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Trunc

TRUNC Function

The TRUNC (truncate) function in Excel is used to truncate a number to an integer by removing the fractional part of the number. Unlike the ROUND, ROUNDUP, and ROUNDDOWN functions, TRUNC simply cuts off the decimal without any rounding.

Syntax:

TRUNC(number, [num_digits])
  • number: The numeric value you want to truncate.
  • num_digits (optional): Specifies the precision of the truncation. If omitted, it defaults to 0 (zero), which means truncating to the nearest whole number. If a positive number, TRUNC will leave that many digits after the decimal point. If a negative number, it truncates off digits to the left of the decimal point.

Examples:

  1. =TRUNC(8.9) would return 8. It simply removes the decimal part .9, leaving the integer 8.
  2. =TRUNC(-3.7) would return -3. Unlike INT, which rounds negative numbers down, TRUNC just removes the decimal part.
  3. =TRUNC(15.789, 1) would return 15.7, keeping one digit after the decimal point.

Usage Notes:

  • TRUNC is useful when you need to remove the fractional part of a number without rounding.
  • It's particularly handy in financial calculations where fractional parts of a number are not valid, or when working with time calculations.
  • The behavior of TRUNC is similar to INT for positive numbers, but it differs for negative numbers, as INT rounds negative numbers down.

Note: The TRUNC function is often used when the goal is to discard the decimal portion of a number entirely, regardless of whether the remaining integer part is closer or farther to the original number.