Convert CSV to XLSX online in seconds — free, with no sign-up. XLSX is lossless and ideal for data, calculations and shared spreadsheets. Your files are encrypted and deleted automatically after 24 hours.
CSV
Comma-Separated Values — Plain-text tabular data that opens in any spreadsheet or database.
XLSX
Microsoft Excel — Excel's format storing sheets, formulas and charts as XML.
How to convert CSV to XLSX
- 1Upload your CSV file
Click “Choose a file” or drag and drop your CSV file onto the page — no sign-up or email needed.
- 2Convert to XLSX
XLSX is already selected as the output. Open Options to fine-tune quality if you like, then click Convert.
- 3Download your XLSX file
Your XLSX file is ready in seconds — click Download to save it. Files are automatically deleted after 24 hours.
CSV vs XLSX
| CSV | XLSX | |
|---|---|---|
| Full name | Comma-Separated Values | Microsoft Excel |
| Type | Spreadsheet | Spreadsheet |
| Compression | Lossless | Lossless |
| Best for | exporting and importing raw data between tools | data, calculations and shared spreadsheets |
Frequently asked questions
Does converting CSV to XLSX lose quality?
Converting CSV to XLSX preserves your text, images and most formatting. Very complex elements — macros, live formulas or unusual fonts — may not carry over perfectly, but the content stays intact.
What's the difference between CSV and XLSX?
Comma-Separated Values (CSV) is lossless and best for exporting and importing raw data between tools. Microsoft Excel (XLSX) is lossless and best for data, calculations and shared spreadsheets. Convert CSV to XLSX when you need a spreadsheet for data.
Is the CSV to XLSX converter free?
Yes — converting CSV to XLSX is completely free. There's no watermark, no sign-up and no email required, and you can convert as many files as you like.
Are my CSV files private and secure?
Yes. Your uploads are encrypted in transit, processed privately, and automatically deleted within 24 hours. We never share, sell or look at your files.
Can I convert CSV to XLSX on iPhone, Android, Mac or Windows?
Yes. The converter runs entirely in your browser, so it works on any device — iPhone, iPad, Android, Mac, Windows or Linux — with nothing to download or install.
How long does it take to convert CSV to XLSX?
Most files convert in a few seconds. Larger files take a little longer, and your upload speed is usually the limiting factor. There's no queue and no waiting for an email.
What else can I convert CSV files to?
Besides XLSX, you can convert CSV to JSON, ODS, PDF, TSV, YAML and more — see the full list of CSV conversions below.
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Last updated July 2026