construction calculator

Roofing Square Footage Calculator

Estimate roof area and the number of roofing squares needed for shingles or metal panels. for planning material orders before final site measurements.

Important Use Notice

Planning calculator only. Do not rely on this page alone for structural design, permitting, code compliance, engineering signoff, procurement quantities, or contractual commitments.

Context

Roof area = length × width × pitch factor. One roofing square = 100 sq ft.

Estimate

Enter job values, review the estimate, then use the decision hints before ordering or quoting.

Estimate Results

Enter values to see the result.

Next Step

New roof installation or replacement
Estimating shingle or metal roofing quantity
Planning gutter and underlayment needs

Check

Using floor dimensions instead of actual roof slope
Forgetting ridge cap and valley flashing

Reference

lengthwidthpitchsquares
30401.0513
24361.1211

Example

30 ft × 40 ft roof, 4/12 pitch → 1,260 sq ft = 13 squares
24 ft × 36 ft roof, 6/12 pitch → 1,080 sq ft = 11 squares

Formula

Roof Area = Length × Width × Pitch Factor

Pitch factor: 4/12 = 1. 05, 6/12 = 1. 12, 8/12 = 1. 20. One square = 100 sq ft.

Add 10% waste for hips, valleys and ridge

Next Step

System note: validate this estimate against local code and supplier requirements before ordering.

FAQ

What is a roofing square?

100 square feet of roof surface. Shingles are sold by the square.

How do I find my roof pitch?

Measure rise over 12 inches of run or use online pitch finder.