Duct Size Calculator - HVAC 4+

A tool for HVAC engineers

Ionut Beleiu

Designed for iPhone

    • 5.0 • 1 Rating
    • $5.99

iPhone Screenshots


Duct Size Calculator is a useful application tool designed for HVAC professionals for performing quick sizing analysis. This Duct Sizer app allows you to calculate the flow rate, duct size, pressure drop and velocity for HVAC ductwork (like a classic cardboard ductulator).

NOTE: Duct Size Calculator is using Imperial Units.

In the “Size By Airflow” tab you can input the airflow, friction or velocity and the aspect ratio. The app calculate the round (diameter) dimension and the equivalent rectangular diameter based on aspect ratio that you desire. It also calculate the velocity (if you input the friction) and the friction (if you input the velocity)

In the “Size By Dimension” tab you can analyse an existing duct system. You have the option to enter either a round duct diameter or rectangular duct lengths and you also can chose to enter between airflow and velocity. The Duct Size Calculator app calculate the friction and either the velocity either the airflow based on your inputs.

In "Pressure Drop" tab, you can convert between duct length, pressure drop, and friction find out the pressure drop of a given installation. You can also calculate the maximum duct length that can be used at a desired pressure drop.

In “Settings” tab you can select the duct material that will automatically adjust the roughness value. Roughness value can be manually input as well. You can also set the temperature and the air pressure values.

This application uses slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results. You can also use the text field to enter the precise value.

You can navigate through the app by pressing the tab bar items or sliders left/right.

If you have any suggestions to improve this Duct Size Calculator or if you are not fully satisfied with it please email us at ductsizecalculator@gmail.com before posting any negative reviews. Thank you.

Icons on this app are made by Icons8 team.

What’s New

Version 1.2

This app has been updated by Apple to display the Apple Watch app icon.

- user interface design completely changed
- fix a bug on Pressure drop / Duct length conversion tab

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

App Privacy

The developer, Ionut Beleiu, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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