Convert CSV to XLS

Convert CSV to XLS instantly in your browser. Your spreadsheet data is processed on your device and never uploaded.

Your file never leaves your device.

How to convert CSV to XLS

XLS is the legacy Excel format still required by some older systems and upload portals. This tool reads the CSV with SheetJS, a proven spreadsheet engine, directly in your browser and writes a correct XLS file with the right encoding, escaping and structure. There are no rows to copy by hand and no data leaves your computer.

Step 1: Choose your CSV file
Drag and drop a .csv file onto the converter or click to browse. It works on desktop, tablet and phone.
Step 2: Automatic conversion
Rows and columns are read and written as XLS in a fraction of a second.
Step 3: Download the XLS
Save each result individually, or download everything as a single ZIP when you convert several files.

Good to know

Numbers and dates are detected automatically, so they arrive as real numeric cells instead of text.
UTF-8 text, accents and emoji are preserved.

Why use this CSV to XLS converter?

XLS is the legacy Excel format still required by some older systems and upload portals.
Handles large files with thousands of rows.
Correct quoting and UTF-8 encoding.
100% local: spreadsheets often contain personal or financial data, and here it never leaves your device.

Is it free?

Yes. Converting CSV to XLS is free, with no watermark, signup or email required. Local conversions have no artificial file-size or daily cap; the practical limit is your device.

Is my file uploaded?

The CSV file is processed entirely in your browser. It is never uploaded, never stored and never seen by anyone, so this is safe for confidential files.

About the formats

What is CSV?

CSV (comma-separated values) is a plain-text format that stores tabular data, one row per line and fields separated by commas. It needs no special software: any text editor, spreadsheet application or database can read it. Because of its simplicity, CSV is the universal interchange format between databases, spreadsheets and other programs.

Use CSV whenever you need to move tabular data between systems, exporting a database, importing contacts or sharing a table with someone who uses different software. Choose CSV when plain, predictable data matters more than formatting.

CSV (Comma-Separated Values)

What is XLS?

XLS is the binary workbook format used by Microsoft Excel up to version 2003. It stores sheets, formulas, formatting, charts and macros in a single file. Each sheet is limited to 65,536 rows and 256 columns, a limit that the XML-based XLSX, the default since Excel 2007, raised considerably.

Use XLS only when an old version of Excel or a legacy system requires it. For new work, XLSX handles far larger sheets and is less prone to corruption, and CSV is the simpler choice when you only need to move raw data.

XLS (Excel 97-2003 workbook)

Frequently Asked Questions

Is CSV to XLS conversion free?

Yes. It is free, with no watermark, signup or email required. Local conversions have no artificial file-size or daily cap; the practical limit is your device.

What happens to formulas when converting CSV to XLS?

The calculated values are exported. The formulas themselves are not part of the output format.

Is it safe to convert csv to xls here?

Yes. The work happens on your own device with WebAssembly and browser APIs, so the file is not uploaded at all. You can even disconnect from the internet once the page has loaded.

Do I need to install anything?

No. Everything runs in a modern browser (Chrome, Edge, Firefox or Safari) on Windows, macOS, Linux, Android and iOS. There is no app, plugin or account.

Can I convert XLS back to CSV?

Yes, there is a dedicated XLS to CSV converter linked in the related tools below. Keep in mind that information dropped in one direction cannot always be restored in the other.

Need the opposite? Convert XLS to CSV

ExcelProcessed locally