Fast.com speed test app now measures your device's upload and latency speeds
Download speed measures how fast data travels from the internet to your device, and upload speed measures how fast data travels from your device to the internet. Latency measures the time it takes for data to travel from your device, to the server, and back. The app will measure latency on both an unloaded basis (no other traffic on a user's network) and a loaded basis (data heavy apps are being employed on the network). Both measurements should be about the same.
Fast.com says that usage of its app has doubled over the last seven months, and it has now performed over half a billion speed tests around the world. To install the app on your iOS or Android handset, click on the appropriate link: (iOS|Android).