Tons to BTU: Convert AC Tonnage to BTU per Hour
Convert tons of air conditioning to BTU per hour. 1 ton = 12,000 BTU. Table for 1 to 5 ton systems with square footage each size typically covers.
BTU per hour
Formula: BTU/hr = tons × 12,000
Going the other way? BTU to Tons converter.
tons to BTU/hr conversion table
| Tons of cooling | BTU per hour |
|---|---|
| 0.5 tons | 6,000 BTU/hr |
| 0.75 tons | 9,000 BTU/hr |
| 1 tons | 12,000 BTU/hr |
| 1.5 tons | 18,000 BTU/hr |
| 2 tons | 24,000 BTU/hr |
| 2.5 tons | 30,000 BTU/hr |
| 3 tons | 36,000 BTU/hr |
| 3.5 tons | 42,000 BTU/hr |
| 4 tons | 48,000 BTU/hr |
| 4.5 tons | 54,000 BTU/hr |
| 5 tons | 60,000 BTU/hr |
| 6 tons | 72,000 BTU/hr |
| 7.5 tons | 90,000 BTU/hr |
| 10 tons | 120,000 BTU/hr |
About this conversion
Multiply tonnage by 12,000 to get BTU per hour. A 2.5-ton central air conditioner, the most common size on American houses, moves 30,000 BTU of heat out of the home every hour it runs. A 5-ton system, about as large as residential equipment gets before splitting into two units, is 60,000 BTU/hr.
You will use this conversion when comparing a contractor's tonnage quote against a room-by-room estimate in BTU, or when checking whether the mini-split heads in a multi-zone system add up to the outdoor unit's rating. Ductless outdoor units are labelled in BTU (a '36k' unit is 3 tons); ducted condensers are labelled in tons on the paperwork but you can read the BTU from the model number, where '036' means 36,000 BTU.
As a rough check on any quote: 400 to 600 square feet per ton is normal for cooling in the US. Under 400 sq ft per ton suggests the system is oversized unless the house is a glass box in Phoenix; over 700 sq ft per ton is only plausible in a very well-insulated home in a mild climate.
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 3 ton air conditioner?
36,000 BTU per hour (3 × 12,000).
How many BTU is a 1.5 ton AC?
18,000 BTU per hour, the same as a large window unit or an 18k mini-split.
How many tons do I need for 1,500 square feet?
About 2.5 tons under average conditions (1,500 × 20 = 30,000 BTU). A hot, sunny climate with average insulation pushes that to 3 tons; a well-insulated home in a mild climate may get by with 2 tons.