Flooring
Square footage is easy; running short mid-room is not. Get sealed-box counts with waste margin already inside.
Your buy list
0
boxes · covers 0 sq ft- Room area
- —
- With waste
- —
- Leftover after job
- —
Keep one full box unopened — that's your future repair stash.
Why the waste percentage exists
Every row ends in a cut, and the offcut rarely fits anywhere else — that's the waste. Straight runs in honest rectangles lose about 8–10%; diagonals and herringbones cut at angles on both ends and eat 15–20%. Buying exactly the naked area means the last row is where you discover the math was against you.
The leftover line tells you what the rounding bought you: most jobs end one partial box heavy, which is precisely the box you'll want in five years when a dishwasher dents three planks and the product line has been discontinued.
Acclimation counts too
Floating floors need 48 hours open-boxed in the room before install — plan the buy two days ahead of the weekend you're laying it.
On the counter
The assumptions this calculator ships with — every one is adjustable in the form.
- Waste allowance
- 10% by default for cuts, defects, and the one board you mismeasure
- Box coverage
- Entered from your product's label — nothing assumed silently
- Rounding
- Boxes always round up to the sealed unit
Questions from the aisle
How much extra flooring should I buy?
10% for straight lays in rectangular rooms; 15% for diagonal, herringbone, or rooms with lots of jogs and closets. The waste box above is set to 10% — change it before you shop.
How many square feet are in a box?
It varies by product: laminate and vinyl plank typically pack 17–30 sq ft per box. The number is printed on the label — enter it exactly and the count comes out right.
Should I measure the whole room or just the floor?
Just the usable floor at its widest points. Closets count; under built-ins usually does not. Measure twice — boxes are returnable only if unopened.
Does this work for tile too?
The math is identical — square footage plus waste. Tile breaks differently than plank though: use 15% for straight-set subway and 20% for patterns or large-format.
The reasoning behind this one
Waste allowance, explained
Where the assumptions above come from, what changes them, and the mistakes that cost a second trip. Free to read, no account needed.