🪵 Flooring Calculator
Calculate how much flooring you need for a room, including waste, how many boxes to buy, and the total material cost.
Quick answer: Boxes = room area × (1 + waste %) ÷ coverage per box, rounded up. A 12 × 12 ft room is 144 sq ft; with 10% waste you need 158.4 sq ft, or 8 boxes of 20 sq ft – $560 at $3.50 per sq ft.
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Flooring Calculator inputs
Result
Boxes to buy
8 boxes
160 sq ft of flooring
| Room area | 144 sq ft |
| Area incl. 10% waste | 158.4 sq ft |
| Boxes | 7.92 → 8 |
| Material cost | $560.00 |
- Square feet
- 144
- Square meters
- 13.38
- Square yards
- 16
Boxes needed by waste allowance
| Waste | Area (sq ft) | Boxes | Cost |
|---|---|---|---|
| 0% | 144 | 8 | $560.00 |
| 5% | 151.2 | 8 | $560.00 |
| 10% | 158.4 | 8 | $560.00 |
| 15% | 165.6 | 9 | $630.00 |
| 20% | 172.8 | 9 | $630.00 |
How to calculate flooring
Measure the length and width of the room at its widest points, multiply to get the area, add a waste allowance for cuts and mistakes, then divide by the coverage printed on each box.
Boxes = ⌈length × width × (1 + waste ÷ 100) ÷ box coverage⌉
Worked example
A 12 × 12 ft room is 144 sq ft. Adding 10% waste gives 158.4 sq ft. With boxes covering 20 sq ft, you need 158.4 ÷ 20 = 7.92 – round up to 8 boxes (160 sq ft). At $3.50 per sq ft the flooring costs $560.
Recommended waste allowance
| Installation | Waste to add |
|---|---|
| Straight lay, simple rectangular room | 5–10% |
| Rooms with closets, alcoves or many doorways | 10–15% |
| Diagonal layout | 15% |
| Herringbone or chevron | 15–20% |
| Large-format tile | 10–15% |
Tips before you buy
- Check that all boxes share the same batch or dye-lot number so colour and texture match.
- Let laminate and hardwood acclimatise in the room for 48 hours before installing.
- Budget separately for underlayment, transition strips, trim and adhesive – they are not included here.
- Keep one spare box for repairs; matching the product years later can be impossible.
- Working in metric? Switch the units to meters and enter coverage and price per m².
Measuring the room
Measure each wall at floor level with a tape measure, rounding up to the next inch or centimeter. If the room is not square, take the longest length and widest width. For L-shaped rooms, split the floor into two rectangles and add their areas before applying the waste allowance.
Frequently asked questions
How much extra flooring should I buy?
Add about 10% for a standard straight installation, 15% for diagonal layouts or rooms with many corners, and up to 20% for herringbone patterns. Extra boards also cover future repairs.
How do I measure an irregular room?
Split it into rectangles, measure each one and add the areas together. Run the calculator for each section or use the square footage calculator for L-shaped rooms.
Why is the cost based on whole boxes?
Flooring is sold by the box, so you pay for the full box even if you only use part of it. The cost shown is boxes × coverage per box × price.
Should I include closets and doorways?
Yes – measure into closets and to the middle of doorways where the floor continues. It is better to have a little extra than to run short with a discontinued batch.