Problem:

Rounding the numbers in List1 (column A) to the nearest multiple of 50. We want to round both up and down.

Solution:

To round up, use the CEILING function in the following formula:

=CEILING(A2,50)

To round down, use the FLOOR function in the following formula:

=FLOOR(A2,50)

A better way would be to use the MROUND formula.

=MROUND(A2,50) would round up or down depending on which is closer.

Thanks dear u solved my problem by using

CEILING : round the Number specified above up to the nearest multiple.

Only if you want to round up or down at the same time. Those functions are good if there is an absolute cycle, i.e. a cycle that is of a specific time. So if the cycle starts, it runs (for example) 30 minutes, even if the value representing the cycle is between 0 and 30 minutes. For example 1.2 cycles is always 2 cycles; never rounded down to 1 cycle. The use of CEILING(1.2, 0.5) would make it work.