How come we are in the 21st century if we are in the 2000s and not 2100s?

Question

How come we are in the 21st century if we are in the 2000s and not 2100s?

In: Other

Answer 1

1 AD to 99 AD was the 1st century so the 100s are the 2nd century and so on until 2000s which are the 21st century.