v157 · approximate geolocation

Accuracy radius visualiser

A position's accuracy is a radius in metres, and a number in metres is hard to feel. Drag it here and watch the circle grow against a fixed scale — a building, a block, a neighbourhood, a city — or plot the radius your own browser actually returns.

How much ground does this radius cover?

The slider is logarithmic, from 5 m (a good GPS fix outdoors) to 20 km (a coarse network-derived region). Chrome's approximate mode targets the upper end of that range; a precise fix on a phone is usually 5–30 m.

Accuracy circle drawn to scale A circle whose radius is the selected accuracy, drawn over reference squares for a building, a city block, a neighbourhood and a city.
Radius
120 m
Area covered
0.05 km²
Comparable to
a city block
Still works for
store locator
Drag the slider, or plot the accuracy your browser reports.

code path

navigator.geolocation.getCurrentPosition((position) => {
  const { accuracy } = position.coords;         // radius, in metres
  const areaKm2 = Math.PI * (accuracy / 1000) ** 2;
  console.log(`[approx-geo] ${accuracy} m radius covers ${areaKm2.toFixed(2)} km²`);
}, onError, { accuracyMode: "approximate" });

see also