# RC Circuit vs 555 Calc

The clearest difference is rating: RC Circuit at 4.8 against 555 Calc's 4.0. RC Circuit also leads on ads (none vs shown) and update cadence (every 6 months vs every 20 months). 555 Calc's advantage is in-app purchases (none vs 1). On price, ratings volume, device support and iOS requirement there is nothing between them.

Both are free to download. RC Circuit sells 1 one-off in-app purchase. 555 Calc asks for nothing beyond the download.

RC Circuit holds the better App Store score, 4.8 against 4.0. Both are backed by a comparable volume of ratings — 5 and 3 respectively.

RC Circuit ships an update every 6 months, 555 Calc every 20 months. The most recent releases landed on October 5, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | RC Circuit | 555 Calc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (5 ratings)](https://appshunter.io/ios/app/rc-circuit/id824460716/reviews)** | [4.0 (3 ratings)](https://appshunter.io/ios/app/555-calc/id868058244/reviews) |
| Number of ratings | **5** | 3 |
| Positive reviews | — | 50.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 6 months** | Every 20 months |
| Monetization | **Free** | Ad-supported |
| Size | 16 MB | 18 MB |
| Requires iOS | 12.0 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Siu Yuen Ho](https://appshunter.io/developer/814088527) | [Jibiki Works](https://appshunter.io/developer/556845808) |

## What reviewers say

### RC Circuit

[App page](https://appshunter.io/ios/app/rc-circuit/id824460716)

Calculate RC charging and filter circuits, including time constants and cutoff frequencies. Find component values from these parameters or get voltage at specific times. Save and share data easily.

**Highlights:** Calculate time constant, Find component values, Get voltage at time t, Calculate cutoff frequency, Save data to CSV, Upload CSV via AirDrop/iCloud Drive, Multi-language support

**Features:** Vision Pro support

**In-app purchases (1)**

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


### 555 Calc

[App page](https://appshunter.io/ios/app/555-calc/id868058244)

This utility app helps engineers and hobbyists calculate resistor values for circuits using the Timer IC 555. Simply input frequency, duty ratio, and capacitor values to get the required resistor outputs.

**Highlights:** Calculate resistor values, Input frequency, Input duty ratio, Input capacitor value, Timer IC 555 circuit design

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is RC Circuit free?

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

### Is 555 Calc free?

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

### Which has better reviews, RC Circuit or 555 Calc?

RC Circuit is rated higher. RC Circuit averages 4.8 out of 5 from 5 ratings, while 555 Calc averages 4.0 from 3 ratings.

### Do RC Circuit or 555 Calc have ads?

555 Calc shows ads; RC Circuit does not.

### Which is updated more often, RC Circuit or 555 Calc?

RC Circuit ships an update every 6 months, and 555 Calc every 20 months. Most recently, RC Circuit was updated on October 5, 2026 and 555 Calc on October 13, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*