Cooling · Tonnage
AC Tonnage Calculator
1 ton of cooling = 12,000 BTU/h. A typical bedroom needs about 1 ton, a 13 m² / 140 sq ft room in a hot climate about 1.5 tons. Enter your room's dimensions to get the exact tonnage.
Room dimensions
- Tons
- 2.45 t
- Kilowatts
- 8.64 kW
- Horsepower
- 3.68 HP
- Room area
- 19.32 m²
- Room volume
- 58.9 m³
AC tonnage
2.45tons
29,450 BTU/h · 8.64 kW
05
Tons → BTU → kW → room size
Room-size column assumes a shaded room with a 2.7 m (9 ft) ceiling in a hot climate, using the same formula as the calculator.
| Tons | BTU/h | kW | Covers (shaded) |
|---|---|---|---|
| 0.75 | 9,000 | 2.64 | ≈ 7 m² / 72 sq ft |
| 1 | 12,000 | 3.52 | ≈ 9 m² / 96 sq ft |
| 1.5 | 18,000 | 5.28 | ≈ 13 m² / 144 sq ft |
| 2 | 24,000 | 7.04 | ≈ 18 m² / 191 sq ft |
| 2.5 | 30,000 | 8.8 | ≈ 22 m² / 239 sq ft |
| 3 | 36,000 | 10.56 | ≈ 27 m² / 287 sq ft |
Working in BTU instead? Use the BTU calculator, or start from the question "what size AC do I need".
The formula
BTU/h = length(m) × width(m) × height(m) × 500 (600 with sun)
tons = BTU/h ÷ 12,000
kW = tons × 3.52FAQ
- What is a ton of air conditioning?
- One ton of refrigeration equals 12,000 BTU/h — historically the cooling delivered by melting one ton of ice in 24 hours. A 1.5 ton AC therefore moves 18,000 BTU/h, and a 2 ton unit 24,000 BTU/h.
- What room size does a 1.5 ton AC cover?
- In a hot climate with a standard 2.7 m (9 ft) ceiling, 1.5 tons (18,000 BTU/h) covers roughly 13 m² / 140 sq ft of shaded room. With direct sun, plan for about 11 m² / 120 sq ft.
- How do I convert tons to kW?
- Multiply tons by 3.52. A 1 ton unit delivers about 3.5 kW of cooling, 1.5 tons about 5.3 kW, and 2 tons about 7 kW.
- Why does my result differ from the 500-600 sq ft per ton rule?
- That rule describes whole-house central AC in mild climates with insulation, after a full Manual J. This calculator sizes a single room in a hot climate, where solar gain and ceiling height push the per-room requirement much higher. Use the number that matches your situation.
- Should I buy a bigger ton rating to be safe?
- No more than one step up. Oversized units short-cycle: they cool fast but stop before dehumidifying, so the room feels clammy and the compressor wears faster.