DEC2HEX - HEX2DEC Issues - Number too Long?

Note that numbers that large go beyond standard double precision (~15 digits) that Excel uses to store numbers. If you need more than double precision can hold, you will need to figure out exactly how you want to do this -- which will probably depend a lot on what you are doing with these numbers.

If you need to perform calculations on these numbers, you may consider peforming all calculations and storage in VBA using a Decimal data type that can store integers up to about 29 digits (see here for limits of different data types: https://msdn.microsoft.com/en-us/lib...=vs.60%29.aspx ).

If there are not calculations needed, you may use VBA to convert from hexadecimal into a Decimal data type (not double or integer or long), then convert that Decimal data type to string and store the "numbers" in Excel as strings (though you may need to take extra measures to make sure Excel does not convert the "numbers as text" into numbers and truncate them to the limits of double precision).

I'm sure there are other strategies as well. You are dealing with very large numbers here. Large enough that you will need to pay careful attention to data type and the limits imposed on those data types by whatever programming language you choose to use.