Flooring Quantity Calculator
Planks and packs from room size and board format, with waste by laying pattern.
Quick answer
With the default inputs: Room length 5 · Room width 4 · Board length 1200 etc.Pieces needed 117 pcs
Edit the inputs below to recalculate.Inputs
Result
Pieces needed
117pcs
| Floor area | 20.00m² |
| Area per piece | 0.180m² |
| Waste allowance | 5% |
| Area with waste | 21.00m² |
| Packs to buy | 15packs |
| Pieces bought | 120pcs |
| Spare pieces | 3pcs |
| Pieces per m² | 5.56pcs/m² |
Waste by pattern: 3% straight, 5% staggered, 10% diagonal, 12-15% herringbone. Keep a spare pack from the same batch — later batches differ in shade and sometimes in size.
Reverse: known result, work out one input
Enter a target result; the other inputs stay fixed and this one is worked out.
Formula
| Area | A = length × width |
| Per piece | a = board length × width ÷ 10⁶ |
| Pieces | n = ceil(A × (1 + waste) ÷ a) |
| Packs | P = ceil(n ÷ pieces per pack) |
| Per m² | 1 ÷ a |
A 5 × 4 m room with 1200 × 150 mm boards, 8 per pack, staggered: 20 m² needs 117 pieces, so 15 packs (120 pieces) with 3 spare.
How to work it out
- Measure net length and width for the laying area; at doorways the flooring runs under the architrave, so add the reveal depth.
- Establish the area of one board and do a setting-out: divide room width by board width and check what is left for the last row.
- If the last row would be narrower than a third of a board, start the first row with a half board so the final strip is not a sliver.
- Add waste by pattern: 3-5% straight lay, 5-8% brick bond, 12-15% herringbone.
- Divide by boards per pack and round up. Skirting, trims and underlay are separate.
Where it goes wrong
- Ordering straight from an area division — where the width is not a whole multiple of board width the last row is ripped full length, nearly half a row wasted, which doubles the real allowance.
- Running boards along the long wall — flooring should run with the light, perpendicular to the window, otherwise joints read strongly in side light.
- Forgetting the expansion gap — 8-12 mm at every wall, covered by skirting. Without it the floor crowns in the humid season and has to come up.
- Using standard laminate over underfloor heating — it needs a rated board; standard products have neither the thermal resistance nor the dimensional stability and open at the joints within a season.
Material and cost
Laminate 80-200 CNY/m², SPC 60-120, engineered timber 200-400, solid timber 300-800. Labour 15-30 CNY/m², 40-60 for herringbone. Underlay and trims 3-6 CNY/m².
On site
- Even a single batch can shade slightly — open three or four packs and mix as you go rather than laying in zones.
- Check flatness with a 2 m straightedge; gaps over 3 mm need a self-levelling compound or the floor will sound hollow underfoot.
- Let packs acclimatise on site for 48 hours so moisture content matches the room, or the joints open up later.
Basis
- GB 50209-2010 Code for acceptance of building floor construction, Chapter 7 (timber surfacing)
- GB/T 20238-2018 Code for installation, acceptance and use of wood flooring
- GB/T 18102-2020 Laminate floor coverings
FAQ
Why not just divide the area?
Boards are laid whole and cut at the edges, and offcuts are usually unusable. Room dimensions are rarely exact multiples of the board width, so the last row may be cut nearly in half. Hence the waste allowance: 5% staggered, 10% diagonal. The more complex the pattern, the more waste — physics, not upselling.
Is waste the same as a spare pack?
No, keep both. Waste is material cut off and discarded, already inside the piece count; a spare pack is extra kept for future repairs. Shades vary noticeably between batches and matching a few years later is nearly impossible — one spare pack can save re-laying a whole room.
Which way should boards run?
Along the longer dimension and toward the main light source: the room reads longer and joint shadows are less visible. Stagger at least a third of the board length — shorter offsets look stepped and concentrate stress. Over underfloor heating leave an 8-10 mm expansion gap, hidden by the skirting.
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Flooring Quantity Calculator. 2026-10-25. https://jianzhujisuan.com/en/flooring
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.