# Timer 555 Calculator vs +XP  BASE

The clearest difference is in-app purchases: +XP  BASE at none against Timer 555 Calculator's 1. Timer 555 Calculator's advantage is update cadence (every 3 months vs every 16 months). On price, ads, device support and iOS requirement there is nothing between them.

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

Timer 555 Calculator ships an update every 3 months, +XP  BASE every 16 months. The most recent releases landed on September 24, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | Timer 555 Calculator | +XP  BASE |
| --- | --- | --- |
| 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 16 months |
| Monetization | Free with in-app purchases | — |
| Size | 3 MB | 67 MB |
| Requires iOS | 13.2 | **12.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Siu Yuen Ho](https://appshunter.io/developer/814088527) | [Qingdao Richmat Intelligence Technology Inc.](https://appshunter.io/developer/1814751082) |

## 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 |


### +XP  BASE

[App page](https://appshunter.io/ios/app/plus-xp-base/id6743686541)

**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 +XP  BASE free?

+XP  BASE is free to download, with no in-app purchases.

### Do Timer 555 Calculator or +XP  BASE have ads?

Neither Timer 555 Calculator nor +XP  BASE shows ads.

### Which is updated more often, Timer 555 Calculator or +XP  BASE?

Timer 555 Calculator ships an update every 3 months, and +XP  BASE every 16 months. Most recently, Timer 555 Calculator was updated on September 24, 2026 and +XP  BASE on September 9, 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.*