How to use the Excel FLOOR function

Summary

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.

Purpose

Round a number down to the nearest specified multiple

Return value

A rounded number.

Syntax

=FLOOR (number, multiple)

Arguments

number - The number that should be rounded.
multiple - The multiple to use when rounding.

Usage notes

The Excel FLOOR function rounds a number down to a given multiple. For example, the following could be used to round a price in A1 down to the nearest 5 dollars.

=FLOOR(A1,5)

FLOOR can be a can be a useful function to set pricing after currency conversion, discounts, etc. For example, the formula below will round a value in A1 down to the nearest 1 dollar, then subtract 1 cent, to get a price like $2.99, $5.99, $49.99, etc.

=CEILING(A1,1) - 0.01

If you need more control over how FLOOR rounds negative numbers, see the FLOOR.MATH function.

FLOOR vs FLOOR.MATH

The FLOOR function differs from the FLOOR.MATH function in these ways:

FLOOR.MATH provides a default significance of 1, rounding to nearest integer.
FLOOR.MATH provides support for rounding negative numbers (toward zero, away from zero).
FLOOR.MATH appears to use the absolute value of the significance argument. Changing the sign of significance has no effect on the result.

Notes

FLOOR works like the MROUND function, but FLOOR always rounds down.
With a positive number, the value is rounded down toward zero.
With a negative number, the value is rounded down away from zero.
The FLOOR function can be a good way to can be a good way to set pricing after currency conversion, discounts, etc.

Related functions

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 CEILING Function

The Excel CEILING function returns a given number rounded up to a specified multiple. For example, =CEILING(A1,5) could be used to round a price in A1 to the nearest 5 dollars. CEILING always rounds up.

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 ROUNDDOWN Function

The Excel ROUNDDOWN function returns a number rounded down to a given number of decimal places. Unlike standard rounding, where only numbers less than 5 are rounded down, ROUNDDOWN rounds all numbers 1-9 down.

Excel ROUNDUP Function

The Excel ROUNDUP function returns a number rounded up to a given number of decimal places. Unlike standard rounding, where numbers less than 5 are rounded down, ROUNDUP always rounds numbers 1-9 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 EVEN Function

The Excel EVEN function returns the next even integer after rounding a given number up. The EVEN function always rounds numbers up (away from zero) so positive numbers become larger and negative numbers become smaller (i.e. more negative).

Excel ODD Function

The Excel ODD function returns the next odd integer after rounding a given number up. The ODD function always rounds numbers up (away from zero) so positive numbers become larger and negative numbers become smaller (i.e. more negative).

Excel INT Function

The Excel INT function returns the integer part of a decimal number by rounding down to the integer. Note the INT function rounds down, so 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.

Good links

Microsoft FLOOR function documentation

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