Free · No signup · Files deleted after 1h

XLS to XLSX
Converter

Modernise an Excel 97-2003 workbook to XLSX — formatting intact — or pull the data straight out as CSV or JSON.

Convert XLS to XLSX free →

No account needed · Up to 25 MB free · Files permanently deleted after 1 hour

Formatting kept
The workbook is re-saved by a full spreadsheet engine, so formulas, number formats, multiple sheets and cell styling survive the trip to XLSX.
Or just the data
Need the values, not the styling? Choose CSV for spreadsheets-anywhere, or JSON if the data is headed into code.
Private & secure
Uploaded over HTTPS, processed on EU servers, never shared with third parties, and permanently deleted after 1 hour. Never used to train AI.

How it works

1
Upload your XLS
Drag and drop the .xls workbook, or click to browse.
2
Pick XLSX, CSV or JSON
XLSX modernises the whole workbook; CSV and JSON extract the data.
3
Download the result
Ready in seconds — multi-sheet CSV exports arrive as a ZIP, one CSV per sheet.

Common questions

Why does Excel complain about my .xls file?

XLS is the binary format from Excel 97-2003. Modern Excel still opens it in “compatibility mode” but warns about it, blocks some features, and many web apps reject it outright. XLSX is the current standard.

Do formulas survive the conversion?

Converting to XLSX: yes — the workbook is re-saved whole. Extracting to CSV or JSON: you get each cell's calculated value (CSV and JSON have no concept of formulas).

What happens to multiple sheets?

XLSX keeps them all. CSV export produces one file per sheet, bundled as a ZIP. JSON export returns an object with one array of rows per sheet.

Is there a file size limit?

Free users can convert files up to 25 MB without an account. Pro raises that to 500 MB per file with 3,000 credits a month; Business goes to 5 GB.

Related converters
Excel → CSV Excel → JSON CSV → Excel Repair CSV