Flooring Calculator

Work out how much flooring to buy. Add each room or area, choose your flooring type and layout pattern, and the calculator adds the right waste allowance, converts to boxes using the coverage on the carton, and estimates underlayment and total cost.

How to measure a room for flooring

1. Measure the length and width of each room at the widest points, wall to wall, in feet and inches; round up to the next inch.
2. Convert inches to decimal feet: 6 inches is 0.5 ft, 3 inches is 0.25 ft.
3. For L-shaped or irregular rooms, split the floor into rectangles, measure each, and add them as separate areas.
4. Include closets, alcoves and the area under built-in appliances if the flooring will run under them.
5. Measure doorways separately if the new floor will extend into them.

The calculator multiplies each area's length by width and adds them up, then applies a waste allowance for cuts.

How much extra flooring to buy

It is also wise to keep a box of leftovers after installation for future repairs; flooring lines are discontinued and dye lots vary, so matching later can be difficult.

Converting to boxes

Flooring is sold by the box, and each carton lists its coverage in square feet — for example 23.64 sq ft for a box of vinyl planks. Divide the area to buy, including waste, by the coverage per box, and round up to whole boxes. Check that all boxes come from the same production lot or dye lot, printed on the carton, especially for hardwood and tile, where colour and shade can vary between batches.

Worked example

A living room of 18 × 14 ft (252 sq ft) and a hallway of 12 × 3.5 ft (42 sq ft) total 294 sq ft. With luxury vinyl plank laid straight in a simple layout, a 7% waste allowance brings the purchase to about 315 sq ft. At 23.64 sq ft per box that is 13.3 boxes, so 14 boxes, covering 331 sq ft. At $2.79 per sq ft, the material costs about $923. If the planks do not have an attached pad and the manufacturer requires underlayment, three 100 sq ft rolls cover the 294 sq ft.

Choosing a flooring type

• Luxury vinyl plank (LVP) — waterproof core, good for kitchens, bathrooms and basements; floating click installation.
• Laminate — durable wear layer at a lower price; many are water-resistant but not fully waterproof.
• Engineered hardwood — real wood veneer on a stable core; can float, glue or nail down.
• Solid hardwood — can be refinished many times; not suitable below grade or in wet rooms.
• Tile — ceramic or porcelain; very durable and water-resistant; needs thinset, grout and more labour.
• Carpet — sold by the square yard (9 sq ft), usually installed with pad and tack strip.

Underlayment and subfloor preparation

Floating floors such as laminate and many LVP products need an underlayment unless one is attached to the planks. Underlayment smooths minor imperfections, reduces noise and, for laminate over concrete, often includes a vapour barrier. Check the manufacturer's instructions: some LVP warranties prohibit adding extra underlayment to planks with an attached pad. Whatever the floor, the subfloor must be clean, dry and flat within the manufacturer's tolerance — often around 3/16 inch over 10 feet — or the joints can separate or click locks can break.

Other materials to budget for

• Transition strips and thresholds at doorways and where floor types meet.
• Quarter-round or shoe moulding to cover expansion gaps at walls.
• Stair nosing for steps.
• Adhesive, nails or thinset and grout, depending on the floor type.
• Tools: tapping block, pull bar, spacers, saw and cutter.

Acclimatising and expansion gaps

Many floors — especially hardwood and some laminates — should acclimatise in the room where they will be installed for a period specified by the manufacturer, often 48 hours or more, with the heating or air conditioning running normally. Floating floors expand and contract with temperature and humidity, so leave the expansion gap around walls and fixed objects that the instructions require, typically about 1/4 to 1/2 inch, and cover it with baseboard or quarter-round rather than filling it.