How to Use a Stud Finder and How it Works

TopProducts may earn commissions from affiliate links on this page. Not only does this help us maintain our website, but it also helps support our scholarship program. Learn More.

Also known as a stud detector or stud sensor, this is a handheld device used to detect the wooden studs (usually 2 x 4’s) behind or inside a wall. These wooden studs are known as wall framings.

A stud finder works by battery and has an electromagnetic charge that detects where the studs are located inside walls. Stud finders are an essential tool in the home or office, especially if you have a wall hanging project that requires sturdy support.

With a stud sensor, you’ll make fewer mistakes than the old school knocking on the wall and listening for a sound difference. And you’ll avoid having those ugly looking holes from the near misses!

Or better yet, you’ll never deal with your pictures falling later because your nails or screws only went through drywall with no wood behind it. And don’t even attempt to try to mount your new Flat Screen TV on the wall without first finding the studs.

Builders incorporate studs into walls for structural support when erecting buildings — but they also add more than are actually needed to make it easier to drill holes in your wall for hanging things. Building conventions are to place framing studs 16 or 24 inches apart. Measuring from the corner, electrical outlet or light switch should lead you to a stud, but there are no guarantees.

With a stud detector, you will be able to find out the right spot – every time!



Get your International Tool items delivered to your home.

Related: Best Stud Finder Reviews


How to Use a Stud Finder

Before we get to the “how”, let’s first do a quick overview of the types of stud finders. Stud sensors fall under two broad categories:

  • Magnetic Stud Detectors: Just like the name suggests, magnetic stud detectors have special magnets and an indicator that alerts when it is placed over metal that is magnetic. Finding studs with this type is a bit more time-consuming because instead of searching for the entire stud, the sensor is looking for the screws and nails within it — which means a lot more moving around. On the positive side, not only you have located the stud, but you will also know where on the stud NOT to put your next nail or screw.
  • Electric Stud Detectors: Electric detectors, on the other hand, depend on signals that are as a result of the dielectric constant of the wall. This constant changes when the device moves over a stud. What this type of sensors does is determine a change in the density behind the wall. In simple terms, the area behind the wall where there is a stud will be thicker than when it’s just drywall. We’ll talk more about how electric stud finders work in a bit.

There is one more distinction you need to know about stud finders before we get started. Some locate the edge or start of the stud and some help you find where the center is. This is important so you know where to put your screw or nail — you don’t want it to close to the edge of the stud or it will split the wood and/or not have as firm of a grip.

Okay, now let’s get to the good stuff, how to find a stud with a stud finder.

If you are hanging something light, it is not absolutely necessary to have a stud. However, for heavier items drywall alone is not strong enough and will crumble under the pressure. The weight of a heavy mirror, for example, will cause the screws or nails to pull right out of the wall.

Crash! Seven years of bad luck. Or so they say.

To avoid this and still be able to have shelves and hangings on your walls, builders put studs inside the wall to ease the process of drilling nails and screws through them. But to find them, since they are hidden behind the drywall, you will need a stud finder.

Here is how to put one into proper use.

Step One: Consider where you want to place your hangings

Whether you want to hang some pictures, a mirror or shelf, you first need to identify the exact place for it. This is a matter of eyeballing things to get a general idea. Simply bring the object to that part of the wall and check to see if it matches what you desire. It’s easy with wall hangings but can be quite tricky when it’s a TV or a floating shelf you want to hang, but it is still doable. You just may need an extra hand or two.

You can use a pencil to lightly mark the general area where you want your item to go. By the way, another handy tool to have during this type of process is a line level, preferably a laser level. Having one will ensure that the things you hang are straight and evenly spaced.

Alternately, if you are planning on hanging multiple items on the wall, or the exact location does not matter, you can find all the studs first and then determine the best locations for your hangings.

Step Two: Get your stud sensor ready

Stud finders use batteries to operate so once you identify where you want to place your hangings, prepare your stud sensor by putting in new batteries. It is advised to use new batteries for accurate readings. Also, check to see that the flat surface, which you will be running on the wall, is free from dust and/or debris.

If you are really concerned about scratching your wall, you can place a piece of thin sheet between your sensor and your wall for peace of mind.

