Roof Area Calculator
Result
Roof Area Calculator — free online calculator.
Formula
- Calculate rectangular roof area from the entered length and width.
- The main inputs are Roof Length, Roof Width (span), Roof Pitch. Enter them in the units and format shown in the calculator.
- Keep measurements and project assumptions consistent before comparing or combining values.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Roof Area
- Roof Length: 10 m
- Roof Width (span): 8 m
- Roof Pitch: 30 °
This page currently uses the site’s rectangular area engine. Enter two positive dimensions in the same unit; the result is returned in square units.
Sample result: Calculating…
Frequently asked questions
What does the Roof Area calculate?
A roof rectangle 10 units long and 5 units wide has an area of 50 square units.
Which values should I enter?
Enter Roof Length, Roof Width (span), Roof Pitch using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Rafter=(Width/2)/cos(pitch°); roof surface area=2×Length×Rafter; plan area=Length×Width.
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.