AC Tonnage Calculator Per Square Foot (+Tonnage Table)

Before buying an air conditioner, you have to make the AC tonnage calculation. Not sizing an AC unit properly can cause $100s in wasted unit or electricity costs. 

According to the DOE, “…an air conditioner generally needs 20 BTU for each square foot of living space.” We need to convert BTU to tonnage. 1 ton equals to 12,000 BTU. That means that, on average, we will need 0.0016 tons per square foot

To properly get the tonnage of the AC you need, you can use the AC tonnage calculator here:

Calculated Tonnage:

0.00 Tons


For example, a standard 1,500 sq ft house would need a 2.5-ton air conditioner. To help us out here is a quick table showing how many tons (and BTU) air conditioners we need for certain square footage:

Tonnage Table

Area (Square Feet):BTUTonnage
600 sq ft12,000 BTU1 Ton
900 sq ft18,000 BTU1.5 Tons
1,200 sq ft24,000 BTU2 Tons
1,500 sq ft30,000 BTU2.5 Tons
1,800 sq ft36,000 BTU3 Tons
2,100 sq ft42,000 BTU3.5 Tons
2,400 sq ft48,000 BTU4 Tons
2,700 sq ft54,000 BTU4.5 Tons
3,000 sq ft60,000 BTU5 Tons
3,300 sq ft66,000 BTU5.5 Tons
3,600 sq ft72,000 BTU6 Tons

In short, you can use 0.0016 tonnage per sq ft.

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