How to Measure a Room for Flooring

Ordering flooring comes down to one number: how many boxes you need. Get there by measuring the room accurately, adding a sensible waste allowance and dividing by the coverage printed on each box. The whole job takes a tape measure and a few minutes.

Before you start

Have a tape measure or laser measure, a notepad, a calculator and the coverage figure for the floor you plan to buy. Every box lists how many square metres it covers, and that number is what turns your measurements into an order.

• Tape measure or laser measure
• Notepad and pen for a rough floor plan
• Calculator
• Box coverage in square metres (from the product page)

Calculating floor area

For a rectangular room, measure the length and the width in metres and multiply them. A room 5 m long and 4 m wide is 20 square metres. Measure to the nearest centimetre and round up rather than down, since a short measurement leads to a short order.

Adding a waste allowance

Never order the bare area. Cuts at walls, doorways and around fixtures create offcuts you cannot reuse, and a few boards get damaged during fitting. Add 5% for a simple straight lay, and 10% for diagonal, herringbone or heavily patterned layouts, or rooms with lots of corners.

Odd-shaped rooms

Split an L-shaped or irregular room into simple rectangles. Measure and calculate each rectangle on its own, then add the areas together for the room total. Treat alcoves, bay windows and doorway thresholds as their own small rectangles and include them, since flooring runs into those spaces too.

Converting to boxes

Divide the total area, waste included, by the coverage of one box, then round up to the next whole box. You cannot buy part of a box, so always round up.

Measuring for more than one room

A multi-room project is not just several single rooms added together. If the floor runs continuously through doorways, the layout in one room dictates the starting line in the next, and cutting waste rises where plank runs must carry through openings cleanly. Measure each room separately, sketch how they connect, and note every doorway where the floor either flows through or breaks at a threshold. Then total the areas and apply the waste allowance to the whole project, keeping a little extra where continuous runs pass through narrow openings. A rough sketch on paper prevents most multi-room ordering mistakes before they happen.

Plank direction changes the maths

The same room can consume noticeably different amounts of material depending on which way the planks run. Long runs parallel to the longest wall usually waste least, because offcuts from row ends restart the next row. Run planks across the short dimension and you multiply the number of rows and end cuts. Decide direction before ordering, not on installation morning: usually along the longest sightline or toward the main light source, but always with quantity in mind. Diagonal layouts are handsome and hungrier still. If you are torn between directions, lay a few loose planks both ways in daylight before committing; ten minutes of looking beats a theory.

Do not forget the accessories

The planks are only part of the shopping list, and the forgotten items are what stall an installation on day one. Walk the room with a checklist before ordering.

• Thresholds and transition profiles for every doorway and floor-type change
• Skirting or quadrant beading to cover the expansion gap
• Stair nosings if any steps are involved
• Underlay if your chosen plank does not have an attached acoustic layer
• Flexible sealant for perimeter joints in wet rooms

Attic stock: the smartest leftover

Deliberately keep one unopened box, or at least several full planks, after the job is done and label it with the design name and batch number. Floors get injured by dropped pans and dragged appliances, and a click floor lets you swap a damaged plank, but only if you have matching material from the same production batch. Buying a single box years later almost guarantees a slight colour difference. Attic stock is the cheapest insurance in flooring, and almost nobody thinks of it until the day it is needed.

Store it flat, in the dry, and somewhere you will remember. A box balanced on garage rafters above a damp car is not attic stock, it is a science experiment. The planks themselves do not mind time; what ruins spares is moisture on the carton and forgetting they exist when the accident finally happens.

What a professional fitter checks that you might not

Watch a good installer measure and you notice they spend as much time looking down and around as measuring across. They check the subfloor for flatness with a straightedge, probe for damp, note which way the joists or board joints run, test door swings against the new finished height, and look for out-of-square walls that will force tapered cuts along one side. Each finding changes either the quantity, the preparation list or the layout. Copy that discipline and your order will survive contact with reality. If any single check feels beyond you, that is the part worth paying a professional to do.