Will Excel still strip my leading zeros?

Not from this file — those values are stored as text in the workbook, so Excel has nothing to reinterpret.

Can I convert to OpenDocument instead?

Yes, .ods output is available in the same data panel.

No. It is parsed and written on your device.

Convert CSV to Excel (XLSX)

Turn a CSV into a real .xlsx workbook in your browser, keeping leading zeros and long IDs intact. Nothing uploaded.

Opening a CSV directly in Excel is how 007 becomes 7, a ZIP code loses its first digit, and a 20-digit order number turns into 1.23457E+19. Excel guesses that anything made of digits is a number, and the damage is done before you see the sheet.

This writes a proper .xlsx instead, and stores digit strings such as 007 or a long ID as text, so they arrive in Excel exactly as they were in the CSV.

Quoted fields, commas inside values and line breaks inside quotes are handled. Tab-separated TSV files convert the same way.

Worth knowing. The workbook is built in your browser, so a very large CSV is limited by your device's memory rather than by an upload cap. The result opens in Excel, LibreOffice, Numbers and Google Sheets.

Questions

Will Excel still strip my leading zeros?: Not from this file — those values are stored as text in the workbook, so Excel has nothing to reinterpret.
Can I convert to OpenDocument instead?: Yes, .ods output is available in the same data panel.
Is the CSV uploaded?: No. It is parsed and written on your device.

Everything the converter reads and writes →

Runs entirely in your browser. The file is never uploaded, so there is nothing for us to store, log or lose. No account, no watermark, no size paywall.