Flooring Calculator
Work out exactly how many planks and boxes of laminate, vinyl or hardwood you need, with the right wastage allowance for your layout already built in. Add your own box and underlayment prices for a full cost estimate.
How this calculator works
The calculator divides your total floor area by the area of one plank, applies your layout's wastage allowance, and rounds up to whole planks and then whole boxes:
planks = ceil( area ÷ (plank length × plank width) × (1 + wastage%) )
Boxes are then worked out either from the coverage printed on the box, or from the plank count per box — whichever your supplier lists.
Worked example
A 12 ft × 11 ft room, planks 48 in × 7 in, laid in a straight run:
- Floor area: 12 × 11 = 132 sq ft.
- Each plank covers 48 × 7 in = 336 sq in ≈ 2.33 sq ft.
- 132 ÷ 2.33 ≈ 56.7 → 57 whole planks to cover the floor.
- Add 10% for a straight layout: 57 × 1.10 ≈ 62.7 → buy 63 planks.
If boxes cover 20 sq ft each, that's 7 boxes (132 × 1.10 ÷ 20 ≈ 7.26, rounded up) — check both figures against what's on the box, since suppliers sometimes round coverage differently.
Choosing the right wastage allowance
| Layout | Allowance | Why |
|---|---|---|
| Straight run | 10% | Cuts only at the room's perimeter |
| Diagonal (45°) | 15% | Every perimeter plank is an angled cut |
| Herringbone / chevron | 20% | Angled cuts throughout, offcuts rarely reuse |
Small rooms, rooms with lots of closets or alcoves, and rooms with many doorways all push toward the higher end of each range, since the cut perimeter is large relative to the floor area.
Underlayment — do you need it?
Most floating laminate and click-lock vinyl floors need a separate underlayment layer for cushioning, sound dampening and a moisture barrier — unless the planks already have underlayment pre-attached to the back, which some vinyl products do. Solid hardwood nailed directly to a subfloor typically skips this layer entirely. Check your specific product's installation guide before assuming either way.
Frequently asked questions
How much extra flooring should I buy?
About 10% extra for a straight layout, 15% for diagonal, and 20% for herringbone or chevron patterns. The extra covers perimeter cuts, occasional damaged planks, and spares for future repairs from the same batch.
Does plank direction change how much flooring I need?
Running planks lengthwise versus across a room doesn't change the total area covered, but it does shift how many full-length planks get used without cutting. Diagonal and herringbone layouts increase waste substantially since almost every perimeter plank needs an angled cut.
Do I need underlayment under laminate or vinyl flooring?
Most laminate and click-lock vinyl needs a separate underlayment layer, unless the product has it pre-attached to the back of each plank. Solid hardwood nailed to a subfloor usually skips this layer. Check your specific product's instructions.
Can I mix flooring boxes from different batches?
It's best to avoid it — color and texture can vary slightly between production runs, or lot numbers, even for the same product line. Buying enough from one batch up front, including the wastage allowance, avoids a visible mismatch later.