How much wastage should I allow for flooring?

Ten percent for a straightforward rectangular room with a grid layout, fifteen percent for diagonal layouts, wide planks, large tiles, or rooms with many corners. The spare is worth keeping for future repairs, so do not try to trim it too tight.

Do I measure into doorways?

Yes — flooring should extend under the door frame so there is no visible gap at the threshold. Measure to the wall behind the door frame, not to the threshold, and allow a little extra wastage for the doorway cut.

How do I measure an L-shaped room?

Split the L into two rectangles, measure each, and add the areas (including each one’s wastage). Averaging the dimensions of an L-shape in one calculation understates the area and the cuts, so per-rectangle is more accurate.

Should I order carpet by area or by roll width?

Carpet is sold in fixed roll widths, so the supplier calculates the linear metres from your room’s narrower dimension rounded up to the roll width. Use the area figure as a check on their quote, but let the supplier do the final cut calculation.

Cooking & DIY/Home Calculators

How to Measure a Room for Flooring

Measuring a room for flooring is the first and most important step of the job: order too little and you stop mid-room for a second batch that may not match; order too much and you pay for material you cannot return. The measurement itself is simple — length × width, plus a wastage allowance — but the details (irregular rooms, multiple spaces, the right unit for the supplier) catch out first-timers. This guide walks through the process so you order the right amount the first time.

Pair it with the Floor Area Calculator and Tile Quantity Calculator to turn the measurements into an order quantity. The core idea is to measure each rectangular section separately, add the areas, and apply a wastage percentage that matches the layout.

In detail

Measure length and width at the longest points

Measure the room’s length and width at their longest points, including any alcoves or recesses you plan to floor. Use a tape measure and measure in metres (or feet if your supplier sells by the square foot), rounding up to the nearest centimetre. Measure into doorways — the flooring should extend under the door frame, not stop at the threshold — and note any fixed furniture you are flooring around. For a rectangular room, the area is simply length × width.

Break irregular rooms into rectangles

L-shaped rooms, rooms with bays, or rooms with angled corners cannot be measured as one rectangle. Break the floor into rectangles — an L-shape becomes two rectangles, a bay window becomes a small rectangle — measure each, and add the areas. Do not try to average the dimensions of an irregular room into one calculation: that hides where the cuts fall and understates both the area and the wastage. Per-rectangle measurement is more accurate and only takes a minute longer.

Allow wastage for cuts and offcuts

Add a wastage percentage to the total area to cover cuts at the edges, offcuts around doorways, and the inevitable mistakes. Ten percent is standard for a straightforward rectangular room with a grid layout. Fifteen percent is better for diagonal layouts, wide planks, large-format tiles, or rooms with many corners and alcoves where each cut wastes more. The wastage is not wasted money — the spare boxes are worth keeping for future repairs, especially for tiles and laminate where a matching batch may be unavailable later.

Order in the unit your supplier uses

Flooring is sold by the square metre in Europe and much of the world, by the square foot or square yard in the United States, and carpet is often sold in fixed roll widths (typically 2 m or 12 ft) which means you may need to round the room’s narrower dimension up to the roll width. The Floor Area Calculator shows the area in both m² and ft² so you can order in whichever unit the supplier uses without a second conversion. For carpet, confirm the roll width with the supplier and let them calculate the linear metres — the area figure is your check, not the order quantity.

Multiple rooms and doorways

For several rooms, measure and calculate each separately, then add the areas including each room’s wastage. Keep a note of each room’s area so you can check the supplier’s quote line by line. Where flooring runs continuously through a doorway between two rooms, you can treat them as one area if the flooring direction is the same, but allow a little extra wastage for the doorway cut. Where the direction changes at a doorway, treat them as separate areas — the change of direction wastes more at the join.

Frequently asked questions

How much wastage should I allow for flooring?: Ten percent for a straightforward rectangular room with a grid layout, fifteen percent for diagonal layouts, wide planks, large tiles, or rooms with many corners. The spare is worth keeping for future repairs, so do not try to trim it too tight.
Do I measure into doorways?: Yes — flooring should extend under the door frame so there is no visible gap at the threshold. Measure to the wall behind the door frame, not to the threshold, and allow a little extra wastage for the doorway cut.
How do I measure an L-shaped room?: Split the L into two rectangles, measure each, and add the areas (including each one’s wastage). Averaging the dimensions of an L-shape in one calculation understates the area and the cuts, so per-rectangle is more accurate.
Should I order carpet by area or by roll width?: Carpet is sold in fixed roll widths, so the supplier calculates the linear metres from your room’s narrower dimension rounded up to the roll width. Use the area figure as a check on their quote, but let the supplier do the final cut calculation.

Related calculators

Concept guide based on standard flooring measurement practice. Wastage defaults: 10% straight layout, 15% patterned or large-format. Last updated: September 2026.

These guides are provided for general information only and do not constitute financial advice. Exchange rates, tax rules, customs allowances and tipping customs vary by country, provider and over time. Always confirm critical figures with the relevant authority or a qualified adviser before acting on anything here.