Roof Calculator - Calculator See


Roof Calculator

Calculate roof surface area, roofing squares, bundles of asphalt shingles, and pitch multiplier adjustments.

Calculator Inputs

ft
Building length plus overhangs.
ft
Building width plus overhangs.
Vertical rise per 12 inches of horizontal run.
%
10% for gable roofs, 15% for hips/valleys.

Calculated Results

Roofing Squares Required
24.00 Roofing Squares
Shingle Bundles (3/square) 72 Bundles
Actual Roof Surface Area 2,400 sq ft
Pitch Multiplier 1.202 (6/12 pitch)
Values calculate live as you adjust inputs.

About Roof Calculator

Estimates total roof surface area, roofing squares (100 sq ft per square), and shingle bundles needed for roof replacements.

What is Roof Calculator?

Estimates total roof surface area, roofing squares (100 sq ft per square), and shingle bundles needed for roof replacements.

How to Use This Calculator

  1. Enter building footprint length and width.
  2. Select roof pitch.
  3. Read total squares and shingle bundles.

The Mathematical Formula & Variables

Roof Area = Footprint Area * Pitch Multiplier * (1 + Waste / 100); Squares = Roof Area / 100; Bundles = Squares * 3

Step-by-Step Worked Example

Scenario: 50 ft by 35 ft house with a 6/12 pitch roof and 10% waste buffer.

  1. Footprint = 50 * 35 = 1,750 sq ft.
  2. Pitch multiplier for 6/12 = 1.118: 1,750 * 1.118 = 1,956.5 sq ft.
  3. With 10% waste: 1,956.5 * 1.10 = 2,152 sq ft = 21.5 squares.
  4. Bundles = 21.5 * 3 = 65 bundles of shingles.

Result: 21.5 Squares (65 Bundles)

Frequently Asked Questions

What is a "square" in roofing?

One roofing square equals exactly 100 square feet of roof surface area. Three standard bundles of architectural shingles cover one square.