Air Conditioning Calculator

To estimate the BTU range (cooling capacity) you'll need from a room air conditioner to sufficiently cool any room in your home, just tell us how big your room is and hit "Calculate Now" to tabulate your results. Please note: the largest room size that may be cooled by a room air conditioning unit is 40' x 40' (1,600 square feet). This calculator does not estimate whole-house cooling.

Calculator Inputs

Room Length


Room Width


Room Height


A standard room height of 8 feet is assumed for this calculator. Entering a room height greater than 8 feet will increase your dimensions by 10%.

Calculator Results

Cooling Capacity: 0 BTU's

For kitchens, add 4,000 BTUs to the calculated results.

Other Calculators


Important Disclaimer: This calculator is provided for general information and illustration purposes only; the results are to be used only as estimates and are not intended as definitive advice or as a resource applicable to any specific circumstance and should not be relied upon or used as such. The Home Depot cannot guarantee that you will achieve proper results without verifying your measurements and assumptions. For specific advice regarding your project, you should engage the services of an associate in your local Home Depot store.