# RedoCalc vs Stopwatch Library

The clearest difference is in-app purchases: RedoCalc at none against Stopwatch Library's 1. Stopwatch Library's advantage is ads (none vs shown). On price, update cadence, device support and iOS requirement there is nothing between them.

Both are free to download. Stopwatch Library sells 1 one-off in-app purchase. RedoCalc asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 3 days. The most recent releases landed on September 25, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | RedoCalc | Stopwatch Library |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 3 days | Every 3 days |
| Size | 3 MB | 5 MB |
| Requires iOS | 18.0 | **17.0** |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Toshiyuki Kuwabara](https://appshunter.io/developer/1649322074) | [Naoyuki Hasegawa](https://appshunter.io/developer/6777422704) |

## What reviewers say

### RedoCalc

[App page](https://appshunter.io/ios/app/redocalc/id6743318834)

**Features:** macOS Compatibility

**In-app purchases:** none


### Stopwatch Library

[App page](https://appshunter.io/ios/app/stopwatch-library/id6794338987)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 広告を削除 | $2.99 | one-time |


## Frequently asked questions

### Is RedoCalc free?

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

### Is Stopwatch Library free?

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

### Do RedoCalc or Stopwatch Library have ads?

RedoCalc shows ads; Stopwatch Library does not.

### Which is updated more often, RedoCalc or Stopwatch Library?

RedoCalc ships an update every 3 days, and Stopwatch Library every 3 days. Most recently, RedoCalc was updated on September 25, 2026 and Stopwatch Library on September 28, 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.*