Spell out whole-number words for one to ten; use figures for numbers above ten.
- EXAMPLE: There were two people ahead of me, and six behind me.
- EXAMPLE: I need to buy Christmas presents for 12 people this year.
If there are a lot of figures in a paragraph or text, some above ten and some below, use figures throughout to allow easy comparison by readers.
- EXAMPLE: There were 2 people ahead of me, and 22 behind me. The queues for other advisors had 10, 3 and 12 people.
Spell out words for ‘first’, ‘second’ and so on up to and including ‘tenth’; use numbers and ‘st’/ ‘nd’/ ‘rd’/ ‘th’ for larger ordinal numbers. Don’t use superscript (to prevent problems with line spacing).
- EXAMPLE: She was the first person from her family to go to university.
- EXAMPLE: The 44th president of the United States was Barack Obama.
With hundred and thousand there is a choice of using figures or words:
- EXAMPLE: 300 or three hundred
- AVOID: 3 hundred
- EXAMPLE: EUR 3,000 or three thousand euros
- AVOID: EUR 3 thousand
Note that the numbers 1 through 10 are not spelt out in the following cases: seconds, minutes, hours, days, weeks, months, years, but two decades, three centuries.
As a rule, avoid combining single-digit figures and words using hyphens
- AVOID: a 2-hour journey, but write out instead:
- EXAMPLE: a three-year period; the four-minute mile
NOTE: some set phrases do use numbers
- EXAMPLE: a 40-hour week, a 24-hour clock
When two numbers are adjacent, spell out one of them:
- EXAMPLE: 90 fifty-gram weights, seventy 25-cent stamps
A sentence starting with a figure will often look out of place. Consider writing it out in full or inverting the word order.
- EXAMPLE: During 1992 ..., Altogether 92 cases were found...
However, a sentence beginning with a percentage may start with a figure:
- EXAMPLE: ‘32 % of the funds ...’
Language Boutique 'Writing Numbers – Periods or Commas?' Retrieved from https://language-boutique.com/lost-in-translation-full-reader/writing-numbers-points-or-commas.html