# Scientific Timer vs Three

The clearest difference is price: Three at Free against Scientific Timer's $0.99. Three also leads on update cadence (every 8 days vs every 16 months). Scientific Timer's advantage is in-app purchases (none vs 1). On ads, device support and iOS requirement there is nothing between them.

Three is free to download; Scientific Timer costs $0.99 up front. Three sells 1 one-off in-app purchase. Scientific Timer asks for nothing beyond the download.

Scientific Timer ships an update every 16 months, Three every 8 days. Both last shipped on November 8, 2026.

## The numbers

| Metric | Scientific Timer | Three |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 16 months | **Every 8 days** |
| Size | 8 MB | 2 MB |
| Requires iOS | **18.0** | 18.2 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Stephane Boutet](https://appshunter.io/developer/1794014850) | [Daniel Schmidt](https://appshunter.io/developer/1816451541) |

## What reviewers say

### Scientific Timer

[App page](https://appshunter.io/ios/app/scientific-timer/id6741395405)

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

**In-app purchases:** none


### Three

[App page](https://appshunter.io/ios/app/three-minimal-to-do-and-planner/id6747890852)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Three Pro (Lifetime) | $3.99 | one-time |


## Frequently asked questions

### Is Scientific Timer free?

Scientific Timer costs $0.99, with no in-app purchases.

### Is Three free?

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

### Do Scientific Timer or Three have ads?

Neither Scientific Timer nor Three shows ads.

### Which is updated more often, Scientific Timer or Three?

Scientific Timer ships an update every 16 months, and Three every 8 days. Most recently, Scientific Timer was updated on November 8, 2026 and Three on November 8, 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.*