Python is the gold standard for data processing. With the pandas library, you can convert hundreds of Excel files to CSV in seconds.

Step-by-Step Instructions:

Sample Python Script:

import pandas as pd
import os
import glob

# Set your folder paths
input_folder = "C:/Users/YourName/Excel_Files/"
output_folder = "C:/Users/YourName/CSV_Files/"

# Create output folder if it doesn't exist
os.makedirs(output_folder, exist_ok=True)

# Find all Excel files (.xls and .xlsx)
excel_files = glob.glob(input_folder + "*.xls") + glob.glob(input_folder + "*.xlsx")

for file_path in excel_files:
    # Read Excel file
    df = pd.read_excel(file_path, sheet_name=0)  # First sheet only
    
    # Create CSV filename
    base_name = os.path.basename(file_path)
    csv_name = os.path.splitext(base_name)[0] + ".csv"
    csv_path = os.path.join(output_folder, csv_name)
    
    # Save as CSV (UTF-8 encoding)
    df.to_csv(csv_path, index=False, encoding='utf-8')
    print(f"Converted: {base_name} → {csv_name}")

print("Batch conversion complete!")

If you already have Microsoft Excel, you can use a VBA macro to convert all XLS files in a folder to CSV without installing anything extra.

Step-by-Step Instructions:

Sample VBA Macro:

Sub ConvertAllXLSToCSV()
    Dim folderPath As String
    Dim fileName As String
    Dim wb As Workbook
    
    ' Change this to your folder path
    folderPath = "C:\Users\YourName\Excel_Files\"
    
    fileName = Dir(folderPath & "*.xls*")
    
    Do While fileName <> ""
        Set wb = Workbooks.Open(folderPath & fileName)
        csvName = Replace(fileName, ".xlsx", ".csv")
        csvName = Replace(csvName, ".xls", ".csv")
        
        ' Save as CSV (UTF-16LE is default for Excel)
        wb.SaveAs fileName:=folderPath & csvName, FileFormat:=xlCSV
        wb.Close SaveChanges:=False
        
        fileName = Dir()
    Loop
    
    MsgBox "Batch conversion complete!"
End Sub

For Windows users with Excel installed, PowerShell can automate batch conversion. Mac/Linux users can use a simple bash script with libreoffice (free).

Windows PowerShell Script:

# Save as "batch_convert.ps1"
$excel = New-Object -ComObject Excel.Application
$excel.Visible = $false
$folderPath = "C:\Users\YourName\Excel_Files\"
Get-ChildItem -Path $folderPath -Include *.xls, *.xlsx -Recurse | ForEach-Object {
    $workbook = $excel.Workbooks.Open($_.FullName)
    $csvPath = $_.DirectoryName + "\" + $_.BaseName + ".csv"
    $workbook.SaveAs($csvPath, 6) # 6 = xlCSV
    $workbook.Close()
    Write-Host "Converted: $($_.Name)"
}
$excel.Quit()

Mac/Linux (using LibreOffice – Free):

# Install LibreOffice first: brew install --cask libreoffice
for file in *.xls *.xlsx; do
    libreoffice --headless --convert-to csv "$file"
done

Several online tools support batch conversion (multiple files at once). However, free tiers usually limit file size and number of files.

Recommended Online Batch Converters:

• Convertio – Up to 5 files at once (100MB total daily)
• CloudConvert – Batch upload, 25 free minutes/day
• Zamzar – 2 free conversions/day (not true batch)

For small batches (2-10 files), our internal free XLS to CSV converter is an excellent choice. While it processes one file at a time, it offers unmatched privacy – your files never leave your browser.

How to Use for Batch Conversion: