M is the Roman numeral for thousand and MM is meant to convey one thousand-thousand — or million.

Is M the abbreviation for million?

The most common abbreviations for million are:

M. MM.

How do you abbreviate 1000?

For the most part, the abbreviation “M” is used as in settings that deal with money and financing, such as bank and corporate accounting records. “K” is a more casual abbreviation. Using “M” as an abbreviation for thousand dates back to the Roman numeral system, where “M” was the symbol for thousand.