University of Tasmania, Australia

Centuries and decades

Dates, events and periods

Time of day

Centuries and decades

Numerically described periods are not capitalised:

• 21st century
• twenty-first century
• the nineteen-nineties
• 1990s (no apostrophe, i.e. not 1990's)

The preferred style is to use numerals rather than text.

Dates, events and periods

• 27 November 1999 (not 27th)
  
• Monday 27 November 1995 (day, month, year with no punctuation)
• Antarctic summer 1992–93 (with an 'en' dash, not a hyphen)
• 1980s or early 2000s
• '50s and '60s
• in the twentieth century or in the 20th century, but 19th-century literature
• semester 1 or first semester
• semester 1 1996 or the first semester 1996
• World War I and World War II
• the Vietnam War and the French Revolution.

Also refer to Time of day.

Time of day

For time spans, use as few figures as possible and no full points after 'am' and 'pm':

• 9–11 am, not 9am – 11am
• 9 am to 3 pm or 9 am–3 pm, not 9.00 am – 3.00 pm
• noon to 1.30 pm, not noon to 1:30pm

Normally the dash used for time spans is an en rule. For website content, replace the en rule with a hyphen because the en rule does not always display correctly.