Ton to BTU Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026Where the "ton" of cooling comes from
Long before electric air conditioning existed, cooling capacity was measured by how much ice was needed to absorb a given amount of heat. One "ton" of cooling represents the rate of heat absorption from melting one short ton (2,000 lbs) of ice over 24 hours, a figure that works out to almost exactly 12,000 BTU per hour.
Worked example
For a 3-ton residential air conditioning system:
BTU/hr = 3 x 12,000 = 36,000 BTU/hr
| Tonnage | BTU/hr |
|---|---|
| 1.5 tons | 18,000 BTU/hr |
| 2 tons | 24,000 BTU/hr |
| 3 tons | 36,000 BTU/hr |
| 5 tons | 60,000 BTU/hr |