FLOOR(number, significance)
=FLOOR(3.7,2)
The FLOOR function can be used to round numbers down to the nearest multiple of a number. For example, this rounds 3.7 down to the nearest multiple of 2, which is 2.
=FLOOR(-2.5,-2)
The FLOOR function can also be used to round negative numbers down to the nearest multiple of a number. This example rounds -2.5 down to the nearest multiple of -2, which is -4.
=FLOOR(2.5,-2)
When using the FLOOR function, the number and the multiple must be the same sign. For example this formula returns an error because 2.5 and -2 have different signs.
=FLOOR(1.58,0.1)
The FLOOR function can also be used to round decimal numbers down to the nearest multiple of a given decimal. This example rounds 1.58 down to the nearest multiple of 0.1, which is 1.5.
The FLOOR function is used to round a number down towards zero, to the multiple of significance. If the sign of the number is positive and the significance is negative, the function returns the #NUM! error.