BMP to GZ Converter
Processing entirely on your device — large files may take a moment.
Bitmap Image and Gzip Compressed File exist for different jobs: BMP is Windows’ native uncompressed bitmap format. Every pixel is stored exactly as captured, which makes files large but trivially simple to read — common in older software and scanners. Unpack a .gz into a normal file or repack it as ZIP/TAR when the receiving tool does not understand gzip.
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 BMP compares to GZ
| BMP | GZ | |
|---|---|---|
| Compression | Usually none (RLE optional) | DEFLATE |
| Best for | Legacy software and scanner output | Logs, dumps, datasets |
How to convert BMP to GZ
- 1
Select your files
Select your BMP 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 BMP format
BMP is Windows' native bitmap format, dating to 1990. It stores pixels essentially raw — rows of BGR values padded to 4-byte boundaries — with optional RLE compression that almost nobody uses. That simplicity is its whole personality: any program written since the dawn of Windows can read one in a dozen lines of code, which is why scanners and ancient lab software still emit it.
The cost of that simplicity is size: an uncompressed BMP of a photo runs dozens of times larger than a JPG. There is no meaningful metadata standard, transparency only exists via the rarely-implemented V5 header, and no modern workflow needs it. Treat BMP as a legacy interchange format you convert away from.
+Strengths
- ✓Zero compression artifacts — pixels stored as captured
- ✓Trivially easy to decode, even in ancient software
- ✓Universal inside the Windows world
!Limitations
- −Enormous files — dozens of times larger than JPG
- −No real metadata or color-management story
- −No role in modern web or print workflows
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 BMP to GZ?
There is a concrete reason this conversion exists: Enormous files — dozens of times larger than JPG 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 BMP 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.
Will I lose quality converting BMP to GZ?
No — GZ is a lossless format, so every pixel of the converted image matches your original BMP file. You can also adjust the quality/size balance before converting when the target format supports compression.
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 BMP file.
Are the files inside my BMP archive modified?
No. Contents are unpacked in memory and repacked into GZ byte-for-byte — the conversion changes the container, never the files inside it.