Calculate how many sheets of plywood or OSB you need to cover a floor, wall or roof area, including a waste allowance.
We divide the total area (plus waste) by the area of a single sheet and round up to the next whole sheet, because you cannot buy part of a sheet.
In the UK and US the standard sheet is 8 × 4 ft (2440 × 1220 mm), giving about 2.98 m² (32 sq ft) per sheet.
For a simple rectangular floor 10% is usually enough. For roofs, walls with openings or complex shapes, allow 15%.
Yes. It works for any sheet material — plywood, OSB, chipboard flooring or sheathing — as long as you use the correct sheet size.
Standard sheets are 2440 × 1220 mm (8 × 4 ft). The calculator divides your area by the sheet size and adds waste.
About 10% for most layouts; more if the area is irregular or has many openings to cut around.
Calculate how much concrete you need for slabs, footings, columns and walls in cubic yards or metres.
OpenWork out the cement, sand and aggregate (ballast) quantities for a concrete mix by volume and ratio.
OpenCalculate the concrete volume and number of bags needed for strip, pad and pier footings.
Open