LZMA File Compressor & Extractor
Compress any file to .lzma, or open and extract .lzma files back to the original — batch several files at once, pick a compression level, all in your browser with no upload.
Input
LZMA Files
Add files and press Compress to .lzma — each file becomes its own .lzma. Everything runs in your browser; nothing is uploaded.
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Guides
Compress any file into a .lzma, or open a .lzma file and get the original back. Both directions run entirely in your browser, so your files are never uploaded. You can drop in several files at once: each one is compressed or extracted separately, and you can download them one by one or all together as a .zip.
How to use it
- Choose a Mode: Compress files to .lzma or Decompress .lzma files.
- Drop your files into the box, or click to browse. You can add up to 20 files, 64 MB in total.
- When compressing, pick a Compression Level. Balanced (level 5) is a good default. Smallest file (level 9) uses a much larger dictionary, which helps on big files and is several times slower.
- Press Compress to .lzma or Decompress and watch the progress, then download the results. When compressing, each row shows the before and after size and how much was saved.
What is a .lzma file?
A .lzma file is a single file compressed with LZMA, the Lempel–Ziv–Markov chain algorithm that 7-Zip introduced. It usually beats gzip and bzip2 on size, at the cost of slower compression. The .lzma container (also called "LZMA alone" or "legacy LZMA") is just a 13-byte header followed by the compressed stream. You'll meet it in older Linux source tarballs (.tar.lzma, .tlz), firmware images, and game or embedded data files.
Like .gz, a .lzma holds exactly one file and does not store its name. Decompressing data.csv.lzma gives you data.csv.
Is .lzma the same as .xz or .7z?
No. All three use the LZMA family of algorithms, but the containers are different and not interchangeable:
| Format | What it is |
|---|---|
.lzma |
The original bare stream. One file, no checksum, no filename. |
.xz |
Its successor (LZMA2). One file, with integrity checks. |
.7z |
An archive that can hold many files and folders. |
.lz |
lzip, another single-file LZMA container. |
This tool reads and writes .lzma only. If you drop in an .xz, .7z or .lz file by mistake, it tells you which format it actually is.
Can other programs open the files this makes?
Yes. The output is a standard .lzma stream with the uncompressed size in its header. xz --format=lzma -d, unlzma, lzma -d and 7-Zip all open it. Files those tools create open here too.
What happens if I decompress a .tar.lzma or .tlz?
You get the .tar archive that was inside it. To list and extract its individual files, open that .tar with the Tar File Creator.
Why did my file barely shrink?
Files that are already compressed, such as JPG, PNG, MP4, ZIP or PDF, have little redundancy left to remove. Text, CSV, JSON, logs, SQL dumps and other uncompressed formats usually shrink the most.
Why is there a size limit?
Compression runs in JavaScript inside your browser tab rather than on a server, and LZMA is a slow algorithm by design. Expect roughly 1–4 MB per second depending on the level and your device. For multi-gigabyte files, the xz command-line tool is the better fit.
Privacy
All compression and extraction happens locally in your browser with JavaScript. No file is ever sent to a server.
Related tools
To compress many files into a single archive, use the Zip File Creator or the Tar File Creator.