In popular perception and practice, centuries are structured by grouping years based on sharing the 'hundreds' digit(s). In this model, the 'n' -th century starts with the year that ends in "00" and ends with the year ending in "99"; for example, the years 1900 to 1999, in popular culture, constitute the 20th century.

Is 2020 the 21st century?

The 21st (twenty-first) century (or the XXIst century) is the current century in the Anno Domini era or Common Era, under the Gregorian calendar. It began on January 1, 2001 (MMI) and will end on December 31, 2100 (MMC).

Is 2000 the 20th Century or 21st century?

The 20th Century consists of the years 1901 through 2000 and will end Dec. 31, 2000. The 21st Century will begin Jan. 1, 2001.”