Calculators
Floor measuring, waste and conversion calculators
Areas of odd rooms, waste by layout, boxes from coverage, perimeters for trim, stairs and the weight of the delivery.
Every flooring estimate rests on three numbers: the area, the waste allowance and the coverage of the package you are buying. Get the area wrong by a closet and every calculator on this site is wrong by a box; pick the waste for a straight layout and lay the floor on the diagonal and you run short on the last afternoon. This group is the measuring tape of the site: it works out areas from the rectangles of a real room, converts between square feet, square yards, square metres and boxes, and chooses the waste factor from the layout, the room shape and the material.
It also holds the quantities that follow the perimeter rather than the area: baseboard and quarter round by the length and the corners, thresholds by the doorway, tack strip by the wall, and stairs by the step. Finally there is the weight calculator, because a pallet of porcelain for a 400 sq ft floor weighs close to a ton and the delivery, the stairs and the floor it sits on all need to know that.
10 calculators
Floor Area Calculator
The area of an L-shaped or odd room from up to six rectangles, with parts to add or subtract.
Flooring Unit Converter
Square feet, square yards, square metres and boxes at a coverage, converted with exact factors.
Flooring Waste Factor Calculator
The waste percentage for your material, layout, room shape, grade and installer, and the area to order.
Boxes & Cartons Calculator
Whole boxes or cartons from the area, the coverage and the waste, with the leftover and the cost.
Diagonal & Herringbone Layout Calculator
Pieces, wall cuts and the real waste for a 45° diagonal, herringbone or chevron floor, and where to start.
Perimeter Calculator
The wall length for baseboard, shoe moulding or tack strip, less doorways and fixtures.
Baseboard & Quarter Round Calculator
Pieces of baseboard and shoe moulding by length, with the nails and caulk, and which walls need a joint.
Thresholds & Transition Strips Calculator
T-mouldings, reducers, thresholds and carpet edges by doorway, in the strip lengths they are sold in.
Stair Flooring Calculator
Treads and risers, stair nose pieces or tile and nosing for a flight of stairs in wood, vinyl or tile.
Flooring Weight Calculator
What a floor's worth of tile, stone, wood or vinyl weighs, the trips to carry it and the load it adds.
Guides for this topic
Carpeting stairs: full-width carpet or a runner, and how much
Stair carpet is counted by the step, not by the area. Each step takes the tread, the riser and the nosing, and a flight of fourteen is about 22 ft of carpet before landings.
Expansion gaps: how wide, where, and why floors buckle
Every floor moves. The gap at the walls is the room it moves into, and a floor without one buckles, cracks or lifts. Here are the gaps for each type and the arithmetic behind them.
Removing an old floor: cost, time, debris and what to watch for
Taking up the old floor is the dirty, heavy part of every flooring job. Carpet comes up in an afternoon; tile set in mortar takes days and weighs a ton. Here is what to expect for each.
Flooring waste factors: 5%, 10%, 15% or 20%?
The right waste allowance is the one that matches your layout and room, not the one everybody repeats. Here is where 10, 15 and 20% come from, and the adjustments that move them.
Garage tiles, gym rubber and play mats: counting the floor
Garage, gym and playroom floors are sold as tiles, rolls or mats rather than boxes of flooring, and each format wastes differently. Here is how to count each one, and what each weighs.
How much flooring do I need? The complete method
Measure the room in rectangles, add the waste your layout demands, divide by what the box really covers, round up once, and count the trim. Here is each step, with a living room worked from start to finish.
Buying luxury vinyl plank: boxes, wear layer, pad and price
Vinyl plank is the easiest floor to buy wrong, because boxes, thicknesses and wear layers vary so much. Here is what to read on the label and how to turn a room into boxes.
Measuring L-shaped, angled and odd rooms for flooring
Any room can be measured as rectangles that do not overlap. Here is how to split the awkward ones, what to include and leave out, and why an L-shape has the same perimeter as a plain rectangle.
Refinishing a hardwood floor: grits, sandpaper, time and finish
A worn wood floor can look new again for a fraction of the cost of replacing it. The job is mostly sanding, and the sanding is mostly arithmetic: area, grits, abrasive life and time.
Rug size rules for living rooms, dining rooms and bedrooms
A rug is sized by the furniture on it, not by the room. Too small is the common mistake. Here are the rules for each room and the standard sizes they lead to.
Sheet vinyl: roll widths, seams, pattern match and how much to buy
Sheet vinyl comes in rolls 6, 12 or 13.2 ft wide, and you buy a length. A room that fits the roll needs no seam and wastes little; a room just over it can waste 40%.
Square feet, square yards and boxes: the units of flooring
Tile is priced per square foot, carpet per square yard, European products per square metre, and you buy all of them by the box or the roll. Here are the exact conversions and the traps between them.
Questions people ask
- How do I convert square feet to square yards?
- Divide by 9: a square yard is 3 × 3 feet. A 180 sq ft room is 20 sq yd. Going the other way, multiply by 9. For square metres, divide square feet by 10.764, so the same room is 16.7 m².
- How do I measure an L-shaped room for flooring?
- Split it into two rectangles, measure each at its longest and widest points, multiply length by width for each and add them. A 12 × 10 ft main area with a 6 × 4 ft leg is 120 + 24 = 144 sq ft. Include closets and the floor under doors; exclude only built-in fixtures that will never move. The floor area calculator adds up to six rectangles and subtracts fixtures.
- How much waste for a herringbone floor?
- Plan on 20% over the measured area. Every row ends in a 45-degree cut at both walls and the offcuts rarely fit anywhere else. Chevron, where the ends are cut at an angle so the planks meet in a point, is similar. For a small room or a room with alcoves, 25% is safer.
- How do I work out boxes from the coverage on the carton?
- Multiply your area by one plus the waste, divide by the coverage on the box and round up. 250 sq ft at 10% waste is 275 sq ft; at 19.6 sq ft per box that is 14.03, so you buy 15. The boxes calculator also shows the leftover, which is worth keeping for repairs.
- How many 8-foot lengths of baseboard do I need?
- Measure the perimeter, subtract the doorways and openings, add 10% for the mitre cuts and round up to whole lengths. A 12 × 14 ft room with one 3 ft door has 49 ft of wall, so about 54 ft with waste, which is 7 lengths of 8 ft. Use 12 or 16 ft lengths on long walls to avoid joints in the middle of a wall.
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