HVAC Duct Calculators
Size ductwork, check airflow and compare system losses.
Browse all 68 calculatorsStart with a practical check.
Common calculators for duct dimensions, airflow, pressure budgets, and material estimates.
Duct Size Calculator Use airflow with a velocity or friction target to calculate round or rectangular duct dimensions. Duct Airflow and Velocity Checker Enter duct dimensions and CFM or air speed to solve for airflow, velocity, or capacity. Duct Pressure Drop Calculator Enter duct dimensions, airflow, and length to estimate friction and documented fitting pressure losses. Available Static Pressure and Friction Budget Subtract component losses from available pressure and use route length to find the friction budget. Fan Power Calculator Use airflow, pressure, and efficiencies to estimate fan shaft power and electrical input. Duct Surface Area and Weight Calculator Use duct dimensions, lengths, and material properties to estimate sheet area and bare material weight.
Understand the method and the result.
Start with a guide to choose a calculation, move from airflow to pressure, or decide what to check next.
Choose the duct calculation that matches the job Start with the decision you need to make, then choose the airflow, sizing, pressure, component, or system check that supports it. Duct design workflow: from airflow to a pressure check Connect an established airflow requirement to clear duct geometry, constructible routes, compatible losses, and an equipment pressure boundary in a traceable sequence. How to read a duct calculator result A useful result includes the number, its unit, its method, its assumptions, and the next check the number still needs.