Single shed section
Input
L=10m, D=4m, Pitch=30°, Overhang e=0.45m
Output
Ap=44.50m², As=51.38m², k=1.1547
Roof Area Calculator with Pitch
Calculate sloped installation area from horizontal plan dimensions and roof pitch.
For complex roofs, split into sections and sum them in one result.
All dimensions are treated as horizontal projection
Shed and gable sections can be combined
Degrees / Rise:Run / % / sun are cross-converted
How to use
- Select unit (m/mm), then enter section shape and plan dimensions.
- Choose pitch format (degrees / Rise:Run / % / sun) and input values.
- Enter overhang, then add sections if the roof needs split input.
- Review summary and breakdown, then copy, share URL, or print.
Sample
L-shape roof split into 2 sections
Input
Section 1: Gable / Section 2: Shed
Output
Sum Ap/As from each section to get total
Formulas
- r = Rise / Run
- k = sqrt(1 + r^2)
- Shed Ap = (L + 2g) × (D + e + e2)
- Gable Ap = (L + 2g) × (S + 2e)
- As = Ap × k
- Total As_total = ΣAs_i
FAQ
Should I enter rafter length?
No. Enter horizontal plan dimensions, not sloped member length.
How is overhang treated?
By default, overhang is treated as horizontal projection. Shed uses one run-side overhang, gable uses both eave sides.
Can I use this for hip roofs or valleys?
Yes, with split input. Divide the roof into rectangles/trapezoids and sum sections.
Will degrees and percent return the same result?
Yes, if they represent the same pitch. Use converted values to confirm.
Notes
- This tool is for area estimation. Confirm overlaps, details, and edge conditions separately for actual work.
- For hip roofs, valleys, dormers, and similar geometry, use section split input.
- All dimensions are assumed to be horizontal projection values.