Laminate Flooring Calculator
Flooring boxes needed from room size, waste allowance, and box coverage.
What it does
Flooring math fails at the store when cuts eat more planks than the room measures. A 15 by 12 ft room is 180 ft2 on paper, yet offcuts around walls and doorways push the buy to 198 ft2 once 10% waste joins. The tool above adds that margin before dividing into boxes.
The imperial default mirrors a standard bedroom: 15 ft by 12 ft, 10% waste, 20 ft2 per box. Area is 180 ft2, the buy is 198 ft2, and 198 / 20 rounds up to 10 boxes. Metric mode tells the same story in meters with 1.86 m2 boxes and lands on 10 as well.
Waste percent follows the layout, not the brand. Straight runs parallel to the longest wall waste near 10%, diagonal patterns climb near 15%, and rooms chopped by halls and closets behave like diagonal ones. Manufacturer guides repeat the 10 and 15 pair across product lines.
Boxes always round up, never down. A result of 9.45 boxes still means buying 10, because the missing half box has to come from somewhere. Hold one full box back after the job for later fixes, since dye lots drift between print runs.
How to use
- Pick imperial (ft) or metric (m).
- Type room length and width in one rectangle.
- Set waste: 10 for straight runs, 15 for diagonal.
- Type one box coverage from its label.
- Buy the rounded up box count, and stash one spare.
Formula
- area
- Room footprint in ft2 or m2.
- waste (%)
- Cutting margin: 10 straight, 15 diagonal.
- box
- Coverage per box from the label.
Rectangles only; L shaped rooms need splitting into two rectangles first. Underlayment, trim, and thresholds sit outside this count.
Worked example
Example: 15 by 12 ft at 10%
Imperial defaults: 15 ft, 12 ft, waste 10, box 20 ft2.
- Area: 15 x 12 = 180 ft2.
- Waste: 180 x 1.10 = 198 ft2 to buy.
- Boxes: 198 / 20 = 9.9, round up to 10.
- Spare advice: fitted 9.45 boxes worth, bought 10.
- Tool shows 180 ft2, 198 ft2, 10 boxes.
Reference table
| Waste | To buy | Boxes |
|---|---|---|
| 0% | 180 ft2 | 9 boxes |
| 5% | 189 ft2 | 10 boxes |
| 10% | 198 ft2 | 10 boxes |
| 15% | 207 ft2 | 11 boxes |
Limits
- One rectangle per run; split L shapes first.
- No deduction for small closets or islands.
- Pattern repeats and plank length limits ignored.
- Box labels vary; confirm coverage before ordering.
Common mistakes
- Buying exact area with zero waste.
- Rounding boxes down instead of up.
- Using 10% waste for a diagonal layout.
- Measuring in mixed units across one room.
- Skipping the spare box, then missing the dye lot later.
Try it yourself
Quick checks. Answers sit tucked under each question.
10 by 10 ft, 10% waste, 20 ft2 boxes?
100 ft2, buy 110 ft2, 110 / 20 = 5.5 so 6 boxes.
5 by 4 m, 5% waste, 2 m2 boxes?
20 m2, buy 21 m2, 21 / 2 = 10.5 so 11 boxes.
12 by 10 ft, 10% waste, 15 ft2 boxes?
120 ft2, buy 132 ft2, 132 / 15 = 8.8 so 9 boxes.
Questions
How much waste for laminate?
10% straight, about 15% diagonal or cut up rooms.
Why round boxes up?
Partial boxes cannot be bought, and cuts consume the margin.
Does underlayment count here?
No. It follows floor area separately by the roll.
What about doorways and closets?
Measure them as extra rectangles or raise waste a little.
Which direction wastes least?
Parallel to the longest wall, with staggered joints.
Should I keep spares?
Yes, one full box covers future plank swaps.