Quick answer: floor area ÷ box coverage
A 6.0 × 5.0 m room is 30 m². A box with 6 planks of 1500 × 180 mm covers 1.62 m², so 30 ÷ 1.62 = 18.5, which rounds up to 19 boxes. Add 10% for cuts and it is 21 boxes. Retailer calculators (Bunnings, for example) work out the area and boxes and leave the allowance for cuts to you.
What the plan adds
The laying plan for the same room, with a 10 mm expansion gap and planks laid lengthways, uses 113 planks in 28 rows. 113 ÷ 6 rounds up to 19 boxes, with 1 plank left over. Here the area count happens to match the plan, and a 10% allowance would add 2 boxes the plan does not use.
Read the coverage on the box
| Plank | Per box | Coverage |
|---|---|---|
| 1500 × 180 × 6.5 mm hybrid | 6 planks | 1.62 m² |
| 1535 × 228 × 5 mm hybrid | 7 planks | 2.45 m² |
| 1235 × 225 × 5.5 mm hybrid | 8 planks | 2.223 m² |
Examples from Australian spec sheets and retailer listings, checked October 2026. Box sizes change between ranges, so read the coverage on your own box.
Never work out the coverage from the plank size alone: the number of planks in a box differs between ranges and thicknesses. Enter the number printed on the box.
Boxes for 15, 20 and 30 m² rooms
Each room below is a real plan from PlankBuddy with 1500 × 180 mm planks laid lengthways and a 10 mm expansion gap. The table compares three counts: by area alone, by area plus 10%, and from the planks in the plan.
| Room | Planks in the plan | Area only | Area + 10% | From the plan |
|---|---|---|---|---|
| 5.0 × 3.0 m (15 m²) | 57 | 10 | 11 | 10 (3 spare) |
| 5.0 × 4.0 m (20 m²) | 78 | 13 | 14 | 13 (0 spare) |
| 6.0 × 5.0 m (30 m²) | 113 | 19 | 21 | 19 (1 spare) |
In these rooms the area-only count is never short of the plan. In 3, the 10% allowance buys boxes the plan does not need. The plan's measured wastage in these rooms is between 2.4% and 5.9%. Your room and boards can fall differently, so check the count in your own plan.
Area count vs layout count
An area count assumes every scrap of every plank ends up on the floor. A laying plan knows where each cut falls: the end pieces in every row, the first and last rows cut to width, and which offcuts are long enough to start a later row. PlankBuddy reuses an offcut only when it meets your minimum end piece and stagger, and counts the rest as waste. The planks it uses, divided by the planks in a box and rounded up, are the boxes to buy.
How much spare to keep
- Buy all the boxes from the same batch, so the colour matches.
- A plank can be damaged or have a faulty joint. If the plan leaves no planks over, consider one more box.
- Keep a few planks for future repairs; a range can be discontinued.
- Add the allowance your manufacturer or supplier recommends for your room.
Questions about how many boxes to buy
How many boxes of hybrid flooring do I need for 20 m²?
With 1500 × 180 mm planks, 6 to a box (1.62 m²), a 5.0 × 4.0 m room needs 78 planks in our plan: 13 boxes. By area alone it is 13 boxes, and 14 with 10% added. Your room, planks and box size will differ, so plan your own room.
Should I add 10% to my flooring order?
Ten per cent is a common allowance for cuts, and awkward rooms may need more. A laying plan shows the planks your room really uses, so you can see whether 10% is too much or too little. Then add what your manufacturer or supplier recommends for damaged planks and spares.
Does PlankBuddy add an allowance to the box count?
No. Enter the planks per box printed on the box, and PlankBuddy rounds the planks in your plan up to whole boxes and shows how many planks are left over. Any extra is your decision.
Read how to work out flooring wastage from the plan, or how to avoid a narrow last row.