About us

Last updated 25 October 2026.

Speedometera answers one question quickly and privately: how fast am I going? It turns any phone, tablet or laptop with location services into a free GPS speedometer for a car, motorcycle, bicycle, train, bus, plane, boat, or a run or walk. It runs in your web browser. There is no app to install and no account to create, and your location is processed on your own device and never sent to us.

Our mission

Our mission is to give everyone an honest, accurate speed reading in seconds, on the device they already carry, without trading away their privacy. We want the page to load fast on a weak mobile signal and to explain plainly what the number means and when it can be trusted.

Three principles guide every decision:

• Accuracy you can check. The maths behind each reading is published on our methodology page and covered by automated tests. When GPS is unreliable we say so on screen rather than show a confident wrong number.
• Privacy by default. Your position is used in your browser to work out speed and distance. It is not uploaded, stored on a server or shared.
• Free and simple. One tap to start. The tools are free to use. We plan to support them with advertising, which will be kept away from the speedometer itself.

Why we built Speedometera

Many people want to know their real speed: a driver who suspects the dashboard reads high after fitting new tires, a cyclist without a bike computer, a passenger curious how fast the train is going, a runner checking pace. Phones have had accurate satellite positioning for years, yet many speedometer websites we tried were cluttered with ads around the reading, gave no hint of GPS accuracy, or asked users to install an app for something a browser can already do.

We built Speedometera to do the job properly: a clean gauge, a large readable number, a clear accuracy indicator, and guides that explain why GPS speed and a car's dashboard often disagree. Vehicle speedometers are commonly designed to read slightly above true speed, and tire size, wear and pressure change the reading further. Our speedometer calibration calculator and tire size calculator exist because readers kept asking about exactly that gap.

Who is behind the site

Speedometera is an independent, one-person project. It is not owned by a car maker, a phone maker, an insurer or an app company.

Izhar Ahmad Danish, Independent Researcher & Blogger, founded the site, builds the tools and researches and writes every guide. His work focuses on how phones measure speed, GPS accuracy and the units people use around the world.

We do not have a separate editor or technical reviewer, and we will not claim one. Instead, every page is built so that you can check it yourself: the formulas are published, the code that runs them is tested automatically, and the sources are linked. Each guide shows its author and the date it was last updated.

Why you can trust the readings

• The number comes from your phone, not from us. Where the device reports a satellite (Doppler) speed, we show it as given. We add no guesswork on top beyond light display smoothing.
• Bad data is filtered, not hidden. Fixes worse than 50 m accuracy are dropped and the accuracy is shown under the gauge, so you can see when the signal is weak.
• Every formula is public. The methodology lists the exact constants (1 mile = 1,609.344 m, 1 knot = 1,852 m per hour) and thresholds the code uses.
• Automated tests guard every release. 43 Vitest tests cover the speed engine, unit conversion, calibration and tire geometry, and a release cannot go live if any fails.
• Sources you can follow. Claims cite primary sources such as W3C, NIST, GPS.gov and UNECE rather than other speedometer sites.
• Honest limits. We say plainly what a phone GPS cannot do: tunnels, indoor use and legal evidence are covered in What Speedometera is not.

How the speedometer works

When you press Start, your browser asks for permission to use your location. If you allow it, the page uses the standard browser Geolocation API with high accuracy requested, so your device combines satellite signals (GPS and, on most modern phones, other systems such as Galileo, GLONASS and BeiDou) with Wi-Fi and cell data where available. The device then sends the page a fresh position fix whenever it has one, typically about once a second on a phone with a clear sky view.

For each fix, Speedometera:

1. Uses the speed the device reports where the chip provides one; this Doppler-based value is usually the most precise source.
2. Otherwise calculates speed from distance and time between two fixes, using the haversine great-circle formula with the mean Earth radius of 6,371,008.8 m.
3. Rejects poor fixes. Positions with a reported accuracy worse than 50 m are ignored, and impossible jumps (over 500 m/s) are discarded as glitches.
4. Removes standing-still jitter. Speeds below 0.5 m/s (about 1.1 mph) are treated as stationary, so the trip distance does not creep up while you wait at a light.
5. Smooths the display lightly so the needle is steady without lagging behind real changes.

