Free HVAC Calculators

Professional-grade MEP calculators. No login required. Use them as often as you need.

Duct Sizer

Calculate duct size based on CFM, velocity, or friction rate using equal friction or velocity reduction methods.

Recommended Duct Size
-
Open Advanced Duct Sizer

Pipe Sizer

Size water pipes based on flow rate and velocity limits per ASHRAE guidelines.

Recommended Pipe Size
-

CFM / Tonnage Calculator

Convert between CFM, BTU/hr, and tons of cooling. Calculate supply air requirements.

Results
-

Psychrometric Calculator

Calculate air properties: humidity ratio, enthalpy, dew point, and wet bulb temperature.

Open Interactive Chart
Air Properties
-

Need More Powerful Tools?

Get access to 1,300+ engineering modules including load calculations, energy compliance, equipment selection, and more. Contact us for licensing information.

Contact Us