Measurements

In most cases, use numerals with units of measurement, even if you spell out the unit.

Body text

For a general audience, use numerals with the unit spelt out

The new record was 100 metres.

The police seized 6 kilograms of the drug.

For a general audience, it’s generally best to spell out the unit of measurement rather than using a symbol, particularly if it is an unfamiliar measurement. But always consider the context. A recipe book, for example, wouldn’t need the measurements spelt out in its ingredient lists.

Where you do spell out, make sure the unit takes an ‘s’ in the plural form.

The Darwin River Dam can hold around 260,000 megalitres of water.

Many external hard drives now allow up to 2 terabytes of storage.

Of course, if you’re writing for a technical audience who will be very familiar with the units, you can use the symbol. It doesn’t take an ‘s’ in the plural form.

Tables and graphics

Where space is tight, use numerals with the recognised SI symbol

100 m

6 kg

Where space is limited, such as in a table, chart or graph, use a numeral with the symbol. Choose the recognised metric symbol from the International System of Units (SI units). The base units from this system are:

Quantity	Unit	Symbol
Time	second	s
Length	metre	m
Mass	kilogram	kg
Electric current	ampere	A
Temperature	kelvin	K
Amount of substance	mole	mol
Luminous intensity	candela	cd

Compound adjectives

Keep a unit of measurement in singular form when using it as an adjective

a 10 kilogram load

a 4.5 metre cord

When the measurement acts as a compound adjective describing a noun, keep the unit in the singular. Only hyphenate the compound if the meaning would otherwise be unclear.

The motorway will bypass a 22 kilometre stretch of local roads.

Five 18-metre steel girders were delivered to the site yesterday.

This approach minimises punctuation and keeps text cleaner and clearer. It is also consistent in that hyphens are used only where a compound adjective may cause ambiguity without one.

Fortunately, the blue-green algae emerged 6 kilometres downstream of the inlet.

Spacing

Add a space between the numeral and the unit, except for percentages (%), degrees (°) and minutes (')

60 km

28°C

Add a space before the unit of measurement except with:

percentages
degrees Celsius for temperature, because the degree symbol also acts as the spacer
the prime symbol representing minutes of an angle, because this could otherwise be missed in the text.

Keep numerals and their units on one line by inserting a non-breaking space.

See also: Money, Numbers, per, Spaces, Temperatures, Times