What Does C Mean in Roman Numerals?
C is one hundred, the century mark. It is the C in dates like MMXXIV, the ceiling of the classic 1 to 100 chart, and one of the three symbols that can be subtracted, which it does to make four hundred and nine hundred.
Where C comes from
C comes from the Latin centum, meaning one hundred, so for once the symbol and the word it stands for begin with the same letter. That happy match helped the C stick where earlier hundred-signs did not.
How C behaves
- C repeats up to three times: C, CC, CCC for one, two and three hundred. Four hundred is CD, not CCCC.
- C is a subtracting symbol. Before D or M it is taken away, giving CD (400) and CM (900).
- C is only subtracted from the next two values up, D and M. It is never placed before anything larger than M.
C in action
The same symbol behaves differently depending on what sits beside it. These worked examples show C added, and where it applies, subtracted.
| Number | Numeral | What C is doing |
|---|---|---|
| 300 | CCC | CCC is three hundreds added together. |
| 400 | CD | CD is a hundred before five hundred: the C is subtracted. |
| 900 | CM | CM is a hundred before a thousand, as in the MCM that opens the 1900s. |
| 1,900 | MCM | MCM is a thousand, then nine hundred, the reason every 1900s year starts this way. |
Try it in the converter
Type any number to see where C lands inside its numeral, or read a numeral back to a number.
100 is written C in Roman numerals.
Frequently asked questions
What does C mean in Roman numerals?
C means one hundred, from the Latin centum. It marks the century and is one of the symbols that can be subtracted.
How do you write four hundred and nine hundred with C?
Four hundred is CD, a hundred before five hundred, and nine hundred is CM, a hundred before a thousand. Both subtract the C rather than repeating it.
Why does C stand for a hundred?
It is the first letter of centum, the Latin word for one hundred, which is why the symbol and the value line up so neatly.