Widely available Supported across all major browsers. Safe to use in production.

Resource size

The decodedBodySize read-only property returns the size (in octets) received from the fetch (HTTP or cache) of the message body after removing any applied content encoding (like gzip or Brotli). If the resource is retrieved from an application cache or local resources, it returns the size of the payload after removing any applied content encoding.

Observers and Performance

Browser support

Feature Desktop Mobile
Chrome
Edge
Firefox
Safari
Chrome Android
Safari iOS
decodedBodySize
54
17
45
16.4
54
16.4
encodedBodySize

The encodedBodySize read-only property represents the size (in octets) received from the fetch (HTTP or cache) of the payload body before removing any applied content encodings (like gzip or Brotli). If the resource is retrieved from an application cache or a local resource, it must return the size of the payload body before removing any applied content…
54
17
45
16.4
54
16.4
transferSize

The transferSize read-only property represents the size (in octets) of the fetched resource. The size includes the response header fields plus the response payload body (as defined by RFC7230).
54
17
45
16.4
54
16.4
1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

Use cases

  • Using Resource size

    The decodedBodySize read-only property returns the size (in octets) received from the fetch (HTTP or cache) of the message body after removing any applied content encoding (like gzip or Brotli).

Cautions

  • May not be supported in older browsers.

Implementation notes

  • Some APIs require a secure context (HTTPS) or user activation. Check the requirements before use.

Related links