DuctChecker vs くじら尺
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DuctChecker
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.
- Constant pressure method calculation
- Static pressure regain method
- Total pressure method
- Velocity method
- Duct dimension determination
- Simplified duct design
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To determine the size of the duct constant pressure method, static pressure regain method, total pressure method, velocity method. Generally uses constant pressure method. This constant pressure method is how to determine the duct dimensions using the same value per 1 m on all duct friction loss. Usually determined by flow diagrams or duct design for slide rules. You can easily determine the duct by using this program.
くじら尺
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To convert from whale scale to cm, you turn the drum-shaped dial to select the value, and to convert from cm to whale scale, you can enter the value directly from the keypad, allowing for quick input and calculations.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | DuctChecker | くじら尺 |
|---|---|---|
| Price | $6.99 | Free — better |
| Positive reviews | 0.0% of reviews | — |
| Update frequency | Every 4 months | Every 2 months — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 23 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | AIR DESIGN, INC. | Masayuki Sato |
In-app purchases
DuctChecker
No in-app purchases
くじら尺
No in-app purchases
