How can I URL encode a string in Excel VBA?

Question

Is there a built-in way to URL encode a string in Excel VBA or do I need to hand roll this functionality?

Answer 1

No, nothing built-in (until Excel 2013 - see this answer).

There are three versions of URLEncode() in this answer.

• A function with UTF-8 support. You should probably use this one (or the alternative implementation by Tom) for compatibility with modern requirements.
• For reference and educational purposes, two functions without UTF-8 support:
  • one found on a third party website, included as-is. (This was the first version of the answer)
  • one optimized version of that, written by me

---

A variant that supports UTF-8 encoding and is based on ADODB.Stream (include a reference to a recent version of the "Microsoft ActiveX Data Objects" library in your project):

Public Function URLEncode( _
   ByVal StringVal As String, _
   Optional SpaceAsPlus As Boolean = False _
) As String
  Dim bytes() As Byte, b As Byte, i As Integer, space As String

  If SpaceAsPlus Then space = "+" Else space = "%20"

  If Len(StringVal) > 0 Then
    With New ADODB.Stream
      .Mode = adModeReadWrite
      .Type = adTypeText
      .Charset = "UTF-8"
      .Open
      .WriteText StringVal
      .Position = 0
      .Type = adTypeBinary
      .Position = 3 ' skip BOM
      bytes = .Read
    End With

    ReDim result(UBound(bytes)) As String

    For i = UBound(bytes) To 0 Step -1
      b = bytes(i)
      Select Case b
        Case 97 To 122, 65 To 90, 48 To 57, 45, 46, 95, 126
          result(i) = Chr(b)
        Case 32
          result(i) = space
        Case 0 To 15
          result(i) = "%0" & Hex(b)
        Case Else
          result(i) = "%" & Hex(b)
      End Select
    Next i

    URLEncode = Join(result, "")
  End If
End Function

---

This function was found on freevbcode.com:

Public Function URLEncode( _
   StringToEncode As String, _
   Optional UsePlusRatherThanHexForSpace As Boolean = False _
) As String

  Dim TempAns As String
  Dim CurChr As Integer
  CurChr = 1

  Do Until CurChr - 1 = Len(StringToEncode)
    Select Case Asc(Mid(StringToEncode, CurChr, 1))
      Case 48 To 57, 65 To 90, 97 To 122
        TempAns = TempAns & Mid(StringToEncode, CurChr, 1)
      Case 32
        If UsePlusRatherThanHexForSpace = True Then
          TempAns = TempAns & "+"
        Else
          TempAns = TempAns & "%" & Hex(32)
        End If
      Case Else
        TempAns = TempAns & "%" & _
          Right("0" & Hex(Asc(Mid(StringToEncode, _
          CurChr, 1))), 2)
    End Select

    CurChr = CurChr + 1
  Loop

  URLEncode = TempAns
End Function

I've corrected a little bug that was in there.

---

I would use more efficient (~2× as fast) version of the above:

Public Function URLEncode( _
   StringVal As String, _
   Optional SpaceAsPlus As Boolean = False _
) As String

  Dim StringLen As Long: StringLen = Len(StringVal)

  If StringLen > 0 Then
    ReDim result(StringLen) As String
    Dim i As Long, CharCode As Integer
    Dim Char As String, Space As String

    If SpaceAsPlus Then Space = "+" Else Space = "%20"

    For i = 1 To StringLen
      Char = Mid$(StringVal, i, 1)
      CharCode = Asc(Char)
      Select Case CharCode
        Case 97 To 122, 65 To 90, 48 To 57, 45, 46, 95, 126
          result(i) = Char
        Case 32
          result(i) = Space
        Case 0 To 15
          result(i) = "%0" & Hex(CharCode)
        Case Else
          result(i) = "%" & Hex(CharCode)
      End Select
    Next i
    URLEncode = Join(result, "")
  End If
End Function

Note that neither of these two functions support UTF-8 encoding.

Answer 2

For the sake of bringing this up to date, since Excel 2013 there is now a built-in way of encoding URLs using the worksheet function ENCODEURL.

