Duct Calc Pro
HVAC Duct Sizing Calculator
Only for iPhone
$5.99 · Designed for iPhone. Not verified for macOS.
iPhone
Duct Calc Pro is a complete duct design toolkit for HVAC technicians, installers, and contractors. Seven calculators, a job workspace with PDF reports, and built-in reference tables - all offline, right in your pocket.
CALCULATORS (7)
- Duct Sizing: CFM + friction rate to recommended round duct size (equal friction method)
- Velocity / CFM: check FPM through round or rectangular duct, both directions
- Equivalent Diameter: rectangular to round conversions
- Room CFM: room dimensions x air changes per hour (typical ACH table built in)
- Grille & Register Sizing: required free area and size from CFM and target face velocity
- Static Pressure Budget: worksheet from external static down to available friction rate
- CFM Capacity Table: airflow and velocity for every standard round size at your friction rate
JOBS - YOUR ON-SITE WORKSPACE
Create a job, add rooms (dimensions or direct CFM), and get per-room duct sizes and velocities instantly. Export a clean Job Summary PDF with totals and recommended trunk size - ready to hand to the builder or inspector.
REFERENCE
Typical velocity recommendations, standard duct sizes, friction rate guidance, and ACH tables - always available offline.
- Imperial and Metric units
- Calculation history with one-tap reuse
- No account, no ads, works fully offline
Note: Results are estimates for preliminary sizing. Final design must follow applicable codes and engineering judgment.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, SHINOBU MIYAHIRA, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- SHINOBU MIYAHIRA
- Size
- 871.4 KB
- Category
- Productivity
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 goonobu
