GPS Speedometer and Trip Distance Tracker
Speed Tracker is a browser-based utility for viewing location information supplied by your phone or computer. When you grant location permission, a compatible browser may provide current coordinates, an estimated speed, heading and an accuracy radius. The values depend on your device, browser, location settings and surroundings; they are estimates, not certified measurements.
How the speed reading works
The page requests location updates through the browser's Geolocation API. It does not control the device's satellite receiver directly. Depending on the phone and operating system, location can be derived from GNSS satellites and may be assisted by Wi-Fi, cellular networks or other device signals. The browser may not provide a speed value for every update, and updates may be delayed when the page is in the background.
How trip distance is estimated
Distance can be estimated by measuring the separation between successive coordinates and adding those segments. A common approach uses the Haversine formula to estimate the great-circle distance between two points on an approximate spherical Earth. This is useful for many everyday observations, but it is not the same as measuring the exact road path. Long gaps between updates can miss turns, while location drift can add distance when you are standing still.
c = 2 · atan2(√a, √(1−a))
d = R · c
Here, φ is latitude, λ is longitude and R is an assumed Earth radius. This formula estimates the direct surface distance between two coordinates; summing those distances approximates a route but cannot recover turns that were never sampled.
Why readings change
- Open sky versus obstructions: roofs, tunnels, dense trees and tall buildings can weaken or reflect satellite signals.
- Device and browser behaviour: hardware quality, operating-system processing, permission settings and background restrictions affect updates.
- Movement and sampling: at slow speeds, position noise can be similar to the distance travelled between updates. At higher speeds, a long gap can miss turns.
- Different measurement systems: vehicle dashboards and phones use different inputs and update methods, so their readings may not match exactly.
Privacy and location permission
Location access is requested through your browser and can be denied or revoked in site settings. Displayed calculations can run in the browser, but this website may send coordinates to OpenStreetMap Nominatim when it requests a human-readable place name. Hosting infrastructure and third-party scripts may also process connection information. Read the Privacy Policy for more detail.
Use the tool safely
Set up the page before travelling. Do not handle or watch a phone while driving or cycling; ask a passenger to manage it if needed. Follow posted speed limits and use approved vehicle instruments. This site is intended for general awareness and informal observation, not legal enforcement, aviation, surveying, emergency response or other safety-critical measurement.
Practical guides
For more detail, read our GPS speed vs speedometer guide, trip-distance calculation guide, troubleshooting guide, and measurement limitations and methodology. Browse all Speed Tracker guides.