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Home & Construction Calculators

9 free calculators for home improvement and building projects. Work out exactly how much material to buy before you get to the store — every one runs in your browser, with no sign-up.

Square Footage Calculator

Measure any room, wall, deck, or lot. Square feet, square yards, square meters, and acres, with waste factor and material cost.

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Paint Calculator

How many gallons for a room. Deducts doors and windows, handles multiple coats and the ceiling, and estimates primer separately.

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Concrete Calculator

Cubic yards and bag counts for slabs, footings, and round columns. Tells you when ready-mix beats mixing bags by hand.

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Flooring Calculator

Boxes needed with waste factor, leftover square footage, and total cost. Costs what you actually buy, not just what you need.

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Tile Calculator

Tile count, boxes, and grout for any tile size. Includes joint width, tile thickness, and sanded versus unsanded guidance.

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Mulch Calculator

Cubic yards and bag counts for mulch, topsoil, or compost by depth — with a bags versus bulk cost comparison.

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Gravel Calculator

Tons and cubic yards for crushed stone, pea gravel, river rock, sand, or decomposed granite. Density varies by material.

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Roofing Calculator

Roofing squares, shingle bundles, and underlayment from footprint and pitch. The pitch multiplier most estimates skip.

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Drywall Calculator

Sheets in 4×8, 4×10, or 4×12, plus joint compound, tape, and screws. Deducts openings and handles ceilings.

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About these calculators

This category covers material quantity estimation — the question every home improvement project starts with, which is how much of something to buy. The maths is deterministic geometry: area, volume, and division by a unit size. There is no judgement involved, only measurement, which is why these numbers are reliable in a way that cost estimates never are.

The Square Footage Calculator is the hub, handling rectangles, circles, and triangles with a feet-or-meters toggle. Paint works from room perimeter and deducts doors and windows at standard US allowances. Concrete covers slabs, footings, and round columns, converting to both cubic yards for ready-mix and bag counts for hand mixing. Flooring and Tile both round to whole boxes and show your leftover, since that spare material is your only perfect-match repair stock later. Mulch and Gravel handle loose material by depth, with gravel accounting for the density differences between stone types that change a ton order. Roofing applies the pitch multiplier that turns a house footprint into actual roof area. Drywall covers sheets plus the consumables — compound, tape, and screws — that estimates routinely forget.

Every calculator includes a waste or compaction allowance where the material genuinely needs one, and none where it does not. Mulch is spread rather than cut, so it gets no waste factor; tile cut on a diagonal gets fifteen percent.

A note on estimates

These calculators give material quantities, not project costs. Where a price field is included it multiplies your own figure by the quantity — it does not look up market rates, which vary too much by region and season to be useful. Labour, delivery, disposal, permits, and the consumables that surround every job are outside what any calculator can tell you.

Structural dimensions — slab thickness, footing depth, drywall fire rating, roof underlayment — are governed by your local building code, which varies widely across the US and takes precedence over any general guidance here.