DuctChecker vs Triangle Calc A
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.
Triangle Calc A
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The fastest way to solve Right Triangles. Triangle Calc A is a minimalist and specialized tool for anyone who needs instant, accurate right triangle calculations. Designed for speed and precision, it eliminates complex menus so you can focus on your work. Key Features: ■ Specialized for Right Triangles: Just enter two known values to solve the rest: ・Two sides (Pythagorean theorem) ・One side and one angle (Trigonometry) ■ Instant Results: Get all sides, angles, Area, and Perimeter immediately. ■ Minimalist Interface: No distractions. Open the app, enter your numbers, and get the answer in seconds. ■ Professional Precision: High-accuracy calculations for engineering, construction, and education. Perfect for: ■ Construction & Carpentry: Calculating pitches, slopes, and framing layouts. ■ Engineering: Quick geometric verification on-site. ■ Education: A reliable companion for trigonometry homework.
Screenshots
Verdict
The clearest difference is update cadence: DuctChecker at every 4 months against Triangle Calc A's every 56 months. DuctChecker also leads on iOS requirement (15.0 vs 26.0). Triangle Calc A's advantage is price ($0.99 vs $6.99). On ads, in-app purchases and device support 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
DuctChecker costs $6.99 and Triangle Calc A $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
DuctChecker ships an update every 4 months, Triangle Calc A every 56 months. Both last shipped on October 8, 2026.
| Parameter | DuctChecker | Triangle Calc A |
|---|---|---|
| Price | $6.99 | $0.99 — better |
| Positive reviews | 0.0% of reviews | — |
| Update frequency | Every 4 months — better | Every 56 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 23 MB | 0 MB |
| Age rating | 4+ | 4+ |
| Developer | AIR DESIGN, INC. | kohei yamane |
In-app purchases
DuctChecker
No in-app purchases
Triangle Calc A
No in-app purchases









