# Thermochemistry vs Periodic

The clearest difference is update cadence: Periodic at every 5 weeks against Thermochemistry's every 4 months. Periodic also leads on price ($1.99 vs $3.99) and iOS requirement (15.1 vs 17.0). On ads, in-app purchases and device support there is nothing between them.

Thermochemistry costs $3.99 and Periodic $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Thermochemistry ships an update every 4 months, Periodic every 5 weeks. The most recent releases landed on October 7, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Thermochemistry | Periodic |
| --- | --- | --- |
| Price | $3.99 | **$1.99** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 5 weeks** |
| Size | 1 MB | 31 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Roman Volinsky](https://appshunter.io/developer/977951850) | [Om Prakash Chapagain](https://appshunter.io/developer/1618620262) |

## What reviewers say

### Thermochemistry

[App page](https://appshunter.io/ios/app/thermochemistry/id1095024444)

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

**In-app purchases:** none


### Periodic

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

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

**In-app purchases:** none


## Frequently asked questions

### Is Thermochemistry free?

Thermochemistry costs $3.99, with no in-app purchases.

### Is Periodic free?

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

### Do Thermochemistry or Periodic have ads?

Neither Thermochemistry nor Periodic shows ads.

### Which is updated more often, Thermochemistry or Periodic?

Thermochemistry ships an update every 4 months, and Periodic every 5 weeks. Most recently, Thermochemistry was updated on October 7, 2026 and Periodic on October 11, 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.*