# DuctChecker vs くじら尺

The clearest difference is price: くじら尺 at Free against DuctChecker's $6.99. くじら尺 also leads on update cadence (every 2 months vs every 4 months). DuctChecker's advantage is ads (none vs shown) and device support (3 vs 1). On in-app purchases there is nothing between them.

くじら尺 is free to download; DuctChecker costs $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

DuctChecker ships an update every 4 months, くじら尺 every 2 months. The most recent releases landed on November 6, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | DuctChecker | くじら尺 |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Paid | — |
| Size | 23 MB | 4 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [AIR DESIGN, INC.](https://appshunter.io/developer/923430781) | [Masayuki Sato](https://appshunter.io/developer/1741867656) |

## What reviewers say

### DuctChecker

[App page](https://appshunter.io/ios/app/ductchecker/id933593987)

Easily calculate duct dimensions using various engineering methods like constant pressure, static pressure regain, total pressure, and velocity. This tool simplifies complex duct design calculations, typically found in flow diagrams or slide rules.

**Highlights:** Constant pressure method calculation, Static pressure regain method, Total pressure method, Velocity method, Duct dimension determination, Simplified duct design

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

**In-app purchases:** none


### くじら尺

[App page](https://appshunter.io/ios/app/id6498873952)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is DuctChecker free?

DuctChecker costs $6.99, with no in-app purchases.

### Is くじら尺 free?

くじら尺 is free to download, with no in-app purchases.

### Do DuctChecker or くじら尺 have ads?

くじら尺 shows ads; DuctChecker does not.

### Which is updated more often, DuctChecker or くじら尺?

DuctChecker ships an update every 4 months, and くじら尺 every 2 months. Most recently, DuctChecker was updated on November 6, 2026 and くじら尺 on October 30, 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.*