Flooring Calculator

Flooring & tileFree calculator

Enter your room size and the coverage printed on the box to see how many boxes of laminate, vinyl plank or engineered hardwood to buy. The calculator adds a waste allowance for cuts and gives you a shopping list with underlay and spacers.

Your shopping list

How to measure

  1. Measure the longest length and width of the room, wall to wall.
  2. For L-shaped rooms, split the floor into two rectangles, work out each one and add the boxes together.
  3. Check the coverage printed on the box. It varies by brand and plank size.

The formula

Area = length × width
Area with waste = area × (1 + waste %)
Boxes = area with waste ÷ coverage per box  (round up)

Worked example

A 15 × 12 ft room is 180 sq ft. With 10% waste that is 198 sq ft. At 20 sq ft per box you need 198 ÷ 20 = 9.9, so buy 10 boxes. In metric, a 4.5 × 3.6 m room is 16.2 m², or 17.8 m² with waste, which is 10 boxes of 1.86 m².

Tips before you buy

  • Leave the boxes in the room for 48 hours before fitting so the boards acclimatise.
  • Keep one spare box after the job for future repairs. Colours change between batches.
  • Laying boards diagonally or in herringbone needs 15–20% waste instead of 10%.

Frequently asked questions

How much extra flooring should I buy?

Add 10% for straight layouts and 15% for diagonal or herringbone patterns, or for rooms with many corners and doorways.

Do I include the area under kitchen units?

No. Measure only the floor you will actually cover, but keep the waste allowance.

Do I need underlay?

Most laminate and many vinyl floors need underlay, sold by area. Some planks come with underlay attached; check the box before buying extra.

Results are estimates for planning only. Always check quantities with your supplier before you buy.