Step Three: Run your sensor along the wall

Once you have prepared your stud finder, walk along the wall moving your stud finder slowly to determine where the studs are placed. When your sensor identifies a stud, there will be some light or a beeping sound on the gadget, depending on type. As you walk around, be sure to have a pencil with you to be able to mark where the stud is located.

This process requires some level of patience on your part, the first stud may take a little time to find but once you find it, you can easily calculate where the next one might be. Keep moving and marking all the stud points until you exhaust them all.

If you are only hanging a single item, you don’t have to mark all the studs. Instead, you can just work in the area where you want to hang the item. Minimally though, you should locate at least 3 studs in a row, in order to ensure that what you found was really a stud.

Step Four: Double-check your findings

Sometimes your stud sensor might give you a false positive, since apart from studs, metal piping or flashing are also found inside the wall. Or not held in the proper position, the sensor may as well give you a wrong signal.

It is not uncommon for people who use a stud finder incorrectly to return them, thinking they do not work (the video below covers the reason this frequently happens).

To counteract this, check the distance between the first stud you find and the next. Usually, studs are placed 16 to 24 inches apart. You can simply measure the distance between your markings to confirm you found the right spot for the stud. This is the best way to ensure you did not get a false positive.

Even Cheap Stud Finders Can Be Accurate If Used Right!

How a Stud Finder Works — Using a Stud Finder, Correctly
| Courtesy of That Kilted Guy DIY Home Improvement

Step Five: Drill or nail away!

Once you have followed the above steps, you are now ready to hang your paintings, pictures, mirrors, shelves or any other thing you needed to hang on the wall. Finding the studs makes it easy for you to drill without damaging your wall, and without too much of a hassle.

More importantly, if you are using screws, the wood stud gives them something to hold on to. If the exact location matters and there is no stud, you need to use a drywall anchor (these are available for different weight ratings). For heavier items or If you are hanging something from the ceiling, you can also use toggle bolts and wingnuts.

But screws or nails that go directly into a stud are the best way to ensure whatever you are hanging stays put!

How a Stud Finder Works

So, you just moved into your new home and can’t wait to start hanging decorations on your wall? That’s a fantastic idea! You have to make your home cozy and inviting. But you shouldn’t just go straight into drilling or hammering, lest you wake up in the middle of the night to a deafening sound of things falling off the wall.

This is why builders place studs in strategic places on your wall to help you hang stuff easily. To figure out where the studs are placed, you need a stud finder.

But how exactly do they work?

Well, there are stud finders that were used in earlier days, and they only detected ferrous metals and were only used in commercial buildings. The modern-day stud finders, however, can detect both metal and wooden studs within walls.

There is a newer stud sensor that also determines the density of the wall. As the days go by, newer and more advanced versions of this gadget are released into the market.

Now to the technical part…

Stud finders use a “radar” system that when placed on the wall, will be able to detect where the studs are placed. There is a plate that is inside the sensor, just on the part that you run on the wall when using the stud finder, to determine the dielectric constant.

Dielectric constant is the measure of how much electric energy a material can store.

Wood, being a poor conductor of electricity, has a low electrostatic field, which is what stud sensors detect when running across the wall. Once the sensor detects a stud inside the wall, it will emit either a LED light, beeping sound, or a light coming out of the device, to let you know where the stud is so you can mark it.

Stud sensors use a combination of metal detectors, density sensors, magnets and radar — depending upon the type — to scan through the wall and discover the hidden material beneath.

Simple sensors will only detect the studs embedded within the walls but advanced ones have the ability to detect beams in the ceiling and floor, metals inside walls and under tiles, hidden metal pipes and even the density of the material used on the walls. It is important to note that stud finders that look for changes in density, can also detect metal and more advanced models allow you to adjust settings to find what you need.

Quick Tutorial – How to Use a Stud Sensor

Tips for Finding Stud with Stud Finder. | FIX IT Home Improvement Channel

Related: Best Cordless Drill Reviews


Stud finders have been around since the 20th century and the early ones relied only on magnets placed inside the gadget to determine where the studs are. Over the years however, several improvements have been made on the internal capacitor to make it possible to determine the changes of density inside the wall as well.

If you don’t have one of these handy dandy devices yet, you can get cheap one for about $10 bucks. Our you can splurge for a Zircon and spend around $25.