In 1 centuries there are 0.1 millennia. Meanwhile in 1 millennia there are 10 centuries. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Millennia to Centuries calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert centuries to millennia, use this rule: 1 millennium = 10 centuries. That means you can convert by dividing centuries by 10.
If you want a quick check in years, remember:
So converting centuries to millennia is the same as moving from 100-year units to 1,000-year units by dividing by 10.
There are 10 centuries in 1 millennium. A century is 100 years, and a millennium is 1,000 years. Since 1,000 divided by 100 equals 10, the conversion is direct.
A century is 0.1 millennia. One millennium equals 10 centuries, so 1 century is one-tenth of a millennium.
Use this formula: millennia = centuries ÷ 10.
Examples: 5 centuries = 0.5 millennia, 12 centuries = 1.2 millennia.
Use this formula: centuries = millennia × 10.
Examples: 2 millennia = 20 centuries, 0.3 millennia = 3 centuries.
Yes. In standard calendar use, a century is always 100 years, and a millennium is always 1,000 years. The math stays the same even when dates and eras change.
No. The conversion is about the length of time, not the label. 300 years is 3 centuries whether it’s BCE or CE.
A century is a 100-year span. In the common counting system, centuries run from year 1 to 100, 101 to 200, and so on. That means the 21st century began in 2001 and ends in 2100.
A millennium is a 1,000-year span. Using the same counting rule, the third millennium began in 2001 and ends in 3000.
Year 2000 is part of the 20th century. The 21st century starts in 2001, not 2000, because the first century began with year 1.
Divide years by 100 to get centuries, and divide years by 1,000 to get millennia.
Examples:
Yes. Time spans can be fractional. For example, 50 years is 0.5 centuries, and 500 years is 0.5 millennia. Fractions are common in science, history, and planning.
Most confusion comes from thinking the change happens when the first digits change (like 1999 to 2000). But counting starts at year 1, not year 0, so the first century is years 1 to 100.
Move the decimal one place to the left.
Examples: 7 centuries = 0.7 millennia, 40 centuries = 4 millennia, 125 centuries = 12.5 millennia.
Move the decimal one place to the right.
Examples: 1.2 millennia = 12 centuries, 0.05 millennia = 0.5 centuries, 3 millennia = 30 centuries.
The Calculate Box tool to convert centuries to millennia uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a centuries value in the box and have it instantly converted to millennia.