# Formula Conversion vs equivalence principle

The clearest difference is in-app purchases: equivalence principle at none against Formula Conversion's 1. Formula Conversion's advantage is iOS requirement (14.1 vs 16.0). On price, ads and device support there is nothing between them.

Both are free to download. Formula Conversion sells 1 one-off in-app purchase. equivalence principle asks for nothing beyond the download.

## The numbers

| Metric | Formula Conversion | equivalence principle |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 26 months | — |
| Size | 2 MB | 0 MB |
| Requires iOS | **14.1** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Janek Soomets](https://appshunter.io/developer/1315295062) | [Sungjun Kim](https://appshunter.io/developer/1602461985) |

## What reviewers say

### Formula Conversion

[App page](https://appshunter.io/ios/app/formula-conversion/id1586539965)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Upgrade Formula Conversion | $3.99 | one-time |


### equivalence principle

[App page](https://appshunter.io/ios/app/equivalence-principle/id6670335382)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Formula Conversion free?

Formula Conversion is free to download, with in-app purchases available.

### Is equivalence principle free?

equivalence principle is free to download, with no in-app purchases.

### Do Formula Conversion or equivalence principle have ads?

Neither Formula Conversion nor equivalence principle shows ads.

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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.*