# DuctSizer Pro vs Duct Calculator

The clearest difference is update cadence: DuctSizer Pro at weekly against Duct Calculator's fortnightly. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. DuctSizer Pro sells 1 one-off in-app purchase and Duct Calculator sells 1 in-app purchase, starting at $9.99 per year. Whichever you choose, the download price is not the number that matters.

DuctSizer Pro ships an update weekly, Duct Calculator fortnightly. The most recent releases landed on October 24, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | DuctSizer Pro | Duct Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (3 ratings)](https://appshunter.io/ios/app/ductsizer-pro/id6772545249/reviews)** | — |
| Number of ratings | **3** | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Weekly** | Fortnightly |
| Monetization | Free | — |
| Size | 5 MB | 8 MB |
| Requires iOS | 17.6 | **17.0** |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [LEONARDO NOVOA](https://appshunter.io/developer/6772526007) | [Vladimir Lukashov](https://appshunter.io/developer/6783697231) |

## 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 |


### Duct Calculator

[App page](https://appshunter.io/ios/app/duct-calculator-hvac-sizing/id6789039757)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Ductulator Pro | $9.99 | per year |


## Frequently asked questions

### Is DuctSizer Pro free?

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

### Is Duct Calculator free?

Duct Calculator is free to download, with in-app purchases available.

### Do DuctSizer Pro or Duct Calculator have ads?

Neither DuctSizer Pro nor Duct Calculator shows ads.

### Which is updated more often, DuctSizer Pro or Duct Calculator?

DuctSizer Pro ships an update weekly, and Duct Calculator fortnightly. Most recently, DuctSizer Pro was updated on October 24, 2026 and Duct Calculator on October 20, 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.*