Count from year 1
For a positive CE year, divide by 100 and round up. An exact multiple of 100 remains the last year of that century.
What Century Is a Year In? Interactive Century and Decade Practice
1900 and 1901.
One year. Different centuries.
A century is a numbered group of 100 years. A named decade such as the 1990s follows a different naming convention. Move the year and see both.
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YOUR RESULT
19th century
Example: 1900 is the last year of the 19th century, which runs from 1801 through 1900. The year 1901 begins the 20th century. A named decade such as the 1900s runs from 1900 through 1909.
Separate century from named decade
The 20th century covers 1901–2000. The named 1990s cover 1990–1999. These labels use different boundaries.
Watch the language in a source
“The 1900s” can mean a decade or, informally, the whole hundred-year period. This lab uses it only as a named ten-year decade.
PastRush: History Detective
Take chronology into a history investigation
PastRush: History Detective includes investigations that ask you to order events, compare sources and judge what evidence supports. Explanations accompany answers, and chronology is one of its investigation modes.
Explore PastRush on the App Store ↗Six investigations are free; an optional one-time purchase unlocks more. This date lab is a separate learning tool, not an app screenshot or saved game.
App details checked against the official App Store listing on November 4, 2026. Availability and purchase terms can change.
Before you use the result
Is 2000 in the 20th or 21st century?
The 20th. The 21st century begins in 2001 and ends in 2100.
Does this support BCE dates?
No. This tool uses positive Common Era years only and does not include a year zero.
Why does the first decade look different?
The named 0s would ordinarily mean 0–9, but this CE-only tool excludes year zero and shows the in-range portion, 1–9.
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