About the Flooring Calculator
This flooring calculator turns room dimensions into a shopping list. Enter the room length and width (plus any extra area such as a closet or hallway), your waste allowance and the coverage printed on one box of flooring, and it tells you how many boxes to buy and what the material and installation will cost.
It suits laminate, luxury vinyl plank (LVP), hardwood, engineered wood and click-lock flooring sold by the box. Because boxes are rounded up, the material cost is based on the square footage you actually buy, not just the room size — which is what the store will charge.
Waste covers offcuts at walls, damaged planks and pattern matching. 5–10% is typical for a straight lay in a rectangular room; use 15% or more for diagonal layouts, herringbone or rooms with many corners. Keep a spare box for future repairs.
With the default inputs, the boxes to buy is 9. Change any value above to recalculate instantly.
How to use the flooring calculator
- 1Measure the room’s length and width at the widest points.
- 2Add any extra area such as closets or a hallway.
- 3Set the waste allowance for your layout pattern.
- 4Enter the coverage per box from the product label.
- 5Add the price per sq ft and installation rate to see the full cost.
Formula and method
Floor area is length × width plus any extra square footage you add for closets or adjoining spaces. That area is increased by the waste percentage and divided by the square feet in one box; the result is rounded up because flooring is sold only in whole boxes.
Material cost uses the square footage you actually buy (boxes × coverage per box) times the price per square foot. Installation is usually quoted on the net floor area, so labor is area × installation rate. Underlayment, trim, transitions and furniture moving are not included.
- L, W
- Room length and width (ft)
- waste
- Waste allowance as a decimal
- ⌈ ⌉
- Round up to a whole box
Worked examples
15 × 12 ft room, 22 sq ft boxes
The room is 180 sq ft; adding 10% waste gives 198 sq ft. 198 ÷ 22 = exactly 9 boxes. Buying 198 sq ft at $3.50 costs $693, and installation at $2/sq ft on 180 sq ft adds $360, for $1,053 in total.
Diagonal laminate in a 20 × 14 ft living room (DIY)
280 sq ft plus 15% waste for a diagonal lay is 322 sq ft. At 24.5 sq ft per box that is 13.1, so buy 14 boxes (343 sq ft) for $771.75.
Vinyl plank bedroom with a closet
An 11 × 10 ft bedroom plus a 6 sq ft closet is 116 sq ft, or 127.6 sq ft with 10% waste. That rounds up to 7 boxes of 20 sq ft ($560), plus $174 of installation.
Frequently asked questions
How much extra flooring should I buy?+
Buy 5–10% extra for a straight installation in a simple room, and 15–20% for diagonal, herringbone or rooms with many angles. Keeping a box for future repairs is also wise, since dye lots change.
How do I measure a room for flooring?+
Measure length and width wall to wall at the widest points and multiply. For L-shaped rooms, split the room into rectangles, calculate each one and add them together.
How many square feet are in a box of flooring?+
It varies by product — laminate boxes commonly hold about 15–25 sq ft, vinyl plank about 18–30 sq ft and hardwood about 20 sq ft. Check the label and enter the exact figure.
What does it cost to install flooring?+
Professional installation is quoted per square foot and varies with the material, subfloor preparation and your location. Get several local quotes; this calculator lets you enter whatever rate you are given.
Do I need underlayment?+
Many laminate and some vinyl products need a separate underlayment or vapor barrier, while others have it pre-attached. It is priced separately per square foot, so add it to the flooring price if needed.