BTU to Tons: Convert Air Conditioner BTU to Tonnage
Convert BTU/hr to tons of cooling instantly. 12,000 BTU = 1 ton. Table from 5,000 to 60,000 BTU with the matching AC tonnage, plus what tonnage means.
Tons of cooling
Formula: tons = BTU/hr ÷ 12,000
Going the other way? Tons to BTU converter.
BTU/hr to tons conversion table
| BTU per hour | Tons of cooling |
|---|---|
| 5,000 BTU/hr | 0.42 tons |
| 6,000 BTU/hr | 0.50 tons |
| 8,000 BTU/hr | 0.67 tons |
| 9,000 BTU/hr | 0.75 tons |
| 10,000 BTU/hr | 0.83 tons |
| 12,000 BTU/hr | 1.00 tons |
| 14,000 BTU/hr | 1.17 tons |
| 18,000 BTU/hr | 1.50 tons |
| 24,000 BTU/hr | 2.00 tons |
| 30,000 BTU/hr | 2.50 tons |
| 36,000 BTU/hr | 3.00 tons |
| 42,000 BTU/hr | 3.50 tons |
| 48,000 BTU/hr | 4.00 tons |
| 60,000 BTU/hr | 5.00 tons |
About this conversion
A ton of cooling is 12,000 BTU per hour. The name is a leftover from the ice trade: melting one short ton (2,000 lb) of ice over 24 hours absorbs 288,000 BTU, which works out to 12,000 BTU every hour. When mechanical refrigeration replaced ice deliveries, the industry kept the unit so customers could compare like with like.
Tonnage is how central air conditioners and larger heat pumps are sold. Residential systems come in half-ton steps from 1.5 to 5 tons (18,000 to 60,000 BTU/hr). Room units, by contrast, are sold in BTU, which is why you end up converting: an 18,000 BTU window unit is a 1.5-ton machine, and a 2-ton central system is the same capacity as two 12,000 BTU mini-split heads.
One thing tonnage does not tell you is efficiency. Two 3-ton systems remove the same heat per hour, but a SEER2 14 unit uses noticeably more electricity to do it than a SEER2 18 unit. Tonnage is capacity; SEER is how much that capacity costs to run.
Need the load for a specific room rather than a unit conversion? Use the BTU calculator, which returns BTU/hr, tons, kW and watts together.
Quick answers
How many BTU is a 2 ton AC?
24,000 BTU per hour. Multiply tons by 12,000.
How many tons is 36,000 BTU?
3 tons. Divide BTU per hour by 12,000.
How many square feet does a ton of AC cool?
Using the 20 BTU per square foot rule, one ton (12,000 BTU) covers about 600 sq ft under average conditions, or 400–500 sq ft in a hot, sunny climate. Many contractors quote 500–600 sq ft per ton.