HTTP Status Codes

416 Range Not Satisfiable

A Range request asked for a byte range the resource cannot satisfy — for instance a start position past the end of the file.

What it means

416 Range Not Satisfiable is returned when none of the requested ranges overlap the resource's current size — commonly a resumed download whose offset exceeds the file length. The response should include Content-Range: bytes */<size> to report the actual length.

Why it matters

  • It lets download managers detect a stale offset and restart correctly.

Common mistakes

  • Returning 200 with the full body instead of 416 for an impossible range.
  • Omitting the Content-Range that tells the client the true size.

How WebInspect checks this

  • WebInspect reports Accept-Ranges and range-request behaviour in performance analysis.