# DuctSizeCalc vs DuctChecker

The clearest difference is update cadence: DuctChecker at every 4 months against DuctSizeCalc's every 58 months. DuctSizeCalc's advantage is price ($2.99 vs $6.99) and iOS requirement (9.0 vs 15.0). On review sentiment, ads, in-app purchases and monetization model there is nothing between them.

DuctSizeCalc costs $2.99 and DuctChecker $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

DuctSizeCalc ships an update every 58 months, DuctChecker every 4 months. Both last shipped on October 8, 2026.

## The numbers

| Metric | DuctSizeCalc | DuctChecker |
| --- | --- | --- |
| Price | **$2.99** | $6.99 |
| Rating | **[2.0 (1 ratings)](https://appshunter.io/ios/app/ductsizecalc/id458032972/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 58 months | **Every 4 months** |
| Monetization | Paid | Paid |
| Size | 2 MB | 23 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Technical Data Service Co.,Ltd.](https://appshunter.io/developer/441746798) | [AIR DESIGN, INC.](https://appshunter.io/developer/923430781) |

## What reviewers say

### DuctSizeCalc

[App page](https://appshunter.io/ios/app/ductsizecalc/id458032972)

Easily calculate duct sizes for air conditioning systems using the constant-pressure method. Input wind volume and tap calculate to determine duct dimensions, pressure, and wind velocity. Useful for blueprints, working drawings, and on-site applications.

**Highlights:** Constant-pressure method duct sizing, Input wind volume for calculation, Supports rectangular and circular ducts, Adjustable friction loss and wind velocity, Automatic height adjustment for WxH interlock, Metric system calculations

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

**In-app purchases:** none


### 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


## Frequently asked questions

### Is DuctSizeCalc free?

DuctSizeCalc costs $2.99, with no in-app purchases.

### Is DuctChecker free?

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

### Do DuctSizeCalc or DuctChecker have ads?

Neither DuctSizeCalc nor DuctChecker shows ads.

### Which is updated more often, DuctSizeCalc or DuctChecker?

DuctSizeCalc ships an update every 58 months, and DuctChecker every 4 months. Most recently, DuctSizeCalc was updated on October 8, 2026 and DuctChecker on October 8, 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.*