Our Mission
Zpeedometer exists to give anyone, anywhere, an instant and accurate speed reading without friction. No app store, no sign-up form, no permissions beyond the one your browser already asks for when you tap "Start GPS." We built it because most speedometer apps ask for more than they need : accounts, push notifications, ad-tracking SDKs, sometimes even your contacts. We think a tool this simple shouldn't come with all of that.
What Zpeedometer Does
At its core, Zpeedometer reads your device's GPS signal through the standard Web Geolocation API and renders it as a live, animated speed gauge directly in your browser. It works for any activity where knowing your real-time speed is useful:
- Car speed checking on a drive
- Motorcycle rides
- Cycling and road biking
- Running pace and splits
- Walking pace tracking
- Train, bus, and boat travel
Alongside the live speedometer, the site also offers a unit converter (km/h, mph, m/s, and knots) and a plain-English explainer of the GPS technology and math behind the readings.
How We Think About Privacy
Your location is processed entirely on your own device. Speed calculations happen in your browser using the Haversine formula and the Doppler-derived speed value your GPS chip already provides — none of it is sent to our servers, stored, or shared. We don't run analytics scripts, we don't set tracking cookies of our own, and we don't ask you to create an account. The only third party involved is Google AdSense, which keeps the site free to use; you can read exactly how that works in our Privacy Policy Terms of Service.
Why It's Free
Zpeedometer is supported entirely by display advertising. There's no premium tier, no paywall, and no plan to add one — the goal is for the tool to stay useful and accessible to anyone who needs a quick, reliable speed reading.
Who Builds and Maintains Zpeedometer
Zpeedometer is built and maintained by a small independent web team, not a company with a sales department. The site has no investors, no staff writers and no content quota to hit. Every page here was written because someone actually asked the question it answers, usually through the contact form.
That smallness shapes the product. We would rather ship one tool that works reliably on a cheap Android phone in a tunnel than five features that demo well. When something breaks, the person reading your bug report is the person who fixes it.
How We Check Accuracy
A speedometer is only worth using if you can trust the number. We validate readings in three ways:
- Against vehicle instruments. We compare our readout against car and motorcycle dashboards at steady speeds. Most factory speedometers read 2–8% high by design and by regulation, so our figure sitting slightly lower is expected, not an error.
- Against known distances. On measured stretches : running tracks, marked motorway sections : we check that the distance total matches reality, which confirms the underlying speed maths.
- Across devices. The same journey is run on different phones and browsers, because GPS chipsets vary more than most people expect. A reading that only works on a flagship phone is not good enough.
What Zpeedometer Is Not Good At
We would rather tell you the limits than have you discover them at a bad moment. GPS speed is a genuinely useful reference, but it is not an instrument of record:
- It will not win you a speeding case. Courts rely on calibrated equipment with a documented chain of custody. A phone reading is not that, and we would not claim otherwise.
- It struggles where satellites cannot reach. Tunnels, underground stations, dense city centres with tall buildings and deep valleys all degrade the signal. The reading may lag or drop out entirely.
- It is not a navigation system. There is no routing, no mapping and no turn-by-turn guidance, and we have no plans to add them.
- It should never be operated while driving. Set it up before you move, or let a passenger handle it. This matters more than any accuracy question on this page.
Who Uses This
The traffic tells us the tool gets used in ways we did not design for, which is the best part of building something open. Cyclists use it as a bike computer they did not have to buy. Passengers on high-speed rail watch the number climb past 300 km/h. Driving instructors use it to show learners the gap between the dashboard and reality. Parents check how fast a school bus actually travels. Runners use the pace figures instead of a watch.
None of that requires an account, and none of it sends us your location. If you are using it for something we have not thought of, we would genuinely like to hear about it.
How This Site Is Kept Up To Date
Pages are revised when the underlying facts change : a browser alters how it handles the Geolocation API, a regulation on speedometer tolerance is updated, or a reader points out something we got wrong. We do not republish pages with a fresh date to look active. If a page has not changed, it has not needed to.
Corrections are welcome and are acted on. If you find an error, tell us and we will fix it and say what changed.
Get in Touch
Found a bug, have a feature idea, or spotted something inaccurate on the site? We'd like to hear about it. Reach us at contact@zpeedometer.com.