BTU Calculator
Estimate room cooling capacity in BTU per hour.
Estimated cooling capacity
6,000BTU/hour
- Room area
- 300 sq ft
- Unrounded estimate
- 6,000 BTU/h
- Assumption
- 20 BTU per sq ft at 8 ft ceiling, adjusted by selected factors
This is a planning estimate based on your inputs and assumptions, not an exact contractor, installer, or supplier quote.
What this calculator does
Estimate cooling capacity from room dimensions, ceiling height, climate, insulation, sun, and occupants.
Inputs and what they mean
- Dimension unit
- — choice value.
- Room length
- — number value.
- Room width
- — number value.
- Ceiling height
- — number value.
- Climate
- — choice value.
- Insulation
- — choice value.
- Regular occupants
- — number value.
- Strong direct sun
- — yes/no value.
How to use it
- Enter the project dimensions and choose their unit.
- Adjust waste, coverage, quantity, and other assumptions.
- Use the rounded purchase estimate as a planning guide.
Formula
Base capacity uses 20 BTU/h per square foot at an 8-foot ceiling, adjusted for height, climate, insulation, sun, and occupants over two.
Worked example
20 × 15 ft room
Estimate cooling capacity for an 8-foot room with average conditions.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
This is a planning estimate based on your inputs and assumptions, not an exact contractor, installer, or supplier quote.