# Combined Log Format

Category: [Log Files](https://seo-geo-glossary.com/en/glossary/category/log-files/) › [Log data & formats](https://seo-geo-glossary.com/en/glossary/category/log-files/log-data-formats/)

The **Combined Log Format** is a line format for web server access logs. It is the Common Log Format plus two fields, the referer and the user agent.

## Field order

Apache defines it like this:

```apache
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" combined
```

- `%h` client IP address
- `%l` client identity per RFC 1413, which Apache calls very unreliable (usually `-`)
- `%u` authenticated user, otherwise `-`
- `%t` timestamp in square brackets
- `%r` request line with method, path and protocol
- `%>s` final HTTP status code
- `%b` response size in bytes, without headers
- referer and user agent, each in quotes

nginx ships a predefined format called `combined` with the same content: `$remote_addr`, `$remote_user`, `$time_local`, `$request`, `$status`, `$body_bytes_sent`, `$http_referer` and `$http_user_agent`. It applies to `access_log` when no other format is named.

IP addresses can be personal data (CJEU, judgment of 19 October 2016, C-582/14, Breyer).

This is not legal advice.

## Use in SEO

The user agent lets you separate search engine and AI bot requests from other traffic, and the status code shows how the server responded. The format has no field for response time. If you need one, define a custom format, because a field that was never logged cannot be added to old lines.

## Example

```txt
66.249.66.1 - - [10/Oct/2026:13:55:36 +0000] "GET /products/ HTTP/1.1" 200 2326 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
```

The referer is `-` because no referring page was sent. The example is invented.

*Diagram: One log line, field by field.* Apache and nginx write the same fields in the same order in the “combined” format. IP addresses can be personal data (CJEU, judgment of 19 October 2016, C-582/14). Not legal advice.

## Related terms

- [Log file](https://seo-geo-glossary.com/en/glossary/log-file/index.md)
- [Log file analysis](https://seo-geo-glossary.com/en/glossary/log-file-analysis/index.md)
- [Access log](https://seo-geo-glossary.com/en/glossary/access-log/index.md)

## Sources

- [Log Files - Apache HTTP Server 2.4](https://httpd.apache.org/docs/2.4/logs.html)
- [Module ngx_http_log_module - nginx](https://nginx.org/en/docs/http/ngx_http_log_module.html)
- [CJEU, judgment of 19 October 2016, C-582/14 (Breyer) – EUR-Lex](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:62014CJ0582)

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Last updated: October 8, 2026
URL: https://seo-geo-glossary.com/en/glossary/combined-log-format/