DIY maths, done for you

Free calculators for concrete, tiles, paint, bricks, decking, aggregate, fencing, turf, plasterboard, wallpaper, loft insulation and skips. Straight answers in metric UK units, with the working shown.

Concrete Calculator

Slabs, footings, trenches or post holes: cubic metres, 25kg bags, ready-mix to order, and ballast and cement to mix your own.

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Tile Calculator

Area or wall dimensions with openings taken off: tile count, boxes, adhesive and grout using the standard grout formula.

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Paint Calculator

Wall lengths and height, doors and windows deducted: litres needed and how many 1L, 2.5L or 5L tins to buy.

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Brick and Block Calculator

Wall length and height, single or double skin: brick or block count with wastage, plus the sand and cement for the mortar.

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Decking Calculator

Deck size and board dimensions: board count, joist count and lengths, and screws, laid out to scale.

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Aggregate Calculator

Gravel, sharp sand, topsoil or hardcore: area and depth to tonnes, bulk bags and 25kg bags.

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Fence Calculator

Run length and panel width: panels, posts, postcrete and gravel boards, gates accounted for.

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Turf Calculator

Up to three lawn areas to turf rolls needed, plus an optional topsoil top-up.

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Plasterboard Calculator

Wall and ceiling area to board count, screws, joint tape and jointing compound.

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Wallpaper Calculator

Room perimeter, height and pattern repeat to the number of standard rolls to buy.

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Loft Insulation Calculator

Loft area, existing and target depth: rolls needed for the top-up.

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Skip Size Calculator

Waste dimensions to cubic yards and the smallest standard skip that fits it.

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About DIYCalcs

Every tool on this site works from fixed geometry and clearly labelled standard conventions, UK brick sizes, joint widths, bulk densities, so the answer you get is a real answer, not a guess. Where a real-world figure genuinely varies, like bulk density or paint coverage, you can edit the default to match the product you're actually buying, and the article on each page explains the typical range.

No accounts, no data collection beyond standard analytics, and every calculation runs in your browser. If a tool you need is missing, or a result looks wrong, get in touch through the contact page.