Content guide - Numbers, measurements, dates and time

Content styles, including numerals, ordinals, dosage, temperature, fractions and percentages

Designing content for people who struggle with numbers

Half of working-age adults in the UK have low numeracy. Around 1 in 20 people have dyscalculia, which is a specific and persistent difficulty in understanding numbers.

People who struggle with numbers may have problems with:

• entering numbers, like their NHS number
• reference numbers and not knowing what to do with them
• distinguishing the number 0 and letter O
• numbers in tables and charts

Try putting numbers into context in sentences.

If you're communicating statistics or treatment risks and benefits, you could consider visual aids. However, we do not yet have enough research to recommend them. If you explore using visual aids, please feedback your user research findings on the GitHub issue for data visualisation (helping users understand data).

Find out more about presenting numbers clearly on:

• the Accessible numbers website
• the GOV.UK poster on designing for users with dyscalculia or low numeracy

Numbers

Numerals (1, 2, 3 and so on)

We use numerals for numbers (including 1 and 2), for example when we're talking about statistics, time, measurements, lists, points or steps. People find numerals easier to read and they scan for them.

For numbers over 999, use a comma for clarity – for example, 1,000.

Avoid decimal points. Round up numbers to the nearest whole number, except for:

• money
• medicines dosage, for example: 0.5mg
• medical tests or measurements, for example: a BMI of 18.5

If you need to use numbers less than 1, use 0 before the decimal point – for example, 0.25.

Using numerals at the start of a sentence

It is OK to use numerals at the start of a sentence but, if it looks confusing, consider rewording your sentence.

Using numerals in headings

It's also OK to use them in headings.

Using numerals in lists

You can use numerals in lists.

Where we do not use numerals

One

We spell out "one" when it means "a" or to avoid repeating a word.

We also use "one" in phrases like:

• "one or the other"
• "one of the most common"
• "one at a time"

Dosage

We do not use numerals in some medicines information about dosage because we've found they can be confusing. Read more about numbers and dosage.

Ordinal numbers (1st, 2nd, 3rd and so on)

We use numerals with letter suffixes for ordinal numbers (including 1st and 2nd), for example, when we're talking about dates, quantities and things in a list or sequence.

The letters should be the same size as the numbers. Do not use superscript, for example 1^st, as it does not always read out correctly on screen readers and could confuse people.

We do not use ordinal numbers in phrases like:

• first aid
• first time
• first visit
• secondhand smoke
• second opinion

Measurements

Calories

We use "calorie" when talking about calories in general, for example "calorie information on menus". Where appropriate, we explain that calories are often written as "kcal".

We use "kcal" as the unit of measurement. We do not put a space between the number and the measurement.

Dosage

We do not use a space between amount and measurement.

Use your judgement when explaining medicines doses. Avoid having 2 sets of numerals next to each other.

We say:	We do not say:
The usual dose is one or two 200mg tablets 3 times a day.	The usual dose is 1 or 2 200mg tablets 3 times a day.

Temperature

We use Celsius for temperature, but only when talking about children under 6 months old. For adults or children over 6 months old, we do not give a specific temperature.

Read more about temperature in the A to Z of NHS health writing.

Metric and imperial

We generally use metric. If it's helpful, add imperial in brackets, for example, for advice on cutting back on alcohol.

Do not use imperial for medicines dosage or infant feeding.

Dates

We use this format: 6 August 2018. If it's helpful to include the day of the week, for example for users booking appointments, we write dates like this: Wednesday 6 August 2018.

As far as possible, spell out months in full. Screen readers read out shortened months (Jan, Feb and so on) in inconsistent and sometimes confusing ways.

Time

We use:	We do not use:
5pm	5.00pm or 1700hrs
5:30pm	5.30pm or 1730hrs
midnight	00:00, 12am
midday	12 noon, 12pm
6 hours 30 minutes	6.5hrs

Ranges of numbers, dates and time

We use "to" for time, date and numerical ranges, not hyphens or dashes.

Fractions and percentages

Spell out common fractions like two-thirds.

For percentages, use the % symbol - for example, 50%. However, it's often better not to use a percentage. Instead of 50%, for example, you could say "1 in 2" or "half".

Statistics

Use statistics sparingly. Consider the style of writing and your target audience. For example, health professionals may have different needs to members of the public who visit the NHS website.

Use the clearest, most meaningful format to explain what you're illustrating. For example, use "1 in 7 people" rather than "14.3% of people".

Avoid mixing different number formats. Use one or the other.

Help us improve this guidance

Share insights or feedback and take part in the discussion. We use GitHub as a collaboration space. All the information on it is open to the public.

Read more about how to feedback or share insights.

If you have any questions, get in touch with the service manual team.

Updated: August 2023