Convert a CSV to Excel (XLSX)
To convert a CSV to Excel, open the converter in Sigmera, drop your .csv file, and download a ready-to-open .xlsx workbook. The conversion happens entirely in your browser — your file is never uploaded to a server, so it’s GDPR-safe by design and works without Excel installed.
Last updated: June 2026
Use the CSV → Excel converter free in your workspace
Free account, no credit card — every tool, unlimited rows, 3 free downloads a month, nothing uploaded.
🔒 Everything runs in your browser — your file is never uploaded, and the workspace even works offline once it has loaded.
How to convert CSV to Excel
- 1. Open the converter in your free workspace. Your CSV is read into the browser’s memory — never sent over the network.
- 2. Drop your .csv file. Sigmera detects the delimiter and encoding automatically, so accents and special characters survive.
- 3. Download the .xlsx workbook. The result opens in Excel, Google Sheets, Numbers, or LibreOffice.
Why convert in the browser?
Most online converters upload your file to a server you can’t see. Because Sigmera converts the file locally with the browser’s built-in engine, there is no server to upload to and nothing is stored — which satisfies GDPR data-minimization because zero bytes leave your device.
Frequently asked questions
- Does this tool upload my CSV?
- No. The CSV-to-Excel conversion runs entirely inside your web browser using client-side JavaScript. Your file is never uploaded to a server, so it is GDPR-safe by design.
- What format does it produce?
- A standard .xlsx workbook that opens in Microsoft Excel, Google Sheets, Numbers, and LibreOffice. Your rows and columns are placed on the first sheet exactly as they appear in the CSV.
- Will it handle accents and other languages?
- Yes. Sigmera auto-detects the CSV's encoding (UTF-8, UTF-16, Windows-1250/1252 and more), so accented and non-Latin characters survive the conversion intact.
- Do I need Excel installed?
- No. The conversion happens in the browser, so you don't need Excel or any other app installed to produce the .xlsx file.