From the same data the page shows maximum and average speed, trip distance (odometer), moving time, altitude, heading and coordinates when your device provides them, plus a live speed graph. Extra features include a speed alert, a mirrored head-up display (HUD) for reading off a windscreen at night, full screen, a digital view and a screen wake lock so the display stays on. You can save your trip as a GPX file; that file is generated in your browser and downloaded straight to your device.

All the speed and distance maths lives in one small library that does nothing except calculations. It has an automated test suite with worked examples covering unit conversion, great-circle distance, accuracy filtering, jitter, pace and GPX export, and every release must pass those tests before it goes live. The methodology page explains the method and sources in more detail.

Our tools

Every tool uses the same tested engine, tuned for the job: the gauge range, default unit and display mode change, the maths does not. Browse them all on the tools hub. Highlights include:

• Speedometer: the main live GPS speedometer, in mph, km/h, knots or m/s.
• Train speed checker: how fast your train is going, with tips for getting a fix through carriage windows.
• Speed converter: mph, km/h, knots, m/s and ft/s with exact conversion factors.
• Tire size calculator: compare two tire sizes and see the effect on your speedometer.
• Speedometer calibration calculator: work out your dashboard's percentage error from a GPS reading.

Presets for cars, bikes, running, walking, flights, buses and boats, along with an odometer, altimeter and compass, are being added to the tools hub as each one is finished and tested.

Privacy by design

Speed tools handle sensitive data, so we designed this one to need as little as possible:

• Location stays on your device. Positions are processed by code running in your browser. We have no server endpoint that receives location, and the site is configured so that only our own pages may request it.
• No account. You never sign up to use a tool.
• Optional newsletter. If you choose to subscribe, we store your email address in a database run by our hosting provider, Cloudflare, together with the page you signed up on, your approximate country (as reported by Cloudflare), the consent wording you agreed to and the time you agreed. We use it only to send the newsletter. You can ask to be removed at any time by emailing us, and every newsletter will include an unsubscribe link. Details are in the privacy policy.

Analytics and advertising, when active, are provided by Google and use cookies as described in our privacy policy, which also explains your choices, including how to opt out of personalized ads, consent options for visitors in the EEA, UK and Switzerland, and rights under US state privacy laws such as California's. The site is intended for a general adult audience and is not directed to children under 13.

How we research and check content

Our guides aim to be the most useful page on their topic, not the longest. Every factual claim is checked against a primary source wherever one exists: standards bodies and regulators for unit definitions and speedometer rules, official GPS performance documents for accuracy figures, and operators' own data for things like train speeds. We build our own tables and examples rather than copying them, and we credit any image we did not make ourselves.

When we find or are told about a mistake, we correct it, update the page's date and, where the change is significant, say what changed. Our full rules are in the editorial standards.

Editorial independence and how we are funded

Speedometera is free. We intend to cover its costs with display advertising through Google AdSense; ads are not running yet, and when they are, these rules apply:

• No ads inside the speedometer. Ads never appear in or over the speedometer card, so nothing gets between you and the reading.
• Ads are labelled and separate. They are clearly distinguishable from our content, and we do not design pages to trick people into clicking them.
• Advertisers have no say. Google chooses which ads appear; we do not write content for advertisers, and no advertiser can review, edit or approve what we publish.
• No paid reviews. We do not accept payment to rank, recommend or mention a product. If we ever publish sponsored content or use affiliate links, it will be clearly disclosed next to the content, in line with the US Federal Trade Commission's endorsement guidance.
• No selling of data. We do not sell or rent subscriber email addresses.

Running costs are kept low (static pages on Cloudflare's network), which means advertising will not need to be aggressive for the site to stay online.

What Speedometera is not

Speedometera is an informational tool. It is not a certified measuring instrument, it is not a replacement for your vehicle's speedometer, and its readings should not be used as evidence in a legal dispute such as a speeding ticket. GPS accuracy depends on your device, the sky view and conditions such as tunnels, tall buildings or heavy tree cover. Please never use the tool in a way that distracts you while driving: set it up before you move, or let a passenger handle it. See our disclaimer and terms of use.

Update log

How to contact us

We read every message. Email hello@speedometera.com to report a wrong reading, point out an error, suggest a tool or make a privacy request. The contact page lists what details help us investigate a reading quickly. We aim to reply within a few business days, and confirmed errors are fixed promptly.

Thank you for using Speedometera. If it helped you, the best support is to tell a friend or bookmark it for your next trip.