BMP to 7Z Converter
Processing entirely on your device — large files may take a moment.
Bitmap Image and 7-Zip Archive 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. 7Z is ideal for big archives you store or share with power users; convert to ZIP when the recipient just needs to double-click.
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 7Z
| BMP | 7Z | |
|---|---|---|
| Compression | Usually none (RLE optional) | LZMA / LZMA2 |
| Best for | Legacy software and scanner output | Maximum compression, secure archives |
How to convert BMP to 7Z
- 1
Select your files
Select your BMP file — it never leaves your device.
- 2
Convert instantly
The engine packs the file, byte for byte, into a 7Z container — no re-encoding, no quality change.
- 3
Download results
Download the finished 7Z archive.
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 7Z format
7Z is the native format of Igor Pavlov's 7-Zip (1999), built around LZMA/LZMA2 compression — for years the ratio king against ZIP and RAR — with AES-256 encryption, solid archiving (similar files compress as one stream) and open, unpatented specifications. A 7Z of the same photos or code is routinely 20–40% smaller than its ZIP.
The trade-off is platform defaults: Windows Explorer and macOS Archive Utility do not open 7Z without third-party tools (7-Zip, PeaZip, Keka). It is the format for maximizing compression on your own terms, and for encrypted archives done properly (header encryption included).
+Strengths
- ✓Top-tier compression ratio (LZMA2)
- ✓Real AES-256 encryption, optional header encryption
- ✓Open format, free tooling everywhere
!Limitations
- −No native OS support — recipients need tools
- −Solid mode makes single-file extraction costly
Why convert BMP to 7Z?
There is a concrete reason this conversion exists: Enormous files — dozens of times larger than JPG 7Z sidesteps that — Top-tier compression ratio (LZMA2) If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this BMP to 7Z 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 7Z?
No — 7Z 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.
Will transparent areas survive the conversion to 7Z?
Transparency is kept whenever 7Z actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
Can I convert several BMP files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.