Frequently asked questions

Yes. A stud finder app uses your phone's magnetometer to detect the metal nails and screws that anchor drywall to the stud. On standard drywall-over-wood construction it is accurate enough for hanging TVs, shelves, and artwork.

Yes. Stud Finder is a free iPhone stud finder app that uses the built-in magnetometer — the same sensor the Compass app uses.

The app reads your iPhone's magnetometer continuously and flags magnetic spikes. Those spikes are the metal fasteners in the stud, which reveal the stud's position behind the drywall.

Yes. Free to download and free to use on the App Store. No subscription, no in-app purchases, no signup.

Yes. All detection runs on-device — no internet connection is needed.

iPhone 8 and newer running recent iOS versions. Every modern iPhone has the magnetometer the app needs.

It can still find nails in lath-and-plaster walls, but in older construction those nails may not line up with a stud the way they do in drywall. For plaster walls, sweep a wider area and verify with a small test hole.

No. The app is tuned for wall studs behind drywall. Concrete, brick, and solid-masonry walls have no studs and are not supported.

Through thin tile over drywall it usually still works. Through thick tile or cement board the signal weakens — expect less precise results.

They measure different things. Hardware finders measure wall density; apps measure the magnetic field of the fasteners. For standard drywall on wood studs both are reliable. For heavy mounts, use both and only drill where they agree.

The magnetometer picks up metal fasteners roughly up to ~3/4" deep — which covers almost all residential drywall construction.

Not directly. The app locates the screws and nails driven into the stud, which sit within an inch of the stud's center. If a section has no fasteners the app will skip it — but studs are fastened roughly every 16" apart, so nearby fasteners still reveal the stud.

Open the app, hold the iPhone flat against the wall, and sweep slowly side to side. Sweep from both directions and mark where the peaks line up. For the best signal, keep the phone flush to the wall and move no faster than a few inches per second.

Three common reasons: the phone is being held too far from the wall, the wall is brick or concrete (no studs), or you are in an old plaster wall with a metal lath that washes out the signal. Try a known location (near an outlet box, which is usually mounted to a stud) to sanity-check.

No calibration is required. Just open the app and scan. The magnetometer self-zeros.

No. The magnetometer is very low-power. You can scan for hours with negligible battery impact.

It can pick up larger metal objects like steel studs, pipes, and junction boxes. It is not a dedicated pipe/wire locator — use a rated tool for that before drilling deep.

Yes with most plastic, silicone, and leather cases. Thick metal, MagSafe wallets, or magnetic mounts can interfere — remove them for the best reading.

Stud Finder is iOS-only. Android magnetometers vary widely in quality across devices, which makes reliable detection harder. For Android, a hardware stud finder is the more dependable option.

Yes. Nothing is collected or transmitted during scanning. The app works fully offline and does not require any account.