# Duct vs ダクトサイズ計算Pro

The clearest difference is ads: Duct at none against ダクトサイズ計算Pro's shown. Duct also leads on iOS requirement (11.4 vs 15.1). ダクトサイズ計算Pro's advantage is update cadence (every 2 days vs every 16 months). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Duct ships an update every 16 months, ダクトサイズ計算Pro every 2 days. The most recent releases landed on October 6, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | Duct | ダクトサイズ計算Pro |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 16 months | **Every 2 days** |
| Monetization | Free | — |
| Size | 3 MB | 34 MB |
| Requires iOS | **11.4** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Izumi Consulting,Inc.](https://appshunter.io/developer/735908925) | [takesi shutou](https://appshunter.io/developer/6778977894) |

## What reviewers say

### Duct

[App page](https://appshunter.io/ios/app/duct-fit/id735908922)

This application simplifies the selection of duct sizes using intuitive design and simple operations. It calculates appropriate duct sizes based on airflow, standard static pressure, and air velocity, supporting both rectangular and round ducts.

**Highlights:** Intuitive design for easy duct size selection, Calculates duct size based on airflow, static pressure, and velocity, Supports both rectangular and round ducts, Visual representation of selected duct shapes, Customizable warning and upper limits for aspect ratio and air velocity, Set default standard static pressure

**Features:** macOS Compatibility

**In-app purchases:** none


### ダクトサイズ計算Pro

[App page](https://appshunter.io/ios/app/pro/id6782080002)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Duct free?

Duct is free to download, with no in-app purchases.

### Is ダクトサイズ計算Pro free?

ダクトサイズ計算Pro is free to download, with no in-app purchases.

### Do Duct or ダクトサイズ計算Pro have ads?

ダクトサイズ計算Pro shows ads; Duct does not.

### Which is updated more often, Duct or ダクトサイズ計算Pro?

Duct ships an update every 16 months, and ダクトサイズ計算Pro every 2 days. Most recently, Duct was updated on October 6, 2026 and ダクトサイズ計算Pro on September 28, 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.*