Convert XLS to CSV Online Free

Drag & drop your .xls file here, or click to browse

Converts to CSV in your browser · first daily conversion free · no signup

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Extract data from legacy Excel .xls files into universal CSV format. Perfect for opening old spreadsheets without Microsoft Office or importing data into modern tools.

By ChangeThisFile Team · Last updated: March 2026

Quick Answer

To convert XLS to CSV, drop your legacy Excel file onto the ChangeThisFile converter. The old binary Excel format is parsed using SheetJS and converted to comma-separated values. Free, browser-based, no Excel needed, and your spreadsheet never leaves your device.

First daily conversion free No signup required Files stay on your device Instant conversion Updated May 2026

XLS vs CSV: Format Comparison

Key differences between the two formats

Feature	XLS (Excel Legacy)	CSV
File format	Binary BIFF format (pre-2007 Excel)	Plain text with comma-separated values
Max rows	65,536 rows	No row limit
Multiple sheets	Supported	Single table only
Formulas	Supported with cell references	Not supported (values only)
Formatting	Fonts, colors, borders	None (plain text)
File size	Binary, moderately compact	Minimal, just raw data
Modern support	Legacy, being phased out	Universal, works everywhere

When to Convert

Common scenarios where this conversion is useful

Recovering data from old Excel files

Open legacy .xls files from the pre-2007 era without installing older versions of Excel. Convert to CSV to access the data in any modern application.

Database imports from legacy spreadsheets

Import data from old XLS files into modern databases by converting to CSV first. All major databases support CSV bulk import.

Migrating legacy data to modern systems

Convert archived XLS files to CSV as part of data migration projects when moving from legacy systems to modern platforms.

Data analysis without Excel

Convert XLS files to CSV for analysis in Python, R, or other data science tools without needing a legacy Excel installation.

Who Uses This Conversion

Tailored guidance for different workflows

Developers

Convert XLS config files to CSV for compatibility with different tools or frameworks
Transform XLS API responses to CSV for debugging, logging, or documentation

Validate the converted CSV output with a linter to catch any structural issues from the conversion

Watch for data type coercion (e.g., numbers becoming strings) when converting between XLS and CSV

Data Analysts

Convert XLS exports to CSV for importing into spreadsheet software, databases, or BI tools
Transform XLS datasets to CSV for sharing with teammates who use different analysis tools

Check that column delimiters and quote escaping are handled correctly in the converted CSV file

Preview the first few rows of the CSV output to verify headers and data alignment

System Administrators

Convert XLS configuration to CSV when migrating between infrastructure tools or platforms
Transform XLS log exports to CSV for ingesting into monitoring or analysis systems

Back up the original XLS config before converting, especially for production systems

Test the converted CSV in a staging environment before deploying to production

How to Convert XLS to CSV

1

Upload your XLS file

Drag and drop your .xls file onto the converter, or click to browse. Legacy Excel 97-2003 format (.xls) is fully supported.
2

Automatic conversion

Your legacy spreadsheet is parsed in the browser. Formulas are resolved to values. Formatting is stripped, leaving only the raw data.
3

Download the CSV result

Click Download to save your .csv file. Values are comma-separated with proper quoting for fields containing commas or newlines.

Automate this conversion

Convert XLS to CSV via API

Integrate this conversion into your pipeline with 3 lines of code. Free tier: 25 conversions/month.

The free converter above runs entirely in your browser — your file is never uploaded. This optional API is a separate server-side endpoint for automating conversions at scale.

curl -X POST https://changethisfile.com/v1/convert \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@input.xls" \
  -F "target=csv" \
  -o output.csv --fail

const form = new FormData();
form.append('file', fileInput.files[0]);
form.append('target', 'csv');

const res = await fetch('https://changethisfile.com/v1/convert', {
  method: 'POST',
  headers: { 'Authorization': 'Bearer YOUR_API_KEY' },
  body: form
});
const blob = await res.blob(); // your converted CSV file

Replace YOUR_API_KEY with your free key — no credit card needed.

Get a free API key

Frequently Asked Questions

What versions of XLS are supported?

The converter supports Excel 97, 2000, 2002 (XP), and 2003 .xls files. These use the BIFF8 binary format that was standard before Excel 2007 introduced .xlsx.

Which sheet is converted?

The first sheet in the workbook is converted. If you need a different sheet, rearrange the sheet order before converting.

Are formulas preserved?

Formulas are resolved to their last calculated values. The CSV output contains computed results, not formula expressions.

How are dates handled?

Excel dates are converted to their text representation based on the cell format. Serial date numbers are converted to readable date strings.

What about merged cells?

Merged cells are unmerged. The value appears in the top-left cell of the original merge range, and remaining cells are empty.

Can I convert password-protected XLS files?

No. Password-protected XLS files cannot be parsed by the browser-based converter. Remove password protection first.

Do I need Microsoft Excel installed?

No. The converter parses XLS files directly in your browser using SheetJS. No Excel or Office installation is required.

Should I convert XLS to XLSX instead?

If you need to preserve formatting, formulas, and multiple sheets, convert to XLSX instead. CSV is best when you only need the raw data.

How large of an XLS file can I convert?

XLS files are limited to 65,536 rows by format. The converter handles all standard XLS files efficiently in your browser.

Is my data secure?

Yes. The conversion happens entirely in your browser. Your legacy spreadsheet data is never sent to any server.

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