AC Tonnage Calculator

What size AC do I need?

This calculator estimates the tonnage and BTU your home needs from its square footage, climate zone, and ceiling height. It uses a conservative load model to avoid the oversizing that causes short-cycling and poor humidity control. For a purchase decision, confirm with a full Manual J.

Frequently asked questions

How many square feet does a ton of AC cool?

Roughly 400 to 600 square feet per ton, but climate and insulation shift that a lot; this tool adjusts for your state’s climate zone.