iPhone scanning a drywall surface to locate hidden wall studs

See behind the wall,
now in your pocket.

Stud Finder is an iOS and Android app that locates wall studs using the phone's built-in magnetometer, replacing $20–$50 hardware stud finders for DIY tasks like mounting TVs, shelves, and cabinets. It's free to try, ad-free, and works offline.

The stud finder app for iPhone and Android. Find wall studs through drywall with your phone's magnetometer — accurate to within an inch, no extra hardware. Free to try, ad-free.

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FEATURES

One last check before the drill comes out.

Magnetic scanning

Your phone's built-in magnetometer detects the screws and nails behind drywall. No extra hardware needed.

Stud spacing estimate

Measures the distance between two studs and verifies standard 16″ / 24″ framing.

Live signal map

An on-screen heatmap shows exactly what the sensor picks up. No guessing, just raw physics.

HOW IT WORKS
Hand sliding an iPhone across a drywall surface to scan for studs

Slide your phone across the wall and Stud Finder reveals what's hiding underneath. No more drilling blind.

A real-time magnetic reading shows you exactly how strong the signal is. Higher numbers mean a screw or nail is right there.

Stud Finder app showing a real-time magnetic field reading on an iPhone

Fine-tune the Stud Finder sensitivity for any surface. Drywall, plaster or brick all get an accurate reading.

Stud Finder sensitivity slider tuned for drywall, plaster, and brick

Track magnetism on all three axes at the same time. You see exactly which direction the metal is pulling from.

Three-axis magnetometer reading showing X, Y, and Z magnetic field components
THE HONEST ANSWER

What a stud finder app can — and can't — do

A stud finder app doesn't see wood through the wall, and any app that claims to is faking it. What your phone's magnetometer actually detects is the steel screws and nails that anchor drywall to each stud: against Earth's ambient magnetic field of 25–65 microtesla (NOAA World Magnetic Model), a fastener at contact distance reads 50–200 microtesla — a sharp, unmistakable spike. Because studs sit on 16-inch centers in U.S. residential framing (IRC §R602.3.1) and fasteners land within an inch of each stud's center, finding the screws means finding the stud.

Where it works

  • Standard 1/2-inch or 5/8-inch drywall screwed to wood studs — the construction most North American homes built after 1960 use
  • Locating studs to within about an inch, which is enough for shelves, picture frames, curtain rods, and most TV mounts
  • Working entirely offline — detection is on-device, with no account and no internet
  • Verifying its own reading: sweep twice at different heights, and a real stud spikes at the same horizontal position both times

Where it doesn't

  • Metal-stud commercial walls — the whole wall reads as magnetic, so there's no spike to lock onto
  • Concrete, brick, and other masonry — there are no studs or fasteners to find
  • Plaster over metal lath — hundreds of lath nails flood the magnetic signal
  • Replacing a second opinion on heavy mounts — above roughly 30 lb, confirm with a hardware finder and drill only where both tools agree

The full physics is on how it works, the head-to-head with a $30 wand is in app vs. hardware, and the detailed honest test is in do stud finder apps work. Platform-specific guides: iPhone and Android.

TESTIMONIAL
  • "Mounting heavy mirrors used to mean three test holes and a lot of patching. Now I scan once, mark the studs and drill with confidence. My walls thank me."

    Avatar of Lena Hoffmann

    Lena Hoffmann

    Interior Designer

FREQUENTLY ASKED QUESTIONS

What's the best free stud finder app for iPhone?

Stud Finder is an app for iPhone and Android that locates wall studs using your phone's built-in magnetometer, replacing $20–$50 hardware stud finders for DIY tasks like mounting TVs, shelves, and cabinets. It's free to try, ad-free, and works offline.

Is there a stud finder app that actually works?

Yes. On standard drywall over wood framing — the construction style most North American homes use post-1960 — a magnetometer-based stud finder app locates studs to within about an inch by reading the metal fasteners holding drywall to each stud. Here's the full breakdown of whether stud finder apps work and how accurate they are.

How accurate is the iPhone stud finder app compared to a real one?

On 1/2-inch drywall over 16-inch-center wood studs, iPhone magnetometer-based detection is comparable to a hardware capacitive stud finder for typical loads (shelves, picture frames, curtain rods, most TV mounts). For heavy mounts above 30 lb, the safest workflow is to use both tools and only drill where they agree.

Which iPhones does the stud finder app work on?

Any iPhone with a built-in magnetometer — every model since the iPhone 3GS. The newer the phone, the cleaner the signal, but even older devices give a usable reading on standard drywall.

Does the stud finder app work with a phone case?

Most plastic, silicone, and leather cases are fine. Thick metal cases, MagSafe wallets and magnetic mounts can interfere with the magnetometer — remove them for the best reading.

Can I use the stud finder app on concrete or brick walls?

Concrete and solid brick walls don't have studs the way drywall construction does, so the app isn't designed for them. For masonry, use the appropriate anchor and a hammer drill.

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See behind the wall,
now in your pocket.

Stud Finder turns your phone into a precision wall scanner. Know where the studs, screws and pipes are before you drill.

Download the App