URL Encode and Decode VBA functions for Excel on Mac or Windows including UTF-8 support. Source: ExcelVBA.ru

excel-url-decode.vba

Function URLDecode(ByVal strIn)
    On Error Resume Next
    Dim sl&, tl&, key$, kl&
    sl = 1:    tl = 1: key = "%": kl = Len(key)
    sl = InStr(sl, strIn, key, 1)
    Do While sl > 0
        If (tl = 1 And sl <> 1) Or tl < sl Then
            URLDecode = URLDecode & Mid(strIn, tl, sl - tl)
        End If
        Dim hh$, hi$, hl$, a$
        Select Case UCase(Mid(strIn, sl + kl, 1))
            Case "U"    'Unicode URLEncode
                a = Mid(strIn, sl + kl + 1, 4)
                URLDecode = URLDecode & ChrW("&H" & a)
                sl = sl + 6
            Case "E"    'UTF-8 URLEncode
                hh = Mid(strIn, sl + kl, 2)
                a = Int("&H" & hh)    'ascii?
                If Abs(a) < 128 Then
                    sl = sl + 3
                    URLDecode = URLDecode & Chr(a)
                Else
                    hi = Mid(strIn, sl + 3 + kl, 2)
                    hl = Mid(strIn, sl + 6 + kl, 2)
                    a = ("&H" & hh And &HF) * 2 ^ 12 Or ("&H" & hi And &H3F) * 2 ^ 6 Or ("&H" & hl And &H3F)
                    If a < 0 Then a = a + 65536
                    URLDecode = URLDecode & ChrW(a)
                    sl = sl + 9
                End If
            Case Else    'Asc URLEncode
                hh = Mid(strIn, sl + kl, 2)    '??
                a = Int("&H" & hh)    'ascii?

                If Abs(a) < 128 Then
                    sl = sl + 3
                Else
                    hi = Mid(strIn, sl + 3 + kl, 2)    '??
                    'a = Int("&H" & hh & hi) '?ascii?
                    a = (Int("&H" & hh) - 194) * 64 + Int("&H" & hi)
                    sl = sl + 6
                End If
                URLDecode = URLDecode & ChrW(a)
        End Select
        tl = sl
        sl = InStr(sl, strIn, key, 1)
    Loop
    URLDecode = URLDecode & Mid(strIn, tl)
End Function

excel-url-encode.vba

Public Function URLEncode(ByRef txt As String) As String
    Dim buffer As String, i As Long, c As Long, n As Long
    buffer = String$(Len(txt) * 12, "%")
 
    For i = 1 To Len(txt)
        c = AscW(Mid$(txt, i, 1)) And 65535
 
        Select Case c
            Case 48 To 57, 65 To 90, 97 To 122, 45, 46, 95  ' Unescaped 0-9A-Za-z-._ '
                n = n + 1
                Mid$(buffer, n) = ChrW(c)
            Case Is <= 127            ' Escaped UTF-8 1 bytes U+0000 to U+007F '
                n = n + 3
                Mid$(buffer, n - 1) = Right$(Hex$(256 + c), 2)
            Case Is <= 2047           ' Escaped UTF-8 2 bytes U+0080 to U+07FF '
                n = n + 6
                Mid$(buffer, n - 4) = Hex$(192 + (c \ 64))
                Mid$(buffer, n - 1) = Hex$(128 + (c Mod 64))
            Case 55296 To 57343       ' Escaped UTF-8 4 bytes U+010000 to U+10FFFF '
                i = i + 1
                c = 65536 + (c Mod 1024) * 1024 + (AscW(Mid$(txt, i, 1)) And 1023)
                n = n + 12
                Mid$(buffer, n - 10) = Hex$(240 + (c \ 262144))
                Mid$(buffer, n - 7) = Hex$(128 + ((c \ 4096) Mod 64))
                Mid$(buffer, n - 4) = Hex$(128 + ((c \ 64) Mod 64))
                Mid$(buffer, n - 1) = Hex$(128 + (c Mod 64))
            Case Else                 ' Escaped UTF-8 3 bytes U+0800 to U+FFFF '
                n = n + 9
                Mid$(buffer, n - 7) = Hex$(224 + (c \ 4096))
                Mid$(buffer, n - 4) = Hex$(128 + ((c \ 64) Mod 64))
                Mid$(buffer, n - 1) = Hex$(128 + (c Mod 64))
        End Select
    Next
    URLEncode = Left$(buffer, n)
End Function