XLSX to XLS Converter

Convert XLSX files to legacy XLS format entirely in your browser. Supports batch processing, metadata extraction, and content-only conversion. Works offline with no data sent to servers.

Upload XLSX Files

Drag & drop files here or click to browse

Output Format

CSV Options

Include headers

About XLSX to XLS Conversion

Converting modern XLSX files to legacy XLS format enables compatibility with older systems while maintaining data integrity. This converter extracts data from XLSX files and creates compatible outputs without external dependencies.

Conversion Process

Upload XLSX files using drag-and-drop or file browser
Select output format (CSV for data, HTML for formatting, or PDF for printing)
Download converted files instantly

Format Compatibility

Feature	XLSX	XLS
Max rows	1,048,576	65,536
Formulas	Full support	Basic support

CSV Preview & Column Tools

Column Operations

Frequently Asked Questions

Can I convert multiple files at once?

Yes, you can upload multiple XLSX files and they will be processed sequentially. Note that very large batches may impact browser performance.

Why can't I get a true XLS file?

Generating native XLS files requires binary formatting that isn't practical in browsers. We output CSV data that can be opened in Excel and saved as XLS.

What happens to formulas and formatting?

Formulas and advanced formatting are preserved in HTML export but will be lost in CSV conversion. Complex formatting may not render perfectly in print preview.

How It Works

Files are read using FileReader APIs and processed entirely in your browser. For XLSX files, we extract data from the ZIP container using DecompressionStream when available. All processing happens offline with no server communication.

For informational and educational purposes only. Conversions run locally in your browser. Complex formats may be partially supported or content-only. For professional workflows verify formatting, fonts, pagination, and compliance before publishing.

References: ECMA 376 Office Open XML XLSX package basics, RFC 4180 CSV specification

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XLSX to XLS Converter

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