Measure net floor area
Split irregular rooms into rectangles, calculate each area and add them. Include alcoves and connected spaces that will receive the same finish.
Pack coverage
Divide required area by the stated coverage per pack, then round up to a whole pack. Use the exact pack coverage rather than estimating from board dimensions if the manufacturer supplies it.
Waste allowance
Straight-lay rectangular rooms generally need less waste than diagonal layouts, herringbone, many doorways or irregular rooms.
Underlay
Underlay is also area-based but roll widths, overlaps and offcuts affect ordering. Some flooring systems have integrated underlay.
Worked example
Product checks
BuildCalc supports the United Kingdom, United States, Canada, Australia, New Zealand, Ireland and South Africa. The geometry is universal, but terminology, units, pack sizes and common product dimensions differ. Use the dimensions printed on the product you intend to buy rather than assuming a regional default is exact.
Confirm acclimatisation, expansion gaps, subfloor preparation and compatibility with underfloor heating where relevant.
Use the related calculators
Use the calculator for your measurements, then return to this guide to check assumptions, allowances and ordering considerations.
Flooring packsUnderlay