# DuctSizer Pro vs UnitNote

The clearest difference is in-app purchases: UnitNote at none against DuctSizer Pro's 1. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. DuctSizer Pro sells 1 one-off in-app purchase. UnitNote asks for nothing beyond the download.

DuctSizer Pro ships an update weekly, UnitNote every 8 days. The most recent releases landed on October 7, 2026 and October 4, 2026 respectively.

## The numbers

| Metric | DuctSizer Pro | UnitNote |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/ductsizer-pro/id6772545249/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Weekly** | Every 8 days |
| Monetization | **Free** | Free with in-app purchases |
| Size | 5 MB | 51 MB |
| Requires iOS | 17.6 | **17.0** |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [LEONARDO NOVOA](https://appshunter.io/developer/6772526007) | [SOON HUH](https://appshunter.io/developer/6795952120) |

## What reviewers say

### DuctSizer Pro

[App page](https://appshunter.io/ios/app/ductsizer-pro/id6772545249)

This tool quickly calculates HVAC duct sizes based on airflow and friction loss. It supports various duct shapes and provides key airflow values for field use.

**Highlights:** Calculate CFM from duct size, Find duct sizes from CFM, Supports square, round, and oval duct, Shows velocity, friction, area, and equivalent round size, Highlights suggested duct sizes, Compares alternate duct sizes

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Catalog Pro | $2.99 | one-time |


### UnitNote

[App page](https://appshunter.io/ios/app/unitnote-conversor/id6795952118)

This tool simplifies unit conversions for everyday and professional needs. Customize your home screen with unit cards, perform quick calculations with a numeric keypad and formula input, and compare values across different units in a workspace. It supports a wide range of units and offers multiple themes and languages.

**Highlights:** Customizable home screen with unit cards, Numeric keypad and formula input, Intuitive unit selection and card arrangement, Workspace for comparing multiple unit conversions, Support for diverse units (length, area, volume, etc.), Favorites and recent history, Multiple themes and languages

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

**In-app purchases:** none


## Frequently asked questions

### Is DuctSizer Pro free?

DuctSizer Pro is free to download, with in-app purchases available.

### Is UnitNote free?

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

### Do DuctSizer Pro or UnitNote have ads?

Neither DuctSizer Pro nor UnitNote shows ads.

### Which is updated more often, DuctSizer Pro or UnitNote?

DuctSizer Pro ships an update weekly, and UnitNote every 8 days. Most recently, DuctSizer Pro was updated on October 7, 2026 and UnitNote on October 4, 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.*