Format comparison
XLS vs HTML
How do XLS and HTMLcompare? Here's everything you need to know to choose the right format — and how to convert between them.
.xls
Full guide →Microsoft Excel Spreadsheet (Legacy)
XLS is the legacy binary format used by Microsoft Excel before 2007. While superseded by XLSX, many existing spreadsheets and enterprise systems still use this format.
.html
Full guide →HyperText Markup Language
HTML is the standard markup language for creating web pages. While primarily a web technology, HTML files are also used as a portable document format with rich formatting and multimedia support.
| Specification | XLS | HTML |
|---|---|---|
| Full name | Microsoft Excel Spreadsheet (Legacy) | HyperText Markup Language |
| Extension | .xls | .html |
| MIME type | application/vnd.ms-excel | text/html |
| Category | Document | Document |
| Developer | Microsoft | W3C / WHATWG |
| Year introduced | 1987 | 1993 |
XLS advantages
- Compatible with older Excel versions
- Widely recognized format
- Supported by all major spreadsheet apps
- Large installed base
XLS limitations
- Limited to 65,536 rows and 256 columns
- Larger file sizes than XLSX
- Binary format — harder to recover
- Missing modern Excel features
HTML advantages
- Viewable in any web browser
- Rich formatting and multimedia
- Accessible and searchable text
- Can include interactive elements
HTML limitations
- Not a fixed-layout format
- Rendering varies between browsers
- External resources may break links
- Not ideal for print or signing
Which should you use?
XLS and HTML serve different purposes. XLS is ideal for legacy spreadsheet compatibility, while HTML excels at web pages and email newsletters.
Best uses for XLS
Legacy spreadsheet compatibility
Older enterprise systems
Historical data archives
Backward-compatible exports
Best uses for HTML
Web pages and email newsletters
Online documentation
E-book content (EPUB basis)
Report generation
Convert between XLS and HTML
Need to switch formats? Convert for free with SquishConvert.