Flooring calculator

How flooring is calculated

Measure each room wall to wall in feet. Feet and inches or meters work too. For a second room, a hallway or a closet, use “+ Add another room”; every room is added to the total before waste is applied.

Laminate, vinyl plank and hardwood are sold by the carton. Divide by the square feet printed on the box and round up to whole cartons.

Carpet is sold by the square yard and cut from a 12 ft wide roll, so the calculator gives both the square yards and the length of roll that covers the same area.

Underlayment and carpet pad are laid edge to edge without overlap, so they are counted from the floor area with no waste.

Worked example: 12 × 12 ft room in laminate

The calculator opens on a 12 × 12 ft room in laminate with 10% waste, 20 ft² cartons and 100 ft² underlayment rolls.

1. Floor area: 12 × 12 = 144.0 ft².
2. With waste: 144.0 × 1.10 = 158.4 ft².
3. Cartons: 158.4 ÷ 20 = 7.92, so order 8 cartons. They cover 160.0 ft², 1.6 ft² more than the waste allowance.
4. Underlayment: 144.0 ÷ 100 = 1.44, so 2 rolls.

Choosing the waste allowance

Waste pays for the pieces you cut off at the walls, the end of every row, around door casings and vents, and the boards you reject for defects. How much you need depends on the layout more than the product.

• Straight layout, rectangular room: 10%. The offcut from the end of one row usually starts the next.
• Diagonal layout, herringbone or a room with many corners, closets and angled walls: 15%. Every row ends in an angle cut, and fewer offcuts can be reused.
• Large open room with few cuts: about 5%, if you are confident in the layout.
• Solid hardwood: at least 10%, because some boards get culled for color, knots or short lengths.
• Carpet: the roll is 12 ft wide, so a room that is not a multiple of 12 ft leaves a long offcut, and patterned carpet has to match at the seams. Ask the installer for a cut sheet before ordering.

Measuring and ordering tips

• Measure at the widest points, wall to wall, and round up to the next inch. Floors run under door casings and into closets, so include them.
• For an L-shaped room, split it into two rectangles and enter each one as its own room with “+ Add another room”. Closets and hallways go in the same way, so the cartons are rounded once for the whole job.
• Leave out areas under fixed cabinets and islands. Most floating floors should not be pinned under them anyway.
• Buy every carton from the same production run and check the run or lot number on the boxes; colors can shift between runs.
• Let laminate, vinyl and hardwood acclimate in the room for the time the manufacturer specifies before installing.
• Keep at least one spare carton for future repairs. Unopened cartons of many products can be returned, so ordering one extra costs little.

Underlayment comes off the roll in strips that butt together, so it has very little waste; seams are taped, not lapped. Check whether your laminate or vinyl plank has a pad attached before buying it, and check the flooring's installation guide for a vapor barrier over concrete. On a slab, many manufacturers call for a polyethylene sheet lapped at the seams, which uses more than the floor area. Set the roll coverage to 0 when no separate underlayment is needed.