field.

` Last-Modified ` is also used by [ crawlers ](/en-US/docs/Glossary/Crawler)
to adjust crawl frequency, by browsers in [ heuristic caching ](/en-
US/docs/Web/HTTP/Caching#heuristic_caching) , and by content management
systems (CMS) to display the time the content was last modified.

Header type  |  [ Representation header ](/en-US/docs/Glossary/Representation_header)  
---|---  
[ Forbidden header name ](/en-US/docs/Glossary/Forbidden_header_name) |  no   
[ CORS-safelisted response header ](/en-US/docs/Glossary/CORS-safelisted_response_header) |  yes   
  
##  Syntax

http

    
    
    Last-Modified: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
    

##  Directives

<day-name>

    

One of "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", or "Sun" (case-sensitive).

<day>

    

2 digit day number, e.g. "04" or "23".

<month>

    

One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct",
"Nov", "Dec" (case sensitive).

<year>

    

4 digit year number, e.g. "1990" or "2016".

<hour>

    

2 digit hour number, e.g. "09" or "23".

<minute>

    

2 digit minute number, e.g. "04" or "59".

<second>

    

2 digit second number, e.g. "04" or "59".

` GMT `

    

Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local
time.

##  Examples

http

    
    
    Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT
    

##  Specifications

Specification  
---  
[ HTTP Semantics  
#  field.last-modified  ](https://www.rfc-editor.org/rfc/rfc9110#field.last-
modified)  
  
##  Browser compatibility

BCD tables only load in the browser  with JavaScript enabled. Enable
JavaScript to view data.

##  See also

  * [ ` If-Modified-Since ` ](/en-US/docs/Web/HTTP/Headers/If-Modified-Since)
  * [ ` If-Unmodified-Since ` ](/en-US/docs/Web/HTTP/Headers/If-Unmodified-Since)
  * [ ` Etag ` ](/en-US/docs/Web/HTTP/Headers/ETag)

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