Method & Data Sources
SignalScout answers one question honestly: what internet speeds do people actually get around a given US address? Not what a provider advertises, and not what it has filed with a regulator — what real connections measured.
Where the data comes from
Measurement Lab (M-Lab) is an open platform, supported by research institutions, that runs internet performance tests and releases every result into the public domain. It is the measurement engine behind a number of well-known speed tests. SignalScout uses M-Lab's published statistics for the 2,425 US counties that have enough measurements to report, covering 2024, along with state-level series back to 2020 and network-level figures for major providers.
We chose M-Lab specifically because its data is CC0 public domain, which means a free tool like this can use it without restriction. Other speed datasets exist with finer geography, but their licences prohibit use in a commercially supported service — so we did not use them.
How a lookup works
- Your address is geocoded by the US Census Bureau Geocoder, which returns coordinates and the county it falls in.
- We look up that county's measured statistics in a dataset bundled with the site.
- The Connectivity Score ranks the county against every other US county — 60% download, 25% upload, 15% latency, each as a national percentile.
Honest limitations
- County, not address. County is the finest geography M-Lab publishes openly. A large county contains fast and slow neighbourhoods, so treat the figure as the area's character rather than your future line rate.
- 2024 data. M-Lab's published county statistics currently run through 2024. Speeds generally rise over time, so treat these as a floor.
- Volunteer sample. People tend to run speed tests when something feels wrong, which can bias results downward, and the sample skews toward people who know what a speed test is.
- Not a provider list. SignalScout does not tell you which ISPs serve an address. That comes from FCC Broadband Data Collection filings, which require a registered account for bulk access. It is on the roadmap.
- Test methodology differs. M-Lab measures throughput to its own servers using the NDT protocol. Numbers are not directly comparable to other speed tests, but they are consistent with each other, which is what matters for ranking.
Why measured beats filed. Regulatory availability data records what a provider says it could deliver. It does not record congestion, oversubscription, ageing copper, or the fact that most households buy a mid-tier plan. Measurement captures all of that, because it is the outcome rather than the promise. See the full explainer.
Cost and privacy
Free, no account, no lookup limit, supported by advertising. Addresses you look up are geocoded through our server and are not logged.
Check a real address
See the measured download, upload and latency for any US address, plus a Connectivity Score ranked against every county in the country.