Flooring calculator for laminate, vinyl and wood

How the flooring calculator works

You need the floor area plus a margin for cuts, divided by the coverage of one box, rounded up. That holds for laminate, click engineered wood and luxury vinyl plank (LVP or SPC), which are all sold by the box with the square footage printed on the label.

1. Area. Length × width of each room, added up. Split an L-shaped room into two rectangles.
2. Extra for cuts. End-of-row cuts and cuts along the walls eat into the boxes. For a straight lay we start at 10%, the figure SWISS KRONO USA gives in its measuring guide. On a diagonal every board against the wall is cut at 45 degrees: Mullican Flooring says 10-15%, and we use 15%. For herringbone, the vinyl maker Floorify allows 15% on its click floors, so we start at 15% there too.
3. Boxes. Area with the extra ÷ coverage of one box, rounded up.
4. Underlayment. Room area ÷ coverage of one roll, rounded up, with no extra.
5. Baseboard. Perimeter of the rooms minus the doors, plus 10% for corners and joints, which is what Alexandria Moulding suggests for baseboard and trim. Divide by the length of one piece and round up.

Worked example: a 12 × 12 ft room

These are the values the calculator opens with in feet: a 12 × 12 ft room, straight lay with 10% extra, 20 sq ft boxes, one 32 in door, underlayment in 100 sq ft rolls and 8 ft baseboard.

• Area: 12 × 12 = 144 sq ft
• With the extra: 144 × 1.10 = 158.4 sq ft
• Boxes: 158.4 ÷ 20 = 7.92, so 8 boxes, which is 160 sq ft
• Underlayment: 144 ÷ 100 = 1.44, so 2 rolls
• Baseboard: perimeter 48 ft, minus the door 45.33 ft, plus 10% 49.87 ft; 49.87 ÷ 8 = 6.2, so 7 pieces

On a diagonal or in herringbone, at 15%, the same room needs 165.6 sq ft, which is 9 boxes.

In the UK, with metres: a 4 × 3.5 m room is 14 m², 15.4 m² with 10% extra, so 8 packs of 2 m². The underlay is one 15 m² roll, and the skirting is 7 lengths of 2.4 m with one 80 cm door.

How many boxes of flooring for common room sizes

20 sq ft boxes, straight lay at 10% and diagonal at 15%, 8 ft baseboard with one 32 in door.

Room	Sq ft	Straight	Diagonal	Baseboard pieces
10 × 10 ft	100	6 boxes	6 boxes	6
12 × 12 ft	144	8 boxes	9 boxes	7
15 × 12 ft	180	10 boxes	11 boxes	8
20 × 15 ft	300	17 boxes	18 boxes	10

Box sizes, underlayment rolls and baseboard lengths

A box of laminate in the US covers about 20 sq ft. The Mohawk RevWood Kingmire sold by Factory Flooring Liquidators covers 20.62 sq ft per box. Type the number from the label of the floor you are buying, decimals included. In the UK a pack covers about 2 m²: the Quick-Step Muse sold by Howarth Timber covers 1.901 m².

Underlayment comes in rolls: 100 sq ft per roll for the pad sold by Factory Flooring Liquidators, 15 m² for the Elka underlay sold by Howarth Timber. If your floor already has a pad attached to the back of the boards, untick the underlay box and the line drops off the list.

Baseboard is sold by the piece. Alexandria Moulding makes it in 8 ft and 16 ft lengths, and the calculator starts at 8 ft. In the UK the flexible Quick-Step skirting is 2400 mm long. Change the length in the advanced options.

Common mistakes

• Keeping the straight-lay extra on a diagonal. Pick the layout in the calculator: the extra changes with it.
• Buying to the last square foot. Mullican Flooring suggests one or two extra cartons to keep for repairs. Buy everything at once, from the same lot.
• Miscounting doors. A door between two rooms you measure together breaks the baseboard on both sides: count it twice.
• Forgetting closets and alcoves. Add them as extra rooms. They are only a few square feet, but nearly every board there gets cut.