Flooring Calculator
Calculate how many boxes of flooring you need. Enter room length, width, box coverage and waste percentage for an instant box count with the formula shown.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Flooring Calculator Works
This calculator tells you how many boxes of flooring to buy for a room. Enter the room’s length and width in feet, the square footage each box covers, and a waste percentage for cuts and mistakes. It instantly returns the floor area, the area including waste, and the number of full boxes you need.
It works for any plank or tile product sold by the box — laminate, luxury vinyl plank (LVP), engineered hardwood, solid hardwood, and floor tile — as long as you know the coverage printed on the box label.
The Formula
Floor area (sq ft) = length × width Area with waste = floor area × (1 + waste% ÷ 100) Boxes = ⌈ area with waste ÷ coverage per box ⌉
The square brackets (⌈ ⌉) mean round up to the next whole number, because flooring is only sold in complete boxes. The waste percentage covers the offcuts created when planks are trimmed at walls and around obstacles.
Worked Example
For a room that is 15 ft long and 12 ft wide, with 20 sq ft boxes and a 10% waste allowance:
- Floor area = 15 × 12 = 180 sq ft
- Area with waste = 180 × (1 + 0.10) = 180 × 1.10 = 198 sq ft
- Boxes = ⌈198 ÷ 20⌉ = ⌈9.9⌉ = 10 boxes
So you should buy 10 boxes, which covers 200 sq ft and leaves a small surplus for repairs.
Choosing the Right Waste Allowance
The waste percentage matters more than people expect. The more cutting your layout requires, the more material ends up in the bin.
| Layout / room type | Suggested waste |
|---|---|
| Simple rectangular room, straight planks | 5% |
| Standard room with a few doorways | 8–10% |
| Diagonal or 45° layout | 12–15% |
| Herringbone / chevron pattern | 15%+ |
| Irregular room, many corners or angles | 12–15% |
Tips for an Accurate Estimate
- Measure twice. Take length and width at the widest points and round up to the nearest few inches.
- Buy from one dye lot. Order all your boxes at once so the color and grain match; reordering later can produce a visible mismatch.
- Keep a spare box. A leftover sealed box is cheap insurance against future scratches or water damage on a discontinued line.
- Check the box coverage. Coverage per box varies a lot between products (often 16–30 sq ft), so always read the actual label rather than assuming.
Frequently asked questions
How do I calculate how much flooring I need?+
Measure the room length and width in feet and multiply them to get the floor area in square feet. Add a waste allowance of about 10 percent, then divide by the square footage each box covers and round up. For a 15 × 12 ft room with 20 sq ft boxes and 10 percent waste you need 11 boxes.
How much waste should I add for flooring?+
Add 5 to 10 percent for straight, rectangular rooms with simple cuts. Use 10 to 15 percent for diagonal layouts, herringbone patterns, or rooms with many corners, doorways and angles, where more pieces are trimmed and discarded.
How many boxes of laminate do I need for a 12x15 room?+
A 12 × 15 ft room is 180 sq ft. With a 10 percent waste allowance that is 198 sq ft. If each box covers 20 sq ft, divide 198 by 20 to get 9.9 and round up to 10 boxes; with smaller 18 sq ft boxes you would need 11.
Should I round flooring boxes up or down?+
Always round up. Flooring is sold in whole, sealed boxes, and running short mid-install can mean a different dye lot or a discontinued product. Buying one extra box also leaves matching planks for future repairs.
Do I include closets and doorways in the area?+
Include closets and any floor you will actually cover, since they need planks too. You can subtract large permanent fixtures like a kitchen island base, but it is usually safer to count the full footprint and rely on the waste allowance.