Roofing Calculator

Choose roof shape, size, overhang, and pitch. We estimate area, squares, shingles, underlayment, ridge caps, starter, drip edge, and cost.

Settings

Units

Waste or overage (%)

Common: 5 to 15. Add more for complex roofs.

Roof shape

Pitch mode

Length

US: feet (ridge direction)

Width

US: feet (gable span)

Overhang each side

US: inches. Applied to all sides.

Rise / run

US example: 6 in rise per 12 in run

Shingle bundles per square

Most architectural shingles: 3 bundles per 100 ft²

Price per shingle bundle $

Ridge length (editable)

Gable default = length. Shed = 0. Hip ≈ shorter side. Edit if needed.

Ridge cap coverage per bundle

Typical 20 to 33 linear ft per bundle

Price per ridge-cap bundle $

Starter coverage per bundle

Linear ft along eaves. Example 100 ft per bundle

Price per starter bundle $

Underlayment

US coverage per roll

Custom underlayment coverage per roll

Price per underlayment roll $

Drip edge piece length

Feet per piece

Price per drip edge piece $

Include sheathing estimate

Simple count using plan area. 4×8 sheets.

Price per sheet $

Roof area = plan area × slope factor. Slope factor = √(rise² + run²) ÷ run, or 1 ÷ cos(°).
Overhang is added to all sides to estimate plan area. Edit ridge length if your roof differs.
Bundle and roll coverages vary by brand. Always check labels and add waste.
This is planning info only. Local codes and manufacturer instructions control.