Writing numbers

Overview

Numbers should be written and formatted in a clear and consistent way. We always use numerals when presenting statistics, however, there are some instances where we do use words for clarity and readability.

Using words and numerals

Write all numbers 10 and over as numerals, up to 999,999.

Write numbers zero to nine as words unless they are technical or precise, such as dates, figure or table titles, or relate directly to the statistics being presented.

Where a range crosses the 10 boundary, use numerals.

Write out generalised numbers as words.

Rankings

Write out rankings first to ninth, then use numerals. Do not use superscript for “st”, “nd”, “rd” and “th”.

Sequences

A sequence of numbers should use the same format for both, which should follow the higher number.

Fractions

Write out and hyphenate fractions as words. Do not use numerals and slash symbols.

Avoid using too many fractions as it can be difficult to compare several together.

Also avoid using large denominators, such as three-sixteenths. Always simplify your fraction, or consider using a percentage if the fraction could cause confusion.

Write out decimal fractions as numerals. Use the same number format for a sequence of fractions and decimals.

Millions and billions

Write out and use lower case. Do not use “0.xx million” for numbers less than 1 million, unless part of a sequence of numbers.

Roman numerals

Do not use Roman numerals, except when referring to a monarch by their title.

Formatting numbers

Do not use abbreviations of “numbers”, such as “no” or “nos”. They can be read incorrectly.

Use commas to separate thousands in numbers of four digits or more, and never spaces (except when writing years – these should have no punctuation).

Avoid writing sets of numbers together in the same sentence. For example, use "In 1961 just over 2,500 births were recorded" not "In 1961 2,543 births were recorded".

Do not start a sentence with a numeral, unless it is a bullet point. Rearrange the sentence accordingly.

Do not use a hyphen to indicate a range of numbers, separate with “to”.

Decimals

Always use the same number of decimal places when listing a sequence of numbers or percentages.

Use a 0 where there is no digit before the decimal point in a number. For example, 0.6% not .6%.

Positive and negative numbers

In text, when referring to positive and negative numbers, write out “positive” and “negative” in full. Do not use the minus or plus symbol in your main content.

Read more about why symbols and special characters may not be accessible

In a dataset, use the symbols with no space between them and the number.

Page numbers

Use the fewest digits possible while remaining clear. Separate them with “to” and always use numerals.

Read more about cross referencing in citations, references and sources

Superscript and subscript

Do not use superscript and subscript formatting for numbers within text (except in equations properly formatted as such).

For numbers used as footnote markers, write these in full size, preceded by the word “note” and placed in square brackets:

Write numbers in chemical elements at full size.

Read more about how to reference chemical elements in our climate change guidance

Telephone numbers

When writing telephone numbers, think about your users. The format of the telephone number will depend on the target users.

For content that is only targeted or relevant to a UK audience, for example, survey invitation letters, always start with 0 instead of +44 to avoid confusion.

For content that is targeted at, or may be of interest to, international users, remove the leading zero from the number and replace it with the UK’s international dialling code: +44.

Add a space between this code and the rest of the phone number. Group the remaining numbers and use spaces between them to make them easier to read and input.

Do not include the zero you have removed in brackets; this is particularly important for accessibility as it can affect how some assistive technologies read the number. Do not use 00 instead of the plus symbol (+) as it does not work from all countries.

This is in line with the UN’s International Telecommunication Union standards, which are recognised worldwide.