Journals Library

Use of numbers

Use of numbers


  • Ages should be written in full from one to ten and as numerals for 11 upwards. For example: over 40, under nine
  • Always use numerals and hyphens for the adjectival form, e.g. ‘8-year-old child’ or ‘80-year-old woman’

Equation numbering

Please number all equations in your report in the following format, aligned to the right of the equation. For example:

S= −2.59N2+8.74N+90.07                                                                                      (1)

Numbers, units and dates

  • Numbers in the text should usually be written in full from one to ten and as numerals for 11 upwards
  • Ordinal numbers up to and including nine in full, thereafter numerals, e.g. 21st
  • However, numerals may be used for numbers less than ten if presented in parentheses, and numbers at the beginning of a sentence should always be written in full
  • Numbers followed by units should always be presented as numerals
  • Units of time should not be abbreviated: years, months, weeks, days, hours, minutes, seconds
  • Compound units separated by a slash: kg/m2, ml (not mL)


  • Per cent should normally be written in full; however, if this appears several times within a paragraph it is acceptable to use the % symbol
  • The % symbol should always be used in mathematical and statistical contexts, tables and lists
  • The % symbol must always be associated with a numeral, e.g. 7% not seven %

Units of measurement

Units must always be use SI or SI-derived units.