How to Round Numbers Down in Excel With the ROUNDDOWN Function

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Excel's ROUNDDOWN Function

Rounding Numbers in Excel with the ROUND Function
Rounding Numbers in Excel with the ROUND Function. © Ted French

The ROUNDDOWN Function:

  • is used to reduce a value by a specific number of decimal places or digits;
  • will always keep the rounding digit the same;
  • alters the value of the data in the cell - unlike formatting options that allow you to change the number of decimal places displayed without actually changing the value in the cell;
  • affects the results of calculations due to this change in data.
  • always rounds towards zero. Negative numbers, even though they are increased in value by the function, are said to be rounded down - as shown in the examples in rows five and six in the image above).

The ROUNDDOWN Function's Syntax and Arguments

A function's syntax refers to the layout of the function and includes the function's name, brackets, and arguments.

The syntax for the ROUNDDOWN function is:

= ROUNDDOWN (Number, Num_digits)

The arguments for the function are:

Number - (required) the value to be rounded

  • This argument can contain the actual data for rounding or it can be a cell reference to the location of the data in the worksheet.

Num_digits - (required) the number of digits that the Number argument will be rounded to.

  • if the Num_digits argument is set to 0, the function rounds the value down to the nearest integer
  • if the Num_digits argument is set to 1, the function leaves only one digit to the right of the decimal point and rounds it down to the next number
  • if the Num_digits argument is negative, all decimal places are removed and the function rounds that number of digits to the left of the decimal point towards zero
    • for example, if the value of the Num_digits argument is set to -2, the function will remove all digits to the right of the decimal point and round the first and second digits to the left of the decimal point down to the nearest 100 as shown in the example in row 6 in the image above

ROUNDDOWN Function Examples

The image above displays examples and gives explanations for a number of results returned by Excel's ROUNDDOWN function for data in column A of the worksheet.

The results, shown in column B, depend upon the value of the Num_digits argument.

The instructions below detail the steps taken to reduce the number in cell A2 in the image above to two decimal places using the ROUNDDOWN function. Because the function always rounds down, the rounding digit will not change.

Entering the ROUNDDOWN Function

Options for entering the function and its arguments include:

  • Typing the complete function: =ROUNDDOWN(A2,2) into cell C3 in the worksheet;
  • Selecting the function and arguments using the function's dialog box.

Using the dialog box simplifies entering the function's arguments. With this method, it is not necessary to enter commas between each of the function's arguments as must be done when the function is typed into a cell - in this case between A2 and 2.

The steps below covering entering the ROUNDDOWN function using the dialog box.

  1. Click on cell C3 to make it the active cell - this is where the results of the ROUNDDOWN function will be displayed;
  2. Click on the Formulas tab of the ribbon menu;
  3. Choose Math & Trig from the ribbon to open the function drop down list;
  4. Click on ROUNDDOWN in the list to bring up the function's dialog box;
  5. In the dialog box click on the Number line;
  6. Click on cell A2 in the worksheet to enter that cell reference into the dialog box as the location of the number to be rounded;
  7. Click on the Num_digits line;
  8. Type a two " 2 " to reduce the number in A2 from five to two decimal places;
  9. Click OK to close the dialog box and return to the worksheet;
  10. The answer 567.96 should appear in cell C3;
  11. When you click on cell C2 the complete function = ROUNDDOWN( A2 , 2 ) appears in the formula bar above the worksheet.