UseCalcPro
Home
Math
Percentages, fractions, ratios
Finance
Loans, mortgages, investments
Health
BMI, calories, fitness metrics
Construction
Materials for building projects
Auto
Car payments, fuel, insurance
Pets
Pet age, feeding, housing
Garden
Lawn care, irrigation, compost
Crafts
Yarn, fabric, candle making
Food & Brewing
Bread, dough, brewing, recipes
Tools
Age, date, GPA, converters
Blog
  1. Home
  2. Construction

Roofing Calculator

Calculate roofing materials needed

Total Bundles Needed

45

Roof Area

1341.6 ft²

Squares

13.42

Pitch

6/12

Units

Common: 4/12 (low), 6/12 (medium), 8/12 (steep)

Standard: 33.3 sq ft per bundle (3-tab shingles)

Roof Area

1341.6 sq ft

Squares

13.42

Base Bundles

41

Total + Waste

45

Bundle Breakdown

Base Bundles41
Waste (10%)+5
Total Bundles45

Material Quantities

Base Bundles41 bundles
Waste Bundles (+10%)5 bundles
Total Bundles45 bundles

Waste Allowance

Waste as % of total order11%

Roof Details

Roof Area1341.6 sq ft
Squares (100 sq ft)13.42
Roof Pitch6/12

Frequently Asked Questions

Q

How do you calculate roofing materials?

Calculate roof area by multiplying length × width × pitch multiplier. Divide by bundle coverage to get bundles needed. Add 10% waste for cuts and errors. Roof pitch increases the surface area compared to flat roof.

Q

What is a roofing square?

A roofing square equals 100 square feet. Roofers use squares to measure and quote roofing jobs. For example, a 2,000 sq ft roof = 20 squares.

Q

How many bundles of shingles per square?

Typically 3 bundles per square (100 sq ft) for standard 3-tab shingles. Architectural shingles may require 4 bundles per square. Always check manufacturer specifications.

Q

What roof pitch should I use?

Common pitches: 4/12 (low slope), 6/12 (medium, most common), 8/12 (steep). Measure the vertical rise over 12 inches of horizontal run. Steeper pitches require more material.

Example Calculations

1Standard Roof (40 × 30 ft, 6/12 pitch)

Inputs

Roof Length40 ft
Roof Width30 ft
Roof Pitch6/12
Bundle Coverage33.3 sq ft

Result

Total Bundles45 bundles
Roof Area1341.6 sq ft
Squares13.42
Base Bundles41
Waste (10%)5

Pitch multiplier = sqrt(1 + (6/12)^2) = sqrt(1.25) = 1.118. Roof area = 40 × 30 × 1.118 = 1,341.6 sq ft. Squares = 1,341.6 / 100 = 13.42. Bundles = 1,341.6 / 33.3 = 40.3. With 10% waste: 40.3 × 1.1 = 44.3, rounded up to 45 bundles.

2Steep Roof (50 × 25 ft, 10/12 pitch)

Inputs

Roof Length50 ft
Roof Width25 ft
Roof Pitch10/12
Bundle Coverage33.3 sq ft

Result

Total Bundles60 bundles
Roof Area1601.4 sq ft
Squares16.01
Base Bundles49
Waste (10%)5

Pitch multiplier = sqrt(1 + (10/12)^2) = sqrt(1.694) = 1.302. Roof area = 50 × 25 × 1.302 = 1,627.5 sq ft. Squares = 16.28. Bundles = 1,627.5 / 33.3 = 48.9. With 10% waste: 48.9 × 1.1 = 53.7, rounded up to 54 bundles.

Formulas Used

Roof Area

Roof Area = Length × Width × Pitch Multiplier

Multiplies the flat footprint by a pitch multiplier to account for slope.

Where:

Length= Roof length in feet
Width= Roof width in feet
Pitch Multiplier= sqrt(1 + (pitch/12)^2), e.g. 1.118 for 6/12

Roofing Squares

Squares = Roof Area / 100

One roofing square equals 100 square feet.

Where:

100= Square feet per roofing square

Bundles Needed

Total Bundles = ceil((Roof Area / Bundle Coverage) × 1.10)

Divides roof area by bundle coverage (typically 33.3 sq ft) and adds 10% waste.

Where:

Bundle Coverage= Sq ft per bundle (33.3 for 3-tab shingles)
1.10= 10% waste factor

Understanding Roofing Calculations

Roofing calculations account for roof pitch, which increases the surface area compared to a flat roof.

A roofing square equals 100 square feet and is the standard unit for roofing materials.

Always add 10-15% waste for cuts, overlaps, and errors when ordering materials.

Related Resources

  • Concrete Calculator

    Calculate concrete needed

  • Paint Calculator

    Calculate paint needed

  • Flooring Calculator

    Calculate flooring materials

Related Calculators

Concrete Calculator

Calculate concrete volume

Square Footage

Calculate area

More Construction Calculators

Plan your construction project

View All

Last Updated: Feb 12, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

UseCalcPro
FinanceHealthMath

© 2026 UseCalcPro