Flooring calculator — planks, boxes and carpet
A 6×4 m room at 10% waste needs 26.4 m² of flooring — 101 planks and 12 boxes of laminate. Enter your room below for planks, boxes, carpet roll length and underlayment rolls — free, no signup, metric or imperial.
Your quantities
How the flooring quantities are worked out
The room's net area is increased by your waste factor — 5% for a straight grid, 10% standard, more for diagonal or herringbone — and that gross area drives everything: planks are the gross area divided by one plank's area, rounded up; boxes are the gross area divided by the box coverage, rounded up.
Carpet is sold by the roll, so the calculator divides the gross area by the roll width to give the length to cut — 3.66 m rolls are the metric standard. Underlayment comes in 10 m² rolls, one per started 10 m² of gross area.
Running these jobs? Wood & Vinyl Flooring
How to use the flooring calculator
- Measure the room: length × width, in metres or feet.
- Pick the material — hardwood, laminate or vinyl planks, or carpet by the roll.
- Set the waste for your pattern: 5% straight, 10% standard, 15% diagonal, 20% irregular.
- Type the plank size and the box coverage printed on your box, then read planks, boxes and rolls.
How many boxes of laminate cover a 6×4 m room?
The room is 24 m² net. At the standard 10% waste the order is 26.4 m² gross — and that gross area drives everything that follows.
At 2.2 m² per box that is 12 boxes. In planks of 19 × 138 cm (0.2622 m² each) it is 101 planks, and the underlayment takes 3 rolls of 10 m².
Waste factors and coverages the calculator uses
Waste by laying pattern
| Pattern | Waste to add |
|---|---|
| Straight grid | 5% |
| Standard staggered | 10% |
| Diagonal or herringbone | 15% |
| Irregular, many cuts | 20% |
Typical box and roll coverage
| Material | Typical coverage |
|---|---|
| Solid hardwood box | About 1.86 m² (20 sq ft) |
| Laminate box | About 2.23 m² (24 sq ft) |
| Luxury vinyl (LVP) box | About 2.23 m² (24 sq ft) |
| Underlayment roll | 10 m² (metric) · 100 sq ft (imperial) |
Flooring mistakes that cost a second order
- Stagger the end joints of neighbouring rows by at least 150–200 mm. Rows that line up weaken click-lock joints and the floor starts to gap and sound hollow.
- Over a concrete slab, lay a 0.15 mm polythene moisture barrier under floating wood or laminate — skipping it voids most manufacturer warranties.
- Buy full boxes from one batch and round up. Loose planks are rarely stocked, and a later box can differ in shade and click profile.
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How much flooring waste should I add?+
5% for a straight grid in a square room, 10% for a standard staggered layout, 15% for diagonal or herringbone, and 20% for irregular rooms with many cuts. The waste is added to the area before planks and boxes are counted.
How many boxes of laminate cover 24 m²?+
With 10% waste the job needs 26.4 m² of flooring. At 2.2 m² per box that is 12 boxes — and 101 planks at a 19×138 cm plank size, counted by the calculator from the same numbers.
How is carpet quantity calculated?+
By length off the roll, not by the box. The gross area — net area plus waste — is divided by the roll width: a 20 m² room with 10% waste off a 3.66 m roll needs 6.01 metres of carpet.
What width are carpet rolls in metric?+
3.66 m is the standard metric roll — the 12 ft roll — and 4.57 m (15 ft) is the wide option. The calculator divides your gross area by the roll width you pick to give the length to cut.
How are flooring box counts worked out?+
Divide the gross area — net area plus your waste — by the coverage printed on one box, then round up to full boxes. Part-boxes are not sold, so the rounding is part of the answer, not a fudge.
What is the difference between net and gross area?+
Net area is the floor you can measure: length × width. Gross area is what you order — net plus the waste factor for cutoffs, angled walls and alcoves. Ordering the net area guarantees a shortage at the perimeter cuts.
How many underlayment rolls do I need?+
Underlayment comes in 10 m² rolls in metric and 100 sq ft rolls in imperial. Divide the gross area by the roll coverage and round up: the 24 m² room at 10% waste needs 3 rolls for its 26.4 m².
Why are plank joints staggered?+
Staggering spreads the end joints so no two rows break at the same line. Offsets of at least 150 mm keep click-lock joints strong and stop the repetitive pattern that makes a floor look cheap and feel weak.
Do I need a vapour barrier over a concrete slab?+
Yes, under floating wood or laminate floors: a 0.15 mm polythene barrier blocks ground moisture rising through the slab. Skipping it is the commonest cause of swollen, cupped laminate — and it voids most warranties.
How do I measure an L-shaped room?+
Split it into rectangles, work out each rectangle’s area and add them together. Then enter one rectangle with the same total area — 6 × 4 m for 24 m², for example — and let the waste factor cover the extra cuts.
Can I use this calculator for carpet tiles?+
Yes — use the plank path: enter the carpet tile’s size as the plank size and the coverage printed on its box. The maths is the same area-plus-waste sum, and the box count is the number that matters.
What does this calculator not include?+
No prices and no labour — quantities only. Skirting, door thresholds and transition strips are not counted, so measure and add those separately. The quantities do not carry into InstaJack automatically yet.