The 2000s (decade) was the previous decade that started on January 1, 2000 and ended on December 31, 2009. It was the decade in which the 21st century and 3rd millennium began, with 2000 a part of the 20th century and 2001-2009 part of the 21st century.

The 2010s, pronounced "twenty-tens",[1] "two thousand (and) tens", or simply "the tens",[2][3][4][5] is the current decade, which began on January 1, 2010 and will end on December 31, 2019. It is the first decade to completely take place within the 3rd millennium as the previous decade (2000-2009) took place across two different millennia.

The 21st century is the current century of the Christian Era or Common Era in accordance with the Gregorian calendar. It began on January 1, 2001 and will end on December 31, 2100.[1]