To use it in your VBA code you just need to call

EncodedUrl = WorksheetFunction.EncodeUrl(InputString)

Documentation

Answer 3

Version of the above supporting UTF8:

Private Const CP_UTF8 = 65001  
Private Declare Function WideCharToMultiByte Lib "Kernel32" (
    ByVal CodePage As Long, ByVal dwflags As Long, 
    ByVal lpWideCharStr As Long, ByVal cchWideChar As Long, 
    ByVal lpMultiByteStr As Long, ByVal cchMultiByte As Long, 
    ByVal lpDefaultChar As Long, ByVal lpUsedDefaultChar As Long) As Long

Public Function UTF16To8(ByVal UTF16 As String) As String
Dim sBuffer As String
Dim lLength As Long
If UTF16 <> "" Then
    lLength = WideCharToMultiByte(CP_UTF8, 0, StrPtr(UTF16), -1, 0, 0, 0, 0)
    sBuffer = Space$(lLength)
    lLength = WideCharToMultiByte(
        CP_UTF8, 0, StrPtr(UTF16), -1, StrPtr(sBuffer), Len(sBuffer), 0, 0)
    sBuffer = StrConv(sBuffer, vbUnicode)
    UTF16To8 = Left$(sBuffer, lLength - 1)
Else
    UTF16To8 = ""
End If
End Function

Public Function URLEncode( _
   StringVal As String, _
   Optional SpaceAsPlus As Boolean = False, _
   Optional UTF8Encode As Boolean = True _
) As String

Dim StringValCopy As String: StringValCopy = 
    IIf(UTF8Encode, UTF16To8(StringVal), StringVal)
Dim StringLen As Long: StringLen = Len(StringValCopy)

If StringLen > 0 Then
    ReDim Result(StringLen) As String
    Dim I As Long, CharCode As Integer
    Dim Char As String, Space As String

  If SpaceAsPlus Then Space = "+" Else Space = "%20"

  For I = 1 To StringLen
    Char = Mid$(StringValCopy, I, 1)
    CharCode = Asc(Char)
    Select Case CharCode
      Case 97 To 122, 65 To 90, 48 To 57, 45, 46, 95, 126
        Result(I) = Char
      Case 32
        Result(I) = Space
      Case 0 To 15
        Result(I) = "%0" & Hex(CharCode)
      Case Else
        Result(I) = "%" & Hex(CharCode)
    End Select
  Next I
  URLEncode = Join(Result, "")  

End If  
End Function

Enjoy!

Answer 4

Although, this one is very old. I have come up with a solution based in this answer:

Dim ScriptEngine As ScriptControl
Set ScriptEngine = New ScriptControl
ScriptEngine.Language = "JScript"

ScriptEngine.AddCode "function encode(str) {return encodeURIComponent(str);}"
Dim encoded As String
encoded = ScriptEngine.Run("encode", "€ömE.sdfds")

Add Microsoft Script Control as reference and you are done.

Just a side note, because of the JS part, this is fully UTF-8-compatible. VB will convert correctly from UTF-16 to UTF-8.

Answer 5

Similar to Michael-O's code, only without need to reference (late bind) and with less one line .
* I read, that in excel 2013 it can be done more easily like so: WorksheetFunction.EncodeUrl(InputString)

Public Function encodeURL(str As String)
    Dim ScriptEngine As Object
    Dim encoded As String

    Set ScriptEngine = CreateObject("scriptcontrol")
    ScriptEngine.Language = "JScript"

    encoded = ScriptEngine.Run("encodeURIComponent", str)

    encodeURL = encoded
End Function

Answer 6

Since office 2013 use this inbuilt function here.

If before office 2013

Function encodeURL(str As String)
Dim ScriptEngine As ScriptControl
Set ScriptEngine = New ScriptControl
ScriptEngine.Language = "JScript"

ScriptEngine.AddCode "function encode(str) {return encodeURIComponent(str);}"
Dim encoded As String


encoded = ScriptEngine.Run("encode", str)
encodeURL = encoded
End Function

Add Microsoft Script Control as reference and you are done.

Same as last post just complete function ..works!

Answer 7

One more solution via htmlfile ActiveX:

Function EncodeUriComponent(strText)
    Static objHtmlfile As Object
    If objHtmlfile Is Nothing Then
        Set objHtmlfile = CreateObject("htmlfile")
        objHtmlfile.parentWindow.execScript "function encode(s) {return encodeURIComponent(s)}", "jscript"
    End If
    EncodeUriComponent = objHtmlfile.parentWindow.encode(strText)
End Function

Declaring htmlfile DOM document object as static variable gives the only small delay when called first time due to init, and makes this function very fast for numerous calls, e. g. for me it converts the string of 100 chars length 100000 times in 2 seconds approx..

Answer 8

(Bump on an old thread). Just for kicks, here's a version that uses pointers to assemble the result string. It's about 2x - 4x as fast as the faster second version in the accepted answer.

