xlwings add-in

To get access to Run main (new in v0.16) button or the RunPython VBA function, you’ll need the xlwings addin (or VBA module), see Add-in & Settings.

For new projects, the easiest way to get started is by using the command line client with the quickstart command, see Command Line Client (CLI) for details:

$ xlwings quickstart myproject

Call Python with “RunPython”

In the VBA Editor (Alt-F11), write the code below into a VBA module. xlwings quickstart automatically adds a new module with a sample call. If you rather want to start from scratch, you can add a new module via Insert > Module.

Sub HelloWorld()
    RunPython "import hello;"
End Sub

This calls the following code in

import numpy as np
import xlwings as xw

def world():
    wb = xw.Book.caller()
    wb.sheets[0]['A1'].value = 'Hello World!'

You can then attach HelloWorld to a button or run it directly in the VBA Editor by hitting F5.


Place xw.Book.caller() within the function that is being called from Excel and not outside as global variable. Otherwise it prevents Excel from shutting down properly upon exiting and leaves you with a zombie process when you use Use UDF Server = True.

Function Arguments and Return Values

While it’s technically possible to include arguments in the function call within RunPython, it’s not very convenient. Also, RunPython does not allow you to return values. To overcome these issues, use UDFs, see User Defined Functions (UDFs) - however, this is currently limited to Windows only.