Free contractor calculator
Roofing Calculator
Enter your building footprint and roof pitch, and this calculator applies the slope multiplier to return the actual roof area, the number of roofing squares, and the shingle bundles to order with waste. The same area math JobPlumb's takeoff runs when you measure roof planes on a plan.
Your measurements
Result
- Roofing squares
- 13.4squares
- Roof area
- 1,342sq ft
- Shingle bundles
- 45bundles
How this is calculated
Slope multiplier
√(1 + (rise ÷ 12)²) = 1.118 for a 6/12 pitch
Roof area
footprint length × width × slope multiplier
Squares
roof area ÷ 100 sq ft per square
Bundles
squares × (1 + waste %) × 3 bundles per square, rounded up
Taking this off a real plan?
JobPlumb measures slabs, walls, roofs and runs straight off your drawings, then prices the job and sends a proposal your client accepts online. Free to start, no install.
See JobPlumb estimatingHow to use it
- 1Enter the building footprint length and width in feet.
- 2Choose the roof pitch (the rise in 12).
- 3Set a waste allowance (10 to 15% for hips and valleys).
- 4Read the roof area, squares and shingle bundles to order.
Roofing Calculator, answered
A roofing square is 100 square feet of roof surface. Shingles, underlayment and labor are usually priced per square, so quantities are expressed in squares rather than raw square feet.
Measure it off the real plan in JobPlumb.
Free to start. No install, no sales call. Works in any browser.