This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.


This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Secure context

This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.


This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The DPR header is a Client Hints header which represents the client device pixel ratio (DPR), which is the number of physical device pixels corresponding to every CSS pixel.

Header type Request header
Forbidden header name ?

Note: Client Hints are accessible only on secure origins (via TLS). Server has to opt in to receive DPR header from the client by sending Accept-CH and Accept-CH-Lifetime response headers.


DPR: <number>


Server first needs to opt in to receive DPR header by sending the response headers Accept-CH containing DPR and Accept-CH-Lifetime.

Accept-CH: DPR
Accept-CH-Lifetime: 86400

Then on subsequent requests the client might send DPR header back:

DPR: 1.0

Browser compatibility

BCD tables only load in the browser

See also