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Extended Log Format

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated June 16, 2026

Extended Log Format (ELF) is a standardized text file format that is used by web servers when generating log files. In comparison to the Common Log Format (CLF), ELF provides more information and flexibility.

01Example

#Version: 1.0 #Date: 12-Jan-1996 00:00:00 #Fields: time cs-method cs-uri 00:34:23 GET /foo/bar.html 12:21:16 GET /foo/bar.html 12:45:52 GET /foo/bar.html 12:57:34 GET /foo/bar.html
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This article is adapted from the Wikipedia article “Extended Log Format”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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Related topics

Common Log Format

For computer log management, the Common Log Format, also known as the NCSA Common log format, is a historically standardized text file format from 2004 that was used by web servers when generating server log files. Because the format was standardized, the files had been readily analyzed by a variety of web analysis programs, for example Webalizer and Analog.