Finding studs in a wall is part of many home improvement projects, from simply hanging a picture to anchoring wall cabinets, to running plumbing pipes or electrical cable for new circuits.
While some items can be hung using hollow wall anchors attached to drywall, supporting heavy items depends on driving mounting screws firmly into framing members. Almost every homeowner will sometimes find it necessary to precisely identify the location of wall studs and other framing members.
Before You Begin
In most homes, the vertical framing members (studs) that support the wall are spaced 16 inches apart, measured from the center of each stud. This spacing makes for a good strong wall, and it also matches a standard width of fiberglass batt insulation. Walls that are 16 inches on-center (O.C.) are generally built from 2x4 lumber.
This spacing is so common that standard carpenter's tape measures have red marks spaced at these 16-inch intervals. There are exceptions to this spacing, since the space between studs may be smaller where a window or door interrupts the wall span, or at the end of the wall.
But not all walls use 2x4s with this spacing. Some newer, higher efficiency homes are built with 2x6 studs to allow for extra insulation, and here the studs can be spaced 24 inches on-center since the bigger studs offer better structural strength. Either way, though, once you identify the location of one stud, it's generally possible to find the adjacent studs by measuring 16 or 24 inches along the wall from the located stud.
There are two fairly surefire methods for locating studs, but an understanding of wall framing will also allow you to locate a stud without any tools at all:
- In residential house framing, window and door openings will always have studs along their sides. In fact, they will usually have two doubled-up studs—the inner jack studs and the outer king studs. Keep in mind that the location of these studs is determined by where the window or door is located in the wall. These special studs are not necessarily 16 inches from the center of the adjacent studs.
- In new construction building, electricians usually nail the electrical boxes for light switches and outlets onto the sides of studs. This can help you find the general location of a stud in a wall. By removing the cover plate, you can often see which side of the box has been nailed to the stud. Remember, though that not all electrical boxes are nailed to studs. Retrofit or old-work boxes are mounted to the drywall in wall cavities between studs. You can identify these boxes because they always have a small screw at the top and bottom of the box, which is used to turn the plastic wings that hold the box tight against the drywall.
- HVAC ductwork and its visible vents often fill a wall cavity, with studs on either side. There's a good chance you will find studs running upward along each side of the visible vent grill.
- Carefully listening as you rap on the wall with your knuckles may help you narrow down but not necessarily pinpoint the studs. The wall will sound hollow between studs, with a slightly more solid sound when you hit an area backed by a stud. This method can lead you to the general vicinity of a stud but it is not considered to be accurate.
Types of Stud Finders
If you are a regular DIYer, you should have at least one stud finder in your toolbox.
There are several types to choose from: the inexpensive and ever-ready magnetic stud finder, the popular and moderately accurate dielectric stud finder, and the high accurate (but often costly) ultra wide-band and RF scanners.
Magnetic Stud Finder
The first-generation stud finders were simple plastic tools with a magnetic pointer that moved when the device sensed a metal nail or screw that secured drywall or plaster lathe to the studs.
They are very inexpensive gadgets, but they have a limited function since they will only sense the random screws or nails driven into the studs. You may have to roam the wall quite a bit to land on the screw or nail locations—which can be a considerable distance from where you need to work.
But this little tool can be a good choice if your walls are constructed of plaster over wood lath, since the closely spaced lath boards are nailed at every stud location, giving the stud finder plenty of nail heads to detect.
Dielectric Electronic Stud Finder
The dielectric stud finder is the tool that most homeowners will want to own. Battery-operated, the dielectric stud finder is a small hand-held box with red and green diode lights that announce the presence of studs as you move the tool across the wall.
Newer designs have a digital screen that displays the findings. Dielectric stud finders work by creating an electrical field and measuring how the wall responds—lighting up when they sense greater density, such as that created by wall studs. This type of stud finder does a good job of identifying both edges of a stud.
Some practice is necessary to learn how to effectively use this tool, but an electronic stud finder is an affordable tool that DIY homeowners will use often. This is the tool used in the method described below.
Ultra Wide-Band (UWB) Wall Scanners
More sophisticated electronic finders have the ability to distinguish between different materials causing the shift in wall density—they can distinguish wall studs from water pipes, for example.