Public Declare PtrSafe Sub Mem_Copy Lib "kernel32" _
    Alias "RtlMoveMemory" (ByRef Destination As Any, ByRef Source As Any, ByVal Length As Long)

Public Declare PtrSafe Sub Mem_Read2 Lib "msvbvm60" _
    Alias "GetMem2" (ByRef Source As Any, ByRef Destination As Any)

Public Function URLEncodePart(ByRef RawURL As String) As String

    Dim pChar As LongPtr, iChar As Integer, i As Long
    Dim strHex As String, pHex As LongPtr
    Dim strOut As String, pOut As LongPtr
    Dim pOutStart As LongPtr, pLo As LongPtr, pHi As LongPtr
    Dim lngLength As Long
    Dim cpyLength As Long
    Dim iStart As Long

    pChar = StrPtr(RawURL)
    If pChar = 0 Then Exit Function

    lngLength = Len(RawURL)
    strOut = Space(lngLength * 3)
    pOut = StrPtr(strOut)
    pOutStart = pOut
    strHex = "0123456789ABCDEF"
    pHex = StrPtr(strHex)

    iStart = 1
    For i = 1 To lngLength
        Mem_Read2 ByVal pChar, iChar
        Select Case iChar
            Case 97 To 122, 65 To 90, 48 To 57, 45, 46, 95, 126
              ' Ok
            Case Else
                If iStart < i Then
                    cpyLength = (i - iStart) * 2
                    Mem_Copy ByVal pOut, ByVal pChar - cpyLength, cpyLength
                    pOut = pOut + cpyLength
                End If

                pHi = pHex + ((iChar And &HF0) / 8)
                pLo = pHex + 2 * (iChar And &HF)

                Mem_Read2 37, ByVal pOut
                Mem_Read2 ByVal pHi, ByVal pOut + 2
                Mem_Read2 ByVal pLo, ByVal pOut + 4
                pOut = pOut + 6

                iStart = i + 1
        End Select
        pChar = pChar + 2
    Next

    If iStart <= lngLength Then
        cpyLength = (lngLength - iStart + 1) * 2
        Mem_Copy ByVal pOut, ByVal pChar - cpyLength, cpyLength
        pOut = pOut + cpyLength
    End If

    URLEncodePart = Left$(strOut, (pOut - pOutStart) / 2)

End Function

Answer 9

Same as WorksheetFunction.EncodeUrl with UTF-8 support:

Public Function EncodeURL(url As String) As String
  Dim buffer As String, i As Long, c As Long, n As Long
  buffer = String$(Len(url) * 12, "%")

  For i = 1 To Len(url)
    c = AscW(Mid$(url, 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$(url, i, 1)) And 1023)
        n = n + 12
        Mid$(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

  EncodeURL = Left$(buffer, n)
End Function

Answer 10

If you also want it to work on MacOs create a seperate function

Function macUriEncode(value As String) As String

    Dim script As String
    script = "do shell script " & """/usr/bin/python -c 'import sys, urllib; print urllib.quote(sys.argv[1])' """ & Chr(38) & " quoted form of """ & value & """"

    macUriEncode = MacScript(script)

End Function

Answer 11

I had problem with encoding cyrillic letters to URF-8.

I modified one of the above scripts to match cyrillic char map. Implmented is the cyrrilic section of

https://en.wikipedia.org/wiki/UTF-8 and http://www.utf8-chartable.de/unicode-utf8-table.pl?start=1024

Other sections development is sample and need verification with real data and calculate the char map offsets

Here is the script:

Public Function UTF8Encode( _
   StringToEncode As String, _
   Optional UsePlusRatherThanHexForSpace As Boolean = False _
) As String

  Dim TempAns As String
  Dim TempChr As Long
  Dim CurChr As Long
  Dim Offset As Long
  Dim TempHex As String
  Dim CharToEncode As Long
  Dim TempAnsShort As String

  CurChr = 1

  Do Until CurChr - 1 = Len(StringToEncode)
    CharToEncode = Asc(Mid(StringToEncode, CurChr, 1))
' http://www.utf8-chartable.de/unicode-utf8-table.pl?start=1024
' as per https://en.wikipedia.org/wiki/UTF-8 specification the engoding is as follows

