Why use this calculator
Flooring is ordered by the box and made in production runs, and both facts punish a wrong estimate. Run short and the next batch can differ slightly in colour, gloss or even board width, and a discontinued range may be gone entirely. Order far too much and you pay for boxes that sit in the garage.
The floor area alone is never enough: every wall, doorway and corner needs a cut, and the offcut is often too short to start the next row. Diagonal and herringbone patterns cut a piece at every wall, and grain or tile-look matching throws away boards that do not suit their neighbours.
This calculator applies waste by pattern and room shape, rounds up to whole boxes, and shows the cost and the spare you will be left with.
How to use it
- Choose metric or imperial to match your tape measure and the box label.
- Enter the room length and the room width, measuring wall to wall at the longest and widest points and including any doorway recess the flooring runs into.
- Select the laying pattern: straight along the room, diagonal at 45 degrees, or herringbone and chevron.
- Choose simple rectangle or the complex option for L-shapes, bay windows and rooms with many doorways.
- Add any extra allowance for pattern matching or spare boards.
- Copy the area per box from the end label on the carton, and enter the price per square metre or square foot to see the cost.
What each result means
- Boxes to buy
- The number of whole boxes or cartons to order, after waste, rounded up because boxes are not sold part-full.
- Real cost per m² of floor
- The flooring bill divided by the floor you actually cover, so waste and part boxes are counted. It is always higher than the price per square metre on the ticket.
- Real cost per sq ft of floor
- The flooring bill divided by the floor you actually cover, so waste and part cartons are counted. It is always higher than the price per square foot on the ticket.
- Flooring to order
- The floor area plus the waste allowance. This is the area of material the installer needs on site.
- Room floor area
- Length times width, the area the finished floor covers before any offcuts or damaged boards are allowed for.
- Waste allowance
- Material lost to cuts, pattern matching and defects, shown as an area and as the total percentage applied.
- Area supplied by the boxes
- What the rounded number of boxes actually contains, which is always a little more than the amount ordered.
- Spare after laying
- Supplied area minus floor area: offcuts plus any unopened boxes. Keep a few boards for future repairs.
- Room perimeter for trims
- The distance around the room for skirting, scotia or expansion trims. Take the doorway widths off before ordering.
- Estimated flooring cost
- The area supplied multiplied by the price per area. Underlay, trims, adhesive and labour are extra.
The formula
Floor area = length x width, in square metres or square feet
Waste percentage = the pattern allowance (10 per cent straight, 15 per cent diagonal, 20 per cent herringbone or chevron) + 5 per cent for a complex room shape + any extra allowance you enter
Flooring to order = floor area x (1 + waste percentage / 100)
Boxes = flooring to order divided by the area per box, rounded up to the next whole box
Area supplied = boxes x area per box
Spare = area supplied minus floor area
Cost = area supplied x price per square metre or square foot
Room perimeter = 2 x (length + width), in metres or feet
How this number is used in practice
Installers and manufacturers generally allow around 10 per cent waste for a straight lay in a plain room, 15 per cent for a diagonal lay and 15 to 20 per cent or more for herringbone and chevron, where every board meeting a wall needs an angled cut.
Short rooms with long boards waste more than big rooms, because each row's offcut is less likely to be long enough to start the next row. Tile-look and heavily grained products add a further allowance, since installers reject boards that repeat a pattern too closely or clash with their neighbours.
Buy every box for the job from the same batch or dye lot, and open several boxes at once while laying so small colour variations are spread across the floor. Timber and many laminates need to acclimatise in the room, unopened or opened as the maker directs, before laying.
Keep one or two spare boxes, or at least a handful of boards, after the job; ranges are discontinued often and a matching board for a water-damaged patch can be impossible to find a few years later.
Floating floors need an expansion gap at every wall, usually about 10 millimetres, hidden by the skirting or a scotia trim, which is why the perimeter is useful when ordering trims. Across doorways and long runs, most manufacturers call for expansion joints or transition strips, and the underlay is ordered by the floor area without the pattern waste.
