Volume = 3 × 3 × 0.1 = 0.9 cubic metres. With the standard 1:2:3 cement/sand/aggregate mix, that requires roughly 7-8 bags of 50kg Portland cement. The Concrete Calculator does this instantly for any dimensions and lets you add a waste buffer.

Always. For a straight lay, add 10%. For a diagonal or herringbone lay, add 15%. Our Tile Calculator adds the recommended buffer automatically — you can adjust it from 5% to 20% depending on cut complexity.

For weed suppression: 7-10 cm deep. For moisture retention only: 5 cm is enough. The Mulch Calculator lets you specify the desired depth so your estimate matches your goal.

Measure total wall area (perimeter × height) and subtract doors and windows. Standard paint covers 10-12 sq metres per litre per coat. The Paint Calculator handles all of this and shows total litres for your chosen number of coats.

Building codes in most countries target 150-175 mm rise and 250-300 mm run, with rise + run close to 450 mm. The Stair Calculator checks your inputs against standard comfort ranges and warns you if they fall outside.