# CalcKit vs CalcFlex

The clearest difference is in-app purchases: CalcKit at none against CalcFlex's 6. CalcKit also leads on iOS requirement (15.6 vs 17.0). CalcFlex's advantage is update cadence (every 9 days vs every 30 months). On price, ads and device support there is nothing between them.

Both are free to download. CalcFlex sells 3 one-off in-app purchases. CalcKit asks for nothing beyond the download.

CalcKit ships an update every 30 months, CalcFlex every 9 days. The most recent releases landed on October 10, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | CalcKit | CalcFlex |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 80.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 30 months | **Every 9 days** |
| Monetization | Free | — |
| Size | 0 MB | 2 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Akkyra Systems](https://appshunter.io/developer/300710095) | [Daniel Chiu Loong Ng](https://appshunter.io/developer/1755978644) |

## What reviewers say

### CalcKit

[App page](https://appshunter.io/ios/app/calckit/id321006774)

Design and build your own custom calculators with personalized formulas and input labels. Organize them into groups for easy access. Ideal for students, scientists, and engineers needing more than standard calculator functions.

**Highlights:** Design calculators with custom formulas, Up to seven user-defined variables, Built-in trig and math functions, Organize calculators into groups, Unlimited personal calculator creation

**Features:** macOS Compatibility

**In-app purchases:** none


### CalcFlex

[App page](https://appshunter.io/ios/app/calcflex-calculator/id6520389768)

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| +3 New Variables | $1.99 | one-time |
| +20 New Equation Slots | $1.99 | one-time |
| +1 New Calculator | $3.99 | one-time |


## Frequently asked questions

### Is CalcKit free?

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

### Is CalcFlex free?

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

### Do CalcKit or CalcFlex have ads?

Neither CalcKit nor CalcFlex shows ads.

### Which is updated more often, CalcKit or CalcFlex?

CalcKit ships an update every 30 months, and CalcFlex every 9 days. Most recently, CalcKit was updated on October 10, 2026 and CalcFlex on October 6, 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.*