Flooring calculator — how many packs of laminate?
Enter the room dimensions and the pack coverage from the label. You get the area with allowance, the number of packs to buy, and the thing most calculators leave out: how many square metres you actually end up buying, since packs cannot be split.
The formula
area × (1 + allowance) ÷ pack coverage = packs (rounded up)
Worked example for a 4 × 5 m room, 2.22 m² packs, 5% allowance:
- Area: 4 × 5 = 20 m²
- With allowance: 20 × 1.05 = 21 m²
- Packs: 21 ÷ 2.22 = 9.5 → 10 packs
- Actual purchase: 10 × 2.22 = 22.2 m²
Allowance by laying pattern
| Pattern | Allowance | Notes |
|---|---|---|
| Straight, along the longer wall | 5% | Least waste |
| Straight, room with recesses | 10% | More cuts |
| Diagonal (45°) | 10–15% | Every row ends in an angled cut |
| Herringbone / chevron | 15% | Most waste, needs experience |
| Loft with roof slopes | 10–15% | Irregular edges |
What the calculator will not count, but you still have to buy
- Underlay — in square metres, same as the floor.
- Vapour barrier — over a concrete subfloor, with overlaps.
- Skirting boards — in running metres of the room perimeter, less the door width, plus an allowance for cutting corners.
- Corners, connectors and a threshold strip — where the floor meets another room or another floor covering.
- A 10 mm expansion gap at every wall — not optional, it is a warranty condition for most manufacturers.
Not sure of the exact area? Decoria.Studio scans the room with your phone, works out the floor area itself, then builds a shopping list with quantities and prices — flooring and skirting included.
Questions and answers
How many packs of flooring for a 20 m² room?
With a 5% allowance and a typical 2.22 m² pack, 10 packs, which is 22.2 m² of material. It always comes out higher than the room area itself, because packs cannot be bought by the plank.
How much extra should I allow for flooring?
5% is enough for straight laying. For diagonal or herringbone laying allow 10–15%, because every row ends in an angled cut. A room with recesses or roof slopes also needs 10%.
Do I need an expansion gap?
Yes, about 10 mm at every wall and around every fixed element such as a pipe or door frame. Laminate and vinyl move with the humidity of the air — without the gap the floor buckles. The gap is hidden by the skirting board.
What else do I need besides the flooring itself?
Underlay in square metres, a vapour barrier over a concrete subfloor, skirting boards in running metres of the room perimeter, plus corners and connectors. Underfloor heating needs an underlay with low thermal resistance.
Can I mix planks from different packs?
Not only can you, you should. Open several packs at once and alternate the planks — a single pack is often uniform, and mixing gives a natural, non-repeating pattern.