What is a linear metre?

In simple terms, a linear metre is, “a metre of length measured in a single direction”. 

A linear metre is used to calculate the length and area of an item when the width of that item is known and consistent. Linear metres are used in tiling, carpeting and flooring, construction, haberdashery (curtains and other fabric), and printing. 

A linear metre is 100 centimetres and 1000 millimetres, just like a regular metre. But where the other value (length or width) of a product is known, linear metres can help you to calculate the total quantity of a product you need for an area.

How do you calculate linear metres?

A simple example is the measurement of carpet for a room. Imagine you are trying to carpet a room that is 2.5 metres by 3.5 metres. If you know your roll of carpet is 2.5 metres wide, you’ll need 3.5 linear metres of carpet to cover the floor of that room. 

Now floorboards. Imagine your floorboards are 25cm wide. To cover an area of 1 square metre (1 metre by 1 metre) you need 4 metre-long floorboards that are each 25cm wide. In this instance, you’ll need 4 linear metres of floorboards.

In both examples, a linear metre is used to measure the value that is variable. The carpet is 2.5 metres wide, and the floorboards are 25cm wide; it is the other measurement of each where you need to use linear metres. 

How do you use linear metres?

You can calculate an area by measuring its two sides and multiplying the two values. For example, a space that is 5 metres wide and 5 metres long has an area of 25 square metres. Once you know the area, you can calculate the number of linear metres required by dividing the area by the known width or length of your product. 

Products like timber decking and floorboards are often sold by the linear metre. In each instance, the width of the product is known so you can easily calculate the number of linear metres you need by dividing the total area by the known width of the product. 

When should I use linear metres for my project?

Using linear metres is a great way to calculate square metres, and an easy way to calculate product requirements if you understand the area (in square metres) you are working in.

Linear metres can be used for any flooring project when you know the total floor area of the room and one of the measurements (length or width) of the product you are using. Carpet is usually manufactured in rolls of a particular width and then sold by the linear metre. 

Floorboards and decking boards are usually produced with a consistent width, so both are sold by the linear metre. Where floorboards or decking boards are produced with a consistent width and length, they are often sold by the square metre instead.

Tiles can be sold by the linear metre, especially when one of the tile’s measurements (length or width) is a number that can be multiplied by a simple number to a total of 1 metre (10 centimetres, 25 centimetres, 50 centimetres, etc). Otherwise, tiles are generally sold by the square metre.

Is it linear metre or lineal metre?

In measurement, mathematics and construction (the context in which we’re using the term here) they are simply different ways of saying the same thing. 

Most Australian tradies and product manufacturers use “linear” but that is because “lineal” can also be used in a different context (a descendant on a family tree) whereas “linear” only has one meaning. So to avoid any confusion, people favour “linear”.