999 (nine hundred [and] ninety-nine or nine-nine-nine) is a natural number following 998 and preceding 1000. It is the largest 3-digit decimal integer.

• In some parts of the world, such as the UK and Commonwealth countries, 999 (pronounced as 9-9-9) is the main emergency telephone number.^[1]
• 999 are an active punk band based in London.^[2]
• 999 is also the short name for the visual novel Nine Hours, Nine Persons, Nine Doors.
• 999 is the last 3-digit number. When using thousands separators in English-speaking countries, it is the last number written without a comma, as numbers 1,000 and above require at least one.
• 999 is the number the late rapper Juice WRLD chose as his moto, he explains it as ”999 is 666 flipped upside down to resemble taking carnality and turning it upside down turning it into spirituality.“
• In many video games, 999 is the maximum score that can be displayed.