Convert cooling capacity instantly. Enter either value — the other updates live. Click any reference card to load it.
Educational estimate only. 1 ton = 12,000 BTU/hr is an exact conversion, but system selection should always be based on a proper load calculation. Use the Load Calculator for a BTU estimate before sizing equipment. Consult a licensed HVAC engineer for commercial or permitted work.
A "ton" of cooling has nothing to do with weight — it's a leftover unit from the ice industry. One ton of cooling capacity equals the energy needed to melt one ton of ice in 24 hours, which works out to exactly 12,000 BTU per hour. So a 3-ton AC and a 36,000 BTU/hr AC are the same machine described two different ways.
You'll see BTU used on equipment spec sheets and load calculations, while tons show up on permits, contractor quotes, and equipment model numbers. Being able to convert between them quickly saves you from comparing two units and thinking one is bigger when they're actually identical.
| BTU/hr | Tons | Typical Home Size (moderate climate) |
|---|---|---|
| 18,000 | 1.5 | ~700–900 sq ft |
| 24,000 | 2.0 | ~1,000–1,300 sq ft |
| 30,000 | 2.5 | ~1,300–1,600 sq ft |
| 36,000 | 3.0 | ~1,600–2,000 sq ft |
| 48,000 | 4.0 | ~2,400–3,000 sq ft |
| 60,000 | 5.0 | ~3,000–3,600 sq ft |
The same six numbers from the reference table above, plotted out — it makes the size jumps between standard equipment sizes easier to see at a glance.
BTU/hr = tons × 12,000, at each standard residential equipment size.
Residential equipment is manufactured in fixed increments — 1.5, 2, 2.5, 3, 3.5, 4, 5 tons — because that's how compressors and coils are built at the factory. If your calculated load comes out to 33,400 BTU/hr, there's no such thing as a "2.78-ton" unit to buy. A contractor rounds up to the nearest standard size, usually 3 tons, rather than rounding down and leaving the system undersized on the hottest day of the year.