Convert Excel .xls to .xlsx with Python: A Step‑by‑Step Guide

Introduction

Python has become extremely popular for office automation, offering a more convenient alternative to VBA for batch processing.

Previously we covered converting Word documents; now we focus on handling Excel files.

Common Python libraries for Excel

xlrd : read‑only, supports both .xls and .xlsx.

xlwt : write‑only, supports only .xls.

openpyxl : read and write, supports only .xlsx.

When both .xls and .xlsx files need processing, it is advisable to convert them to a unified format first.

For the less‑supported .xlsm format, you can use a locally installed Microsoft Excel application via COM automation to convert the file.

Key points about SaveAs FileFormat

FileFormat=51 → .xlsx

FileFormat=56 → .xls

FileFormat=52 → .xlsm

FileFormat=23 → .csv

Code example

# Call Excel application
ExcelApp = win32com.client.Dispatch("Excel.Application")
ExcelApp.Visible = 0
ExcelApp.DisplayAlerts = 0
wb = ExcelApp.Workbooks.Open(path)
newpath = allpath + '\\converted.xlsx'
wb.SaveAs(newpath, FileFormat=51)
ExcelApp.Quit()

The full script includes imports, a function definition, and usage to convert a given .xls file to .xlsx, printing the current directory and demonstrating the conversion.

Resulting file is saved as shown in the screenshot.