ROUNDDOWN function
Rounds a number down, toward zero.
Syntax
ROUNDDOWN(number,num_digits)
Number is any real number that you want rounded down.
Num_digits is the number of digits to which you want to round number.
Remarks

ROUNDDOWN behaves like ROUND, except that it always rounds a number down.

If num_digits is greater than 0 (zero), then number is rounded down to the specified number of decimal places.

If num_digits is 0, then number is rounded down to the nearest integer.

If num_digits is less than 0, then number is rounded down to the left of the decimal point.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example

Create a blank workbook or worksheet.

Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In the worksheet, select cell A1, and press CTRL+V.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

