Flooring calculator
Convert room measurements into the number of flooring boxes to buy, including a waste allowance and the total material cost.
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Area
208 sq ft
Area
132 sq ft
Measured area
340 sq ft
With 10% waste
374 sq ft
In square metres
34.75 m²
In square yards
41.56 sq yd
Boxes to buy
19
20 sq ft each
Estimated cost
$0.00
enter a price to see this
| Area | Shape | Dimensions | Sq ft |
|---|---|---|---|
| Lounge | Rectangle | 16' 0" × 13' 0" | 208 |
| Bedroom | Rectangle | 12' 0" × 11' 0" | 132 |
Formula and working
Area of each shape
Rectangle: length × width · Rectangle: length × width Lounge: 16.00 × 13.00 ft = 208.00 sq ft Bedroom: 12.00 × 11.00 ft = 132.00 sq ft = 340 sq ft total
Boxes required
boxes = area × (1 + waste) ÷ coverage per box, rounded up = 340.00 × 1.10 ÷ 20 = 18.70 boxes = 19 boxes
Metric conversion
1 sq ft = 0.09290304 m² exactly (1 ft = 0.3048 m) 340.00 × 0.09290304 = 31.587 m²
Feet-and-inches entries such as 12′ 6″ are read exactly, and the conversion to metres uses the international foot of 0.3048 m, which is exact by definition.
Assumptions
- Measure the longest and widest points of each space, and split awkward rooms into two rectangles rather than trying to describe them with one shape.
- Waste allowance covers off-cuts, breakages and mistakes. Ten per cent is the usual figure; go to fifteen for diagonal layouts, herringbone patterns or a room with many angles.
- Quantities are always rounded up to whole units — cans, boxes and bags are not sold in fractions.
- Square footage is a plan area. It does not account for skirting, thresholds, or the direction a plank or tile will run.
- Nothing is uploaded. Saving is off by default and writes only to this browser, with a delete button next to the switch.
Rooms in, boxes out
Flooring is sold by the carton, and every product covers a different area per carton. The calculation is therefore always the same three steps:
area = Σ (length × width) for every room
area to buy = area × (1 + waste)
boxes = area to buy ÷ coverage per box, rounded upA 300 square foot job at 10% waste needs 330 square feet. At 20.1 sq ft per carton — a very common laminate figure — that is 17 boxes, covering 341.7 sq ft. The rounding up is not optional; you cannot buy two-thirds of a carton.
Coverage per box varies enormously
| Product | Typical sq ft / box | Typical m² / box |
|---|---|---|
| Laminate | 18–24 | 1.7–2.2 |
| Luxury vinyl plank (LVP) | 24–36 | 2.2–3.3 |
| Engineered hardwood | 20–30 | 1.9–2.8 |
| Solid hardwood | 18–24 | 1.7–2.2 |
| Floor tile (12 × 12 in) | 15–16 | 1.4–1.5 |
Always read the end label rather than assuming. Most cartons print the coverage in both square feet and square metres, and it changes between ranges from the same manufacturer.
How much waste
- 7–10% — a simple rectangular room, planks running the long way.
- 10–15% — several rooms, doorways, a hallway, or an irregular plan.
- 15–20% — diagonal or herringbone layouts, which produce a lot of angled off-cuts.
- + 1 box — worth keeping sealed for future repairs, because ranges are discontinued constantly.
Long narrow rooms waste more than square ones for the same area, because there are more end cuts per row and fewer opportunities to start a row with a previous off-cut.
Measure to the wall, then add the expansion gap
Floating floors — laminate and most LVP — need an expansion gap of 8–12 mm (about 3/8 in) around the entire perimeter, hidden under skirting or beading. Measure wall face to wall face and let the waste allowance absorb the gap; do not try to subtract it, because the material still has to be bought and cut.
Include doorways and thresholds in the measurement if the flooring will run through them, and remember that flooring continues under the skirting or beading, so the visible floor is slightly smaller than the quantity you buy.
Which direction should the planks run?
Convention is to run planks parallel to the longest wall, or towards the main light source, because it makes the room look longer and the seams less visible. On a suspended timber subfloor, planks should run perpendicular to the joists for stability, which sometimes overrides the aesthetic choice. Neither affects the quantity much — but a diagonal layout does, by roughly five extra percentage points of waste.
What else to order
- Underlay — usually sold in rolls of 100–200 sq ft. Some laminates have it pre-attached; check before you buy twice.
- Moisture barrier — required over concrete slabs and in basements, sometimes integrated into the underlay.
- Transition strips — one per doorway, plus any change of material.
- Beading or new skirting — measured by the perimeter in linear feet or metres, not by area.
Add a separate row per room and read the per-room square footage in the table if you want to order underlay room by room.
Acclimatisation, before you cut anything
Wood and laminate move with humidity. Most manufacturers require the boxes to sit flat in the room where they will be installed for 48–72 hours before installation, and will refuse a warranty claim if they were not. Order early enough for that to happen.
Batch numbers
Like tile, flooring is produced in batches and shade varies between them. Buy the whole job including waste in one order, and check the batch code is identical across every carton before you start — it is far easier to swap a box at the merchant than to rip up a finished row.
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No server, no account, no analytics. The measurements, the box count and the CSV, Excel and PDF exports are all produced by JavaScript in your browser, so the page works in an empty house with no signal and your room list never leaves the device unless you export it yourself.
Questions
How many boxes of flooring do I need?
Divide the room area plus waste by the coverage printed on the carton, then round up. A 300 square foot room at 10% waste needs 330 square feet, which is 17 boxes at 20 square feet each.
Why is coverage per box different for every product?
Because plank size and pieces per pack vary by range. Always read the carton rather than assuming — it is usually printed in both square feet and square metres on the end label.
How much waste should I allow for planks?
Ten per cent for a simple rectangular room laid straight, fifteen for diagonal layouts, long narrow rooms, or anywhere with lots of doorways and cuts. Keep a few spare planks after the job for repairs.
Do I measure under the skirting?
Measure the full floor to the wall face and add the expansion gap on top of your waste allowance. Flooring runs under the skirting or behind beading, so the visible floor is slightly smaller than what you buy.