# Duct Calculator - DuctCalc — HVAC Sizing & Psychrometric

> Professional HVAC duct sizing and psychrometric calculations tool. (iPhone/iPad app by Mikhail Nikitin.)

- Source: https://appshunter.io/ios/app/duct-calculator-ductcalc/id6757307937 (this page in markdown: same URL + `.md`)
- Developer: [Mikhail Nikitin](https://appshunter.io/developer/1826368571)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Rating: 4.60/5 from 32 App Store ratings · 3 written reviews indexed
- Age rating: 4+
- Requires: iOS 17.0 · 48 MB
- Languages: American English
- Released: 2026-01-07
- Data updated: 2026-08-21
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/duct-calculator-ductcalc/id6757307937/reviews.md

## What is Duct Calculator?

Professional HVAC duct sizing and psychrometric calculations in one powerful app. DuctCalc replaces your physical ductulator with a modern, accurate digital tool trusted by engineers, contractors, and HVAC professionals.

  DUCT SIZING CALCULATOR

  Size round, rectangular, and flexible ductwork with ASHRAE-compliant calculations:

  • Forward Mode: Enter CFM airflow → Get multiple duct size options with velocity, friction loss, and pressure drop for each
  • Reverse Mode: Select a duct size → See CFM capacity at minimum, ideal, and maximum velocities

  Supports 6 duct materials:
  - Galvanized Steel
  - Flex Duct (extended & compressed)
  - Duct Board
  - Fiberglass Lined
  - PVC/Plastic

  FITTINGS & PRESSURE DROP

  Calculate total equivalent length and pressure loss with 10+ standard fittings:
  - 90° and 45° Elbows (smooth, 3-piece, mitered)
  - Tees (branch and straight-through)
  - Reducers and Transitions
  - Takeoffs (90° and 45°)
  - Register Boots

  PSYCHROMETRIC CALCULATOR

  Complete humid air property analysis with interactive chart:

  • 4 Input Modes: Dry bulb + wet bulb, relative humidity, dew point, or humidity ratio
  • Calculates: Enthalpy, specific volume, vapor pressure, saturation pressure, degree of saturation
  • Altitude correction for non-standard atmospheric pressure
  • Visual psychrometric chart showing current state point

  APPLICATION TYPES

  Pre-configured velocity limits per ASHRAE/ACCA guidelines:
  - Residential Supply (400-1000 FPM)
  - Residential Return (300-800 FPM)
  - Commercial Low Velocity (600-1500 FPM)
  - Commercial High Velocity (1000-2500 FPM)

  PROFESSIONAL FEATURES

Imperial (I-P) and Metric (SI) units
Airflow in CFM, m³/h, or L/s
Color-coded status indicators
Real-time validation warnings
Built-in reference documentation
Standard duct size tables (ASHRAE/SMACNA)

  WHY DUCTCALC?

  Unlike other apps that only size ducts OR calculate psychrometrics, DuctCalc combines both essential HVAC tools. No more switching between apps. Professional-grade accuracy in your pocket.

  Perfect for:
  • HVAC Engineers
  • Mechanical Contractors
  • MEP Design Firms
  • HVAC Technicians
  • Building Inspectors
  • Engineering Students

  Download DuctCalc and replace your old ductulator with the modern HVAC calculator trusted by professionals.

Privacy Policy: https://docs.google.com/document/d/1r9oCuYYtQZlKWhZTlrP8Ck73V6NoR8lx82027oWszsA/edit?usp=sharing
Terms of Service: https://docs.google.com/document/d/1MAY_7_uIVMnf4QYSpeaaSaSV7cm3-TJApqYVLfTHQ7w/edit?usp=sharing

## Key features

- Duct sizing for round, rectangular, and flexible ducts
- Fittings pressure drop calculation
- Psychrometric analysis with interactive chart
- Supports Imperial and Metric units
- Pre-configured velocity limits for application types
- Real-time validation warnings

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| premium | $4.99 | per month |
| premium | $29.99 | per year |


## Recent user reviews (3 of 3)

All indexed reviews: https://appshunter.io/ios/app/duct-calculator-ductcalc/id6757307937/reviews.md

### 5/5 — Pro grade ductulator

*2026-04-12*

Been in the HVAC trade 18 years and this app is an absolute game-changer. Quick CFM-to-duct sizing, round-to-rectangular conversions on the fly, friction loss, all right there on my phone. Saves me time on every job, especially on commercial takeoffs.

### 1/5 — Another deceptive application

*2026-03-19*

Stay away from it. Nothing in the description suggests that any charges. However when you get it installed, you are hit with the highest subscription fees. They tell you that you can use it for 7 days for free but want you to sign up right away and lock any calculation results if you don’t. Say it upfront. Don’t lie.

**Developer response:** Thank you for your feedback. Our pricing is clearly displayed before any purchase is made — you are never charged without seeing the cost first. The 7-day free trial allows you to explore the app with no commitment. We're sorry the app wasn't the right fit for you, but we do not hide any fees.

### 5/5 — Duct Calculator

*2026-01-30*

easy app to read duct sizing

**Developer response:** Thank you for your positive feedback! It means a lot to us. We designed the app to be as simple and practical as possible for everyday use. We hope it continues to serve you well on the job!

## Frequently asked questions about Duct Calculator

### What is Duct Calculator used for?

Duct Calculator is a professional tool for HVAC engineers and contractors to perform accurate duct sizing and psychrometric calculations. It helps determine optimal duct sizes, calculate pressure drops for fittings, and analyze humid air properties.

### Does Duct Calculator offer a free trial?

Yes, the premium subscription plan for Duct Calculator offers a 7-day free trial. This allows users to explore the full features before committing to a purchase.

### What types of ductwork can Duct Calculator size?

Duct Calculator can size round, rectangular, and flexible ductwork. It supports calculations for 6 different duct materials, including galvanized steel, flex duct, and duct board.

### How does Duct Calculator handle fittings and pressure drop?

The app calculates the total equivalent length and pressure loss for over 10 standard fittings, such as elbows, tees, reducers, and register boots, providing comprehensive data for system design.

### What psychrometric calculations does Duct Calculator perform?

Duct Calculator provides complete humid air property analysis, calculating enthalpy, specific volume, vapor pressure, saturation pressure, and degree of saturation. It also includes an interactive psychrometric chart.

### Can Duct Calculator be used with different units?

Yes, Duct Calculator supports both Imperial (I-P) and Metric (SI) units, allowing users to work with their preferred measurement systems for airflow (CFM, m³/h, or L/s) and other parameters.

### How often is Duct Calculator updated?

The app was last updated on January 8, 2026, with version 1.0. Future updates will likely include new features and improvements based on user feedback and industry standards.

### Is Duct Calculator suitable for beginners?

While designed for professionals, Duct Calculator's intuitive interface and built-in reference documentation can assist engineering students and new technicians. Its accuracy and comprehensive features make it a valuable learning tool.

## Version history (last 1 release)

### 1.0 — 2026-01-08

No release notes.

## Apps similar to Duct Calculator

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| [Omni CFM Calculator](https://appshunter.io/ios/app/omni-cfm-calculator/id6744829758) | — | Free | Utilities |
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All apps by Mikhail Nikitin: https://appshunter.io/developer/1826368571

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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 2026-08-21.*