# NBackCalc vs WAIS

The clearest difference is update cadence: NBackCalc at every 2 days against WAIS's every 8 days. WAIS's advantage is iOS requirement (15.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. NBackCalc sells 1 one-off in-app purchase and WAIS sells 1 in-app purchase, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

NBackCalc ships an update every 2 days, WAIS every 8 days. The most recent releases landed on October 17, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | NBackCalc | WAIS |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 8 days |
| Size | 1 MB | 10 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [YOSHINORI KONNO](https://appshunter.io/developer/1883074860) | [Burning Tribe](https://appshunter.io/developer/1888072646) |

## What reviewers say

### NBackCalc

[App page](https://appshunter.io/ios/app/nbackcalc-working-memory/id6760832395)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 開発者を応援する | $0.99 | one-time |


### WAIS

[App page](https://appshunter.io/ios/app/wais-4/id6763717128)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| WAIS4 プレミアム | $2.99 | per month |


## Frequently asked questions

### Is NBackCalc free?

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

### Is WAIS free?

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

### Do NBackCalc or WAIS have ads?

Neither NBackCalc nor WAIS shows ads.

### Which is updated more often, NBackCalc or WAIS?

NBackCalc ships an update every 2 days, and WAIS every 8 days. Most recently, NBackCalc was updated on October 17, 2026 and WAIS on October 7, 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.*