How to use the Excel ROUNDDOWN function

Summary

The Excel ROUNDDOWN function returns a number rounded down to a given number of places. Unlike standard rounding, where only numbers less than 5 are rounded down, ROUNDDOWN rounds all numbers down.

Purpose

Round down to given number of digits

Return value

A rounded number.

Syntax

=ROUNDDOWN (number, num_digits)

Arguments

number - The number to round down.
num_digits - The place at which number should be rounded.

Version

Excel 2003

Usage notes

The ROUNDDOWN function rounds numbers down. Unlike standard rounding, where only numbers less than 5 are rounded down, ROUNDDOWN rounds all numbers down. For example:

=ROUNDDOWN(3.9,0) // returns 3

ROUNDDOWN takes two arguments, number and num_digits. Number is the number to be rounded, and num_digits is the place at which number should be rounded. When num_digits is greater than zero, the ROUNDDOWN function rounds on the right side of the decimal point. When num_digits is less or equal to zero, the ROUNDDOWN function rounds on the left side of the decimal point. Use zero (0) for num_digits to round to the nearest integer. The table below summarizes this behavior:

Digits	Behavior
>0	Round down to nearest .1, .01, .001, etc.
<0	Round down to nearest 10, 100, 1000, etc.
=0	Round down to nearest 1

Round to right of decimal

To round down values to the right of the decimal point, use a positive number for digits:

=ROUNDDOWN(A1,1) // Round down to 1 decimal place
=ROUNDDOWN(A1,2) // Round down to 2 decimal places
=ROUNDDOWN(A1,3) // Round down to 3 decimal places
=ROUNDDOWN(A1,4) // Round down to 4 decimal places

Round to left of decimal

To round down values to the left of the decimal point, use zero or a negative number for digits:

=ROUNDDOWN(A1,0) // Round down to nearest 1
=ROUNDDOWN(A1,-1) // Round down to nearest 10
=ROUNDDOWN(A1,-2) // Round down to nearest 100
=ROUNDDOWN(A1,-3) // Round down to nearest 1000
=ROUNDDOWN(A1,-4) // Round down to nearest 10000

Nesting inside ROUNDDOWN

Other operations and functions can be nested inside ROUNDOWN. For example, to round down the result of A1 divided by B1, you can use a formula like this:

=ROUNDDOWN(A1/B1,0) // round down result to nearest integer

Other rounding functions

Excel provides a number of of rounding functions, each with a different behavior:

To round with standard rules, use the ROUND function.
To round to the nearest multiple, use the MROUND function.
To round down to the nearest specified place, use the ROUNDDOWN function.
To round down to the nearest specified multiple, use the FLOOR function.
To round up to the nearest specified place, use the ROUNDUP function.
To round up to the nearest specified multiple, use the CEILING function.
To round down and return an integer only, use the INT function.
To truncate decimal places, use the TRUNC function.

Related functions

Excel ROUND Function

The Excel ROUND function returns a number rounded to a given number of digits. The ROUND function can round to the right or left of the decimal point.

Excel ROUNDUP Function

The Excel ROUNDUP function returns a number rounded up to a given number of decimal places. Unlike standard rounding, where only numbers less than 5 are rounded down, ROUNDUP rounds all numbers up.

Excel ROUNDDOWN Function

The Excel ROUNDDOWN function returns a number rounded down to a given number of places. Unlike standard rounding, where only numbers less than 5 are rounded down, ROUNDDOWN rounds all numbers down.

Excel CEILING Function

The Excel CEILING function rounds a given number up to the nearest specified multiple. CEILING works like the MROUND function, but CEILING always rounds up.

Excel FLOOR Function

The Excel FLOOR function rounds a given number down to the nearest specified multiple. FLOOR works like the MROUND function, but FLOOR always rounds down.

Excel MROUND Function

The Excel MROUND function returns a number rounded to a given multiple. MROUND will round a number up or down, depending on the nearest multiple.

Excel INT Function

The Excel INT function returns the integer part of a decimal number by rounding down to the integer. Note that negative numbers become more negative. For example, while INT(10.8) returns 10, INT(-10.8) returns -11.

Excel TRUNC Function

The Excel TRUNC function returns a truncated number based on an (optional) number of digits. For example, TRUNC(4.9) will return 4, and TRUNC(-3.5) will return -3. The TRUNC function does no rounding, it simply truncates as specified.