Metal Detector

Reads your phone's magnetometer and flags spikes in magnetic field strength — the kind nearby metal or magnets cause.

Android + Chrome only, may need a browser flag
Novelty tool, not precision equipment This detects magnetic field changes, not metal specifically — it can't tell a steel pipe from a stray magnet or a speaker. It's far less sensitive than a real metal detector and easily thrown off by other electronics. For anything that actually matters (utility lines before digging, treasure hunting, safety checks), use proper equipment.
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µT (microtesla)
Not started
—Baseline
—Deviation

How it works

Every location has an ambient magnetic field — mostly Earth's own field, usually somewhere between 25 and 65 microtesla. This tool samples your phone's magnetometer, averages a few seconds of readings as your baseline, then watches for deviation from that baseline. A sudden jump usually means something magnetic — metal, a magnet, or a speaker — has entered the field nearby. Move your phone slowly and evenly for the clearest signal.

Frequently asked questions

Why does this only work on some Android phones?

It uses the web Magnetometer sensor API, only implemented in Chrome on Android — and on some devices it needs an experimental flag enabled. iPhone Safari and desktop browsers don't expose raw magnetometer data to web pages.

How sensitive is a phone-based metal detector?

It can pick up large or close ferrous objects like pipes or appliances, but it's far less sensitive than a purpose-built detector and won't reliably find small or buried items.

Why does it go off with nothing metal nearby?

Speakers, other phones, and building wiring produce magnetic fields too. Recalibrate away from electronics for a cleaner reading.