Blog · Plain-English GPS guides
Notes on measuring speed with satellites
Short, practical articles from the maker of this speedometer. No filler, no listicles-for-clicks: each piece answers one real question — how GPS speed actually works, what the accuracy badge means, and how to get an honest number on foot, on a bike, in a car, on a train or on the water. Every claim is tested against the live tool on the homepage.
How Accurate Is a GPS Speedometer? Real Numbers, Tests & Limits
Short answer: ±1–3 km/h on open road at steady speed, worse in cities and at walking pace. Inside: accuracy tables by activity, what the ± meters badge really means, GPS vs car dashboard numbers, 7 accuracy killers, and a 5-minute test to check your own phone.
How Does a GPS Speedometer Work? The Science Behind Accuracy
Your phone has no speed sensor — yet it reports your speed within 1–3 km/h outdoors. This is the science behind that number: satellite clocks, Doppler shift, why speed beats position, what degrades a fix, and a 10-minute test to calibrate your own device.
What this blog will cover
Tool pages answer “what does it say right now” — the blog answers “why should I believe it” and “how do I get a better number.” Every article is written by the developer who built the speedometer and tested against the live tool in real browsers, so the advice always matches what the page actually does. Here is what is queued:
- Reading the ± meters badge like a pro. What the accuracy figure really means, the green/amber thresholds we use, and when to wait versus when to move.
- GPS vs car dashboard, with real numbers. A measured shootout at cruise speeds, the 2–6% optimism rule, and why both instruments can be right at once.
- Battery-saving setups for long rides. How much screen-on GPS really drains per hour, and the settings that stretch a ride without losing the track.
- Units for travellers: km/h vs mph vs knots. Which countries use what, exact conversion factors, and the mistakes that cost drivers abroad.
New articles are linked from the homepage when they land — or just bookmark this page. Spotted an error or want a topic covered? Write tohello@gpsspeedometer.bondvia the contact page.