# Easy Duct — Easy Duct Calculator

> HVAC air duct sizing calculator for engineers and designers. (iPhone/iPad app by Iman Alizadeh.)

- Source: https://appshunter.io/ios/app/easy-duct/id6810881020 (this page in markdown: same URL + `.md`)
- Developer: [Iman Alizadeh](https://appshunter.io/developer/6810881022)
- Category: Utilities, Productivity
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 15.0 · 3 MB
- Languages: American English
- Released: 2026-09-22
- Data updated: 2026-09-28
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/easy-duct/id6810881020/reviews.md

## What is Easy Duct?

Easy Duct is an air duct sizing calculator built by an HVAC engineer for real design work. Enter what you know and get a buildable duct size in seconds, on site or at your desk.

Easy Duct solves for whatever is missing: airflow, head loss, velocity or duct size. Set a maximum head loss and a maximum velocity together, and the duct is sized to whichever limit is reached first. The governing limit is always named, so you know exactly why you got that size.

SIZE THE WAY YOU DESIGN
- Head loss and velocity limits checked at the same time
- Rectangular and round duct, with aspect ratio shown for every size
- Buildable size steps (½, 1 or 2 in) so results match what gets fabricated
- EN 1506 standard sizes for metric round duct
- Pick any duct size and see its spare capacity live

SAFETY FACTOR AND ADD TO FLOW
- Apply a flow safety factor that is built into the design flow
- Adding a branch or outlet? Type the extra airflow and it goes straight onto the total

CROSS-CHECK: TWO SCENARIOS, ONE DUCT
Size a single duct against two sets of conditions, such as normal and peak operation. Link Scenario B to Scenario A by percentage, added value, equal or absolute, and see side-by-side results with the scenario that governs named up front.

UNITS YOUR WAY
- Switch between IP and SI with one tap
- Tap any unit to change it, field by field: a mm duct with L/s or cfm airflow is fine

ENGINEERING YOU CAN CHECK
- Darcy-Weisbach with your choice of friction model: Colebrook, Haaland or Altshul
- Duct wall roughness by material
- Air density and viscosity from temperature and altitude
- Full results: design flow, velocity, head loss, equivalent diameter, required round size, cross-section, Reynolds number, friction factor and velocity pressure

SIMPLE AND FAST
- Minimal interface with results that fold away until you need them
- Works fully offline
- Also available on Windows and Android

Easy Duct is for HVAC and mechanical engineers, designers, estimators and students who size ductwork every day and want a quick, reliable answer.

## Key features

- Airflow, head loss, velocity, or duct size calculation
- Simultaneous head loss and velocity limit checking
- Buildable size steps for fabrication
- Offline functionality
- IP and SI unit conversion
- Multiple friction models and engineering data


## Frequently asked questions about Easy Duct

### What is Easy Duct?

Easy Duct is an air duct sizing calculator designed for HVAC engineers and designers. It helps determine appropriate duct sizes based on various parameters like airflow, head loss, and velocity, offering buildable size steps and detailed engineering outputs.

### Does Easy Duct work offline?

Yes, Easy Duct works fully offline, making it convenient for use on-site or in locations without internet access. This ensures you can perform calculations anytime, anywhere.

### What engineering standards does Easy Duct use?

Easy Duct utilizes the Darcy-Weisbach equation with user-selectable friction models including Colebrook, Haaland, and Altshul. It also supports EN 1506 standard sizes for metric round duct.

### Can I compare two different duct sizing scenarios with Easy Duct?

Yes, Easy Duct allows you to size a single duct against two sets of conditions simultaneously. You can link Scenario B to Scenario A by percentage, added value, equal, or absolute values to see side-by-side results.

### How does Easy Duct handle units?

Easy Duct offers flexible unit management, allowing you to switch between IP and SI units with a single tap. You can also change individual units for fields like duct size or airflow to match your specific project requirements.

### What is the update frequency for Easy Duct?

The latest version of Easy Duct is 1.11, last updated on September 25, 2026. While specific update frequency isn't detailed, the app has seen regular updates to its functionality and standards.

### Is Easy Duct available on other platforms?

Yes, in addition to its availability on iPhone and iPad, Easy Duct is also available on Windows and Android devices. This broad platform support ensures accessibility for a wide range of users.

### What is the age rating for Easy Duct?

Easy Duct has an age rating of 4+. This indicates it is suitable for users of all ages, with no mature content or complex functionalities that would restrict younger users.

## Version history (last 3 releases)

### 1.11 — 2026-09-25

New in 1.11:
- Friction factor methods: choose the friction equation in Settings — Colebrook (default), Haaland or Altshul–Tsal. The method in use is shown under Friction factor in the results.
- Spare capacity under Air flow is now rounded down, so it never overstates the room left in the duct.

### 1.10 — 2026-09-24

UI Fixed

### 1.9 — 2026-09-22

No release notes.

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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 2026-09-28.*