year that follows a year with a multiple of 100 (except the first century as it began after the year 1 BC) and ends with the next coming year with a multiple of 100 (100n), i.e. the 20th century comprises the years 1901 to 2000, and the 21st century comprises the years 2001 to 2100 in strict usage.

In common 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