Classic tool
BTU Calculator for Air Conditioners
Estimate the BTU/h your room needs from size, ceiling height, occupancy, sunlight and kitchen use.
Use this BTU calculator to estimate the air conditioner capacity that fits a bedroom, living room, small office, studio or open kitchen more closely. Instead of guessing the unit size, you can enter room dimensions, ceiling height, occupancy and sunlight exposure to get a faster planning number.
The calculation starts from a room-size cooling chart and then applies practical adjustments for sunny spaces, extra occupants, kitchen use and ceilings above the standard 8-foot baseline. The result shows estimated BTU per hour, the closest standard equipment size and an approximate tonnage reference to help you compare window, portable, split and mini-split options.
This is a quick sizing estimate, not a full HVAC load calculation. If your room has large glass areas, heavy equipment, unusual insulation issues or demanding commercial heat loads, confirm the final spec with a qualified professional before buying.
Use clear inputs to get a more useful result.