# Incrementing Numeric Portions of Serial Numbers

Ted has a range of serial numbers in the format A12345678B. He would like to find a formula that will increment the numeric portion of the serial numbers by 1. Thus, the next number in sequence would be A12345679B, then A12345680B.

There are actually a couple of ways you can go about this, and the first doesn’t really involve a formula at all. Instead you can create a custom format that displays your serial number. How you go about creating custom formats has been described in other ExcelTips; the format should look like this:

```"A"#"B"
```

Then, in a cell that has this format applied, you only need to include the numeric portion of the serial number (12345678). You can then use regular AutoFill techniques to fill out as many cells as necessary with the serial number.

If you have your heart set on using a formula, then the following should work just fine as long as the pattern for the serial number is a single letter, eight numeric digits, and a single terminating letter:

```=LEFT(A1,1) & MID(A1,2,8)+1 & RIGHT(A1,1)
```

This assumes that cell A1 contains the beginning serial number. If you put the formula in cell A2, it could be copied down as many times as necessary for the desired number of serial numbers.

If the numeric portion of the serial number could start with leading zeroes, then you need to use a different formula to provide the proper zero padding:

```=LEFT(A1,1) & TEXT(VALUE(MID(A1,2,8))+1,"00000000") & RIGHT(A1,1)
```