Air conditioner BTU calculator

Estimate the cooling capacity a room needs — by floor area, ceiling height, sun exposure, occupants and kitchen use.

Numbers stay in this browser — nothing is sent anywhere.

Quick sizing rule (≈20 BTU per ft², ±10% for sun, +600 BTU per extra person beyond two, +4,000 for kitchens, scaled for ceiling height). It's a first estimate for room ACs — insulation, windows, climate, and open floor plans all move the real load. For exact sizing a Manual J calculation is needed.

How to use

  1. Enter the floor area and ceiling height (m or ft).
  2. Set sun exposure, occupants, and kitchen.
  3. Read the estimated BTU and the suggested unit size.

What it supports

Quick rule ≈20 BTU/ft², ±10% for sun, +600 BTU per person beyond two, +4,000 for kitchens, scaled for ceiling height. A first estimate for room ACs — insulation, windows, climate and open plans move the real load; exact sizing needs a Manual J calculation.

Related tools

Related guides