Math and trigonometry
FLOOR
Function
Rounds number towards zero, to the nearest multiple of
significance.
by
Charley Kyd, MBA Microsoft Excel MVP, 20052014
The Father of Spreadsheet Dashboard Reports

Syntax
FLOOR(number, significance)
 number Required. The number you
want to round.
 significance Required. The multiple to
which you want to round.
Applies To
Excel 2003 and above
A Note About
"Rounding"
In Excel, numbers can "round" in two ways.
First, they can round up or down. With this type of rounding,
numbers
get larger when they are rounded up, and smaller when they are
rounded down.
Second, numbers can round towards zero or away from zero.
When positive numbers are rounded towards zero, they get
smaller; when negative numbers are rounded towards zero, they get larger.
Although Microsoft uses "round up" and "round down" to
describe both types of rounding, we use "round up" or "round
down" to describe the first type of rounding. And we use "round
towards zero" or "round away from zero" to describe the second
type.
Remarks
 If either argument is nonnumeric, FLOOR returns an
error.
 FLOOR returns an error value if the number is positive
and significance is negative, as shown in Example 8a below.
But contrary to Microsoft documentation, FLOOR doesn't
return an error if the number is negative and the
significance is positive, as shown in Example 2.
Examples
You can
download this example workbook here,
along with all other example workbooks I've completed for this
Excel help area.
Rounds both positive and negative numbers down. A significance value of 1 rounds the number down to the nearest integer.
To illustrate how FLOOR works, examples 3b and 4b show how INT can produce the same results as FLOOR in 3a and 4a, respectively.
INT and FLOOR can produce the same results even when the significance value is not an integer.
In 8a, FLOOR returns an error value if the number is positive and significance is negative. But the other combinations calculate successfully.
Other Help
Related Functions
In total,
Excel 2013 offers 15 functions that round data in
various ways. Here's a
summary of Excel's rounding functions.
