How do I find a stud in the wall with my phone?
Stud Finder Pro: Stud Sensor uses the magnetometer inside your iPhone to locate the screws and nails fixing drywall to a stud. Take the case off, hold the top edge flat against the wall, slide sideways, and mark where the reading peaks.
How it works
- Take the case off
A MagSafe case, a magnetic wallet or a metal-backed case will swamp a sensor measuring microtesla, and so will a watch held nearby. Bare phone, and step back from radiators, pipes and metal furniture.
- Calibrate in open air
Hold still for about two seconds away from the wall. That zeroes the room's own magnetic field so the scan measures the change your phone crosses rather than the background.
- Slide across the wall
Put the top edge of the phone flat to the wall and move it sideways, slowly and steadily, in a horizontal line. The reading climbs as you approach metal, peaks over it, then drops away.
- Mark the peak, then confirm it
Mark where the signal peaked, not where it started rising. Scan again a foot higher and mark that peak too. Two marks in a vertical line is a stud; one mark on its own could be anything.
The app
- Price
- Free to download, first scan free. From the second scan on it is a one-time purchase. There is no subscription.
- Requires
- iPhone with a magnetometer, iOS 17.0 or later. The phone case has to come off.
- Account
- None. No sign-up, and the sensor data never leaves the device.
- Publisher
- Cloud Motion Lab LLC
Common questions
Is it finding the wood, or something else?
Something else. Wood has no magnetic signature at all, so no phone can sense it. What the sensor picks up is the steel drywall screw or nail driven through the board into the timber, spaced every foot or so up the length of the stud. Find two of those in a vertical line and the stud runs between them, centred roughly on the screws.
How do I find a stud with no app and no tools?
Studs in a US home usually sit 16 inches apart centre to centre, sometimes 24. Start at a corner or an electrical box, since boxes are normally nailed to the side of a stud, then measure across in 16-inch steps and tap. Over a cavity the wall sounds hollow and gives slightly; over a stud it is tight and dull. Looking along the wall with light raking across it also shows faint dimples where screws were filled.
What will it not detect?
Wood on its own, plastic pipe, copper and aluminium, and live electrical current. It responds to ferrous metal and nothing else, which means a quiet reading is not proof that a spot is safe to drill. Before you make a hole near a switch, an outlet or a kitchen, check where the cable is likely to run, or use a dedicated live-wire detector.
Is Stud Finder Pro free?
The first scan is free and complete: full magnetometer readout in microtesla, the arc gauge, the tone that climbs as the signal rises and the haptic tap at the peak. From the second scan on, the app asks for a one-time purchase, and there is no subscription.
Support
dev@slyapp.coIf it found nothing on a wall you are sure has studs in it, tell us the wall type and your iPhone model before you drill again. Some walls are outside what a magnetometer can read, and we would rather say that than defend the scan.