32+ free calculators · 4 trades
Order the right amount, the first time.
Free material calculators for roofing, concrete, fencing, and drywall — built from real trade formulas, not guesswork. Every tool comes with a full written guide explaining the math.
Roofing Shingles — Quick Estimate
LiveThis is a simplified preview. Open the full Roofing Shingles Calculator →
Why this site exists
Built by people who've stood on the roof, not just read about it.
Most online calculators stop at a single number. We built this site to show the work — every calculator is paired with a full guide explaining the formula, the trade rules of thumb, and the mistakes that most commonly throw off a real order.
Whether you're a contractor building a bid or a homeowner sanity-checking a quote, the goal is the same: order the right amount of material, the first time, without paying for a guess.
Pick a trade
Four categories, thirty-two tools.
Each category page lists every calculator and its matching guide in one place.
Roofing
Shingles, pitch, cost, nails, underlayment, drip edge, gutters, metal panels, and vents.
View calculators →Concrete
Slabs, driveways, footings, columns, mix ratios, rebar, gravel base, and stairs.
View calculators →Fencing
Materials, cost, post length, post concrete, chain link, vinyl panels, gates, and stain.
View calculators →Drywall
Sheets, cost, screws, mud and tape, corner bead, framing, fire rating, and texture.
View calculators →Learn the math
Featured guides
Every guide walks through the real formula, a worked example, and the mistakes that most commonly throw off an order.
How to Calculate Roofing Shingles: Squares, Bundles & Waste Factor
Convert a flat footprint into real roof area and order the right bundle count.
Read guide →How to Calculate Concrete for a Slab: Cubic Yards & Bag Count
Turn length, width, and thickness into cubic yards or a bag count.
Read guide →Why Your Fence Post Needs to Be Longer Than the Fence
The one-third burial rule, explained with a real worked example.
Read guide →How Many Sheets of Drywall Do I Need?
Total area, sheet length, and the waste factor that saves a mid-job supply run.
Read guide →How to Calculate Roof Pitch: Rise, Run & Rafter Length
The one number nearly every other roofing calculation depends on.
Read guide →Concrete Mix Ratio Guide: Turning 1:2:3 Into Real Quantities
What a mix ratio actually means, and how to convert it to real bags.
Read guide →Common questions
FAQ
Yes — every calculator on this site is free, with no account, email, or payment required. There's no limit on how many times you can use them.
Each calculator is built on standard industry formulas and includes an adjustable waste factor. They're accurate for planning and ordering purposes, but always confirm final quantities against your specific product's coverage spec and local building code before a large order.
No — just enter your measurements and the calculator does the math. The written guides are there if you want to understand exactly how the number was reached, or double-check it by hand.
Many contractors use these for quick material takeoffs when building a bid. For code-critical items (footing depth, fire-rated assemblies), always confirm against your local building department before finalizing a bid.