Wondering "how fast am I going?" GPS Speedometer shows your real time speed right in the browser. Open the page, tap allow, and you're driving. No download, no account, and your location never leaves your device. Works in MPH or KPH on any phone or laptop, using the same GPS your maps app reads. It even shows the gap between your car's dash and reality, since dashboards read 1 to 3 percent high on purpose. Prefer an app? The iOS companion adds trip recording, HUD mode and live maps.