How Much Flooring Do I Need? Square Footage, Waste and Boxes

Flooring is sold in boxes, not square feet, and the box count is where most people get caught out. Measure the room, add an allowance for cuts and mistakes, then round up to whole boxes.

Step 1: measure the room

For a rectangular room, multiply length by width. A 14 ft x 18 ft room is 252 square feet. In metric, a room 4.2 m x 5.5 m is 23.1 square metres.

For an L-shaped or irregular room, split it into rectangles, work out each area and add them together. Subtract areas that will not be floored, such as a built-in cupboard, but not a small island or a doorway.

Step 2: add a waste allowance

You will cut boards to fit walls and around corners, and some pieces will be damaged or unusable. Typical allowances are:

• 5 to 10 percent for a straightforward straight lay in a simple room
• 10 to 15 percent for diagonal layouts, herringbone or rooms with many corners

Using 10 percent: 252 x 1.10 = 277.2 square feet. In metric: 23.1 x 1.10 = 25.4 square metres.

Step 3: divide by the coverage per box

The coverage is printed on the box. Divide your area, including waste, by that figure and always round up.

• Imperial example: 277.2 / 22.5 square feet per box = 12.3, so buy 13 boxes
• Metric example: 25.4 / 2.2 square metres per pack = 11.5, so buy 12 packs

Step 4: price it

Multiply the number of boxes by the price per box. In the imperial example, 13 boxes at 45 dollars is 585 dollars before underlay, trim and fitting. Remember to include underlay, skirting or baseboard, transition strips and adhesive or fixings if your floor needs them.

Tips that save money and trouble

• Buy from the same batch. Colour can vary slightly between production runs, so buy all boxes together.
• Keep a spare box. If a board is damaged years later, a matching one is hard to find.
• Let it acclimatise. Many floors need to sit in the room for a day or more before fitting. Check the manufacturer’s instructions.
• Measure twice. Walls are rarely perfectly square, so measure the longest length and widest width.

Use the calculator

Our free flooring calculator does these steps for you in feet or metres and gives you a shopping list. To keep the whole renovation in one place, the DIY Project Budget and Materials Planner adds a budget tracker and project timeline.

These are planning estimates. Check box coverage and installation requirements with your supplier and the manufacturer before you buy.