Ultra wide-band, or UWB, scanners work in the same way as basic electronic stud finders, but they have inner memory programming that compares the tool's findings with stored data on the common densities of various materials—wood, ferrous metal like metal studs, nonferrous metals such as copper pipes, etc. Thus, you will know if the tool is sensing an actual stud, a water pipe, or a heating duct. Many wall scanners can also detect the voltage of live electrical circuit wires.
Once quite expensive, costing $500 or more, these more sophisticated electronic stud finders used by contractors have come down in price so that they're more affordable to do-it-yourselfers.
Radio Frequency (RF) Imagers
When attached to an Android-based smartphone, these scanners use radio frequency waves to determine what is inside a drywall and wood stud wall. Rather than using flashing lights or a digital display,
RF imagers such as the Walabot DIY produce a 3D display that reproduces the look of the wall interior, including studs, wires, pipes, insulation, and more. Radio frequency wall scanners can even detect movement in the wall, such as rodents scurrying through the walls or dripping water.
Much more sophisticated surface scanners, generally used by professionals and costing many hundreds of dollars, have built-in display screens and can be used to scan concrete or any other surface, identifying dozens of different hidden materials.
Using a dielectric wall scanner on the outer surface of the wall is safe. Radio frequency scanners generally are designed and manufactured not to exceed radio frequency emission limits.
One method, finding a wall stud with a finish nail or drill bit, can be dangerous if you penetrate the wallboard and make contact with a live electrical wire. Use an abundance of caution and turn off all electric circuits that possibly might be running through the wall.
Equipment / Tools
Finding Studs With a Finish Nail or Drill Bit
- Finish nail or drill with 1/8-inch bit
- Hammer (if needed)
- Tape measure
Finding Studs With a Stud Finder
- Stud finder
- Tape measure
How to Find Wall Studs With a Finish Nail or Drill Bit
Mark Starting Point on Wall
At a location roughly equal to the height where you'll be driving anchor nails or screws, mark a starting point on the wall. For example, if you are hanging wall cabinets, make the mark at the height where the cabinet's nailing strip will be located.
Drill or Drive Exploratory Holes
Using a hammer and small finish nail, or a drill fitted with a 1/8-inch twist bit, drive a series of holes in the wall to either side of the marked starting point, about 1/2 inch apart. It should become clear when you hit a stud; a finish nail will meet resistance, and a drill bit will show wood dust on the tip of the bit.
Outline First Stud
Pinpoint both edges of the stud using the exploratory holes, then mark the edges of the stud on the wall with a pencil.
Measure Other Studs
Measure at 16-inch intervals from the first stud (or 24-inch intervals on walls framed with 2x6s) and mark the centers of adjacent studs.
Verify Other Studs
Verify that you've located the studs with another exploratory hole at each stud location.
Mark Other Studs
If necessary, you can make lines to mark the locations of the studs along the wall, using a level.
Once the stud locations are marked, use a drywall taping compound (mud) to fill in the exploratory holes on the wall. After the mud dries, you can lightly sand, then paint the wall.
If the holes will be covered by cabinetry, it's not necessary to fill the holes.
How to Find Wall Studs With an Electronic Stud Finder
Make sure the stud finder has fresh batteries, then, following the manufacturer's directions, turn on the tool and calibrate it. Often this is a simple matter of just holding the tool on the wall for a few seconds until its sensors adjust to the density of your wall. If you happen to have placed the tool directly on a stud, the tool will flash; just move the tool so it is lying over a stud cavity and wait a few seconds until it calibrates.
Calibration methods vary according to design, so make sure to read the manufacturer's instructions for your stud finder.
Mark One Stud Edge
Move the tool slowly across the wall while depressing the activation button or trigger. On some models, red diodes will flash when the tool senses the greater wall density caused by a hidden stud. On other models, a digital display gives you the indication that the tool has sensed a stud.
When the light indicates that you have reached the one edge of the stud, mark it with the pencil.
Mark Other Stud Edge
Another pass on the opposite side of the stud will be necessary to pinpoint both edges of a stud. Slide the stud finder toward the first mark to locate the opposite edge of the stud 1-3/4 inches away.
If you wish, you can mark long vertical lines on the wall between the two marks to indicate the centers of the studs.
Dielectric stud finders aren't always accurate. Repeat the previous steps once more, a few inches higher, and then again a few inches lower. Three sets of vertically-stacked marks not only help you verify the readings, they assist you with drawing lines with a straight edge, if needed.