keencalculator
  1. Home
  2. Home & Construction
  3. Flooring Calculator

Flooring Calculator

Enter the room’s length and width to find the square footage of laminate, vinyl plank or hardwood flooring to buy, the number of boxes and the cost. Waste for cuts is added before boxes are rounded up.

Quick examples
%

Use 5–10% for straight planks, 15% for diagonal or herringbone.

sq ft

Printed on the carton; usually 18–25 sq ft.

$
Your numbers stay in your browser. Nothing is uploaded.
Flooring needed198 ft²
Room area
180 ft²
Boxes to buy
9
Area in those boxes
198 ft²
Cost of the boxes
$693.00

Saved setups

Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.

    Your recent calculations

    Results you calculate here are kept on this device so you can come back to them.

      Formula

      Room area = length × width
      Flooring needed = room area × (1 + waste %)
      Boxes = flooring needed ÷ coverage per box, rounded up
      Cost = boxes × coverage per box × price per square foot

      How to use it

      1. Measure the room at its longest and widest points and enter both.
      2. Set the waste allowance for your layout.
      3. Enter the square feet per box from the carton.
      4. Enter the price per square foot to see what the boxes cost.

      Worked examples

      A 15 × 12 ft room with 10% waste, 22 sq ft boxes at $3.50 a square foot

      Room area
      180 ft²
      Flooring needed
      198 ft²
      Boxes to buy
      9
      Area in those boxes
      198 ft²
      Cost of the boxes
      $693.00

      A 20 × 14 ft room with 10% waste, 20 sq ft boxes at $4

      Room area
      280 ft²
      Flooring needed
      308 ft²
      Boxes to buy
      16
      Area in those boxes
      320 ft²
      Cost of the boxes
      $1,280.00

      Measuring rooms that are not rectangles

      Split an L-shaped room into two rectangles, calculate each, and add them. Include closets and the floor under doorways. Do not subtract small things like floor vents.

      Remember the extras: underlayment for floating floors, transition strips at doorways, and quarter-round or baseboard to cover the expansion gap.

      Waste allowance

      Allow 5–10% for planks laid straight in a simple room, and about 15% for diagonal or herringbone layouts. Keep one unopened box after the job for future repairs, since product lines are discontinued often.

      Questions people ask

      How much flooring do I need for a 12×15 room?

      The room is 180 sq ft. With 10% waste you need 198 sq ft, which is 9 boxes at 22 sq ft per box.

      How many boxes of flooring do I need for 300 square feet?

      With 10% waste that is 330 sq ft: 15 boxes at 22 sq ft per box, or 17 boxes at 20 sq ft per box.

      Should I round up boxes?

      Always. Flooring is sold by the full box, and running one plank short can mean a second trip for a product from a different production lot.

      Related calculators

      Square Footage CalculatorSquare feet of a room, lot or odd shape, with cost per sq ft.Carpet CalculatorSquare yards of carpet for a room and what it will cost.Tile CalculatorTiles and boxes for a floor or wall, with grout gap and waste.Price per Square Foot CalculatorPrice per sq ft and per m² for a home, office or rental.Paint CalculatorGallons of paint for a room, minus doors and windows.