T-Mobile on Monday added a new spin to carrier coverage maps. The company released new data for the United States that shows what sorts of coverage and speeds customers can expect, and T-Mobile says it’s not just random blotches, but actual data from existing T-Mobile customers.

“For years, every carrier has produced their network map in the same way, based on ‘predictive coverage estimations,” T-Mobile chief technology officer Neville Ray said. “The problem is that these maps are exactly that—best estimates. But for some time now, there have been far more advanced methods and technologies available to produce far more accurate coverage maps—based on the actual experience of real customers, like you and your family.”

Ray said customers can use the new map to see where T-Mobile offers 3G, 4G or 4G LTE data speeds – or no coverage at all. He explained that the map is updated twice a month with new data, a  “majority” of which is gathered by T-Mobile customers who are willingly reporting coverage and speeds.

You can use T-Mobile’s site to search for a specific address, too, and it will then return results providing real world data speeds. A quick search near my home, for example, shows I can expect 7.2Mbps down on average. Another search near the beach doesn’t provide speed data and says I can expect “satisfactory coverage in some homes,” which suggests that T-Mobile’s coverage may not be as strong there.

It’s a pretty impressive tool, and if you want to know how T-Mobile will perform in a specific area before making the switch, it’s one worth checking out. Hit the source below to try it.