Flooring Calculator: Area, Tiles, Planks and Boxes You Need

The calculator turns room dimensions into an order list: the floor area, the number of pieces, the waste allowance and the number of boxes. Enter measurements in feet and inches, piece sizes in inches, and the waste percentage, then press Calculate.

Step by step

1. Pick the flooring type: tile, plank or sheet/roll. The piece-size fields change to match.
2. Enter the room length in feet and inches.
3. Enter the room width in feet and inches.
4. Enter the piece size: tile or plank length × width in inches, or the roll width for sheet flooring.
5. Set the waste allowance. The default is 10%.
6. Optional: enter the box coverage in sq ft to get the number of boxes to order.
7. Press Calculate and read the results below the form.

What you get

• Floor area in square feet and square yards
• Pieces needed — tiles or planks, rounded up
• Total with waste — the number to actually order
• Boxes to order, when you enter the box coverage
• Roll length in feet, when sheet/roll is selected

The calculation order

• Floor area = length (ft) × width (ft)
• Piece area = (length in × width in) ÷ 144
• Pieces = ceiling(floor area ÷ piece area)
• Total with waste = ceiling(pieces × (1 + waste % ÷ 100))
• Boxes = ceiling(total material area ÷ box coverage)

Tiles — ceramic, porcelain and stone — are sized in inches per piece: 12 × 12, 18 × 18 and 24 × 24 are the common squares, with 12 × 24 a popular rectangle. Enter the tile length and width and the calculator divides the floor area by the area of one tile. Our tile calculator goes deeper on grout lines, gaps and layout patterns if you are tiling a bathroom or kitchen.

Planks — laminate, hardwood and luxury vinyl — are long rectangles, often around 48 × 6 in or 36 × 5 in. The same length × width entry applies; the math does not change, only the piece shape does. Plank offcuts can often be reused to start the next row, which is why plank waste can stay near 10% on a straight lay even though every row ends in a cut.

Sheet and roll flooring — vinyl sheet and carpet — is sold by the roll, not the piece. Enter the roll width in inches (a 12 ft roll is 144 in) and the calculator returns the total area with waste plus the linear feet of roll to buy: linear feet = waste-included area ÷ roll width in feet.

Common tile sizes and what they mean for a 120 sq ft room

Piece area in sq ft = (length × width) ÷ 144. The last column assumes the 10% default waste.

Tile size	Area per tile	Tiles per sq ft	Tiles for 120 sq ft (10% waste)
6 × 6 in	0.25 sq ft	4	528
12 × 12 in	1.00 sq ft	1	132
12 × 24 in	2.00 sq ft	0.5	66
18 × 18 in	2.25 sq ft	0.44	60
24 × 24 in	4.00 sq ft	0.25	33

Bigger tiles mean fewer pieces and fewer grout lines, but each miscut wastes more material — which is why large-format tile on an irregular room can push the waste allowance above 10%.

The waste allowance covers cut pieces at walls and corners, broken or chipped pieces, and a spare for future repairs. A straight grid lay wastes the least; any angled or patterned layout turns more edge pieces into offcuts. Use this guide to pick your percentage.

Install pattern	Waste factor	Notes
Straight lay	7–10%	Standard for tile, plank and laminate
Large pattern tile	10–15%	Pattern repeat drives layout waste
Diagonal (45°)	15%	More triangular cuts at walls
Herringbone or chevron	15–20%	Angled cuts on nearly every edge piece
Complex room shape	+5%	Add on top of the base factor

Two rules save money. First, buy all boxes from the same dye lot: shades drift slightly between production batches, and mixing lots can leave a visible patchwork on the finished floor. Second, keep one spare box after the job. Finding a matching lot months later is difficult, and a single cracked tile should not force a whole new purchase.

The calculator defaults to 10%, which suits a rectangular room with a straight lay. Raise it to 15% if you are laying diagonally and to 20% for herringbone, chevron or a room with many corners.

A flooring estimate is only as good as the measurements behind it. These are the errors that show up most often.

Measure wall to wall at the longest and widest points

Rooms are rarely perfect rectangles. Measure the longest run for the length and the widest run for the width — the calculator assumes one rectangle, so the largest dimensions keep you from under-ordering.

Include closets and alcoves

If the closet or alcove will get the same flooring, measure it separately and add its area to the room, or measure the full run including it. Leaving it out is the classic reason an order comes up one box short.

Do not subtract small doorways

Subtracting a doorway saves a fraction of a box and adds error. Only subtract large openings — a wide cased opening into another room, for example — and let the waste allowance absorb the rest.

Convert carefully before entering

7 ft 6 in is 7.5 ft, not 7.6 ft. If your tape gave you inches or yards, convert the area first with our area converter rather than guessing the decimal.