Use the free AC BTU Calculator on ToolVexa to estimate the cooling capacity needed for a room from its length and width.
How to Use
Enter the room length and width in feet, then press Calculate. The result shows the room area and an estimated BTU figure.
Formula in Plain Words
Multiply length by width to get the area in square feet, then multiply the area by 20 BTU per square foot.
Worked Example
For a room 20 ft by 15 ft, the area is 300 sq ft and the estimated cooling needed is 6,000 BTU.
FAQs
Is this exact for every room?
No. It is a simple estimate. Sunlight, ceiling height, insulation and room use can change the real need.
What if my room is not rectangular?
Split it into rectangles, calculate each part, and add the areas together before using 20 BTU per square foot.
Should I buy exactly this BTU?
Use the result as a starting point and check the manufacturer’s guidance for the model you are considering.