# Interval Timer for HIIT | Cero vs Core

The clearest difference is ads: Core at none against Interval Timer for HIIT | Cero's shown. Core also leads on review sentiment (100% vs 75%) and rating (5.0 vs 4.7). Interval Timer for HIIT | Cero's advantage is update cadence (every 3 days vs every 33 months) and ratings volume (438 vs 4). On price, in-app purchases, monetization model and device support there is nothing between them.

Both are free to download. Interval Timer for HIIT | Cero sells 2 in-app purchases, starting at $2.99 per month and Core sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

Core holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Interval Timer for HIIT | Cero has 438 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 75% of Interval Timer for HIIT | Cero's written reviews are positive against 100% of Core's.

Interval Timer for HIIT | Cero ships an update every 3 days, Core every 33 months. The most recent releases landed on November 2, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | Interval Timer for HIIT | Cero | Core |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.7 (438 ratings)](https://appshunter.io/ios/app/interval-timer-for-hiit-cero/id1256319392/reviews) | **[5.0 (4 ratings)](https://appshunter.io/ios/app/core-interval-and-hiit-timer/id1562215374/reviews)** |
| Number of ratings | **438** | 4 |
| Positive reviews | 74.6% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 33 months |
| Monetization | Free with in-app purchases | Freemium |
| Size | 45 MB | 9 MB |
| Requires iOS | 16.0 | **15.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Flawless Studio LLC](https://appshunter.io/developer/1228312508) | [Yating Lu](https://appshunter.io/developer/1526204219) |

## What reviewers say

### Interval Timer for HIIT | Cero

[App page](https://appshunter.io/ios/app/interval-timer-for-hiit-cero/id1256319392)

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:** macOS Compatibility, Apple Watch app, Vision Pro support, iPhone Duo support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Cero Pro Monthly | $2.99 | per month |
| Cero Pro | $14.99 | one-time |

**What reviewers like**

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

**What reviewers complain about**

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

**Reported bugs**

- 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**

- 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


### Core

[App page](https://appshunter.io/ios/app/core-interval-and-hiit-timer/id1562215374)

This app helps you stay focused during workouts by managing intervals, work times, and rest periods with clear visual and audio cues. Save custom routines for HIIT, Tabata, or boxing, and track your training history to monitor progress.

**Highlights:** Customizable interval timers, Audio cues for work/rest phases, Save and reuse workout routines, Visual countdown and color coding, Workout history and trend tracking, Optional Pro features via in-app purchase

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $1.99 | per month |
| Yearly | $9.99 | per year |
| Lifetime | $14.99 | one-time |


## Frequently asked questions

### Is Interval Timer for HIIT | Cero free?

Interval Timer for HIIT | Cero is free to download, with in-app purchases available.

### Is Core free?

Core is free to download, with in-app purchases available.

### Which has better reviews, Interval Timer for HIIT | Cero or Core?

Core is rated higher. Interval Timer for HIIT | Cero averages 4.7 out of 5 from 438 ratings, while Core averages 5.0 from 4 ratings.

### Do Interval Timer for HIIT | Cero or Core have ads?

Interval Timer for HIIT | Cero shows ads; Core does not.

### Which is updated more often, Interval Timer for HIIT | Cero or Core?

Interval Timer for HIIT | Cero ships an update every 3 days, and Core every 33 months. Most recently, Interval Timer for HIIT | Cero was updated on November 2, 2026 and Core on October 30, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*