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(1066): the 11th century, the years 1001 to 1100.
: the 19th century, not the 20th. It is the last year of the century that began in 1801.
(44 BC): the 1st century BC, the years 100 BC to 1 BC.
(around 2560 BC): the 26th century BC and the 3rd millennium BC.

What century is it now?

It is the 21st century. The 21st century began on January 1, 2001 and ends on December 31, 2100. It is also the third millennium, which runs from 2001 to 3000.

When is the next century?

The 22nd century begins on January 1, 2101, which is 75 years after 2026. The next millennium, the 4th, begins on January 1, 3001, 975 years after 2026.

A century is 100 years and a millennium is 1,000 years, or ten centuries. A century before 2026 was 1926.

How to work out the century of a year

For most years, take the hundreds (the digits before the last two) and add one. 1066 has 10 hundreds, so it is in the 11th century; 2026 has 20, so it is in the 21st.

The exception is a year ending in 00, which closes its century rather than opening the next one. The 1st century was the years 1 to 100, because counting started at year 1, so every century ends on a round hundred. 1900 is the last year of the 19th century and 2000 the last year of the 20th, which is why the third millennium began in 2001, not 2000.

Why the 1900s are the 20th century

A century's number is one ahead of the hundreds in its years: the years 1901 to 2000 are the 20th century because they are the twentieth block of a hundred years counted from AD 1. People also name a century by its hundreds, as in "the 1900s", meaning 1900 to 1999. The two names cover the same years except for 1900 and 2000.

In everyday use most people treat the 20th century as 1900 to 1999, and that is what Preceden does when you type 20th century as an event date, so the event lines up with the 1900s. This calculator shows the strict count, which is the one the US Naval Observatory and most reference works use.

List of centuries and how long ago they were

Each century's years use the strict count, and how long ago is counted from 2026.

Century	Years	Years ago
21st	2001 to 2100	Now
20th	1901 to 2000	26 to 125
19th	1801 to 1900	126 to 225
18th	1701 to 1800	226 to 325
17th	1601 to 1700	326 to 425
16th	1501 to 1600	426 to 525
15th	1401 to 1500	526 to 625
14th	1301 to 1400	626 to 725
13th	1201 to 1300	726 to 825
12th	1101 to 1200	826 to 925
11th	1001 to 1100	926 to 1,025
10th	901 to 1000	1,026 to 1,125
9th	801 to 900	1,126 to 1,225
8th	701 to 800	1,226 to 1,325
7th	601 to 700	1,326 to 1,425
6th	501 to 600	1,426 to 1,525
5th	401 to 500	1,526 to 1,625
4th	301 to 400	1,626 to 1,725
3rd	201 to 300	1,726 to 1,825
2nd	101 to 200	1,826 to 1,925
1st	1 to 100	1,926 to 2,025
1st BC	100 to 1 BC	2,026 to 2,125
2nd BC	200 to 101 BC	2,126 to 2,225
3rd BC	300 to 201 BC	2,226 to 2,325
4th BC	400 to 301 BC	2,326 to 2,425
5th BC	500 to 401 BC	2,426 to 2,525
6th BC	600 to 501 BC	2,526 to 2,625
7th BC	700 to 601 BC	2,626 to 2,725
8th BC	800 to 701 BC	2,726 to 2,825
9th BC	900 to 801 BC	2,826 to 2,925
10th BC	1000 to 901 BC	2,926 to 3,025

Centuries BC

Years BC count down toward AD 1, and so do centuries. The 1st century BC is 100 BC to 1 BC, the 2nd century BC is 200 BC to 101 BC, and so on. There is no year zero and no century zero: the 1st century BC is followed directly by the 1st century AD.

So the 5th century BC, the age of classical Athens, runs from 500 BC to 401 BC. BCE and CE are other names for BC and AD with the same numbers, so the 5th century BCE is the same hundred years.

What millennium are we in?

We are in the 3rd millennium, which began on January 1, 2001 and ends on December 31, 3000. Millennia work the same way as centuries, in thousands. The 1st millennium AD is the years 1 to 1000, the 2nd is 1001 to 2000, and the 3rd began in 2001. Before AD 1, the 1st millennium BC is 1000 BC to 1 BC.

Related tools

To count the years between two years BC or AD, or how many years ago one was, use the BC/AD years calculator. To find the date halfway between two dates, use the date midpoint calculator. To write a year or a date in Roman numerals, use the Roman numeral date converter. To see which generation a birth year belongs to, use the generation calculator.

Seeing centuries on a timeline

Centuries are easier to compare when you can see them side by side. Preceden can put dates BC and AD on one timeline, and an event's date can be a whole century, such as 5th century BC.

More free date and time tools

What Century Is It? Century Calculator