files/en-us/web/http/reference/headers/age/index.md
The HTTP Age {{Glossary("response header")}} indicates the time in seconds for which an object was in a proxy cache.
The header value is usually close to zero.
If the value is 0, the object was probably fetched from the origin server; otherwise, the value is usually calculated as a difference between the proxy's current date and the {{HTTPHeader("Date")}} general header included in the HTTP response.
Age: <delta-seconds>
<delta-seconds>
Age: 24
{{Specifications}}
{{Compat}}