Stud finder app for iPhone

Why iPhone is the right phone for a stud finder app

iPhones have used the same three-axis magnetometer family for a decade, exposed to apps through Apple's Core Motion framework and calibrated by Apple for the Compass and ARKit. That consistency matters: a magnetometer-based stud finder depends on a stable, well-characterized sensor. Earth's magnetic field at the surface ranges from roughly 25 to 65 microtesla (NOAA World Magnetic Model), and a drywall screw seated in a wood stud reliably perturbs that field by several microtesla at scanning distance — well above the iPhone magnetometer's noise floor. On Android the magnetometer varies across thousands of device models, which is why a reliable cross-platform stud finder app is hard to build.

The 16-inch and 24-inch stud spacing the app expects to find isn't a guess, either — it's the maximum on-center spacing set by International Residential Code §R602.3.1 for load-bearing wood studs in U.S. residential construction. Predictable spacing plus a predictable sensor is what makes an iPhone stud finder app work as well as it does.

Compatible iPhone models

Stud Finder works on iPhone 8 and every iPhone released since — iPhone SE (2nd and 3rd generation), iPhone X, XR, XS, 11, 12, 13, 14, 15, 16, and newer, across every storage and carrier variant. All of them include the magnetometer the app requires.

How to use the app on your iPhone

1. Open the app. No setup, no calibration, no account.
2. Hold the iPhone flat against the wall, screen facing you.
3. Sweep slowly side to side — a few inches per second is ideal.
4. Watch for the magnetometer peak. That's a fastener in the stud.
5. Sweep from both directions and mark where the peaks align. That's your stud center.

iPhone-specific tips

• Remove MagSafe. MagSafe wallets, chargers, and magnetic mounts will saturate the magnetometer and ruin the reading.
• Avoid metal cases. Plastic, silicone, and leather are fine; thick metal cases cause false peaks.
• Hold the phone flush. The magnetometer drops off sharply with distance — even half an inch of air gap weakens the signal.
• Start near an outlet. Outlets are almost always mounted directly to a stud, so they're a perfect sanity check for the reading.

When an iPhone stud finder isn't enough

For heavy mounts — large TVs, full-length mirrors, heavy shelves — use the app and a hardware capacitive stud finder together. The two tools measure different things (the app finds fasteners, the hardware finder measures wall density), and only drilling where both agree is the safest workflow.