Free Construction Calculators

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Buying too little means a stalled project and a second delivery fee; buying too much means money sitting in bags in the garage. The expensive mistakes are always in the estimate, not the labor. Each calculator below converts your measurements into exactly what to order — including the waste allowance pros actually use.

Calculators by project

Start from what you are building — each project lists the calculators in the order you will need them.

Pouring a patio, slab or footing

The classic three-step estimate. First, calculate gravel for the compacted base layer under the slab (usually 4 inches of crushed stone). Then calculate concrete for the slab itself — it gives cubic yards for ready-mix orders and converts to 60 lb or 80 lb bags for DIY pours. Pouring a footing for a wall or deck posts? Same concrete calculator, different dimensions.

Building a driveway

Driveways are a gravel or asphalt base plus a surface. Estimate the gravel by volume, then convert to tons (about 1.4 tons per cubic yard) — suppliers sell by the ton, and the calculator does that conversion with a compaction allowance built in.

Tiling a floor, wall or backsplash

Calculate the tiles from your area and tile size, with a 10–15% waste allowance for cuts and breakage. Then calculate grout for the joints — it depends on tile size and joint width, which is why a separate calculator exists instead of a guess.

Painting or wallpapering a room

Estimate paint from wall area minus doors and windows, at real coverage rates per gallon, for one or two coats. Prefer wallpaper? The wallpaper calculator works out rolls from wall dimensions and accounts for pattern repeat waste.

Building raised garden beds

Calculate topsoil for the fill (length × width × depth, converted to cubic yards or bags), then calculate mulch for the 3-inch top layer that keeps weeds down and moisture in.

Starting or overseeding a lawn

Calculate grass seed from your lawn area and the seeding rate for new lawns vs. overseeding. Fixing patchy soil first? Topsoil goes down before the seed.

How the estimates work

Every calculator on this page uses the same honest method: your measurements become a volume or area, the volume converts to the unit suppliers sell in (cubic yards, tons, gallons, bags, rolls), and a waste allowance is added — 5–10% for bulk materials like concrete and gravel, 10–15% for tile. The formulas are the industry-standard ones (for example, concrete volume in cubic yards = length × width × thickness in feet ÷ 27), and each calculator page shows its formula and the test cases it was verified against.

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Frequently asked questions

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