YY

Units & Measurements abbreviation · Time

YY
Stands forYear (two-digit)
CategoriesUnits & Measurements

YY stands for Year (two-digit), a time abbreviation.

Two-digit year placeholder, as in MM/YY on credit card expiration dates or DD/MM/YY on receipts. It saves space but omits the century, so 05 could mean 1905 or 2005.

Example: Use MM/YY for the expiry, so a card valid through September 2029 is entered as 09/29.

Usage notes

Two-digit years caused the Y2K problem, when software that assumed 19YY faced the year 2000. Many systems interpret YY with a pivot year, treating low values as 20YY and the rest as 19YY. In Java date patterns, lowercase yy is the calendar year while uppercase YY is the week-based year, which differs around New Year.

More time abbreviations

  • a – Annum (year)
  • a.m. – Ante meridiem (before midday)
  • AD – Anno Domini (in the year of the Lord)
  • BC – Before Christ
  • BCE – Before the Common Era
  • BP – Before Present
  • CE – Common Era
  • CY – Calendar year
  • d – Day
  • DD – Day (two-digit, in date formats)
  • DD/MM/YYYY – Day/month/year (date format)
  • FY – Fiscal year

See all 51 time abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.