See Numbers

Percentages, units of measurements, fractions and ranges of numbers

Writing Percentages

Always use figures and symbols for percentages, measurements and currency. 

  • EXAMPLE:  Question 12 is worth 10% of the available marks.
  • EXAMPLE: The average height of a woman in the UK is 1.61m.
  • EXAMPLE: The cost, at £5.99, was less than their overall budget of £50.

Note, that in British English per cent is two words.  Use per cent where the number is also spelt out in words:

  • EXAMPLE: twenty per cent.

With figures, use the per cent sign (%) preceded by a hard space

  • EXAMPLE: 25 %

Writing units of measurement

Always use figures with units of measurement that are denoted by symbols or abbreviations.

  • EXAMPLE: EUR 50, 250 kW, 205 μg, 5 °C

The converse does not hold. If the units of measurement are spelt out, the numbers do not also have to be spelt out but may be written with figures:

  • EXAMPLE: 250 kilowatts, 500 metres.

Writing units of measurements (tips for tricky words)

Write gram, kilogram      AVOID: gramme, kilogramme

However, use tonne       AVOID:  ton (‘ton’ refers to the non-metric measure).

Write metre for the unit of length, meter for measuring instruments.

  • EXAMPLE: the track was 6 metres 
  • EXAMPLE: you should check the electricity meter regularly 

Writing about fractions

Insert hyphens when a fraction is used as an adverb or adjective 

  • EXAMPLE: two-thirds complete, a two-thirds increase

Do not insert hyphens when the fraction is used as a noun

  • EXAMPLE: an increase of two thirds

Avoid combining figures and words:

  • EXAMPLE: two-thirds completed  AVOID: 2/3 completed

When using figures for a fraction, use the fraction symbol where possible and close it up to any previous figure

  • EXAMPLE: 1⁄2 years.

Ranges of numbers

When a range is written out, repeat symbols and multiples (ie. thousand, million, etc.):

  • EXAMPLE: from EUR 20 million to EUR 30 million between 10 °C and 70 °C

Abbreviated form of a range

When a range is indicated by a hyphen, do not repeat the symbol or multiple if they do not change and close up the hyphen between the figures:

  • EXAMPLE: €20-30 million, 10-70 °C

If the symbol or multiple changes, however, leave a blank space on either side of the hyphen:

  • EXAMPLE: 100 kW - 40 MW


Language Boutique 'Writing Numbers – Periods or Commas?' Retrieved from