What is the Roman numeral for 100?

The Roman numeral for 100 is C.

C represents 100 in the Roman numeral system. It is written as a single capital C, rather than as a combination of smaller symbols, because C is one of the system’s basic numeral values.

The symbol developed from earlier Etruscan and Roman signs for 100. Its resemblance to the Latin word centum, meaning “hundred,” likely helped C become the standard form. Roman numerals were originally used for practical counting, inscriptions, dates, numbering, and commerce rather than for modern positional arithmetic.

The other major Roman numeral values are I for 1, V for 5, X for 10, L for 50, D for 500, and M for 1,000. This makes C easy to confuse with L, which is 50, or D, which is 500. In a larger number, symbols can be combined: CC means 200, while CD means 400 under the familiar subtractive convention.

Roman numeral usage was not perfectly uniform in ancient times, but C as 100 is the standard answer in modern quizzes and notation.