Construction & Home Calculators
Material-quantity estimators for home improvement and construction: paint, tiles and flooring, concrete, bricks, plaster, roofing, rebar, stairs and water tanks.
Wall Panelling Calculator
Wainscoting and box moulding layout: panel sizes, moulding length, marking guide and cut list.
Paint Calculator
Estimate how much paint you need for a room based on its dimensions, number of coats, and paint coverage.
Concrete Calculator
Estimate the volume of concrete needed for a slab, footing, square column or round column, with a wastage allowance and an optional cement bag estimate.
Tile & Flooring Calculator
Work out how many tiles or flooring planks (wood, laminate, vinyl), and optionally how many boxes, you need for a floor or wall, including a wastage allowance for cuts and breakage.
Roof Area Calculator
Find the sloping roof area from the building size, pitch and overhang, and estimate roofing sheets or shingle bundles.
Brick Wall Calculator
Estimate how many bricks, and how much mortar, a wall needs from its size, brick size, mortar joint, openings and wastage.
Concrete Mix Calculator
Turn a concrete volume and a mix ratio such as 1:2:4 into cement bags, sand and coarse aggregate quantities.
Plaster Calculator
Estimate the cement and sand needed to plaster a wall from the area, thickness and mix ratio, with wastage.
Rebar Weight Calculator
Work out the weight of reinforcing bars from the bar size, length and number of bars, for metric (mm) and imperial (#) bar sizes.
Stair Calculator
Split a total rise and run into steps and get the riser height, tread depth, stringer length and a comfort check.
Water Tank Capacity Calculator
Work out the capacity of a rectangular or cylindrical water tank in liters, US gallons and UK gallons, for a full tank or a chosen water depth.
About these calculators
Ten estimators help you buy the right amount of material before a building or home improvement job. Paint Calculator works out wall area from a room's length, width and height, subtracts the doors and windows you tell it about, multiplies by the number of coats and divides by the paint's coverage, giving liters or US gallons. If you leave the coverage blank it assumes 10 square meters per liter, or 400 square feet per gallon in US units. Concrete Calculator finds the volume of a slab, footing, square column or round column in metric or imperial units, adds a wastage percentage (10% by default) and can estimate cement bags for a 1:2:4 mix. Concrete Mix Calculator turns a volume and a ratio such as 1:2:4 into cement, sand and aggregate using a dry volume factor of 1.54. Tile & Flooring Calculator divides the room's area by the tile's area, in meters, centimeters, feet or inches, adds wastage, and rounds up to whole tiles, or to boxes if you give the tiles per box.
Roof Area Calculator multiplies the building footprint, with overhang, by the slope factor from your pitch, then estimates roofing sheets or shingle bundles. Brick Wall Calculator counts bricks from the wall size, brick size, mortar joint, openings and wastage, and gives the mortar volume. Plaster Calculator estimates cement and sand from an area, a thickness and a cement:sand ratio. Rebar Weight Calculator applies d² ÷ 162 kilograms per meter to metric and imperial bar sizes. Stair Calculator splits a total rise and run into equal steps with a stringer length and a comfort check. Water Tank Capacity Calculator gives liters and gallons for rectangular and upright cylindrical tanks. These are estimates for simple shapes. They do not account for patterned layouts, uneven surfaces, structural design or local building rules, so check supplier guidance and your plans before ordering. Each page includes the formula and a worked example, and the calculations run in your browser.
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