FLOOR

FLOOR(number, significance)

Returns the number rounded down to the nearest integer or multiple.

number	The number to be rounded down.
significance	The multiple you want the number rounded to.

REMARKS

* FLOOR.MATH was added in Excel 2013 to replace this function.
* Positive decimal numbers with a positive significance are rounded down.
* Positive decimal numbers with a negative significance returns #NUM!
* Negative decimal numbers with a positive significance are rounded down.
* Negative decimal numbers with a negative significance are rounded up.
* If "significance" = 0 and "number" <> 0, then #DIV/0! is returned.
* If "significance" = 0 and "number" = 0, then zero is returned.
* This function is only available for backwards compatibility and should not be used.
* There was also a CEILING function that rounded a number down.
* This function has been available since Excel 1997.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=FLOOR(1.9, 1) = 1
2	=FLOOR(1.1, 1) = 1
3	=FLOOR(1.1, -1) = #NUM!
4	=FLOOR(3.1, 3) = 3
5	=FLOOR(9.1, 9) = 9
6	=FLOOR(15.1, 15) = 15
7	=FLOOR(-1.1, 1) = -2
8	=FLOOR(-1.1, -1) = -1
9	=FLOOR(-1.1, 1) = -2
10	=FLOOR(-1.1, 1) = -2
11	=FLOOR(-1.1, 3) = -3
12	=FLOOR(-1.1, 3) = -3
13	=FLOOR(-1.1, 9) = -9
14	=FLOOR(-1.1, 15) = -15
15	=FLOOR(13, 2) = 12
16	=FLOOR(-13, 2) = -14
17	=FLOOR(8.26, 0.05) = 8.25
18	=FLOOR(0.234, 0.01) = 0.23
19	=FLOOR(15, 0) = #DIV/0!
20	=FLOOR("", 1) = #VALUE!

1 - What is 1.9 rounded down to a multiple of 1.
2 - What is 1.1 rounded down to a multiple of 1.
3 - What is 1.1 rounded down to a multiple of -1. When "multiple" < 0, the absolute value is not taken.
4 - What is 3.1 rounded down to a multiple of 3.
5 - What is 9.1 rounded down to a multiple of 9.
6 - What is 15.1 rounded down to a multiple of 15.
7 - What is -1.1 rounded down to a multiple of 1.
8 - What is -1.1 rounded down to a multiple of -1. This is actually rounded up.
9 - What is -1.1 rounded down to a multiple of 1.
10 - What is -1.1 rounded down to a multiple of 1.
11 - What is -1.1 rounded down to a multiple of 3.
12 - What is -1.1 rounded down to a multiple of 3.
13 - What is -1.1 rounded down to a multiple of 9.
14 - What is -1.1 rounded down to a multiple of 15.
15 - What is 13 rounded down to a multiple of 2.
16 - What is -13 rounded down to a multiple of 2.
17 - What is 8.26 rounded down to a multiple of 0.05.
18 - What is 0.234 rounded down to a multiple of 0.01.
19 - What is 15 rounded down to a multiple of 0.
20 - If any of the arguments are not numeric.