You can find a wall stud with what you already have at home. The most reliable approach is to combine two methods: one that tells you roughly where the stud should be, and one that confirms it by finding the screws in it. Here are six methods, from a quick guess to a confirmed location.
In most houses in the United States, interior walls are framed with vertical wooden studs spaced 16 inches apart, measured center to center. Some walls use 24-inch spacing. A standard stud is about 1.5 inches wide, so the target is narrow. Drywall is fastened to each stud with a column of steel screws or nails, and those fasteners are what most of the methods below actually find.
Electrical boxes are usually fastened to the side of a stud. Take a close look at an outlet or switch: the stud is normally right next to it, on the left or the right. Knock on both sides to tell which. From there you can measure sideways in 16-inch steps to estimate the next studs.
Studs are often laid out at 16-inch intervals starting from one end of the wall. Measuring 16, 32 and 48 inches from a corner gives you a first guess. Treat it as a guess only: walls are not always laid out from the corner you chose, and doors and windows change the spacing.
Baseboards and crown molding are nailed into studs, so a filled nail hole in the trim usually marks one. On the wall itself, hold a flashlight flat against the surface and look along it. Screw heads under the paint often show as faint dimples or bumps in a vertical line.
Knock along the wall with a knuckle. Between studs the sound is hollow and low. Over a stud it becomes shorter and higher. This works better on some walls than others and is easy to misjudge, so use it to narrow the area, not to pick the drilling spot.
A strong small magnet, such as a neodymium magnet from a hardware store, will stick to the wall where a drywall screw sits. Slide it slowly in an S pattern across the area where you expect a stud. When it grabs, you have found a screw. Find a second one directly above or below it and you have found the stud line.
Your phone has a magnetic sensor that reacts to steel the same way a magnet does, except that it shows a number instead of sticking. With an app such as Ferrum, you take off any magnetic case, calibrate in the air, then slide the phone flat and slowly across the wall. The reading peaks over each screw. Mark the peak, then check 12 to 16 inches above and below: several peaks in a vertical line are a stud.
The advantage over a bare magnet is that you see how strong the signal is and where it peaks, which helps on textured walls and when the screw sits deeper under filler. The limits are the same: this finds steel fasteners, not the wood itself. More on that in do stud finder apps really work?
Plaster-and-lath walls, walls with metal studs and masonry walls behave differently. Plaster over metal lath attracts a magnet almost everywhere, and old lath is nailed all along its length. For those walls a dedicated wall scanner, or a small exploratory hole in a place that will be covered, is the more dependable route.
Start at an outlet or switch, because electrical boxes are usually fastened to the side of a stud, then confirm by finding the drywall screws with a magnet or a phone magnetometer app. Two or more screws in a vertical line mark the stud.
In most US houses studs are 16 inches apart, measured center to center. Some walls use 24-inch spacing, and doors, windows and corners interrupt the pattern.
Yes, to find the steel screws or nails in a stud. A phone's magnetometer reacts to iron and steel, so an app can show where the fasteners are. It cannot detect the wood itself.
About Ferrum. Ferrum: Stud Finder & Metal is an iPhone app (iOS 17 or later) by 55DIGITS LLC that uses the phone's magnetometer to find the screws in a stud, steel behind walls and wiring that is carrying current. $4.99 once, no subscription, no ads, no data collected. It does not detect wood, copper, aluminum or plastic, and it does not measure depth.
Ferrum is not a substitute for a professional scanner where safety matters, for example when drilling near mains wiring or gas lines. Always verify by another means before drilling.