Home, Utility and Project Calculators
Planning a room or a bill involves the same two questions: how much of something is needed, and what it will cost. Getting the quantity roughly right before buying avoids both a second trip and a cupboard full of leftover material.
Home & Utility Calculators (13)
Always Buy More Than the Calculation Says
Material estimates assume clean rectangles and no mistakes. Reality includes cuts around corners, breakages, pattern matching, and the odd botched piece. A margin of roughly ten percent is normal for tile and wallpaper, and more when the pattern needs aligning or the room has awkward angles. Running out mid-job often means a different dye lot, which is visible.
Coverage Figures Are Optimistic
Paint coverage printed on a tin assumes a smooth, primed, similarly coloured surface. Bare plaster, textured walls, and dark-to-light changes all drink more paint and often need an extra coat. Treat the stated coverage as a best case and plan for two coats unless you are repainting the same colour on a sound surface.
Energy Costs Need Your Actual Tariff
An appliance's running cost is its power draw multiplied by hours used multiplied by your unit rate. The first two are printed on the device; the third is on your bill and varies widely by region, supplier, and time of day. Standing charges apply regardless of usage, so a calculation using an average national rate can be some way off what you are actually billed.
Measure the Room, Not the Floor Plan
Plans and listings round their numbers, and buildings settle. For anything you are buying by area, measure the actual space at more than one point, because walls are rarely perfectly parallel. Subtract doors and large windows for paint and wallpaper, but not for flooring, where you want the full floor area plus the cutting margin.