Example: Room area: 400 sq ft · Ceiling height: 8 ft · Room type: Living area → Cooling capacity needed: 10,000 BTU/hr.
Window unit size: 12,000–14,000 BTU
Frequently asked questions
How do I calculate btu? Enter your numbers above and the result updates instantly. For example: Room area: 400 sq ft · Ceiling height: 8 ft · Room type: Living area → Cooling capacity needed: 10,000 BTU/hr.
Is this BTU Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for btu. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.