What the Flooring Material Calculator does
This calculator tells you how many boxes of laminate, vinyl plank or engineered wood flooring to buy, and how many rolls of underlay, from your room sizes and the coverage printed on the pack. It adds a waste allowance that depends on how the planks are laid - straight, diagonal or herringbone - because the pattern, more than the room, decides how much ends up as offcuts.
Plank flooring is sold by the box, not by the square metre, so the answer is always a whole number of boxes. The calculator shows what you actually buy, what is left over, and how the box count changes between patterns.
How to use it
- Choose metres or feet, then add each room's length and width. Enter a cut-out for any area you will not floor, such as fitted units or a hearth.
- Pick the laying pattern. It sets a waste allowance of 10% for straight, 15% for diagonal and 20% for herringbone; change it if your fitter or the manufacturer recommends a different figure.
- Enter the coverage per box from the pack label, and optionally planks per box and price per box.
- Enter the underlay roll coverage (or 0 if the flooring has underlay attached), its overlap allowance and price.
- Read the boxes and rolls to buy, then download the shopping list.
Reading the results
Boxes is the order area (floor area plus waste) divided by the coverage per box, always rounded up. The leftover figure is what remains after allowing for waste - useful as spare planks for future repairs.
The pattern chart shows the same rooms laid three ways. Herringbone and diagonal layouts cut more planks at the walls, so they need noticeably more boxes.
Underlay is laid without the pattern waste, but it needs a small allowance for overlaps and trimming at the edges.
Worked example: laminate in a living room and bedroom
The living room is 5.2 x 3.9 m = 20.28 m². The bedroom is 3.6 x 3.1 m = 11.16 m², less a 0.6 m² fitted wardrobe, leaving 10.56 m². Together that is 30.84 m².
Laid straight with 10% waste the order area is 30.84 x 1.10 = 33.92 m². At 2.22 m² per box that is 15.28 boxes, so buy 16 boxes (35.52 m²). At 32 a box the flooring costs 512.
Underlay rolls cover 15 m². With 5% for overlaps the underlay area is 32.38 m², which is 2.16 rolls - so 3 rolls, at 18 each. Laid in herringbone at 20% waste, the same rooms would need 30.84 x 1.2 / 2.22 = 16.67, so 17 boxes.
Formulas and scoring rules
- Floor area
net = sum(length x width - cut-out) over all rooms- Order area
order = net x (1 + waste %)Default waste: straight 10%, diagonal 15%, herringbone 20% - trade conventions, not a standard.- Boxes
boxes = ceil(order / coverage per box)- Underlay rolls
rolls = ceil(net x (1 + underlay allowance) / coverage per roll)- Feet
1 ft = 0.3048 m; 1 sq ft = 0.092903 m²
How this differs from the Tile Calculator
The Tile Calculator counts individual tiles and grout for a surface. This calculator is for plank flooring sold by the box: it works from the coverage printed on the pack, returns whole boxes, adds underlay rolls, and applies a waste factor tied to the laying pattern. Use the Tile Calculator for ceramic or stone tiles and this one for laminate, vinyl plank and engineered wood.
Limitations: what the result does not prove
- Rooms are treated as rectangles. Split L-shaped or irregular rooms into rectangles and add each one.
- Waste depends on room shape, plank length and the fitter. Many small rooms, bay windows and staircases waste more than the defaults; a large open rectangle may waste less.
- Boxes from different production batches can differ slightly in colour. Buy everything at once, from the same batch, including the spare.
- It does not cover scotia, thresholds, skirting, moisture barriers or adhesive, and it does not check that the subfloor is suitable - follow the manufacturer's installation instructions.
Privacy: where your data goes
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Standards and sources
- NIST - Unit conversion (area)
- USDA Forest Products Laboratory - Wood Handbook (moisture and dimensional change)
Frequently asked questions
How many boxes of laminate flooring do I need?
Multiply the floor area by 1 plus your waste allowance, divide by the coverage on the box and round up. For 30 m² laid straight with 10% waste and 2.22 m² boxes: 30 x 1.1 / 2.22 = 14.9, so 15 boxes.
How much extra flooring should I buy for waste?
A common allowance is about 10% for a straight lay, 15% for a diagonal lay and 20% for herringbone or chevron. Add more for many small or irregular rooms. It is better to have a few planks spare for future repairs than to run short and find the batch no longer matches.
Why does herringbone need so much more flooring?
Every row meets the wall at an angle, so both ends of many planks are cut, and short offcuts are often too small to reuse. Herringbone planks are also shorter, which multiplies the number of cuts. That is why its default allowance is double a straight lay's.
How many rolls of underlay do I need?
Divide the floor area plus a small allowance for overlaps (about 5%) by the coverage of one roll and round up. Some vinyl and laminate planks have underlay attached; in that case set the roll coverage to 0, unless the maker also asks for a separate moisture barrier.
Is this the same as the Tile Calculator?
No. The Tile Calculator counts individual ceramic or stone tiles and grout. This calculator is for plank flooring sold by the box, adds underlay rolls and adjusts waste by laying pattern.
Should I measure in square metres or square feet?
Use whatever matches the box label. The calculator accepts either metres or feet; enter the coverage per box in the same unit as your room sizes.
Last reviewed by the A2Z.Tools team against the sources listed above.
