AC BTU Calculator
Enter your room details to find the right BTU air conditioner — avoid under-cooling or wasting energy with an oversized unit.
100% client-side · no upload
AC sizing recommendation
BTU/hr needed
Tonnage
How to use
- Enter the room dimensions and ceiling height in feet.
- Select sun exposure (shaded rooms need less capacity) and insulation quality.
- Add the typical number of occupants — each person adds ~600 BTU of heat load.
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FAQ
- Is this tool free?
- Yes, completely free with no signup required.
- Does my data leave my device?
- No. All calculations happen in your browser — nothing is sent to a server.
- Does it work on mobile?
- Yes. The tool is mobile-first and works on any modern browser.