Interior & Decorating Calculators

Free UK calculators for paint, wallpaper, wall & floor tiles, plasterboard, coving & cable sizing. Factors in coverage, pattern repeats & cutting waste.

Interiors
Paint Calculator
Walls, ceiling and woodwork. 8 paint types, interactive wall selector, tin optimiser, mist-coat guide and woodwork trim.
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Interiors
Wallpaper Calculator
Roll count accounting for pattern-match type and repeat length.
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Interiors
Wall & Floor Tile Calculator
Tile count for any room, factoring in grout joints and cutting waste.
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Interiors
Plaster & Board Calculator
Plasterboard sheets and skim-plaster bags for walls and ceilings.
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Interiors
Coving Calculator
Exact coving lengths (2m or 3m), adhesive bags or tubs, joints and cutting wastage.
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Interiors
Electrical Cable Size Calculator
Minimum cable cross-section for safe power delivery over any run length.
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How these calculators work

Interior jobs are decided by coverage rates and waste, not floor area. The paint calculator works per coat by paint type and includes mist-coat guidance for new plaster; wallpaper accounts for pattern repeat and match type; and tiling factors in grout joints and cutting waste rather than assuming perfect coverage. The electrical cable sizing tool follows BS 7671 to give the minimum safe cross-section for a given load and run length.