Corporate document

Hyphens and en dashes

Hyphens and en dashes

Use a hyphen if not using one could cause confusion or it looks strange (for example because of doubled vowels except 'oo'):

  • 'Associated Press interviews lion hunting dentist'

  • reenter

  • antiinflammatory.

Antiepileptic, microorganism or antiarrhythmic do not have a hyphen.

Also use hyphens for compound adjectives if it makes them clearer ('a cost-effective treatment' but 'the treatment was cost effective'). But do not hyphenate adjectives that end in -ly ('strictly defined criteria' but 'well-defined criteria'). It's important to put hyphens in the proper place when using compound adjectives; compare pickled-onion seller with pickled onion-seller.

Always hyphenate 'non-'.

Do not hyphenate compound words in common use (healthcare, childcare, crossover, wellbeing, baseline, breastfeeding, birthweight).

Do not hyphenate prefixes like pre, post or peri. Preoperative, postoperative and perioperative are fine but if possible change them to before surgery, after surgery and during surgery.

Try to avoid multiple hyphens in a row, although sometimes this may be needed (non-small-cell lung cancer).

Use an en dash (Ctrl+dash key on the number pad) to show when there's an equal relationship between 2 things, and names formed from 2 people's names. Examples are:

  • Dose–effect response, cost–utility analysis, doctor–patient relationship

  • Creutzfeldt–Jakob disease, Guillain–Barré syndrome, Kaplan–Meier.

Do not use an en dash for ranges. Some screenreaders do not read them out. Instead, use 'from … to' or 'between … and':

  • the ages ranged from 4 to 42 years

  • he usually went to bed between 10pm and 11pm

  • 95% confidence interval -78 to 87.

Note that it's fine to use an en dash in page ranges in references.