Engineering / Browser calculator

BTU Calculator

BTU Calculator works from the inputs you provide and returns load scenario (w), load scenario (btu/h). Use the calculation panel to explore a scenario, then check the formula and limitations before applying the result.

Your inputs

Minimum: 0
Minimum: 0
Minimum: 0
Minimum: 0

Your results

Enter your values and calculate to see the result.

Estimates depend on the stated method and entered quantities. Check applicable standards before using a result for a real-world design or safety decision.

Formula and calculation method

Watts = room volume × entered W/m³. BTU/h = watts × 3.412141633.

Rough scenario, not professional HVAC sizing. Climate, insulation, solar gain and ventilation are excluded.

How to use btu calculator

  1. Set Room length (m). The example below uses 5.
  2. Set Room width (m). The example below uses 4.
  3. Set Room height (m). The example below uses 2.5.
  4. Set Cooling load assumption (W/m³). The example below uses 40.
  5. Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.

Worked example

Example inputs
Room length (m)
5
Room width (m)
4
Room height (m)
2.5
Cooling load assumption (W/m³)
40
Load scenario (W)
2000
Load scenario (BTU/h)
6,824.283266

Factors affecting your result

Rough scenario, not professional HVAC sizing. Climate, insulation, solar gain and ventilation are excluded.

Changing room length (m) changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.

Frequently asked questions

How does the btu calculator work?

Watts = room volume × entered W/m³. BTU/h = watts × 3.412141633.

What inputs does BTU Calculator need?

Enter room length (m), room width (m), room height (m), cooling load assumption (w/m³). Choose values that correspond to the same situation and measurement convention.

How should I interpret the btu calculator result?

Rough scenario, not professional HVAC sizing. Climate, insulation, solar gain and ventilation are excluded.

Are my btu calculator inputs uploaded?

No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.

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