# Timer 555 Calculator Pro vs Electronic Circuits Calc Pro

The clearest difference is price: Timer 555 Calculator Pro at $0.99 against Electronic Circuits Calc Pro's $4.99. Timer 555 Calculator Pro also leads on iOS requirement (13.2 vs 17.0). Electronic Circuits Calc Pro's advantage is chart position (#200 vs unranked). On update cadence, ads, in-app purchases and device support there is nothing between them.

Timer 555 Calculator Pro costs $0.99 and Electronic Circuits Calc Pro $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Timer 555 Calculator Pro ships an update every 3 months, Electronic Circuits Calc Pro every 2 months. The most recent releases landed on October 23, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | Timer 555 Calculator Pro | Electronic Circuits Calc Pro |
| --- | --- | --- |
| Price | **$0.99** | $4.99 |
| Rating | **[4.7 (3 ratings)](https://appshunter.io/ios/app/timer-555-calculator-pro/id833443125/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 2 months** |
| Monetization | Paid | — |
| Best chart rank | — | **#200** |
| Size | 3 MB | 19 MB |
| Requires iOS | **13.2** | 17.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Age rating | 4+ | 4+ |
| Developer | [Siu Yuen Ho](https://appshunter.io/developer/814088527) | [ALG Software Lab](https://appshunter.io/developer/1650561236) |

## What reviewers say

### Timer 555 Calculator Pro

[App page](https://appshunter.io/ios/app/timer-555-calculator-pro/id833443125)

Calculate parameters for monostable and astable circuits. Find component combinations for desired pulse width or frequency. Share circuit files via iCloud Drive or AirDrop.

**Highlights:** Calculate monostable pulse width, Calculate astable frequency, Find component combinations, Adjust component tolerance, Unlimited combinations (Pro), Share circuit files

**In-app purchases:** none


### Electronic Circuits Calc Pro

[App page](https://appshunter.io/ios/app/electronic-circuits-calc-pro/id1658493129)

**Currently charting:** #200 Top Paid · Utilities (US App Store)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Timer 555 Calculator Pro free?

Timer 555 Calculator Pro costs $0.99, with no in-app purchases.

### Is Electronic Circuits Calc Pro free?

Electronic Circuits Calc Pro costs $4.99, with no in-app purchases.

### Do Timer 555 Calculator Pro or Electronic Circuits Calc Pro have ads?

Neither Timer 555 Calculator Pro nor Electronic Circuits Calc Pro shows ads.

### Which is updated more often, Timer 555 Calculator Pro or Electronic Circuits Calc Pro?

Timer 555 Calculator Pro ships an update every 3 months, and Electronic Circuits Calc Pro every 2 months. Most recently, Timer 555 Calculator Pro was updated on October 23, 2026 and Electronic Circuits Calc Pro on October 19, 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.*