Duct Calc Pro

About

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.