XLS to GZ Converter
Processing entirely on your device — large files may take a moment.
Unpack a .gz into a normal file or repack it as ZIP/TAR when the receiving tool does not understand gzip. If your files are still in XLS format, this page is the shortcut: XLS is the classic Excel 97–2003 workbook format, still produced by many banks, ERP systems and export tools.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How to convert XLS to GZ
- 1
Select your files
Select your XLS file.
- 2
Convert instantly
The file bytes are gzip-compressed in place — the same archive your server or build tool produces, made locally.
- 3
Download results
Download the .gz file — ready to upload, serve or attach.
About the XLS format
XLS is the legacy Excel binary format (BIFF8, Excel 97–2003). It does everything its era supported — sheets, formulas, formatting, VBA macros — under hard limits: 65,536 rows and 256 columns per sheet. Millions of government, banking and manufacturing templates were built on it, which is why it still arrives in inboxes.
There is no reason to create new XLS files: XLSX handles everything better with no row ceiling. The realistic use case is reading — opening or converting historical files, or feeding systems whose import filters predate 2007.
+Strengths
- ✓The only format ancient Excel-era systems accept
- ✓Full BIFF8 feature set: formulas, macros, formatting
!Limitations
- −65,536-row and 256-column ceiling per sheet
- −Obsolete binary spec, awkward for modern tools
- −Macro-enabled files carry security risk
About the GZ format
A .gz file is one file squeezed by gzip — not an archive. kernel.org tarballs are “tar inside gz”, but plenty of logs, JSON dumps and CSV exports travel as plain .gz. Opening one means decompressing it back to the original bytes.
Repacking into ZIP or TAR gives the decompressed file a container that every GUI tool opens without a second thought.
+Strengths
- ✓Everywhere on Linux and macOS
- ✓Fast, well-understood compression
- ✓Streams natively from any tool
!Limitations
- −Single file only — no directory tree
- −No encryption or integrity metadata
Why convert XLS to GZ?
There is a concrete reason this conversion exists: 65,536-row and 256-column ceiling per sheet GZ sidesteps that — Everywhere on Linux and macOS If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this XLS to GZ converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
What about special characters and non-English text?
Everything is handled as UTF-8. When you export CSV for Excel, a UTF-8 BOM is included automatically so Chinese, Japanese, Korean and accented characters display correctly on both Windows and macOS.
What about folders and directory structure?
The full directory tree is preserved: folders stay folders, and deep paths arrive exactly as they were packed in the XLS file.
Is there a size limit for archive conversion?
There is no upload cap because nothing is uploaded — the practical limit is your device memory. A few hundred megabytes of unpacked content works comfortably on a modern computer.