Lempel-Ziv-Welch

data compression algorithm

Also known as: LZW

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Last updated

July 19, 2026

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The Lempel-Ziv-Welch (LZW) algorithm is a lossless data compression technique developed by Abraham Lempel and Jacob Ziv in the 1970s. It works by building a dictionary of sequences encountered in the data. Instead of transmitting full sequences, the algorithm sends a code word for a known sequence and then additional bits to indicate the next element. This creates new, shorter code words for common sequences, reducing redundancy and file size. For example, LZW can compress English text by about 55 percent. This adaptive approach allows it to efficiently compress data without prior knowledge of its probabilities, making it superior to static methods like Huffman coding in many cases. Variations of the Lempel-Ziv algorithm are used in popular compression programs like Zip and gzip.12

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…algorithm commonly referred to as LZW, named after its inventors, Abraham Lempel and Jacob Ziv of Israel and Terry Welch of the United States. LZW was the source of a controversy started by the American Unisys Corporation in 1994, when it was revealed that they owned a patent for LZW…
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…algorithm commonly referred to as LZW, named after its inventors, Abraham Lempel and Jacob Ziv of Israel and Terry Welch of the United States. LZW was the source of a controversy started by the American Unisys Corporation in 1994, when it was revealed that they owned a patent for LZW…
Read More