Converting large numbers into binary

My task is to convert 4503599627370495 into binary. Haven't had any luck with DEC2BIN() due to the number's size. Not only is dec2bin an issue, excel doesn't easily handle the number because it is one too many significant digits. Excel recognizes the number above as 4503599627370490. Any ideas?

Hi excelerat8r and welcome to the forum,

The easy way is to do it by hand. Look at this site and start dividing by 2.

http://m.wikihow.com/Convert-from-Decimal-to-Binary

You might also start subtracting large powers of 2 and keep track what is left over.

Using SHG's UDF 'Dbl2Bin' found here: http://www.box.net/shared/530h20x44e, I came up with 52 straight 1's.

Which, oddly enough, is the same answer I got using the divide by 2 method.

- Moo

I agree with Moo
Try your number on this site
http://www.exploringbinary.com/binary-converter/

Just a note on that: The function converts a Double to binary, and a Double has 53 bits of precision. You're coercing a string to a Double to avoid Excel's cosmetic limitation of 15 digits of decimal precision, which is fine, but it's running close to the edge.

The largest whole number that the function will accurately convert to binary is 2^53-1 = 9,007,199,254,740,991

4,503,599,627,370,495 returns 52 1's

9,007,199,254,740,991 returns 53 1's

Above that, one or more LSBs will always be zero.