    Select Case CharToEncode
'   7   U+0000 U+007F 1 0xxxxxxx
      Case 48 To 57, 65 To 90, 97 To 122
        TempAns = TempAns & Mid(StringToEncode, CurChr, 1)
      Case 32
        If UsePlusRatherThanHexForSpace = True Then
          TempAns = TempAns & "+"
        Else
          TempAns = TempAns & "%" & Hex(32)
        End If
      Case 0 To &H7F
            TempAns = TempAns + "%" + Hex(CharToEncode And &H7F)
      Case &H80 To &H7FF
'   11  U+0080 U+07FF 2 110xxxxx 10xxxxxx
' The magic is in offset calculation... there are different offsets between UTF-8 and Windows character maps
' offset 192 = &HC0 = 1100 0000 b  added to start of UTF-8 cyrillic char map at &H410
          CharToEncode = CharToEncode - 192 + &H410
          TempAnsShort = "%" & Right("0" & Hex((CharToEncode And &H3F) Or &H80), 2)
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40) And &H1F) Or &HC0), 2) & TempAnsShort
          TempAns = TempAns + TempAnsShort

'' debug and development version
''          CharToEncode = CharToEncode - 192 + &H410
''          TempChr = (CharToEncode And &H3F) Or &H80
''          TempHex = Hex(TempChr)
''          TempAnsShort = "%" & Right("0" & TempHex, 2)
''          TempChr = ((CharToEncode And &H7C0) / &H40) Or &HC0
''          TempChr = ((CharToEncode \ &H40) And &H1F) Or &HC0
''          TempHex = Hex(TempChr)
''          TempAnsShort = "%" & Right("0" & TempHex, 2) & TempAnsShort
''          TempAns = TempAns + TempAnsShort

      Case &H800 To &HFFFF
'   16 U+0800 U+FFFF 3 1110xxxx 10xxxxxx 10xxxxxx
' not tested . Doesnot match Case condition... very strange
        MsgBox ("Char to encode  matched U+0800 U+FFFF: " & CharToEncode & " = &H" & Hex(CharToEncode))
''          CharToEncode = CharToEncode - 192 + &H410
          TempAnsShort = "%" & Right("0" & Hex((CharToEncode And &H3F) Or &H80), 2)
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000) And &HF) Or &HE0), 2) & TempAnsShort
          TempAns = TempAns + TempAnsShort

      Case &H10000 To &H1FFFFF
'   21 U+10000 U+1FFFFF 4 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
''        MsgBox ("Char to encode  matched &H10000 &H1FFFFF: " & CharToEncode & " = &H" & Hex(CharToEncode))
' sample offset. tobe verified
          CharToEncode = CharToEncode - 192 + &H410
          TempAnsShort = "%" & Right("0" & Hex((CharToEncode And &H3F) Or &H80), 2)
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40000) And &H7) Or &HF0), 2) & TempAnsShort
          TempAns = TempAns + TempAnsShort

      Case &H200000 To &H3FFFFFF
'   26  U+200000 U+3FFFFFF 5 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
''        MsgBox ("Char to encode  matched U+200000 U+3FFFFFF: " & CharToEncode & " = &H" & Hex(CharToEncode))
' sample offset. tobe verified
          CharToEncode = CharToEncode - 192 + &H410
          TempAnsShort = "%" & Right("0" & Hex((CharToEncode And &H3F) Or &H80), 2)
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000000) And &H3) Or &HF8), 2) & TempAnsShort
          TempAns = TempAns + TempAnsShort

      Case &H4000000 To &H7FFFFFFF
'   31  U+4000000 U+7FFFFFFF 6 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
''        MsgBox ("Char to encode  matched U+4000000 U+7FFFFFFF: " & CharToEncode & " = &H" & Hex(CharToEncode))
' sample offset. tobe verified
          CharToEncode = CharToEncode - 192 + &H410
          TempAnsShort = "%" & Right("0" & Hex((CharToEncode And &H3F) Or &H80), 2)
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H1000000) And &H3F) Or &H80), 2) & TempAnsShort
          TempAnsShort = "%" & Right("0" & Hex(((CharToEncode \ &H40000000) And &H1) Or &HFC), 2) & TempAnsShort
          TempAns = TempAns + TempAnsShort

      Case Else
' somethig else
' to be developped
        MsgBox ("Char to encode not matched: " & CharToEncode & " = &H" & Hex(CharToEncode))

    End Select

    CurChr = CurChr + 1
  Loop

  UTF8Encode = TempAns
End Function

Good luck!

Answer 12

This snippet i have used in my application to encode the URL so may this can help you to do the same.

Function URLEncode(ByVal str As String) As String
        Dim intLen As Integer
        Dim x As Integer
        Dim curChar As Long
        Dim newStr As String
        intLen = Len(str)
        newStr = ""

        For x = 1 To intLen
            curChar = Asc(Mid$(str, x, 1))

            If (curChar < 48 Or curChar > 57) And _
                (curChar < 65 Or curChar > 90) And _
                (curChar < 97 Or curChar > 122) Then
                                newStr = newStr & "%" & Hex(curChar)
            Else
                newStr = newStr & Chr(curChar)
            End If
        Next x

        URLEncode = newStr
    End Function

Answer 13

None of the solutions here worked for me out of the box, but it was most likely due my lack of experience with VBA. It might also be because I simply copied and pasted some of the functions above, not knowing details that maybe are necessary to make them work on a VBA for applications environment.

