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

Syntax
FLOOR.PRECISE(number,
significance)
 number Required. The number to be
rounded down.
 significance Optional. The multiple to
which the number is rounded. If omitted, the default value
is 1.
Applies To
Excel 2010 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
The CEILING.PRECISE function returns the same results as this
this formula:
=INT(number/ABS(significance))*ABS(significance)
FLOOR and FLOOR.PRECISE work
identically, with these exceptions:
 Unlike FLOOR, the significance argument is
optional with FLOOR.PRECISE. When it's omitted, its default
value is 1.
 Unlike FLOOR, the significance argument doesn't
need to be negative when the number
argument
is negative. This is because FLOOR.PRECISE uses the absolute
value of the significance argument in its
calculation.
The reason for the "precise" term in the "FLOOR.PRECISE" name
isn't obvious.
Examples
You can
download this example workbook here,
along with all other example workbooks I've completed for this
Excel help area.
Both FLOOR and FLOOR.PRECISE round positive numbers downward
(towards zero), making the number smaller. FLOOR requires the
significance
argument. FLOOR.PRECISE does not. When the significance
value is omitted, its default value is 1.
For a negative number, FLOOR requires that the sign of the
significance
argument also be a negative number. FLOOR.PRECISE does not.
Both FLOOR and FLOOR.PRECISE round negative
numbers downward (away
from zero).
These examples illustrate how FLOOR.PRECISE returns different
results
when different values are used for the significance argument.
The Remarks above show how FLOOR.PRECISE calulates these values.
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.
