# OTenkeyCalc vs Flex Calculators

The clearest difference is in-app purchases: OTenkeyCalc at none against Flex Calculators's 1. Flex Calculators's advantage is ads (none vs shown). On price, update cadence, device support and iOS requirement there is nothing between them.

Both are free to download. Flex Calculators sells 1 one-off in-app purchase. OTenkeyCalc asks for nothing beyond the download.

OTenkeyCalc ships an update every 2 weeks, Flex Calculators every 10 days. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | OTenkeyCalc | Flex Calculators |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 2 weeks | **Every 10 days** |
| Size | 37 MB | 37 MB |
| Requires iOS | 16.7.10 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) | [An Le](https://appshunter.io/developer/1863975090) |

## What reviewers say

### OTenkeyCalc

[App page](https://appshunter.io/ios/app/otenkeycalc/id6502439720)

**Features:** macOS Compatibility

**In-app purchases:** none


### Flex Calculators

[App page](https://appshunter.io/ios/app/flex-calculators/id6761326502)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $4.99 | one-time |


## Frequently asked questions

### Is OTenkeyCalc free?

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

### Is Flex Calculators free?

Flex Calculators is free to download, with in-app purchases available.

### Do OTenkeyCalc or Flex Calculators have ads?

OTenkeyCalc shows ads; Flex Calculators does not.

### Which is updated more often, OTenkeyCalc or Flex Calculators?

OTenkeyCalc ships an update every 2 weeks, and Flex Calculators every 10 days. Most recently, OTenkeyCalc was updated on October 27, 2026 and Flex Calculators on October 24, 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.*