Flooring is sold in complete packs, so the purchased area is rarely identical to the room area. The Flooring calculator combines area, cutting allowance, pack coverage, underlay and skirting.
For a 23 m² room with 8% allowance, plan 24.84 m². If one pack covers 2.18 m², 24.84 ÷ 2.18 = 11.39, so 12 packs are required. That buys 26.16 m². The extra area is not a second allowance; it comes from rounding to full packs.
Adjust allowance to the layout
A simple rectangular room with straight installation usually creates fewer offcuts than a room with many recesses or a diagonal pattern. Board width and joint staggering also affect reuse of offcuts.
Underlay has its own roll or pack coverage and should be rounded separately. Skirting starts from room perimeter, with door widths deducted where no skirting is installed.
Check the direction of installation before fixing the allowance: it can change the pattern of cuts even though the room area remains the same.
For a tiled alternative use the Tile calculator. If the finished room will be painted, the Paint calculator estimates the separate wall finish.
Record the exact pack coverage, underlay coverage, skirting length and prices from the products you intend to buy. The result then becomes a practical shopping list rather than a generic m² estimate.