BTU Calculator (USA)
Instant AC sizing estimate in BTU/h, tons, and watts. Adjust for insulation, sun exposure, people, and electronics. Download a simple PNG report.
How BTU sizing works
BTU/h (British Thermal Units per hour) measures how much heat an air conditioner can remove. A common reference is that 1 ton of cooling = 12,000 BTU/h. Proper sizing improves comfort and energy efficiency.
Undersizing may run constantly. Oversizing can short-cycle and remove less humidity. Use this tool as a starting point and verify final sizing with a licensed professional.
Frequently asked questions
How do I estimate BTU from square footage?
Start with room area and adjust for insulation, sun exposure, people, and electronics. This calculator automates those steps.
What does “tons” mean in HVAC?
Cooling tons are another way to express capacity: 1 ton = 12,000 BTU/h.
Should I round to a standard AC size?
Yes—real units come in standard increments. We round to common sizing steps to keep results practical.
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Privacy Policy
Summary: We do not collect personal information directly through this calculator.
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Terms
This tool provides informational estimates only and is not professional engineering advice. Real HVAC loads depend on many variables (ceiling height, windows, infiltration, climate zone, equipment efficiency, etc.).
By using this site, you agree the operator is not responsible for decisions made from these estimates. Always verify final sizing with a licensed HVAC professional.
These terms may change over time without notice.