Converting from base-32 to decimal without VBA - ms-access

Question

I've been searching and searching and my Google-fu has failed me. I'm trying to convert an encoded number from base-32 to decimal using either expressions or a macro, but I'm not finding anything. I know Excel has the "Decimal" function, I've been hoping that I could stumble onto something similar.
I'm reluctant to use VBA as I don't want to spend time re-learning the language right now and I'm worried that my organization will flag it as potentially dangerous (which could kill my attempts at making any databases).
With an input of "16O9E55"
I expect a result of 1300543653.
I should clarify that this is "base32hex" according to Wikipedia. It's 0-9, A-V. It's only 7 characters of base-32 that needs to convert to 10 digits of decimal. My use case is decoding a barcode into the data I need.

Answer 1

I doubt this can be accomplished without VBA. Consider code adapted from https://www.excelbanter.com/excel-worksheet-functions/150198-formulat-convert-base-32-decimal.html
Public Function Base32ToDec(Num As String) As Variant
Static Digits As String
Dim i As Integer
Dim myIndex As Integer
Dim myStr As String
Digits = "0123456789ABCDEFGHIJKLMNOPQRSTUV"
For i = Len(Num) To 1 Step -1
myStr = Mid(Num, i, 1)
myIndex = InStr(Digits, myStr) - 1
Base32ToDec = Base32ToDec + myIndex * 32 ^ (Len(Num) - i)
Next i
End Function

Answer 2

According to Wikipedia, Base32 uses a 32-character set comprising the twenty-six upper-case letters A–Z, and the digits 2–7. The variant base32hex starts with 0 - 9 and uses the letters A to V.
If only numbers with a limited range have been encoded, you can decode them easily with VBA, otherwise you would have to return an array of bytes and process it further.
You write, that you have up to 10 decimal digits. The question is, what the maximum number is. The Long type can store numbers up to 2,147,483,647. This are ten digits; however, with 10 digits you could store a number as big as 9,999,999,999.
Therefore, the following function returns the number as Double. If you know that your number will never exceed 2,147,483,647, then you can exchange the Double type by Long for the sum variable and the function return type.
Public Function DecodeBase32hex(ByVal encoded As String) As Double
Dim ch As String
Dim sum As Double
Dim d As Long, i As Long
For i = 1 To Len(encoded)
ch = Mid$(encoded, i, 1)
If ch >= "A" And ch <= "Z" Then
d = Asc(ch) - Asc("A") + 10
ElseIf ch >= "0" And ch <= "9" Then
d = Asc(ch) - Asc("0")
Else
Exit For 'E.g. padding charachters
End If
sum = 32 * sum + d
Next i
DecodeBase32hex = sum
End Function
Test in Access' immediate window:
?DecodeBase32hex("16O9E55")
1300543653