The United States Federal Communications Commission has re-released their FCC Speed Test app for iPhone and iPad and iPad. It lets you directly measure upload, download, latency, and packet-loss over both cellular and Wi-Fi. You can also choose to anonymously submit information to the FCC about your results through the Measuring Broadband America program which aims to create transparency about actual network performance.
FCC Speed Test looks at a couple things when measuring network performance — download, upload, latency, and packet loss. Each time you run a test it'll give you some general information about your cellular network. When testing WiFi networks I didn't get the same amount of information so I'm not sure if there was an incompatibility with my provider (Comcast) or if FCC Speed Test simply doesn't monitor ISPs the same way.
You can then break out data from FCC Speed Test in different time lengths such as a week, month, or year. The expanding graphs give you an overview of what kind of data performance you've been getting. You can choose to share this data with the FCC or you can keep it just for your own reference. You can set limits in settings as well for how much data you want the app to be able to transmit so you ensure you aren't hitting any data caps you may have.
I tested FCC Speed Test against the popular Speedtest.net app by Ookla. Overall, they seemed pretty close on both WiFi and over the cellular network. You can see the results in the screenshots below. FCC Speed Test measures a few more statistics than Speedtest.net does but lacks the server options. In my experience server options can make a huge difference in results. Also, FCC Speed Test is U.S. only while Speedtest.net is available internationally.
I'd recommend the FCC Speed Test app if you're in the U.S. and want more detailed information on the quality of your cellular network connection, especially if you want to contribute to the FCC monitoring program. If you give it a try, let me know — how fast and how well does your connection measure up with FCC Speed Test?