Excel Help tells you that the range of numbers that can be used is
limited to -512 up to +511, as a maximum of 10 places is available for
output (2^10 = 1024).

If you need to show more places then you could split the number by
repeated division by, say, 256, and combine the output strings
together, or you could use a UDF to do the conversion.

Hope this helps.

Pete

On Oct 29, 6:52*pm, sai wrote:
I need to calculate the binary conversion of numbers 511. Is there any
option for it as I am getting a #NUM error whenever i try to calculate that.