Key findings
- The median fiber filing covers 15.8% of its ZIP. Of 60,204 fiber filings, 58.7% cover less than a quarter of their ZIP’s census blocks and only 2.5% cover 90% or more.
- Fiber is filed in 27,013 ZIPs (86.0%), but reaches at least half of the ZIP in 12,828 (40.8%). In 7,007 ZIPs with fiber on file (25.9%), the best fiber filing covers less than a quarter of the ZIP.
- The fastest speed on file is usually not the common one. In 10,084 of 31,229 ZIPs with land-based service (32.3%), the fastest filed speed reaches under 25% of the ZIP; in 6,195 (19.8%), under 10%.
- 5 Gbps is filed in 11,804 ZIPs (37.6%), but in 36.3% of them the best 5-gig filing covers less than a quarter of the ZIP. The median is 37.4%.
Why a provider list overstates what reaches you
The FCC collects availability location by location. Rolled up to a ZIP code, one fiber cabinet serving a single new subdivision puts that provider — and its top speed — on the ZIP’s list, next to a cable network that covers every street. Both are accurate. Read without coverage, they look equal.
Phoenix ZIP 85004, the sample on our home page, shows it clearly: one provider files 5 Gbps fiber across 0.5% of the ZIP’s blocks, while a 2 Gbps cable network covers 72.9%. A list sorted by speed puts the rarest option first.
How far the fastest tiers reach
| Speed filed | ZIPs with it on file | Median share of the ZIP the best filing covers | ZIPs where it covers under 25% |
|---|---|---|---|
| 1 Gbps or more | 29,079 (92.6%) | 67.2% | 9.3% |
| 2 Gbps or more | 18,696 (59.5%) | 58.4% | 22.7% |
| 5 Gbps or more | 11,804 (37.6%) | 37.4% | 36.3% |
The faster the tier, the thinner the footprint behind it. A gigabit is filed across most of most ZIPs; multi-gig is often a pocket.
Where fiber runs thinnest
Among states with at least 40 ZIPs that have fiber on file, this is the median share of the ZIP covered by its best fiber filing.
| Thinnest fiber coverage | Median best-fiber share | Deepest fiber coverage | Median best-fiber share |
|---|---|---|---|
| New Mexico | 17.4% | Rhode Island | 84.2% |
| Alaska | 17.5% | New Jersey | 79.9% |
| Arizona | 17.8% | Connecticut | 79.9% |
| Wyoming | 24.0% | Massachusetts | 73.3% |
| Nevada | 24.8% | New Hampshire | 72.9% |
| Washington | 26.7% | Iowa | 64.9% |
In the Mountain West, a ZIP with fiber on file typically has it on fewer than one block in five. In southern New England it is usually most of the ZIP.
What to do with this
Treat a provider list as a map of possibilities and the coverage share as the odds. A high share means the service is probably on your street; a low one means ask before you plan around it. Either way, the provider confirms the exact address when you order — which is why our results show coverage beside every speed.
Methodology
Source data is the FCC Broadband Data Collection, December 2024 filing, published at broadbandmap.fcc.gov. Residential filings were joined to the Census 2020 ZCTA-to-block crosswalk. A filing’s coverage share is the number of census blocks in the ZIP where the provider reports service, divided by the ZIP’s total blocks.
The analysis covers 342,028 residential filings across 31,409 ZIP codes. “Land-based” means fiber, cable, DSL and fixed wireless; satellite is excluded from the speed measures because it is filed everywhere. For each ZIP, the “fastest filed speed” is the highest advertised download among land-based filings, and its coverage is the largest share held by any filing at that speed. State medians include only ZIPs with fiber on file, in states with at least 40 such ZIPs.
Census blocks are not households: a block can hold one home or hundreds, so a coverage share describes territory, not people. Figures describe reported availability; service at a particular address can differ, and a single filing cannot show change over time. This is our own analysis and has not been independently reproduced; the tables are available on request.
Citing this study
You may quote this analysis with attribution to AZ Wireless (azwireless.us). Suggested citation: “AZ Wireless analysis of the FCC Broadband Data Collection (December 2024), 2026.”
For state-level or ZIP-level tables, reach us at (877) 543-8021. Coverage by state, city and ZIP is published at azwireless.us/internet-providers/.
Frequently asked questions
How much of a ZIP code does fiber usually cover?
In the FCC’s December 2024 filings, the median fiber filing covers 15.8% of its ZIP code’s census blocks. Fiber is on file in 86.0% of 31,409 ZIP codes, but reaches at least half of the ZIP in only 40.8% of them, according to our analysis.
Does the fastest internet speed in my ZIP reach my street?
Often not. In 32.3% of ZIP codes with land-based service, the fastest filed speed reaches less than a quarter of the ZIP, and in 19.8% less than a tenth. Check the coverage share beside the speed, and have the provider confirm your address.
Which states have the thinnest fiber coverage?
Among states with at least 40 fiber ZIPs, the median best-fiber filing covers the least of its ZIP in New Mexico (17.4%), Alaska (17.5%) and Arizona (17.8%), and the most in Rhode Island (84.2%), New Jersey and Connecticut (both 79.9%).
Coverage data: FCC Broadband Data Collection (December 2024) — broadbandmap.fcc.gov. Pricing is indicative, varies by address and changes often; confirm current offers with the provider or call (877) 543-8021.