How do you calculate roof square footage?

Measure the footprint area (length × width) and multiply by the pitch multiplier. For a 30×40 ft home with 6/12 pitch: 1200 sqft × 1.118 = 1,342 sqft of roof area. Add 10% for waste. Our roofing calculator handles complex shapes automatically.

How many shingles do I need for my roof?

One roofing square covers 100 sqft. A bundle covers ~33 sqft (3 bundles per square). For a 2000 sqft roof: 20 squares = 60 bundles. Add 10-15% for waste, valleys, and hips.

How do I calculate roofing squares?

Divide total roof area in square feet by 100. One roofing square = 100 sqft. For a 2,400 sqft roof: 2400 ÷ 100 = 24 squares. Add waste factor (10-15%) for a total of 26-28 squares.

Roofing Calculator - Roof Area, Shingles, Metal & Cost Estimator

Roof Square Footage Calculator

Calculate actual roof surface area from building footprint dimensions and roof pitch.

Building Length (ft)

Building Width (ft)

Roof Pitch

Roof Shape

Waste Factor (%)

Roof Area Results

TIP: Hip roofs typically need 10-15% more material than gable roofs due to extra cuts and waste at hips and valleys. Adjust waste factor accordingly.

Roof Shingle Calculator

Calculate how many shingle bundles and roofing squares you need for your roof.

Total Roof Area (sq ft)

Shingle Type

Waste Factor (%)

Ridge/Hip Length (ft)

Starter Strip (perimeter ft)

Underlayment Layers

Shingle Estimate

NOTE: 1 roofing square = 100 sq ft. Standard bundles cover ~33.3 sq ft (3 bundles per square). Add extra for valleys, dormers, and complex roof lines.

Metal Roof Calculator

Estimate metal roofing panels, standing seam, or corrugated sheets for your project.

Total Roof Area (sq ft)

Panel Type

Panel Length (ft)

Waste Factor (%)

Ridge Cap (linear ft)

Fasteners per Panel

Metal Roofing Estimate

TIP: Standing seam panels cost more but last 40-70 years with minimal maintenance. Corrugated metal is more affordable and suitable for agricultural and commercial buildings.

Roofing Cost Calculator

Estimate total roofing project costs including materials, labor, and disposal.

Total Roof Area (sq ft)

Roofing Material

Material Cost ($/sq ft)

Labor Cost ($/sq ft)

Tear-off Existing Roof?

Tear-off Cost ($/sq ft)

Permits & Dumpster ($)

Tax Rate (%)

Roofing Cost Estimate

NOTE: Costs vary significantly by region, roof complexity, and current material prices. Steep roofs (over 8/12) add 20-50% to labor costs. Get 3+ quotes from licensed contractors.

Roofing Reference Tables

Material	Cost/SqFt	Lifespan	Weight (lbs/sq)	Best For
3-Tab Shingles	$1.50-$2.50	15-25 yrs	200-250	Budget-friendly, simple roofs
Architectural	$2.50-$4.00	25-30 yrs	250-350	Most homes, best value
Premium Shingles	$4.00-$7.00	30-50 yrs	350-450	High-end homes
Standing Seam	$5.00-$12.00	40-70 yrs	100-150	Modern, durability
Corrugated Metal	$3.50-$6.50	25-50 yrs	75-125	Agricultural, commercial
Clay Tile	$7.00-$20.00	50-100 yrs	900-1200	Mediterranean, Spanish
Slate	$15.00-$30.00	75-200 yrs	800-1500	Historic, luxury

Pitch	Multiplier	Walkable?	Min Material
Flat-2/12	1.000-1.014	Yes	Membrane/Built-up
3/12-4/12	1.031-1.054	Yes	Shingles (min 4/12)
5/12-7/12	1.083-1.158	Yes	All shingles/metal
8/12-10/12	1.202-1.302	Caution	All materials, +labor cost
12/12+	1.414+	No	Specialized install required

How to Calculate Roof Square Footage

Accurately calculating roof square footage is the foundation of any roofing project. Whether you're replacing shingles, installing metal roofing, or getting a cost estimate, our roofing calculator gives you precise measurements.

Step-by-Step Roof Area Calculation

To calculate roof square footage, multiply the building footprint area by the pitch multiplier. For a simple gable roof on a 30×40 ft home with 6/12 pitch: 30 × 40 = 1,200 sqft footprint × 1.118 (6/12 multiplier) = 1,342 sqft of actual roof surface. For hip roofs, the calculation is similar but waste factors are higher due to hip and valley cuts.

How to Calculate Roofing Squares

A roofing square is the standard unit of measurement in roofing — it equals 100 square feet. To calculate roofing squares, divide total roof area by 100. A 2,000 sqft roof = 20 roofing squares. Our roofing square calculator adds waste factors automatically.

How to Calculate Roof Shingles

Standard asphalt shingles come in bundles covering ~33.3 sqft (3 bundles per roofing square). For a 20-square roof: 20 × 3 = 60 bundles. Add 10-15% for waste, hips, and valleys. Our roof shingle calculator includes ridge caps, starter strips, and underlayment in the estimate.

Roof Replacement Cost

The average roof replacement cost ranges from $5,000-$15,000 for asphalt shingles. Metal roof cost runs $8,000-$25,000+. Factors include material type, roof size, pitch, complexity, tear-off, and regional labor rates. Our roofing cost calculator provides comprehensive estimates.

Frequently Asked Questions

How do I calculate the square footage of my roof?+

Measure the building's footprint (length × width). Multiply by the pitch multiplier for your roof slope. For 6/12 pitch, multiply by 1.118. For two-story homes, only measure the top roof footprint. Add 10% for waste on gable roofs, 15% for hip roofs.

How many bundles of shingles do I need?+

Divide roof area by 33.3 (for standard 3-bundle squares). A 2,000 sqft roof needs about 60 bundles plus 10-15% waste = 66-69 bundles. Premium shingles may require 4 bundles per square.

How much does a new roof cost per square foot?+

Total installed costs: 3-Tab shingles $3-$5/sqft, Architectural $5.50-$8/sqft, Standing seam metal $8.50-$16/sqft, Tile $10-$25/sqft, Slate $20-$40/sqft. These include materials, labor, and tear-off.

What is a roofing square?+

A roofing square equals 100 square feet of roof area. It's the standard industry unit. A typical home has 15-30 roofing squares. Roofers price materials and labor per square.

How long does a roof last?+

3-Tab shingles: 15-25 years. Architectural shingles: 25-30 years. Metal roofing: 40-70 years. Tile: 50-100 years. Slate: 75-200 years. Climate, maintenance, and installation quality affect lifespan.