Decimal to binary conversion for large numbers in Excel

Question

I have some large numbers in an Excel sheet and I want to convert them to binary.

e.g.

12345678  
965321458  
-12457896

Answer 1

If we are talking positive number between 0 and 2^32-1 you can use this formula:

=DEC2BIN(MOD(QUOTIENT($A$1,256^3),256),8)&DEC2BIN(MOD(QUOTIENT($A$1,256^2),256),8)&DEC2BIN(MOD(QUOTIENT($A$1,256^1),256),8)&DEC2BIN(MOD(QUOTIENT($A$1,256^0),256),8)

NOTE: =DEC2BIN() function cannot handle numbers larger than 511 so as you see my formula breaks your number into four 8-bit chunks, converts them to binary format and then concatenates the results.

Well, theoretically you can extend this formula up to six 8-bit chunks. Maximum precision you can get in Excel is 15 (fifteen) decimal digits. When exceeded, only the most significant 15 digits remain, the rest is rounded. I.e. if you type 12345678901234567 Excel will store it as 12345678901234500. So since 2^48-1 is 15 decimal digits long the number won't get rounded.