Square Footage Calculator

Square footage is the area you have. Material square footage is the area you have to buy. They are rarely the same number. Tile, sheet flooring, and carpet all require cuts at walls, around doorframes, under cabinets, and along diagonal lines. Patterned material — herringbone tile, plaid carpet, woodgrain LVP — has to be aligned across the room, which throws away another few percent at the seams.

Industry rules of thumb: 10% extra for a simple rectangular room with straight-set tile or plank flooring. 15% for an L-shape or any diagonal layout. 20% for hexagons, mosaics, or any pattern wider than 12 inches. Stone tile (travertine, marble, slate) often demands 20% even on simple layouts because natural variation forces you to reject 5–10% of pieces.

Split the L into two rectangles. The main section is 18 × 14 = 252 sq ft. The bump-out is 8 × 6 = 48 sq ft. Total floor area: 300 sq ft. At a 15% waste factor for diagonal-laid 12 × 24 plank LVP, you need to buy 345 sq ft.

If the material costs $4.20/sq ft installed and the labor quote is $3.50/sq ft on the as-measured 300 sq ft, your total budget is 345 × $4.20 + 300 × $3.50 = $1,449 + $1,050 = $2,499. Keep the leftover unopened boxes for repairs — manufacturers regularly discontinue colors after 18 months, so a single damaged plank can force you to refloor an entire room a few years later.

1 square yard = 9 square feet (carpet is typically priced per yard).

1 square meter ≈ 10.7639 square feet (most European-spec flooring is sold per m²).

Linear feet vs square feet: trim, baseboards, and quarter-round are sold by the linear foot. Walls of a 12 × 14 room have a perimeter of 52 ft — that is the linear-foot order for new baseboards.

For paint, square footage of wall is what matters, not floor. Walls of an 8-foot-tall 12 × 14 room total roughly 416 sq ft before subtracting doors and windows.

Always verify rooms with a tape measure rather than relying on a builder's plan. Real-world drift of 2–4 inches per wall is common and adds up to a tile or two.

Break complex rooms into rectangles. An L-shape splits into two rectangles. A T-shape splits into three. A staircase landing splits into a rectangle plus a triangle.

Triangle area = (base × height) / 2. A triangular alcove with a 6-foot base and a 4-foot depth adds 12 sq ft to the room.

Circular areas: π × r². A round breakfast nook with a 5-foot radius adds π × 25 ≈ 78.5 sq ft.

When measuring, always measure twice and write down both numbers. Discrepancies of more than 1 inch usually mean the walls are not parallel — common in pre-1950 construction. Use the larger number for material orders and the smaller number for furniture-fit calculations.

Stair treads and risers are excluded from a home's official 'gross living area' under the ANSI Z765-2021 standard, which is what real-estate appraisers use. They are included in flooring-material orders, so measure them separately.