BTU Calculator

Heating and cooling capacity needed for a room.

m
m
m
Cooling capacity
6,720BTU/hr
In kilowatts
1.97kW
Room volume
48
Floor area
20
Show the working
  1. 1Volume = 48 m³
  2. 2× 140 BTU/m³, adjusted for avg sun
  3. 3+ 0 BTU for extra occupants = 6,720 BTU/hr
Formula
BTU ≈ volume × 140 × sun factor + occupants

How it works

Estimates the air-conditioner size a room needs, adjusted for sun exposure and the number of people.

Example

A 5 × 4 m room with a 2.4 m ceiling needs about 6,700 BTU/hr.

A rough guide only. Insulation, windows and climate all matter — get a professional heat-load survey for a real install.

About the BTU Calculator

Heating and cooling capacity needed for a room. It sits in the Home & Construction section of NWS Calc, a free collection of calculators that run entirely in your browser. There is no signup, no paywall and no tracking — open the page, enter your numbers, get an answer.

Frequently asked questions

Is the BTU Calculator free to use?
Yes. Every calculator on NWS Calc is completely free, with no signup, no usage limits and no ads.
Does my data leave my device?
No. The BTU Calculator runs entirely in your browser using JavaScript. Nothing you type is uploaded, logged or stored on a server.
Can I use the BTU Calculator on my phone?
Yes. The page is fully responsive and works in any modern mobile or desktop browser — there is nothing to install.
What else is in Home & Construction?
Paint, tile, concrete, flooring, lumber and material estimates. You can browse the full Home & Construction category for related calculators.

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