LHA (LHA/LZH Archive)
A compact archive format born in 1980s Japan that powered Amiga scene releases and shipped inside early id Software game installers.
| Full name | LHA/LZH Archive |
| Extension | .lha |
| MIME type | application/x-lzh-compressed |
| Developer | Haruyasu Yoshizaki (Yoshi) |
| Released | 1989 (LHarc v1.00, March 1989) |
| Type | Lossless archive / data compression |
| Compression method | LZSS + static Huffman coding (LH5, LH6, LH7) |
| Common aliases | LHarc, LZH, LHA |
What is a LHA file?
LHA is a lossless archive format that packages one or more files into a single compressed container. It uses a sliding-window algorithm combined with Huffman coding to shrink data before storing it. Files use the .lha extension, while an older variant uses .lzh.
An LHA archive stores each file individually with its own header containing the filename, size, checksum, and compression method identifier. The format supports several compression levels, labeled -lh4- through -lh7-, that use sliding windows of 4 KB to 64 KB. The most common method found in modern archives is -lh5-, which offers a good balance of speed and compression ratio. Archives have no central directory; tools read each file header sequentially to build the listing.
History
Haruyasu Yoshizaki, a Japanese medical doctor who went by the nickname Yoshi, released LHarc v1.00 in March 1989 for MS-DOS. The tool was later renamed LH, then LHa, and finally LHA from version 2.10 onward. Through the 1990s it became the dominant archive format on Amiga computers and was also used inside the installers for id Software titles such as Doom and Quake.
How it works
Each file entry in an LHA archive begins with a level-0, level-1, or level-2 header block. The header stores the original filename, compressed and uncompressed sizes, a CRC-16 checksum, a five-byte compression method string (for example -lh5-), and OS metadata. Compressed data follows immediately after the header with no padding. There is no end-of-archive signature; tools detect the final entry by reaching the expected file size.
What it is used for
- Distributing Amiga software, demos, and scene releases
- Extracting legacy archives from 1990s shareware CDs and BBS collections
- Unpacking older Japanese software packages that shipped in LZH format
- Converting historical archives to modern formats like ZIP or 7z for long-term storage
How to open it
On Windows you can open LHA files with 7-Zip or WinRAR. On Linux and macOS the command-line tool lhasa or the classic lha utility handles both .lha and .lzh files.
Pros and cons
Strengths
- Good compression ratio for text and executable files
- Stores per-file checksums, catching corruption on a file-by-file basis
- Widely supported by modern archivers such as 7-Zip
- Compact header overhead makes it efficient for small file counts
Trade-offs
- No built-in encryption or password protection
- No central directory means random access requires scanning the whole file
- Largely superseded by ZIP, RAR, and 7z for new use cases
- Limited support for Unicode filenames in older archive versions
Convert LHA files
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LHA FAQ
What is the difference between .lha and .lzh files?
They are the same format. The .lzh extension was used on MS-DOS systems where three-character extensions were standard, while .lha became common on Amiga and other platforms. Most tools open both interchangeably.
Who created the LHA format?
Haruyasu Yoshizaki, a Japanese medical doctor known as Yoshi, created it. He originally released it as LHarc in March 1989 and later renamed the tool LHA.
Can 7-Zip open LHA files?
Yes. 7-Zip on Windows and Linux reads both .lha and .lzh archives without any plugins. You can also drag the file onto the 7-Zip file manager window.
Is LHA still used today?
It remains the primary archive format in the Amiga hobbyist community and on Japanese software distribution sites. Outside those niches, most new archives use ZIP or 7z instead.