What Does M Mean in Roman Numerals?
M is one thousand, the largest single symbol in standard Roman numerals. Two M glyphs open every year from 2000 onward, which is why modern date tattoos always begin with MM.
Where M comes from
M comes from the Latin mille, meaning one thousand, so like C it shares its first letter with the word it stands for. Earlier writers used other signs for a thousand, but the initial-letter M won out and stayed.
How M behaves
- M repeats up to three times: M, MM, MMM for one, two and three thousand.
- M is never subtracted, because there is no larger standard symbol to place it before.
- Because M is the ceiling, the largest number standard numerals reach is 3999, MMMCMXCIX. Larger values need an overline that multiplies a symbol by a thousand.
M in action
The same symbol behaves differently depending on what sits beside it. These worked examples show M added, and where it applies, subtracted.
| Number | Numeral | What M is doing |
|---|---|---|
| 1,000 | M | M on its own is one thousand. |
| 2,000 | MM | MM is two thousands, the opening of every 2000s year. |
| 3,000 | MMM | MMM is three thousands, the largest plain run of M's. |
| 3,999 | MMMCMXCIX | MMMCMXCIX is the largest standard Roman numeral, three thousands and 999. |
Try it in the converter
Type any number to see where M lands inside its numeral, or read a numeral back to a number.
1000 is written M in Roman numerals.
Frequently asked questions
What does M mean in Roman numerals?
M means one thousand, from the Latin mille. It is the largest single symbol in the standard system.
What is the largest number M can help write?
3999, written MMMCMXCIX. With only three M's allowed and no larger symbol, standard Roman numerals stop there; bigger values use an overline to multiply by a thousand.
Why do modern years start with MM?
Every year from 2000 to 2999 begins with two thousands, MM, and the letters after it carry the rest. That is why dates from this century open with MM.