Tools in This Collection
Roofing Calculator
Calculate shingles, underlayment, ridge caps, and total roofing materials
Deck Board Calculator
Calculate decking boards, joists, posts, screws, and cost estimates
Fence Calculator
Calculate posts, rails, pickets, and concrete per linear foot of fence
Paver Calculator
Calculate paver count, sand, gravel base, and polymeric sand quantities
Rafter Length Calculator
Calculate rafter length, ridge height, and birdsmouth cuts from pitch and span
Stair Calculator
Calculate riser height, tread depth, step count, and stringer length
Gutter Calculator
Calculate gutter length, downspout count, and hangers for any roofline
Shed Materials Calculator
Estimate framing lumber, roofing, and siding for any shed size
Pergola Materials Calculator
Calculate posts, beams, rafters, and fasteners for a pergola build
Guides & Articles
Plan Your Roofing and Outdoor Structure Project
Outdoor and roofing projects have the least forgiving material estimates of any home improvement category. Roofing materials must be ordered by the full square — ordering short means a second delivery charge and potential shingle lot mismatch. Deck lumber needs to be counted precisely because board lengths are fixed at 8, 10, 12, 16, and 20 feet. These calculators give you accurate material counts before you visit the lumber yard or roofing supplier.
The Right Calculator Workflow
Start with the Rafter Length Calculator for roof framing. It calculates rafter length, ridge height, birdsmouth cut dimensions, and rafter count from pitch and span — with an interactive cross-section diagram. Once framing is sized, move to the Roofing Calculator for shingles, underlayment, ridge caps, drip edge, and nails. It converts footprint area to roof surface area using the pitch multiplier and adds your selected waste factor for valleys and hip cuts.
For the Gutter Calculator, calculate after roofing is specified — gutter length and downspout count depend on eave length and roof drainage area. Building a deck off the back of the house? The Deck Board Calculator estimates decking boards, joists, posts, hardware, and screws from your deck dimensions and board spacing. If stairs connect the deck to grade, use the Stair Calculator to determine riser height, tread depth, step count, and stringer length from total rise.
Fencing, Pavers, and Outbuildings
The Fence Calculator handles post count, rails, pickets, and concrete per linear foot of fence. It supports wood, chain link, vinyl, and split-rail fence styles with separate material counts for each. For patio and walkway work, the Paver Calculator converts area to paver count by size, adds polymeric sand and gravel base quantities, and accounts for your chosen pattern's waste factor.
Adding a shed or pergola? The Shed Materials Calculator and Pergola Materials Calculator estimate framing lumber, decking, roofing, and fasteners from your structure dimensions. Both calculators output a complete cut list and material summary suitable for supplier quotes.
Common Material Rules for Outdoor Projects
Roofing: 1 square = 100 sq ft; 3 bundles of shingles per square for standard architectural shingles. Add 10% waste for gable roofs, 15% for hip roofs with valleys. Decking: standard board spacing is 1/8" gap; add 10% waste for straight lay, 15% for diagonal. Fencing: posts every 6–8 feet for wood, 8–10 feet for chain link. Concrete for posts: typically 0.25–0.5 bags per post for standard fence posts. Running the numbers before purchasing means fewer return trips and fewer leftover materials.
Frequently Asked Questions
How many bundles of shingles do I need for my roof?
Most standard architectural shingles require 3 bundles per roofing square (100 sq ft). First find your roof surface area by multiplying the footprint by the pitch multiplier — for example, a 6/12 pitch has a multiplier of 1.118. Divide the roof area by 100 to get squares, multiply by 3 for bundles, and add 10–15% waste.
How do I calculate rafter length from roof pitch?
Rafter length equals the run (half the building span) divided by the cosine of the pitch angle. For a 6/12 pitch, the angle is 26.57° and cos(26.57°) = 0.894. A 12-foot run gives a rafter length of 12 ÷ 0.894 = 13.42 feet. The Rafter Length Calculator handles this automatically and includes overhang length in the total cut length.
What is the standard post spacing for a deck or fence?
Deck posts are typically 6–8 feet apart for standard decking loads. Fence posts are 6–8 feet on center for wood privacy fences, and 8–10 feet for chain-link. Always check local building codes — high-wind zones and areas with heavy snow loads may require closer post spacing or larger post sizes.
How much waste factor should I use for roofing materials?
Use 10% waste for simple gable roofs with few penetrations, 15% for hip roofs or roofs with dormers and valleys, and 20% for complex roofs with many angles or skylights. Waste accounts for cutting around chimneys, pipe boots, and valleys where shingles must be trimmed to fit.