Worked examples
A 5 m by 4 m bedroom laid straight, simple shape, 2.2 m² boxes at $45 per m²
20 m² of floor plus 10 per cent is 22.0 m², so buy 10 boxes supplying 22.0 m² for $990.00
The same room in herringbone with an L-shaped layout
Waste rises to 25 per cent, so 25.0 m² to order and 12 boxes supplying 26.4 m² for $1,188.00
A 16 by 13 ft US room laid diagonally with 5 per cent extra for grain matching, 20 sq ft cartons
208 sq ft of floor plus 20 per cent waste is 249.6 sq ft, so buy 13 cartons supplying 260.0 sq ft
When people use it
- Ordering laminate, hybrid or vinyl plank flooring for a bedroom or living area
- Comparing the material cost of a straight lay against herringbone before choosing a design
- Checking the quantity and cost allowed in a flooring installer's quote
- Working out skirting or scotia length from the room perimeter
- Budgeting a whole-house floor replacement room by room
Tips
- Take the area per box from the box label for the exact product, not a generic figure. It varies widely.
- Add 5 to 10 per cent extra for strong grain, knots or tile-look designs so the installer can reject clashing boards.
- Order all boxes from the same batch and mix boards from several boxes as you lay them.
- Keep at least one unopened box after the job for repairs. Ranges get discontinued within a few years.
- Measure into doorway recesses and under the kickboards if the flooring runs beneath them.
- Measure an L-shaped room as two rectangles and add the areas, then use the complex shape allowance.
What it assumes, and where it stops being accurate
- The room is treated as a rectangle of length times width. Measure an L-shaped room as two rectangles, or use the complex option.
- Waste is 10, 15 or 20 per cent by pattern, plus 5 per cent for a complex room, plus your extra allowance. Some products specify their own.
- The area per box is taken from the box label. Plank sizes differ, so always use your product's figure.
- Stairs, landings and nosings are not included; they are ordered by the step with matching nosing pieces.
- Cost covers flooring boxes only. Underlay, moisture barrier, trims, adhesive, removal of old flooring and labour are extra.
Terms used on this page
- Waste allowance
- Extra material ordered to cover cutting losses, pattern matching and damaged boards.
- Herringbone
- Short blocks laid at right angles in a zigzag, with square-cut ends meeting the side of the next block.
- Chevron
- A zigzag pattern like herringbone, but with ends cut at an angle so the boards meet in a clean point.
- Dye lot or batch
- One production run. Boards from different runs can differ slightly in colour and finish.
- Expansion gap
- A gap of about 10 mm left at walls so a floating floor can move with humidity.
Questions people ask
- How much waste should I allow for flooring?
- Around 10 per cent for a straight lay in a simple room, 15 per cent for a diagonal lay and 20 per cent for herringbone or chevron. Add about 5 per cent more for L-shaped rooms, bay windows or many doorways, and a further 5 to 10 per cent where grain or tile-look matching matters.
- Why does herringbone need so much more flooring?
- Every board that meets a wall in a herringbone or chevron floor must be cut at an angle, and the triangular offcuts are rarely usable elsewhere. The pattern also needs to be set out from a centre line, which means cuts on every side of the room rather than just two. Twenty per cent waste is a common allowance.
- Is diagonal laying worth the extra material?
- A 45 degree lay can make a narrow room look wider and disguise walls that are out of square, but it cuts a board at every wall and takes longer to install. Expect about 15 per cent waste against 10 per cent for a straight lay, and a higher labour charge from most installers.
- Should I order extra boxes for repairs?
- Yes, keep at least one unopened box or a few spare boards. Flooring ranges are discontinued regularly and later batches can differ in colour or finish, so a matching replacement for a damaged board can be impossible to find. Store the spare flat, in a dry room, with its label.
- Does the calculator work for tiles or carpet?
- The area and waste maths suits any product sold by area, but tiles are best worked out by tile size and grout joint, and carpet comes off a roll of fixed width where seams and pile direction decide the waste. Use the tile calculator for tiles and ask the carpet supplier to measure.
- Do I include the underlay in this figure?
- No. Underlay is laid edge to edge without pattern cuts, so order it by the room floor area plus a small allowance, not by the flooring figure with pattern waste. Many hybrid and vinyl planks have underlay attached, so check whether you need a separate layer at all.
Use this with
Flooring Calculator answers one part of the question. These pick up where it stops: Tile Calculator, Paint Calculator, Area Calculator and Renovation ROI Calculator.
Where these figures come from
This calculation is jurisdiction-neutral arithmetic. No country-specific rules are applied.
- Australian Timber Flooring Association. Installation practice, acclimatisation and expansion gaps for timber floors
- National Wood Flooring Association. US installation guidelines, including waste for patterned floors
- Standards Australia. AS 1884 and related flooring installation standards
Flooring Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.