# Periodic vs 555 Timer & Oscillators Pro

The clearest difference is update cadence: Periodic at every 5 weeks against 555 Timer & Oscillators Pro's every 3 months. Periodic also leads on price ($1.99 vs $4.99). 555 Timer & Oscillators Pro's advantage is chart position (#193 vs unranked). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Periodic costs $1.99 and 555 Timer & Oscillators Pro $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Periodic ships an update every 5 weeks, 555 Timer & Oscillators Pro every 3 months. The most recent releases landed on October 11, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Periodic | 555 Timer & Oscillators Pro |
| --- | --- | --- |
| Price | **$1.99** | $4.99 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 3 months |
| Best chart rank | — | **#193** |
| Size | 31 MB | 22 MB |
| Requires iOS | **15.1** | 16.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Age rating | 4+ | 4+ |
| Developer | [Om Prakash Chapagain](https://appshunter.io/developer/1618620262) | [ALG Software Lab](https://appshunter.io/developer/1650561236) |

## What reviewers say

### Periodic

[App page](https://appshunter.io/ios/app/periodic-table-elements-pro/id1628646759)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### 555 Timer & Oscillators Pro

[App page](https://appshunter.io/ios/app/555-timer-and-oscillators-pro/id6504415162)

**Currently charting:** #193 Top Paid · Education (US App Store)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Periodic free?

Periodic costs $1.99, with no in-app purchases.

### Is 555 Timer & Oscillators Pro free?

555 Timer & Oscillators Pro costs $4.99, with no in-app purchases.

### Do Periodic or 555 Timer & Oscillators Pro have ads?

Neither Periodic nor 555 Timer & Oscillators Pro shows ads.

### Which is updated more often, Periodic or 555 Timer & Oscillators Pro?

Periodic ships an update every 5 weeks, and 555 Timer & Oscillators Pro every 3 months. Most recently, Periodic was updated on October 11, 2026 and 555 Timer & Oscillators Pro on October 12, 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.*