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Formula
Boxes = ⌈(A₁ + A₂ + …) × (1 + Waste ÷ 100) ÷ Coverage per box⌉
- A₁, A₂
- floor area of each room, closet or hallway
- Waste
- extra allowance in percent for cuts, offcuts and damaged boards (default 10%)
- Coverage per box
- square feet (or square meters) of flooring in one box, printed on the carton
What the flooring calculator does
Laminate, luxury vinyl plank and hardwood are sold in boxes that each cover a fixed area. This flooring calculator adds up the rooms you’re covering, adds a waste allowance for cuts and offcuts, and divides by the coverage per box, rounding up because you can’t buy part of a box. It also shows how much flooring you’ll end up with, how much is left over and, if you enter a price, the total cost.
How to use it
- Room areas: type one area per room, closet or hallway, separated by commas, such as 195, 30, 42. Choose square feet, square meters or square yards.
- Coverage per box: copy the area from the carton or product page, such as “21.5 sq ft per box”.
- Waste allowance: 10% by default; see the guide below.
- Price per box: optional, for the total cost and the cost per square foot.
If a room isn’t a simple rectangle, find its area first with the square footage calculator, which splits L-shapes into parts and adds them for you.
How to calculate flooring by hand
Take a 13 × 15 ft bedroom with a 5 × 6 ft closet, in vinyl plank sold at 21.5 ft² per box.
- Bedroom: 13 × 15 = 195 ft²
- Closet: 5 × 6 = 30 ft²
- Total: 195 + 30 = 225 ft²
- With 10% waste: 225 × 1.10 = 247.5 ft²
- Boxes: 247.5 ÷ 21.5 = 11.51, so 12 boxes
- Flooring bought: 12 × 21.5 = 258 ft², which leaves 10.5 ft² beyond the allowance
How the waste percentage changes the order
Here’s how the waste setting affects a 250 ft² floor with flooring at 22 ft² per box, calculated with the flooring calculator. Because you round up to whole boxes, a higher percentage doesn’t always add a box.
| Waste | Area with waste | Boxes | Flooring bought | Extra beyond allowance |
|---|---|---|---|---|
| 5% | 262.5 ft² | 12 | 264 ft² | 1.5 ft² |
| 7% | 267.5 ft² | 13 | 286 ft² | 18.5 ft² |
| 10% | 275 ft² | 13 | 286 ft² | 11 ft² |
| 15% | 287.5 ft² | 14 | 308 ft² | 20.5 ft² |
| 20% | 300 ft² | 14 | 308 ft² | 8 ft² |
Choosing a waste allowance
The common rule of thumb is to add 10% to cover end cuts, offcuts, measuring errors and damaged boards. Adjust it for your floor:
- 5–7%: large, open rectangular rooms with planks laid straight.
- 10%: most rooms in a straight lay, including bedrooms and living rooms with a doorway or two.
- 15%: diagonal layouts, rooms with many corners, closets and doorways, or boards with a strong grain pattern you want to balance.
- 20% or more: herringbone and chevron patterns.
Hardwood with natural defects may need more, because some boards will be set aside or used only in closets.
Measuring tips
- Measure wall to wall, not baseboard to baseboard. Flooring runs under the trim, with an expansion gap hidden beneath it.
- Use the longest measurement in rooms where walls aren’t parallel.
- Include closets, hallways and alcoves that get the same floor.
- Leave out fixed cabinets and islands if the flooring won’t run under them. Floating floors usually shouldn’t be pinned under heavy cabinets.
- Measure stairs separately. They usually need matching stair nosing, sold by the piece.
Ordering tips
- Check the lot number. Make sure every box carries the same production lot so the color and texture match across the floor.
- Let the boards acclimate. Many manufacturers ask for boxes to sit in the room for a period before installation; follow the instructions for your product.
- Open boxes from several cartons at once. Mixing boards from different boxes spreads out any variation in shade and grain.
- Keep one full box after the job. It makes replacing a damaged plank simple years later.
Common mistakes
- Forgetting to round up. 11.51 boxes means 12 boxes.
- Adding waste after rounding. Apply the percentage to the area first, then divide by the box coverage.
- Mixing units. Some imported products list coverage in square meters. The flooring calculator converts automatically; by hand, 1 m² is 10.764 ft².
- Buying from different lots. Color varies between production runs, so buy all your boxes at once and keep a spare.
Tile floors and wall paint
Tiled floors are counted by the tile instead of by coverage, so use the tile calculator for ceramic and porcelain. If you’re repainting the room before the new floor goes in, the paint calculator estimates the gallons.
Glossary
- Coverage per box: the floor area one carton covers, printed on the box.
- Straight lay: planks running parallel to a wall, the layout with the least waste.
