Laminate and hardwood flooring calculator

How to use it

Decide which way the planks will run first, because it changes the row plan (though not the box count). Enter the room dimension along the planks as the length and the dimension across them as the width. For an L-shaped or irregular room, get the total area from the square footage calculator and enter it as a length with a width of 1; then check the row plan separately for the widest part of the room.

Take the coverage per box from the box or the product listing. It is the one number you can rely on: plank dimensions are often nominal, and the tongue does not count towards coverage. For the row plan, measure the visible face width of an actual plank.

The method

Boxes = room area × (1 + waste %) ÷ coverage per box, rounded up.

Rows: subtract the expansion gap from each side of the width to get the usable width. Divide by the plank face width. The whole number is the count of full-width rows; the remainder is the width of the last row, which will be ripped lengthways.

Balanced edges: if the remainder is small, rip the first row too, so that the first and last rows each get (remainder + one plank width) ÷ 2. That is always at least half a plank. The number of rows does not change; one full row becomes two part rows.

The page flags the last row as narrow when it is under a third of a plank. That is a working threshold, not a standard: some installation guides give a fixed minimum instead, and you should use whichever your flooring's instructions state.

A worked example

A 15 × 12 ft room is 180 sq ft (16.72 m²). With 10% waste that is 198 sq ft; at 20 sq ft per box, 9.9 boxes, so 10 boxes and 200 sq ft of flooring. The planks run the 15 ft way, so the rows stack across 12 ft (144 in). Take off 3/8 in at each wall and 143.25 in is usable. 143.25 ÷ 7.5 = 19.1: nineteen full rows and a last row 3/4 in wide. That is a sliver. Ripping the first row as well gives two edge rows of (0.75 + 7.5) ÷ 2 = 4 1/8 in each, and the same 20 rows in total.

Expansion gaps and why they exist

Wood and wood-based flooring swells and shrinks with humidity, mostly across the width of the board. A floor that meets the walls with no gap has nowhere to go when it expands, and buckles or lifts. The gap is hidden by baseboard or quarter-round, which is why it is measured to the wall, not to the trim. Leave it at every fixed vertical surface: walls, door frames, pipes, cabinets, stair nosings.

• Floating laminate: typically around 1/4 to 3/8 in (6 to 10 mm), per the maker.
• Engineered wood: per the maker; floating installations resemble laminate, glued-down ones may differ.
• Solid wood: commonly about the thickness of the board, and more in wide rooms.

Long uninterrupted runs of floating floor may also need expansion breaks at doorways or beyond a set length. Manufacturers state the limit; it varies widely.

Where this stops being reliable

• Out-of-square rooms. If the walls are not parallel, the last row tapers. Measure the width at both ends and check the plan at each.
• Herringbone and chevron. These are sold in their own boxes with their own coverage and need a higher waste figure; the row plan here does not apply.
• Stairs. Treads and risers are finished with dedicated nosings and are counted by the step, not by area.
• Closets and alcoves. A deep closet effectively adds a second, narrow room with its own row plan.