My needs were simply to send xmlhttp requests using urls that contained some special characters of the Norwegian language. Some of the solutions above encode even colons, which made the urls unsuitable for what I needed.

I then decided to write my own URLEncode function. It does not use more clever programming such as the one from @ndd and @Tom. I am not a very experienced programmer, but I had to make this done sooner.

I realized that the problem was that my server didn't accept UTF-16 encodings, so I had to write a function that would convert UTF-16 to UTF-8. A good source of information was found here and here.

I haven't tested it extensively to check if it works with url with characters that have higher unicode values and which would produce more than 2 bytes of utf-8 characters. I am not saying it will decode everything that needs to be decoded (but it is easy to modify to include/exclude characters on the select case statement) nor that it will work with higher characters, as I haven't fully tested. But I am sharing the code because it might help someone who is trying to understand the issue.

Any comments are welcome.

Public Function URL_Encode(ByVal st As String) As String

    Dim eachbyte() As Byte
    Dim i, j As Integer 
    Dim encodeurl As String
    encodeurl = "" 

    eachbyte() = StrConv(st, vbFromUnicode)

    For i = 0 To UBound(eachbyte)

        Select Case eachbyte(i)
        Case 0
        Case 32
            encodeurl = encodeurl & "%20"

        ' I am not encoding the lower parts, not necessary for me
        Case 1 To 127
            encodeurl = encodeurl & Chr(eachbyte(i))
        Case Else

            Dim myarr() As Byte
            myarr = utf16toutf8(eachbyte(i))
            For j = LBound(myarr) To UBound(myarr) - 1
                encodeurl = encodeurl & "%" & Hex(myarr(j))
            Next j
        End Select
    Next i
    URL_Encode = encodeurl 
End Function

Public Function utf16toutf8(ByVal thechars As Variant) As Variant
    Dim numbytes As Integer
    Dim byte1 As Byte
    Dim byte2 As Byte
    Dim byte3 As Byte
    Dim byte4 As Byte
    Dim byte5 As Byte 
    Dim i As Integer  
    Dim temp As Variant
    Dim stri As String

    byte1 = 0
    byte2 = byte3 = byte4 = byte5 = 128

    ' Test to see how many bytes the utf-8 char will need
    Select Case thechars
        Case 0 To 127
            numbytes = 1
        Case 128 To 2047
            numbytes = 2
        Case 2048 To 65535
            numbytes = 3
        Case 65536 To 2097152
            numbytes = 4
        Case Else
            numbytes = 5
    End Select

    Dim returnbytes() As Byte
    ReDim returnbytes(numbytes)


    If numbytes = 1 Then
        returnbytes(0) = thechars
        GoTo finish
    End If


    ' prepare the first byte
    byte1 = 192

    If numbytes > 2 Then
        For i = 3 To numbytes
            byte1 = byte1 / 2
            byte1 = byte1 + 128
        Next i
    End If
    temp = 0
    stri = ""
    If numbytes = 5 Then
        temp = thechars And 63

        byte5 = temp + 128
        returnbytes(4) = byte5
        thechars = thechars / 12
        stri = byte5
    End If

    If numbytes >= 4 Then

        temp = 0
        temp = thechars And 63
        byte4 = temp + 128
        returnbytes(3) = byte4
        thechars = thechars / 12
        stri = byte4 & stri
    End If

    If numbytes >= 3 Then

        temp = 0
        temp = thechars And 63
        byte3 = temp + 128
        returnbytes(2) = byte3
        thechars = thechars / 12
        stri = byte3 & stri
    End If

    If numbytes >= 2 Then

        temp = 0
        temp = thechars And 63
        byte2 = temp Or 128
        returnbytes(1) = byte2
        thechars = Int(thechars / (2 ^ 6))
        stri = byte2 & stri
    End If

    byte1 = thechars Or byte1
    returnbytes(0) = byte1

    stri = byte1 & stri

    finish:
       utf16toutf8 = returnbytes()
End Function

Answer 14

The VBA-tools library has a function for that:

http://vba-tools.github.io/VBA-Web/docs/#/WebHelpers/UrlEncode

It seems to work similar to encodeURIComponent() in JavaScript.