# Interval Timer for HIIT | Cero vs KnowMood

The clearest difference is ads: KnowMood at none against Interval Timer for HIIT | Cero's shown. KnowMood also leads on rating (5.0 vs 4.7). Interval Timer for HIIT | Cero's advantage is ratings volume (438 vs 2) and update cadence (every 3 days vs every 10 days). 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 KnowMood sells 3 in-app purchases, starting at $7.99 per month. Whichever you choose, the download price is not the number that matters.

KnowMood 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 2, so its average is the more settled of the two.

Interval Timer for HIIT | Cero ships an update every 3 days, KnowMood every 10 days. Both last shipped on November 6, 2026.

## The numbers

| Metric | Interval Timer for HIIT | Cero | KnowMood |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.7 (438 ratings)](https://appshunter.io/ios/app/interval-timer-for-hiit-cero/id1256319392/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/knowmood-mood-tracker/id6809382870/reviews)** |
| Number of ratings | **438** | 2 |
| Positive reviews | 74.6% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 10 days |
| Monetization | Free with in-app purchases | Freemium |
| Size | 50 MB | 45 MB |
| Requires iOS | 18.0 | **17.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [Flawless Studio LLC](https://appshunter.io/developer/1228312508) | [YINGJING ZHUO](https://appshunter.io/developer/6796614850) |

## What reviewers say

### Interval Timer for HIIT | Cero

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

Create custom interval workouts for HIIT, Tabata, and circuit training. Features adaptive heart rate training, Siri integration, and Apple Watch support. Track progress and share your custom routines.

**Highlights:** Customizable interval programming, Adaptive heart rate training, Siri and Shortcuts integration, Apple Watch app, Workout history and sharing, Live Activities and Dynamic Island support

**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


### KnowMood

[App page](https://appshunter.io/ios/app/knowmood-mood-tracker/id6809382870)

This app helps you track your daily moods and emotions through simple check-ins. Visualize your feelings in a colorful jar, add context with activities and notes, and gain insights into patterns and trends over time. It offers a private space for self-reflection with optional iCloud backup and no ads.

**Highlights:** Simple mood check-ins, Visual Mood Jar, Add feelings, activities, and notes, Mood trend and pattern analysis, Cycle tracking integration, Home Screen widgets, Optional iCloud backup

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Premium | $7.99 | per month |
| Yearly Premium | $34.99 | per year |
| Lifetime Premium | $59.99 | 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 KnowMood free?

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

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

KnowMood is rated higher. Interval Timer for HIIT | Cero averages 4.7 out of 5 from 438 ratings, while KnowMood averages 5.0 from 2 ratings.

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

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

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

Interval Timer for HIIT | Cero ships an update every 3 days, and KnowMood every 10 days. Most recently, Interval Timer for HIIT | Cero was updated on November 6, 2026 and KnowMood on November 6, 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.*