Question: I need to make a new product code for 6000+ records. In order to do that fast and decipher it in the future, I need to put a formula from the old code to the new code.

sample codes:

```
yas111
bd224
sax112
sd00015
sp00114

```

If my formula is +1, the end result shoulb be:

```
zbt222   
ce335
tby223
te11126
tq11225

```

numbers will +1, and letters will increment to the next letter of the alphabet. 
I tried the substitute function, its working. but it cannot read both if there is a number that is already used. example: 

```
Substitute(substitute(a1,"0","5"),"5","0")

```

It will only read 1.
result will be

```
0 = 0
5 = 0

```

but I'm trying to get this result:

```
0 = 5
5 = 0

```

Answer: 
To do this in pure excel formula will be in my opinion unmanageably complex. The best way would be ti use a vba `UDF`

```
Function IncrCode(rng As Range) As Variant
    Dim strOld As String, strNew As String
    Dim i As Long

    strOld = rng.Cells(1, 1).Value
    strNew = ""
    For i = 1 To Len(strOld)
        strNew = strNew & Chr$(Asc(Mid$(strOld, i, 1)) + 1)
    Next
    IncrCode = strNew
End Function

```

Call it like this

```
=IncrCode(A1)

```

if `A1` = `yas111` result would be `zbt222`

Note that based on your question, all characters are incremented to the next ascii character, eg  

`9` --> `:`  

`z` --> `{`  

`Z` --> `[`
What you need is a single character that will never be used. Let's say that it's `&`.

Armed with this never-used character, you can then do it like this:

Change all of your Z's to &.  

Change all of your Y's to Z.  

Change all of your X's to Y.  

Change all of your W's to X.  

.  

. etc., etc.  

.  

Change all of your &'s to 0.