Roofing area calculator
Sloped roof area from plan area and pitch, with an allowance for laps.
Inputs
m²
°
Measured from horizontal.
%
Result
1.00m²
(1 ÷ cos 0°) × (1 + 0%)
Formula
A = (plan area ÷ cos θ) × (1 + laps%) [m²]
An estimate for take-off, not a design check. Structural design, member sizing and connection capacity are separate calculations made by the responsible design authority.
Assumptions and limits
- Slope factor is 1 ÷ cos θ, so the pitch is measured from horizontal. A 1:5 slope is about 11.3°.
- The lap allowance covers end laps and side laps. Ten percent is typical for profiled sheeting; check the sheet manufacturer for the profile you are using.
- Excludes openings, ridge and verge flashings, gutters and downpipes, which are measured separately.
Other calculators
Next step
Need this quantity priced?
Send the location, the plot size and what the facility needs to handle. You will get a site visit within 72 hours and a costed scope after the drawing review — no obligation, no sales sequence.
Mon–Sat · 9:00 – 19:00 IST · Site visit scheduled within 72 hours of enquiry