Flooring Calculator: Square Feet, Waste and Boxes

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Enter the length and width of your room to get the floor area, add a waste allowance for cuts, and, if you know how much one box covers, see how many boxes to buy. You can add up to three rectangles for L-shaped rooms.

How the flooring calculator works

  • Floor area = length × width, summed over each rectangle
  • Area to buy = floor area × (1 + waste % ÷ 100)
  • Boxes = area to buy ÷ coverage per box, rounded up

Worked example

A 12 × 15 ft living room has 180 sq ft of floor. With 10% waste you should buy 198 sq ft. If a box of laminate covers 20 sq ft, you need 198 ÷ 20 = 9.9, so 10 boxes.

How much extra flooring to buy

  • Straight layouts: about 5 to 10%
  • Diagonal or herringbone layouts: about 10 to 15%, because angled cuts waste more material
  • Small rooms, closets and rooms with many corners tend to need the higher end of the range

Choosing the diagonal pattern in the calculator switches the default to 15%. You can enter your own percentage at any time.

Step by step: measuring and buying flooring

Follow these steps to get the numbers the calculator needs and to order the right amount.

Floor plan of an L-shaped room split into two rectangles with dimension arrows
Step 1. Sketch the floor plan and split L-shaped rooms into rectangles. Enter each rectangle as its own area.
Measuring a room wall to wall with a tape measure
Step 2. Measure each rectangle wall to wall, including closets and the space under doors.
Laminate planks laid in staggered rows with offcut pieces showing waste
Step 3. Lay planks in staggered rows. The offcuts at the walls are why you add a waste allowance.
Stack of flooring boxes with one spare box set aside
Step 4. Buy the number of boxes the calculator shows, and keep one spare box for future repairs.

Tips before you order

  • Measure closets and include the area under doors and thresholds.
  • Buy all boxes from the same production lot so color and texture match.
  • Keep one spare box for future repairs.