You can also just format the cells:
[<100000]0-0000;00-00000

"Striker3070" wrote:

I have a column of numbers, 5 digit up to 9 digit. I need to insert a dash
after the first number of any 5 digit number, and a dash after the second
digit if the number is longer than 5 digits.

so 12345 would need to become 1-2345
and 1234567 would need to become 12-34567

If my original numbers are in column A, I can make the new ones in Column B

.