Use words from one to nine and numerals from 10 upwards. Always use words for numbers at the start of a sentence. Ideally, avoid starting sentences with a number. Within sentences, use either all words or all figures for consistency, for example:
- between 1 and 12, or
- between one and twelve
If spelling out numbers between 21 and 99, hyphenate:
- Twenty-one, twenty-two, twenty-three ... ninety-nine.
Use figures for all abbreviated forms of units, e.g. 13mm. Use figures in mathematical or statistical contexts.
Use a comma in numbers with more than three digits:
Write dates in this format:
- Monday 1 January 2012.
If the year is not relevant or is clear from the context, you can shorten to 1 January.
Do not use 1st, 2nd etc. Avoid writing dates in figures, but if you have to, use full stops to separate the day, month and year, and do not use additional zeros, e.g. 1 December 2012 becomes 1.1.12.
Write financial years with a forward slash, e.g. 2013/14.
Decimals and fractions
Spell out fractions, e.g. three quarters. Use a decimal when a number can't be easily written out as a fraction, like 1.15 or 38.4.
When referring to monetary values in text, use words (pounds, euros, yen) for the currency, e.g. "Early intervention could save millions of pounds a year". Use currency symbols (£, €, ¥) before the amount only when using figures, e.g. £1, £100, £1million.
Do not capitalise names of currencies, e.g. euros not Euros.
Percentage signs (%) can be used in a statistical context. You don't need to write out as "per cent".
Use metric measurements and weights (metres, kilometres, grams and kilograms) where the information is available in that format. Abbreviate the measurement, use the singular form and don't put a space between the measurement and the number, e.g. 300cm or 3kg.
Spell out ambiguous abbreviations for clarity, e.g. inch and litre.
In general, phone numbers should be written as follows:
- London numbers – 020 7388 1266
- mobile numbers – 07733 370 777
- regional numbers – 0161 792 5532
- freephone numbers – 0845 766 9999
Some organisations prefer their phone number to be grouped in a non-standard way to make it easier to remember. For example, the Samaritans write their number like this: 08457 90 90 90. If this is the case, follow the format on the organisation's website.
Use an en dash to indicate a range or a period of time, for example:
- pp. 11–12
- 1–2 tablets
Use the 12-hour clock with am or pm, e.g. 9am, 12pm or 3.30pm.