Flooring Calculator

Enter up to three rooms, rectangular or L-shaped, in feet or meters. The calculator adds the floor areas, applies a waste allowance for your layout pattern, divides by the coverage printed on the carton and rounds up to whole boxes, because that is how flooring is sold. It also gives the material cost for the boxes you actually buy, the leftover area, the underlayment needed and the length of baseboard or trim, and draws the rooms to scale with the plank pattern.

It works for any product sold by area in boxes or cartons: laminate, vinyl plank, engineered or solid hardwood, bamboo, cork and tile. For tile with grout joints and individual tile counts, the tile calculator is more detailed; for walls, use the paint calculator.

Rectangle: A = L × W    L-shape: A = L × W − a × b    Perimeter = 2(L + W)

L and W are the overall length and width of the room, and a × b is the missing corner that turns a rectangle into an L. Measuring the overall size and the cut-out is usually easier than splitting the room into two rectangles, and it avoids counting the overlap twice. A six-sided L-shaped room always has the same perimeter as the rectangle around it, so the trim length is 2(L + W) either way.

A 20 × 15 ft room with an 8 × 5 ft corner cut out covers 300 − 40 = 260 sq ft and has 70 ft of wall. With 10% waste and cartons of 23.4 sq ft that is 286 sq ft, or 13 boxes.

Every row ends with a cut, and some boards have defects or break. Installers commonly add about 10% for a straight layout, 15% for a diagonal layout (more triangular offcuts at the walls) and 20% for herringbone or chevron. These are rules of thumb rather than a standard, and the manufacturer's installation guide takes priority; many rooms with few obstacles need less, while small rooms, closets and many doorways need more. The pattern buttons set these defaults and you can type any figure.

A 15 × 12 ft bedroom

The floor is 180 sq ft. Adding 10% gives 198 sq ft; at 20 sq ft per box that is 9.9 boxes, so you buy 10 (200 sq ft). At $3.50 per sq ft the flooring costs $700.00, or $3.89 per square foot of finished floor once waste and rounding are included. Underlayment in 100 sq ft rolls needs 2 rolls, and the baseboard runs 54 ft before subtracting doorways.

A 5 × 4 m living room in metric

The floor is 20 m². With a 15% diagonal allowance you need 23 m²; cartons of 2.2 m² give 11 boxes (24.2 m²), which at 30 per m² is $726.00 in your currency.

• Underlayment is estimated on the net floor area, since its seams are butted or taped rather than cut to a pattern. Skip it if your vinyl plank has a pad attached.
• Trim equals the room perimeter. Subtract door openings, and remember that transitions are needed at each doorway where the floor meets another surface.
• Measure wall to wall at floor level in two places and use the larger figure; rooms are rarely perfectly square. Include closets and the space under appliances you plan to floor under.
• Buy from one lot. Color can vary between production runs, so buying everything at once, plus a spare box for future repairs, is a common recommendation.
• Prices are estimates for materials only and exclude tax, delivery, adhesive, tools and labor.