Free DIY & Home Improvement Calculators
Work out exactly how much material you need — before you spend a penny. No sign-up, no ads in your face, just answers.
Paint Calculator
How many litres or gallons of paint for your walls and ceilings, accounting for doors, windows, and coats.
Concrete Calculator
Volume of concrete for slabs, footings, and post holes — in cubic metres, cubic yards, or bags of ready-mix.
Flooring Calculator
Boards, planks, or packs of laminate, hardwood, or vinyl you need, including sensible wastage allowance.
Mulch & Gravel Calculator
Bags or bulk volume of mulch, gravel, or topsoil to cover your beds, paths, and driveways at the right depth.
Why measure before you buy?
The two most common DIY mistakes are buying too little material (a second trip to the store, and a batch of paint or concrete that doesn't quite match) and buying far too much (money wasted on materials that sit in the garage for years). Five minutes with the right calculator solves both.
Every calculator on this site shows its working. We tell you the formula, the assumptions we've made, and where you should round up. If you know your room is awkward — sloped ceilings, curved beds, odd angles — the guides under each calculator explain how to handle it.
How our calculators work
Each tool uses the standard trade formulas that professionals use for estimating, with a built-in wastage allowance where that's normal practice (flooring, for example, is always bought with 5–10% extra for cuts and mistakes). Results are estimates: material coverage varies between brands and surfaces, so always check the manufacturer's stated coverage on the product you actually buy.