How do I find the Excel column name that corresponds to a given integer?

Question

How would you determine the column name (e.g. "AQ" or "BH") of the nth column in Excel?

Edit: A language-agnostic algorithm to determine this is the main goal here.

Answer 1

I once wrote this function to perform that exact task:

public static string Column(int column)
{
    column--;
    if (column >= 0 && column < 26)
        return ((char)('A' + column)).ToString();
    else if (column > 25)
        return Column(column / 26) + Column(column % 26 + 1);
    else
        throw new Exception("Invalid Column #" + (column + 1).ToString());
}

Answer 2

I currently use this, but I have a feeling that it can be optimized.

private String GetNthExcelColName(int n)
{
    String firstLetter = "";  
    //if number is under 26, it has a single letter name
    // otherwise, it is 'A' for 27-52, 'B' for 53-78, etc
    if(n > 26)
    {
        //the Converts to double and back to int are just so Floor() can be used
        Double value = Convert.ToDouble((n-1) / 26);
        int firstLetterVal = Convert.ToInt32(Math.Floor(value))-1;
        firstLetter = Convert.ToChar(firstLetterValue + 65).ToString();
    }    

    //second letter repeats
    int secondLetterValue = (n-1) % 26;
    String secondLetter = Convert.ToChar(secondLetterValue+65).ToString();

    return firstLetter + secondLetter;
}

Answer 3

Joseph's code is good but, if you don't want or need to use a VBA function, try this.

Assuming that the value of n is in cell A2 Use this function:

• =MID(ADDRESS(1,A2),2,LEN(ADDRESS(1,A2))-3)

Answer 4

I suppose you need VBA code:

Public Function GetColumnAddress(nCol As Integer) As String

Dim r As Range

Set r = Range("A1").Columns(nCol)
GetColumnAddress = r.Address

End Function

Answer 5

All these code samples that these good people have posted look fine.

There is one thing to be aware of. Starting with Office 2007, Excel actually has up to 16,384 columns. That translates to XFD (the old max of 256 colums was IV). You will have to modify these methods somewhat to make them work for three characters.

Shouldn't be that hard...

Answer 6

A language agnostic algorithm would be as follows:

function getNthColumnName(int n) {
   let curPower = 1
   while curPower < n {
      set curPower = curPower * 26
   }
   let result = ""
   while n > 0 {
      let temp = n / curPower
      let result = result + char(temp)
      set n = n - (curPower * temp)
      set curPower = curPower / 26
   }
   return result

This algorithm also takes into account if Excel gets upgraded again to handle more than 16k columns. If you really wanted to go overboard, you could pass in an additional value and replace the instances of 26 with another number to accomodate alternate alphabets

Answer 7

This does what you want in VBA

Function GetNthExcelColName(n As Integer) As String
    Dim s As String
    s = Cells(1, n).Address
    GetNthExcelColName = Mid(s, 2, InStr(2, s, "$") - 2)
End Function

Answer 8

Here's Gary Waters solution

Function ConvertNumberToColumnLetter2(ByVal colNum As Long) As String
    Dim i As Long, x As Long
    For i = 6 To 0 Step -1
        x = (1 - 26 ^ (i + 1)) / (-25) - 1 ‘ Geometric Series formula
        If colNum > x Then
            ConvertNumberToColumnLetter2 = ConvertNumberToColumnLetter2 & Chr(((colNum - x - 1)\ 26 ^ i) Mod 26 + 65)
        End If
    Next i
End Function

via http://www.dailydoseofexcel.com/archives/2004/05/21/column-numbers-to-letters/

Answer 9

Considering the comment of wcm (top value = xfd), you can calculate it like this;

function IntToExcel(n: Integer); string;
begin
   Result := '';
   for i := 2 down to 0 do 
   begin
      if ((n div 26^i)) > 0) or (i = 0) then
         Result := Result + Char(Ord('A')+(n div (26^i)) - IIF(i>0;1;0));
      n := n mod (26^i);
   end;
end;

There are 26 characters in the alphabet and we have a number system just like hex or binary, just with an unusual character set (A..Z), representing positionally the powers of 26: (26^2)(26^1)(26^0).

Answer 10

This seems to work in vb.net

Public Function Column(ByVal pColumn As Integer) As String
    pColumn -= 1
    If pColumn >= 0 AndAlso pColumn < 26 Then
        Return ChrW(Asc("A"c) + pColumn).ToString
    ElseIf (pColumn > 25) Then
        Return Column(CInt(math.Floor(pColumn / 26))) + Column((pColumn Mod 26) + 1)
    Else
 stop
        Throw New ArgumentException("Invalid column #" + (pColumn + 1).ToString)
    End If
End Function

I took Joseph's and tested it to BH, then fed it 980-1000 and it looked good.

Answer 11

=CHAR(64+COLUMN())

Answer 12

Assuming lngCol is the column number:

function ColNum2Letter(lngCol as long) as string
   dim arAdr
   arAdr = split(cells(1,lngCol).address,"$")
   ColNum2Letter= arAdr(ubound(arAdr))
end function

Answer 13

IF(COLUMN()>=26,CHAR(ROUND(COLUMN()/26,1)+64)&CHAR(MOD(COLUMN(),26)+64),CHAR(COLUMN()+64))

This works 2 letter columns (up until column ZZ). You'd have to nest another if statement for 3 letter columns.