivational metaphor, it is simply what happens when you show up. Session notes are there if you want to capture something when you finish. No structure, no templates. Just a blank field for anything that deserves to be written down. - Stopwatch or countdown timer - Bonsai with 9 growth stages - Post-session notes - Scheduled sessions with reminders - Seasonal bonsai visuals - Session timelapse Time to think. Nothing more.

Screenshots

Interval Timer for HIIT | Cero4 screens
Sudd4 screens

Verdict

The call

The clearest difference is in-app purchases: Sudd at none against Interval Timer for HIIT | Cero's 2. Sudd also leads on ads (none vs shown). On price, update cadence, 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. Sudd asks for nothing beyond the download.

UpkeepUpdate frequency

Interval Timer for HIIT | Cero ships an update every 3 days, Sudd every 2 days. The most recent releases landed on November 2, 2026 and October 24, 2026 respectively.

Scorecard2 real differences · 8 level
Interval Timer for HIIT | Cero versus Sudd: the parameters behind the verdict, then further details
ParameterInterval Timer for HIIT | CeroSudd
PriceFreeFree
Rating4.7 (438 ratings) — better—
Positive reviews74.6% of reviews—
Number of ratings438 — better—
Update frequencyEvery 3 daysEvery 2 days — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, Apple Watch — betteriPhone, iPod
Requires iOS16.015.1 — better
Further details — not scored
Size45 MB43 MB
Age rating4+4+
DeveloperFlawless Studio LLCBrayan Alexis Ramirez Martinez

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

Sudd

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

Sudd

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 Sudd free?
Sudd is free to download, with no in-app purchases.
Do Interval Timer for HIIT | Cero or Sudd have ads?
Interval Timer for HIIT | Cero shows ads; Sudd does not.
Which is updated more often, Interval Timer for HIIT | Cero or Sudd?
Interval Timer for HIIT | Cero ships an update every 3 days, and Sudd every 2 days. Most recently, Interval Timer for HIIT | Cero was updated on November 2, 2026 and Sudd on October 24, 2026.

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