# Ductulator - Duct Sizing — HVAC Duct Design Calculator

> HVAC duct sizing calculator for airflow, friction, or velocity. (iPhone/iPad app by Wassim Murr.)

- Source: https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475 (this page in markdown: same URL + `.md`)
- Developer: [Wassim Murr](https://appshunter.io/developer/1474939474)
- Category: Productivity, Utilities
- Price: $3.99
- Rating: 4.70/5 from 317 App Store ratings · 22 written reviews indexed
- Age rating: 4+
- Requires: iOS 18.6 · 1 MB
- Languages: American English, French (France), European Spanish
- Released: 2019-08-13
- Data updated: 2026-08-28
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475/reviews.md

## What is Ductulator?

Size HVAC ducts instantly using airflow, friction or velocity.
Get accurate duct dimensions in seconds — no charts required.

• Get a range of suitable duct sizes based on friction rate or velocity.
• Get multiple valid duct dimensions instantly.
• Tap on Friction Rate or Velocity to toggle between calculation methods.
• IP and SI units.
• Detailed sizing mode to adjust the duct dimensions and air flow rates.
• Supports rectangular, circular and flexible ducts.
• Automatic friction and velocity updates.

Calculations are based on standard air 0.075 lb/ft3 (1.2 kg/m3) in clean galvanized steel or non-metallic flexible ducts.

Any feedback is welcome, and will be the basis for future updates.

## Key features

- Instant duct sizing
- Friction rate or velocity calculation
- Multiple valid duct dimensions
- IP and SI units support
- Detailed sizing mode
- Rectangular, circular, and flexible ducts

## Chart rankings

- #45 in Top Paid · Productivity (US App Store)

## Recent user reviews (10 of 22)

All indexed reviews: https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475/reviews.md

### 1/5 — Not what I need

*2026-08-04, version 3.5*

This app should be free, it says duct sizing. It only tells you what velocity and CFM a duct can do. I want my money back.

### 5/5 — BEST D**N APP OUT THERE

*2026-07-27, version 3.5*

You couldn’t find a better app for adjusting duct sizes and just overall use

### 5/5 — Duct guy

*2026-07-10, version 3.5*

Very helpful

### 1/5 — Not what I was looking for

*2025-08-11, version 3.4*

Update- I got your email. I understand the way you have the app set up I just didn’t understand it before I bought the app. The function of your app is pretty much pointless for anything I need it for. If I want to size a traditional residential HVAC duct system this does not help. Your app mostly seems to be used to figure out numbers just for fun. Who cares what the velocity of 500 CFM going through 6 inch flex? You can’t get 500 CFM through 6 inch flex anyway so why would you want to know that number? End Update. 
You need to be able to pick 6 inch flex and then the app tell you how many CFM can go through that. The way this is set up now is just silly. I like the idea you can get velocity, but you need to know how many CFM goes through all the different sizes. Now I have to buy another app.

### 1/5 — Not what I was looking for

*2025-08-08*

You need to be able to pick 6 inch flex and then the app tell you how many CFM can go through that. The way this is set up now is just silly. I like the idea you can get velocity, but you need to know how many CFM goes through all the different sizes. Now I have to buy another app.

**Developer response:** Hi, thanks for your feedback! The air flow-rate that could go through a given duct size varies depending on the friction rate or velocity you wish to set as limit. Thus, in ‘Ductulator’ mode, you can set a duct size and then check which CFM yields the Friction/Velocity limit you want; this would be the value you’re looking for, just like using the traditional ductulator! Hope this helps.

### 1/5 — WHY WAS I CHARGED ??

*2025-06-01, version 3.4*

I downloaded the app for free then was charged recently for $4.26 when I never signed up for a subscription or anything. The app is a scam I guess ?

### 4/5 — Solid app, not quite 5/5

*2025-04-15, version 3.4*

The only thing holding the app back IMO is the omission of flat oval ducts. They’re uncommon, but it’s the only thing the app can’t do that has caused me to have to reach for the less convenient methods.

### 1/5 — Decimal point

*2025-04-10, version 3.3.9*

Decimal point doesnt work on calculator, dont waste cash on this…

### 5/5 — Duct Design

*2025-03-25, version 3.3.8*

An excellent tool to have for duct design.  Seamlessly transitions between imperial and metric values when duct sizes are metric with imperial airflow quantities.  Saved me a lot of time and the app is very easy to use.

### 5/5 — Best duculator for IPhone

*2025-02-05, version 3.3.8*

Very easy to use in the field. 
I use it everyday when measuring out
duct runs !!

## Frequently asked questions about Ductulator

### What does Ductulator do?

Ductulator is a mobile application designed to instantly calculate HVAC duct sizes. It allows users to determine accurate duct dimensions based on airflow, friction rate, or velocity, eliminating the need for manual chart lookups.

### What are the key features of Ductulator?

Key features include instant calculation of suitable duct sizes based on friction rate or velocity, support for both IP and SI units, a detailed sizing mode for adjusting parameters, and compatibility with rectangular, circular, and flexible ducts.

### Is Ductulator free to use?

Yes, based on the provided information, Ductulator is a free application. It does not have in-app purchases or advertisements, indicating it is offered at no cost to the user.

### What types of ducts can be sized with Ductulator?

The application supports sizing for a variety of duct types, including rectangular, circular, and flexible ducts. This versatility makes it suitable for a wide range of HVAC design scenarios.

### How does Ductulator calculate duct sizes?

Ductulator calculates duct sizes using either the friction rate or velocity method. Users can toggle between these calculation methods and input parameters like airflow and desired friction or velocity to get accurate duct dimensions.

## Version history (last 5 releases)

### 3.5 — 2026-03-24

* UI Improvements and minor bug fixes.

### 3.4 — 2025-04-15

We're always working on various improvements and new features!

### 3.3.9 — 2025-04-04

We're always working on various improvements and new features!

### 3.3.8 — 2025-02-02

We're always working on various improvements and new features!

### 3.3.5 — 2024-05-02

We're always working on various improvements and new features!
This update includes minor bug fixes and UI improvements.

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## More apps by Wassim Murr

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All apps by Wassim Murr: https://appshunter.io/developer/1474939474

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-28.*