Stud finders are notoriously unreliable at finding studs; some will indicate a "rapidly shifting network of hundreds and hundreds of studs". Is there a way to determine before purchase that a particular stud finder will be more accurately named than most?

Are there certain types of walls for which certain types of stud finders don't work?

  • 1
    LOL. I gave up after I purchased two of them. When I was buying the first one the salesman showed me another model and told it was "a toy for kids of 5-7 years age" and then offered me the model that turned out to be a toy for 8-10 years age. The second one is... well, a bit more accurate. So my advice would be to only listen to people who actually use one for a living.
    – sharptooth
    Commented Dec 26, 2011 at 16:52
  • 2
    are you using it on drywall or plaster? plaster has lath behind it which throws off the stud finders
    – Steven
    Commented Dec 26, 2011 at 17:48

3 Answers 3


There are at least three different types of stud finders; unless you understand what they're doing to try to locate studs, their results may baffle you.

  • Magnetic - these are a pitiful joke, but they were the only thing available when I was a kid. They don't sense the stud itself (unless you're in an office building that uses steel studs!), but rather the nails that secure the drywall to the stud. Since the stud probably doesn't have a continuous line of nails in it - and if it did, how could you possibly add more? - and since the magnet is NOT very strong, you might need to sweep up and down the wall many times to find a nail (and then try again, above and below, to make sure it's really a nail in a stud.) The only thing these have going for them is that they're CHEAP - I've seen them at the 99-cent store.

  • Metal-detecting - these do the same thing as the magnetic type - they don't sense the stud, but only the nails (and other metal in the wall - hence the XKCD joke), but they work on the same principles as a treasure-hunter's metal detector: an electromagnet in the detector induces a small current in nearby electrical conductors, and detects the resulting magnetic field(s). MUCH more sensitive than the old magnetic type, so you don't have to be directly over a nail to find the stud - but also very susceptible to false positives. These often go for $10-$15, but frankly, even at that price they're a waste of time and money.

  • Ultrasound - The only kind that actually does a better job than tap-and-listen. These directly detect the stud (or at least its edges) by sensing a change in the density of the wall. You need to zero the sensor by pressing it against a known void; after that, you slide it along the wall and it beeps (or flashes) to show that it's detected an edge. After years of using worthless magnetic or inductive stud finders, it's a real treat to be able to find the outside edges of a stud - the correct 1.5" apart, no less! - and confidently drive a nail right down the middle.

As for a brand recommendation... I bought a Ryobi at Home Depot and have been happy with it, which probably means that brand doesn't matter much. Get an ultrasound model, of whatever brand.

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    I agree, get an ultrasound stud finder. I picked one up years ago for a few dollars and it has been flawless ever since. I haven't even had to change the battery and it has been at least 8-10 years. I just used it today to mount a TV on the wall, and both studs I drilled into it detected the edges precisely 1.5 inches apart.
    – user4302
    Commented Dec 29, 2011 at 5:53

If you are looking to locate wood studs and or electrical wires behind standard sheetrock type walls, I'd recommend the Zircon with deep stud/electrical alert/ metal detection. I have both a Stanley and a Zircon and find that the Zircon is the most dependable. Neither is 100% accurate, but usually do a good job. Test with a finish nail when you need to be absolutely sure the stud is there before attempting to mount objects etc.


I have had good luck with my Zircon stud finder. It's pretty spot on for modern walls, but works with a little finagling for plaster and lathe.

I've found that going back over the stud at different heights gives me more confidence than just a quick one-off reading. If you have three readings that agree, odds are very good that you're going to hit that stud.

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