- Expansion gap: a space left at the walls so floating floors can expand and contract.
- Floating floor: flooring that clicks together and rests on the subfloor without glue or nails.
Worked examples
Laminate for a living room and hallway
A 238 ft² living room plus a 42 ft² hallway, laminate at 19.63 ft² per box and $41 a box, 10% waste.
Inputs: Room areas = 238, 42; Room areas in = Square feet; Coverage per box = 19.63; Coverage per box unit = Square feet; Waste allowance = 10 %; Price per box (optional) = $41
Floor area: 238 + 42 = 280 ft² With waste: 280 × 1.1 = 308 ft² Boxes: 308 ÷ 19.63 = 15.69 → 16 Cost: 16 × $41.00 = $656.00
Answer: 280 ft² of floor plus 10% waste needs 16 boxes at 19.63 ft² per box.
Vinyl plank through three bedrooms
Three bedrooms of 150, 121 and 99 ft², luxury vinyl plank at 23.6 ft² per box, 7% waste for a simple straight lay.
Inputs: Room areas = 150, 121, 99; Room areas in = Square feet; Coverage per box = 23.6; Coverage per box unit = Square feet; Waste allowance = 7 %
Floor area: 150 + 121 + 99 = 370 ft² With waste: 370 × 1.07 = 395.9 ft² Boxes: 395.9 ÷ 23.6 = 16.78 → 17
Answer: 370 ft² of floor plus 7% waste needs 17 boxes at 23.6 ft² per box.
Engineered wood in metric
An 18.5 m² room laid in a herringbone-style pattern with 15% waste, boards at 1.96 m² per box.
Inputs: Room areas = 18.5; Room areas in = Square meters; Coverage per box = 1.96; Coverage per box unit = Square meters; Waste allowance = 15 %
With waste: 18.5 × 1.15 = 21.28 m² Boxes: 21.28 ÷ 1.96 = 10.85 → 11
Answer: 18.5 m² of floor plus 15% waste needs 11 boxes at 1.96 m² per box.
An exact fit (edge case)
200 ft² with no waste and 20 ft² per box divides exactly, so no extra box is added.
Inputs: Room areas = 200; Room areas in = Square feet; Coverage per box = 20; Coverage per box unit = Square feet; Waste allowance = 0 %
With waste: 200 × 1 = 200 ft² Boxes: 200 ÷ 20 = 10 → 10
Answer: 200 ft² of floor plus 0% waste needs 10 boxes at 20 ft² per box.
Assumptions and limitations
- This is an estimate only, not professional installation advice. Follow the manufacturer's instructions for expansion gaps, acclimation and subfloor preparation.
- The waste allowance defaults to 10% if left empty, the rule of thumb flooring retailers such as Ferguson recommend for cuts, mistakes and damaged pieces. Use 5–7% for large, simple rooms in a straight lay and 15% or more for diagonal or herringbone patterns.
- Boxes are rounded up to whole boxes after the waste allowance is added. Leftover area is the difference between what you buy and the area with waste.
- Room areas are entered as numbers, so measure each room (or split an L-shape into rectangles) first. Areas and coverage can use different units; both are converted using NIST factors.
- Underlayment, transitions, trim and stair nosing are not included.
Frequently asked questions
How do I calculate how much flooring I need?
Measure each room's length and width, multiply to get square feet, and add the rooms together. Add 10% for waste, then divide by the square feet per box and round up. Two rooms of 160 ft² and 90 ft² with 10% extra need 275 ft², which is 13 boxes at 22 ft² per box.
How much extra flooring should I buy?
About 10% for most straight-lay laminate, vinyl plank and hardwood jobs. Use 5–7% in big open rooms with few cuts, and 15–20% for diagonal or herringbone layouts or rooms with many corners and doorways.
How many square feet are in a box of flooring?
It depends on the product. Laminate and vinyl plank cartons often hold around 18–25 ft², and solid hardwood around 18–22 ft². The exact figure is printed on the box and product page.
Should I include closets in the flooring estimate?
Yes, if they get the same floor. Add each closet and hallway as its own area so the total matches what you'll actually install.
Can I return extra boxes of flooring?
Many stores accept unopened boxes, but policies vary. Keeping one spare box is useful for repairs, since later production runs can differ slightly in color.
How do I estimate the cost of new flooring?
Enter the price per box. The calculator multiplies it by the number of boxes and also shows the cost per square foot of floor, which makes it easy to compare products sold in different box sizes.
Sources
- How To Measure for Flooring — Ferguson Home. Checked October 12, 2026.
- NIST Guide to the SI, Appendix B.9: Factors for units listed by kind of quantity — National Institute of Standards and Technology. Checked October 12, 2026.