Disclosure

Transparency about links, funding, accuracy, and your data — per FTC guidance.

rangelab is free. Some outbound links — for example to object storage, CDNs, or media/video hosting providers — may be affiliate links: if you sign up through them we may earn a commission at no extra cost to you. Paid links are marked rel="sponsored nofollow".

We only link to things that are genuinely useful, and a commission never changes what the tool reports. Every result follows the published methodology and the RFC 9110 rules it cites.

Informational, not a conformance test. rangelab resolves the Range and Content-Range rules statically from the values you paste. It does not make a live request and cannot account for server-specific behavior, proxies/CDNs, or non-standard implementations. It is not affiliated with the IETF or any hosting provider. Always confirm against your real server before relying on a result.

Your privacy: this is a static, client-side tool. The headers and sizes you paste are processed in your browser and are never uploaded — there is no backend and nothing is logged.