Units, numbers and dates

Units of measure

We always use metric units – metre, kilometre, Celsius or ºC, kWh, MWh, GWh

• When combining with a number leave a (non-breaking) space between the number and the unit, except for temperature and percentages

• When writing a range do not repeat the unit, and use ‘to’ in running text

• Always use a subscript 2 in the abbreviation for carbon dioxide

Using numbers

• Write numbers one to ten as words, use numerals for numbers 11 and greater.

• Avoid starting sentences with numbers; most can be spelled out, so try to write the sentence a different way.

• Year as this must be written in numerals.

• Money is always expressed in numerals.

• For numbers above one thousand, except dates, use the correct separators: 12,456.98.

• Negative numbers: prefix with a minus sign.

• Percentages:

  • no space between the number and the % sign

  • use either digits and symbol or all words, do not mix

• Units of measure: place a space between the number and the unit of measure abbreviation

Dates and times

To avoid any confusion always write the date in full in running text. Write the month in words and always put the month in the middle. This is the European way of writing dates.

Do not use superscripts with the day number. If the day of the week is included, there is no comma after the day.

When referring to a decade, write the 1990s, no apostrophe, never write ‘the nineties’.