BTU Calculator

Calculate the BTU requirements for heating or cooling a room.

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Insulation Quality

Sun Exposure

Number of Occupants

Climate Zone

Cooling BTU Required

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Heating BTU Required

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Recommended AC Tonnage

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Room Volume

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How It Works

BTU requirements are calculated based on room dimensions, insulation quality, sun exposure, number of occupants, and climate zone. General rule: 20 BTU per sq ft for cooling, 30-40 BTU per sq ft for heating. 1 ton of AC = 12,000 BTU.

About this Calculator

The BTU Calculator is a free, easy-to-use tool for heating, cooling, AC. Simply enter your values and get instant, accurate results — no signup, no ads, no tracking. All calculations run locally in your browser, so your data stays completely private.

Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.