The full form of 1K is One Thousand.

1000 or one thousand is the natural number following 999 and preceding 1001. In most English-speaking countries, it is often written with a comma separating the thousands digit: 1,000.

It may also be described as the short thousand in historical discussion of medieval contexts where it might be confused with the Germanic concept of the “long thousand” (1200).

A period of 1,000 years is sometimes termed, after the Greek root, a chiliad. A chiliad of other objects means 1,000 of them

• The decimal representation for one thousand is
  • 1000—a one followed by three zeros, in the general notation ;
  • 1 × 10³—in engineering notation, which for this number coincides with :
  • 1 × 10³ exactly—in scientific normalized exponential notation ;
  • 1 E+3 exactly—in scientific E notation.