The ROUND function in Excel
We use the ROUND function to work with any number of decimal places. Unlike when we apply a format on the cell to display more or fewer decimal, the ROUND function effectively modifies the stored value in the Excel cell. The syntax for the ROUND function is: ROUND(number, num_digits)
The function only requires two arguments, the first of them the number we want to round, the second is the number of decimal places that we need. Consider the following examples: = ROUND (3.1416, 0). It returns the value 3, because we are indicating zero as the number of decimals we need. = ROUND (3.1416, 3). It returns the value 3,142 because we specified three decimal places.
ROUNDUP and ROUNDDOWN functions in Excel
These functions have the same arguments that the ROUND function and the difference is that ROUNDUP always rounds up the specified number and the ROUNDDOWN function makes rounding down.
In the next picture you can see the difference between each of the three functions by applying rounding the value of the mathematical constant PI.
Each function applies a different rounding even if you applied the same number of decimal places. Notice how the result of the function ROUND sometimes agrees with the result and sometimes ROUNDUP agrees with the result ROUNDDOWN. The next time you need round in Excel know that there are three functions that can help you get the desired result. (Source: Excel Total)