AC Tonnage Calculator

Enter room size and condition. For example, a 12×10 ft normal room needs 1 ton; a top-floor one needs 1.5.

Room length (ft)

Room width (ft)

Room condition

Suggested AC

1 ton

Room area: 120 sq ft
Calculated need: 1 ton

The math says 1 ton ton, so buy a 1 ton ton AC.

Many doors, windows or people → go one size up. Inverter ACs use ~30% less power.

How this was calculated

120 sq ft ÷ 120 = 1 ton → standard size 1 ton

Calculated at: https://xn--d6bxcvd.xn--54b7fta0cc/en/ac-ton-calculator/

How to use

Enter room length and width in feet.
Pick top-floor/sunny if it applies.
See the suggested size.

AC rules

Room	Rule	Example
Normal	Area ÷ 120	120 sq ft = 1 ton
Top floor/sunny	Area ÷ 100	120 sq ft = 1.2 → 1.5 ton

Examples

12×10 normal room: 120 sq ft ÷ 120 = 1 ton.

15×12 top floor: 180 ÷ 100 = 1.8 → 2 tons.

More: power-cost math

A 1.5-ton (~1,800W) AC running 8 hours a day uses ~432 units a month. At 10 per unit that’s ~4,320 taka/month. Check your own unit on the appliance power calculator.

Frequently asked questions

What is the AC tonnage rule?

1 ton per 120 sq ft for normal rooms; per 100 sq ft for top-floor or sunny ones. 120 sq ft is 1 ton.

What does 1 ton mean?

1 ton = 12,000 BTU/hour of cooling. Bigger rooms need more BTU.

Is a bigger AC better?

No. Oversized units cycle on and off, wasting power and dehumidifying poorly. Stay near the math.

Inverter vs non-inverter?

Inverters vary compressor speed and save ~30% power. Pricier upfront, cheaper over years of use.

What about many doors and windows?

Leaks waste cooling. Go one size up (e.g. 1.5 instead of 1 ton) for leaky rooms.

Also searched as

what size ac for room · ac tonnage chart