What Is the Roman Numeral for One Million?

The Roman numeral for one million is the letter M with a horizontal line across the top. This line, which is rarely used, indicates that the number should be multiplied by 1,000. Since the letter M represents 1,000, M plus the line represents 1,000 multiplied by 1,000.

Romans used a set of letters to represent numbers. In addition to M, the following letters were used: