Construction & DIY Calculators

Estimate exactly how much material to buy before you get to the store. Every tool shows the formula and adds a waste allowance.

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🧱 Concrete Calculator (visual)

Length (ft)

Width (ft)

Thickness (in)

Waste allowance (%)

Bag size

Volume—

Cubic yards—

Pre-mixed bags—

🎨 Paint Calculator

Wall length total (ft)

Wall height (ft)

Doors & windows

Coats

Coverage per gallon (ft²)

Paintable area—

Gallons needed—

🔲 Tile & Flooring Calculator

Room length (ft)

Room width (ft)

Tile size (in)

Waste (%)

Floor area—

Tiles needed—

🌱 Mulch & Soil Calculator

Bed length (ft)

Bed width (ft)

Depth (in)

Volume—

2 ft³ bags—

How the concrete calculator works

Concrete is sold by volume — cubic yards for ready-mix trucks and cubic feet for bagged mix. For a rectangular slab or footing, volume is simply length × width × thickness (with thickness converted from inches to feet). For a round column, we use π × radius² × height. We then divide by 27 to get cubic yards and by the bag's yield to estimate how many pre-mixed bags you'll need, adding a waste allowance for spillage and uneven ground.

Tip: always round up

Running short mid-pour means a cold joint and a weak spot. A 10% waste allowance is standard; bump it to 15% for uneven subgrade or hand-mixing.

More tools: Square Footage Calculator — measure any room, floor or plot and estimate material cost.