What is XLSX?
XLSX is the modern Microsoft Excel spreadsheet format. It stores multiple sheets, formulas, formatting and charts in a compressed XML package, and is the standard for sharing rich spreadsheets that go beyond plain CSV.
What is CSV?
CSV is the simplest way to store tabular data: each line is a row and commas separate the columns. It is plain text, opens in Excel, Google Sheets and any programming language, and is the universal format for exporting and importing spreadsheets and databases.
XLSX vs CSV: how they compare
Both formats have their place. This table summarises the practical differences so you can pick the right one for the job.
| XLSX | CSV | |
|---|---|---|
| Format type | Data | Data |
| Compression | Zipped XML | None |
| Quality | Lossless | Lossless |
| Best for | Rich spreadsheets with formulas | Spreadsheet exports and imports |
Why convert XLSX to CSV?
Converting XLSX to CSV gives you a file that is better suited to spreadsheet exports and imports and moving data between apps, and that opens it up to far more apps, devices and websites.
What CSV gives you: opens in every spreadsheet and language, tiny and human-readable and easy to generate.
Where XLSX falls short: needs spreadsheet software, heavier than CSV and harder to parse programmatically than CSV. Converting keeps your content while moving to a format that matches where the file is going.
Tips for the best results
- CSV is lossless, so your converted files keep every detail of the original XLSX.
- You can convert several files in one go — add as many XLSX files as you like and download them together.
- Everything runs locally in your browser, so even large files convert quickly and nothing is uploaded.