# kong calculator vs Flex Calculators

The clearest difference is in-app purchases: kong calculator at none against Flex Calculators's 1. kong calculator also leads on update cadence (every 4 days vs every 10 days). Flex Calculators's advantage is ads (none vs shown). On price, device support and iOS requirement there is nothing between them.

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

kong calculator ships an update every 4 days, Flex Calculators every 10 days. The most recent releases landed on October 6, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | kong calculator | Flex Calculators |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 4 days** | Every 10 days |
| Size | 20 MB | 37 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Changyeol Seo](https://appshunter.io/developer/551904752) | [An Le](https://appshunter.io/developer/1863975090) |

## What reviewers say

### kong calculator

[App page](https://appshunter.io/ios/app/kong-calculator/id1594969449)

**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 kong calculator free?

kong calculator 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 kong calculator or Flex Calculators have ads?

kong calculator shows ads; Flex Calculators does not.

### Which is updated more often, kong calculator or Flex Calculators?

kong calculator ships an update every 4 days, and Flex Calculators every 10 days. Most recently, kong calculator was updated on October 6, 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.*