Hardwood Flooring Calculator
Work out how many hardwood planks and boxes a room needs — with a cutting allowance for end cuts and damaged boards — and what the timber will cost at your price.
Hardwood is sold by the box but laid plank by plank, so you need both numbers: how many planks the floor takes, and how many boxes to order. This calculator gives you both, with a realistic cutting allowance.
It covers solid and engineered hardwood in any plank size. For a diagonal or herringbone layout, raise the wastage to 15%.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Measure the room wall to wall at the longest and widest points.
- Enter the plank size (length × width) and the coverage per box.
- Set wastage — 10% for straight runs, 15% for diagonal.
- Add a price per square foot if you want a cost estimate.
Worked example
| Room | 12 ft × 15 ft = 180 ft² |
|---|---|
| Plank | 48 in × 5 in = 1.667 ft² per plank |
| Raw planks | 180 ÷ 1.667 = 108 planks |
| Planks with 10% wastage | ⌈108 × 1.10⌉ = 119 planks |
| Boxes (20 ft² per box) | ⌈(180 × 1.10) ÷ 20⌉ = 10 boxes |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
How much wastage for hardwood flooring?
Allow 10% for straight plank runs. Use 15% for diagonal layouts, herringbone, or rooms with many doorways and corners. Wide planks waste more than narrow ones, because each end cut discards a bigger piece.
Do I need to acclimatise hardwood before laying it?
Yes. Solid hardwood should sit in the room, in its opened boxes, for at least 72 hours (a week is better) so it adjusts to the room's temperature and humidity. Skipping this is the most common cause of gaps and cupping.
What is the expansion gap?
Hardwood expands and contracts with humidity. Leave a 10–15 mm (about ½ in) gap around all walls, pipes and fixed objects, hidden by skirting boards or beading. This calculator measures wall to wall; the gap is inside that area.
Solid or engineered hardwood — does the calculation change?
No. The plank and box calculation is the same for solid and engineered boards. The difference is installation and moisture tolerance, not quantity.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.