Flooring Calculator
Last updated: 12 August 2026
Work out how many packs of flooring you need for a room, plus the underlay, beading and threshold strips that are easy to forget until you are halfway through the job.
How the calculation works
Packs = (room area + wastage) ÷ pack coverage, always rounded up. Wastage covers the cut ends of each row, which cannot always be reused at the start of the next, plus damaged boards and the offcuts around door frames and radiator pipes.
Underlay is sold by the roll in square metres, so we divide the same area figure by your roll size. Beading or scotia covers the expansion gap at the perimeter, so allow the full room perimeter minus doorways.
Wastage by laying pattern
| Pattern | Wastage | Why |
|---|---|---|
| Straight, square room | 10% | Standard row-end offcuts |
| Diagonal / irregular room | 15% | Angled cuts cannot be reused |
| Herringbone / chevron | 20% | Every perimeter piece is cut |
The bits people forget
Expansion gap of 10–12mm around every edge, including against door frames and pipes — laminate expands and buckles without it. Then: threshold or T-bar strips for every doorway, scotia beading or refitted skirting for the perimeter gap, a damp-proof membrane over concrete subfloors, and pipe rose covers for radiator pipes.
Frequently asked questions
How many packs of laminate flooring do I need?
Divide the room area by the pack coverage and add 10% for wastage. A 4.5m x 3.2m room is 14.4 square metres; at 2.22 square metres per pack with 10% wastage, that is 8 packs.
How much wastage should I allow for flooring?
10% for a straight lay in a square room, 15% for diagonal layouts or irregular rooms, and 20% for herringbone or chevron patterns where every perimeter piece is cut.
How big an expansion gap does laminate need?
10 to 12mm around every edge of the room, including against door frames, pipes and thresholds. Without it, the floor expands with humidity and lifts or buckles in the middle.
Do I need underlay for laminate flooring?
Yes, unless the boards have underlay pre-attached. Underlay evens out minor subfloor variations, cushions the click joints and reduces noise. Over concrete you also need a damp-proof membrane, either separate or built into the underlay.
How much underlay do I need?
The same area as the floor plus a small overlap allowance. Standard foam rolls cover 15 square metres, so a 14.4 square metre room needs one roll — but check the roll size, as premium fibreboard is often sold in 10 square metre packs.
Related calculators
Screed Calculator
Floor screed volume, sharp sand tonnage and cement bags.
Skirting Board Calculator
Lengths of skirting for a room, with mitre wastage.
Tile Calculator
Tiles, adhesive and grout for floors and walls, with wastage.
Estimates are for guidance only. Material dimensions, densities and coverage vary by supplier — always confirm quantities before ordering, and consult a qualified professional for structural work.