How to check cell coverage by carrier before you switch

Short answer

Use coverage maps only to shortlist — carrier maps and the FCC map are modeled, mostly outdoor estimates. Then test on a real device where you actually live and work: borrow a phone on that network or use a free trial eSIM where offered, for several days, indoors and out. Considering an MVNO? Its coverage is its host network’s coverage — judge that network, not the brand.

Step 1 — Shortlist with maps (knowing their limits)

Start with each carrier’s own coverage map and the FCC National Broadband Map mobile view, which shows modeled 4G LTE and 5G coverage per carrier under standardized assumptions. Our cell coverage page compares what the carriers claim. Remember why these maps can be wrong: they are propagation models — predictions, not measurements — and they mostly model outdoor signal.

Step 2 — Resolve the MVNO question first

Budget brands don’t own towers. An MVNO rides a host network — so its coverage is the host’s coverage, while data speed during congestion may be lower if the MVNO’s traffic is deprioritized. Use our MVNO network lookup to find the host network behind a brand, then evaluate that network’s coverage where you live.

Step 3 — Test with a real device, in real places

This is the step that actually answers the question. Options, in order of effort: ask a friend or neighbor on that network how their phone behaves inside your home; borrow such a phone for an evening and walk the rooms you care about; or activate a free trial eSIM on your own phone — several carriers and MVNOs offer trial periods that run alongside your current line (check current offers; availability changes). Test for several days: home, work, commute, and the spots where your current carrier fails.

Step 4 — Plan for the indoor reality

Indoor coverage is where switches go wrong. Building materials cut signal sharply, and the higher frequencies that carry fast 5G penetrate walls worse than low-band spectrum. Two mitigations work regardless of carrier: Wi-Fi calling (calls and texts over your home internet — confirm it works on your handset) and, for larger dead zones, a signal booster. If home coverage is the whole problem, also weigh 5G home internet separately from your phone plan — they are different products with different constraints.

Frequently asked questions

What is the most reliable way to check cell coverage where I live?

Test it on a real device. Coverage maps — carrier or FCC — are modeled estimates, so use them to shortlist. Then try the network at your home, workplace, and commute: borrow a phone on that network, or use a free trial eSIM if the carrier offers one. A week of real use tells you more than any map.

Is MVNO coverage the same as the host network’s coverage?

The radio footprint is the same — an MVNO uses its host network’s towers, so where there is no host signal there is no MVNO signal. Speeds can differ during congestion, since some MVNO traffic may be deprioritized relative to the host’s own customers. First find which network an MVNO uses, then judge that network’s coverage where you live.

Why is my signal bad indoors when the map shows full coverage?

Most coverage maps model outdoor signal. Walls, low-E glass, metal roofs, and basements cut signal sharply, and higher 5G frequencies penetrate worse than low-band. If indoor coverage is weak, Wi-Fi calling usually fixes calls and texts at home regardless of carrier.

Sources, dates & limitations

47 CFR § 1.7004 — Scope and content of required broadband deployment data (Broadband Data Collection), current text — Electronic Code of Federal Regulations, Office of the Federal Register (opens in a new tab) Official (government)

Data as of September 10, 2026. Last checked September 13, 2026.
Establishing the Digital Opportunity Data Collection, Third Report and Order (FCC 21-20, WC Docket No. 19-195) — Federal Communications Commission (opens in a new tab) Official (government)

Data as of January 19, 2021. Last checked September 13, 2026.
2024 Communications Marketplace Report (FCC 24-136, GN Docket No. 24-119) — Federal Communications Commission (opens in a new tab) Official (government)

Data as of December 31, 2024. Last checked September 13, 2026.
Find Home Internet and Cell Phone Coverage In Your Area (coverage map, disclaimer, device band compatibility and the 30-day network trial) — Verizon (opens in a new tab) Provider-owned

Data as of September 13, 2026. Last checked September 13, 2026.
About Network Management — Verizon (opens in a new tab) Provider-owned

Data as of September 13, 2026. Last checked September 13, 2026.
Wi-Fi Calling at Verizon FAQs — Verizon (opens in a new tab) Provider-owned

Data as of September 13, 2026. Last checked September 13, 2026.
Recommendation ITU-R P.2109-2 (08/2023) — Prediction of building entry loss — International Telecommunication Union, Radiocommunication Sector (opens in a new tab) Standards body

Data as of August 23, 2023. Last checked September 13, 2026.

Limitations & caveats

The “modeled, mostly outdoor” description of the maps is the federal requirement, not our opinion: 47 CFR 1.7004(c)(5) requires submitted propagation maps to “depict outdoor coverage,” and FCC 21-20 states that “[m]obile providers are required to submit propagation maps reflecting outdoor coverage.” The standardized assumptions are in 1.7004(c)(3) — 90% cell edge probability, 50% cell loading, terrain and clutter at 100 m resolution or better.
We could not open broadbandmap.fcc.gov itself: it returned HTTP 403 to every request on September 13, 2026, as did every www.fcc.gov path. We cite the rules and orders that govern the map rather than the map interface.
The MVNO point rests on the FCC’s own definition: the 2024 Communications Marketplace Report states that MVNOs “have not owned any network facilities, but instead purchase mobile wireless services on a wholesale basis from facilities-based service providers.” That an MVNO’s radio footprint is therefore its host’s footprint follows from the definition; it is not separately measured.
On deprioritization, the same report defines it as “slowing data speeds during times of network congestion,” records that postpaid users “frequently are given priority over prepaid users on a given network during times of peak congestion,” and quotes Metro by T-Mobile’s terms that host-branded data “has precedence over data of customers who choose non T-Mobile-branded service plans.” Terms differ by brand and change; check the brand you are actually considering.
Free trials are a commercial offer, not a rule. Verizon’s coverage page invited readers to “[t]ry our network free for 30 days” on the date above. We could not read AT&T’s or T-Mobile’s pages server-side — t-mobile.com refused the whole origin and att.com returned almost no extractable text — so treat trial availability as something to confirm with the carrier before you plan around it.
ITU-R P.2109-2 is a standards-body recommendation, not U.S. government data, so we label it third-party under our own source tiers. It models building entry loss statistically across a population of buildings; it cannot tell you the loss through your own walls, which is exactly why step 3 is a device and not a calculation.