# Timer 555 Calculator vs Ok Boss

The clearest difference is in-app purchases: Ok Boss at none against Timer 555 Calculator's 1. Ok Boss also leads on iOS requirement (11.1 vs 13.2). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Timer 555 Calculator sells 1 one-off in-app purchase. Ok Boss asks for nothing beyond the download.

Timer 555 Calculator ships an update every 3 months, Ok Boss every 5 months. The most recent releases landed on October 21, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Timer 555 Calculator | Ok Boss |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.9 (8 ratings)](https://appshunter.io/ios/app/timer-555-calculator/id834044557/reviews)** | — |
| Number of ratings | **8** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 5 months |
| Monetization | Free with in-app purchases | — |
| Size | 3 MB | 90 MB |
| Requires iOS | 13.2 | **11.1** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Siu Yuen Ho](https://appshunter.io/developer/814088527) | [Aurum Consumer Services Private Limited](https://appshunter.io/developer/1481080665) |

## What reviewers say

### Timer 555 Calculator

[App page](https://appshunter.io/ios/app/timer-555-calculator/id834044557)

Calculate monostable and astable circuits for electronics projects. Determine pulse width and frequency, find component combinations, and save/upload data. Supports multiple languages.

**Highlights:** Monostable circuit pulse width calculation, Astable circuit frequency calculation, Component combination finder, Save component values to CSV, Upload CSV via AirDrop/iCloud Drive, Multi-language support

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock Pro feature | $0.99 | one-time |


### Ok Boss

[App page](https://appshunter.io/ios/app/ok-boss/id1481080666)

**In-app purchases:** none


## Frequently asked questions

### Is Timer 555 Calculator free?

Timer 555 Calculator is free to download, with in-app purchases available.

### Is Ok Boss free?

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

### Do Timer 555 Calculator or Ok Boss have ads?

Neither Timer 555 Calculator nor Ok Boss shows ads.

### Which is updated more often, Timer 555 Calculator or Ok Boss?

Timer 555 Calculator ships an update every 3 months, and Ok Boss every 5 months. Most recently, Timer 555 Calculator was updated on October 21, 2026 and Ok Boss on October 29, 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.*