Air Conditioner Size Calculator
Calculate the right BTU air conditioner for your room.
Enter room dimensions and conditions to get an accurate AC size recommendation.
Recommended AC Size
AC sizing is based on the room area, with adjustments for conditions that affect cooling load.
Base BTU = Room Area (sq ft) × 20
Unit conversions:
Imperial: Room area in square feetMetric: Room area in square meters (1 m² = 10.764 sq ft)
Adjustments:
- Sunny room: Add 10%
- Shady room: Subtract 10%
- Kitchen: Add 4,000 BTU
- More than 2 occupants: Add 600 BTU per extra person
- Ceiling above 8 ft (2.4 m): Add 10% per extra foot
BTU sizing guide:
| Room Size (sq ft) | Room Size (m²) | BTU Needed |
|---|---|---|
| 150–250 | 14–23 | 6,000 |
| 250–350 | 23–33 | 8,000 |
| 350–450 | 33–42 | 10,000 |
| 450–550 | 42–51 | 12,000 |
| 550–700 | 51–65 | 14,000 |
| 700–1,000 | 65–93 | 18,000 |
Tips:
- An oversized AC cools quickly but does not dehumidify well — causes a clammy feel
- An undersized AC runs constantly, wasting energy and wearing out faster
- Look for Energy Star rated units for 10–15% savings