# HIIT Interval Timer | Cero vs Progress Training

The clearest difference is in-app purchases: Progress Training at none against HIIT Interval Timer | Cero's 2. Progress Training also leads on ads (none vs shown). HIIT Interval Timer | Cero's advantage is update cadence (every 3 days vs every 2 months) and device support (3 vs 1). On price and iOS requirement there is nothing between them.

Both are free to download. HIIT Interval Timer | Cero sells 2 in-app purchases, starting at $2.99 per month. Progress Training asks for nothing beyond the download.

HIIT Interval Timer | Cero ships an update every 3 days, Progress Training every 2 months. The most recent releases landed on October 12, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | HIIT Interval Timer | Cero | Progress Training |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (435 ratings)](https://appshunter.io/ios/app/hiit-interval-timer-cero/id1256319392/reviews)** | — |
| Number of ratings | **435** | — |
| Positive reviews | 74.6% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 2 months |
| Monetization | Free with in-app purchases | — |
| Size | 43 MB | 52 MB |
| Requires iOS | 16.0 | 16.0 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone |
| Age rating | 4+ | 17+ |
| Developer | [Flawless Studio LLC](https://appshunter.io/developer/1228312508) | [Sergio Andres Soto Arroyave](https://appshunter.io/developer/1705489729) |

## What reviewers say

### HIIT Interval Timer | Cero

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

**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


### Progress Training

[App page](https://appshunter.io/ios/app/progress-training/id6767426252)

**In-app purchases:** none


## Frequently asked questions

### Is HIIT Interval Timer | Cero free?

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

### Is Progress Training free?

Progress Training is free to download, with no in-app purchases.

### Do HIIT Interval Timer | Cero or Progress Training have ads?

HIIT Interval Timer | Cero shows ads; Progress Training does not.

### Which is updated more often, HIIT Interval Timer | Cero or Progress Training?

HIIT Interval Timer | Cero ships an update every 3 days, and Progress Training every 2 months. Most recently, HIIT Interval Timer | Cero was updated on October 12, 2026 and Progress Training on September 18, 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.*