We can apply an array formula to remove letters from strings/numbers/cells in Excel. Please do as follows:

1. Select a blank cell you will return the text string without letters, enter the formula =SUM(MID(0&A2,LARGE(INDEX(ISNUMBER(--MID(A2,ROW($1:$99),1))*ROW($1:$99),),ROW($1:$99))+1,1)*10^ROW($1:$99)/10) (A2 is the cell you will remove letters from) into it, and press the Ctrl + Shift + Enter keys at the same time.

2. Keep selecting the cell, and then drag its Fill Handle to the range as you need. And now you will see all letters are removed from original text strings as below screenshot shown:

Notes:
(1) This array formula will remove all kinds of characters except the numeric characters. For example, the original text string is abc-859*-24test, this array formula will remove all letters and special characters (* and -) and return 85924.
(2) If there is no number in the text string, this array formula will return 0.

All above methods will remove all characters except the numeric characters. But sometimes you may want to remove only letters from text string, but remain numeric characters and others. This method will introduce Kutools for Excel’s Remove Characters utility to get it done easily in Excel.

1. Select the cells that you will remove letters from, and click Kutools > Text > Remove Characters.

2. In the opening Remove Characters dialog box, check the Alpha option, and click the Ok button. And then you will see only letters are removed from selected cells. See screenshot:

Note: If you indeed want to remove all kinds of characters except the numeric ones, you can check the Non-numeric option and click the Ok button in the Remove Characters dialog box. See screenshot:

We can also add a user defined function into Excel for removing letters from strings/numbers/cells. Please do as follows:

1. Press Alt + F11 keys at the same time to open the Microsoft Visual Basic for Applications window.

2. Click Insert > Module, and then copy and paste the following code into the new opening Module window.

VBA: Remove letters from strings/numbers/cells in Excel

Function StripChar(Txt As String) As String
With CreateObject("VBScript.RegExp")
.Global = True
.Pattern = "\D"
StripChar = .Replace(Txt, "")
End With
End Function

3. Save this user defined function. Select a blank cell you will return the text string without letters, and enter the formula =StripChar(A2) (A2 is the cell that you will remove letters from) into it, and drag the Fill Handle down to the range as you need. See screenshots:

Notes:
(1) This user defined function can also remove all kinds of characters except the numeric characters. For example, the original text string is abc-859*-24test, this array formula will remove letters and special characters (* and -) and return 85924.
(2) This user defined function will return numbers stored as text strings.

This method will introduce Kutools for Excel’s EXTRACTNUMBERS function to remove all letters from stings/numbers/cells easily in Excel. Please do as follows:

1. Select a blank cell you will return the text string without letters, and click Kutools > Functions > Text > EXTRCTNUMBERS. See screenshot:

2. In the opening Function Arguments dialog box, specify the cell that you will remove letters from into the Txt box, it’s optional to type TRUE or FAlSE into the N box, and click the OK button.

Note: Typing TRUE will return numeric numbers, while typing nothing or FALSE will return numbers stored as text strings.

3. Keep selecting the cell, and drag the Fill Handle to the range as you need. And then you will see all letters are removed from original text strings. See screenshot:

Notes:
(1) You can type the formula =EXTRACTNUMBERS(A2,TRUE) into selected cell directly, and then drag the Fill handle to the range as you need.
(2) This EXTRACTNUMBERS function will also remove all kinds of characters except the numeric characters.

How to remove numbers from text strings in Excel?