CalcMyHVAC makes free calculators that help homeowners size air conditioners, furnaces, mini splits and heat pumps before they talk to a contractor.
Buying HVAC equipment is expensive, and sizing advice online is often written to sell a particular unit. Our calculators don't sell equipment. They show the method behind every result, use your climate zone, and work on any phone.
Every formula and factor is listed on our methodology page. If you spot an error or want a new calculator, get in touch.