Shingle Calculator – Guide & Formulas
Calculate the total shingles, squares, and bundles of roofing material needed for any sloped or flat roof structure.
Estimate the number of standard shingles, bundles, and roof squares required for your roof replacement or build. Automatically incorporates pitch slope adjustments and starter shingles.
Key Takeaway
Use the free Shingle Calculator to calculate the total shingles, squares, and bundles of roofing material needed for any sloped or flat roof structure. Get instant results with step-by-step explanations.
How to Use the Shingle Calculator
- Enter the base footprint area of the roof (ground area).
- Select the roof pitch (e.g. 6/12) to automatically adjust for slope length.
- Set the waste margin (typically 10-15%) and view the bundles to purchase.
The Formula
Variable Definitions
- Squares: Standard roofing unit of area (1 Square = 100 sq ft)
- M_pitch: The pitch slope correction multiplier
- B: Total shingle bundles to buy (assuming 3 bundles per square)
Shingling a standard gable roof
Find shingle specifications for a house footprint of 2,000 sq ft with a 6/12 roof pitch and 10% waste factor.
- Step 1: Obtain the pitch multiplier for 6/12: approx. 1.118.
- Step 2: Calculate sloped surface area: 2,000 × 1.118 = 2,236 sq ft.
- Step 3: Convert to roof squares: 2,236 / 100 = 22.36 squares.
- Step 4: Add 10% waste: 22.36 × 1.1 = 24.6 squares. At 3 bundles per square, order 74 bundles.
Frequently Asked Questions
What is a "Square" in roofing terms?
A roofing "Square" is a standard unit of area equal to exactly 100 square feet.
How many bundles of shingles make up one square?
For standard 3-tab or architectural shingles, it takes exactly 3 bundles to cover 1 square (100 sq ft).
Should I include starter shingles?
Yes. Starter shingles run along the lower eave edges. Our calculator estimates this separate linear requirement automatically.