To find a stud with your phone, use a magnetometer-based stud finder app and sweep the phone slowly and flat along the wall to detect the metal screws or nails that hold the plasterboard to the stud. Stud Finder in CEMP Life reads the magnetometer for 10 seconds as you sweep left to right and reports a baseline, peak readings and signal strength from None to Very Strong. It detects ferrous metal (iron and steel), works offline, and cannot see wood itself.
The 10-second stud sweep
- Remove a magnetic phone case first
- Hold the phone flat against the wall at about waist height
- Sweep slowly left to right across a metre or so
- Watch for a peak: that is a screw or nail line, usually on a stud
- Repeat higher and lower; fixings on a stud line up vertically
How does a phone find studs?
Plasterboard is fixed to timber or metal studs with steel screws or nails at regular heights. Your phone's magnetometer (the compass sensor) reacts to ferrous metal nearby. When you pass over a fixing, the magnetic reading rises sharply. Find several fixings in a vertical line and you have found the stud. Metal studs give an even stronger, continuous signal.
How to use Stud Finder step by step
- Open Stud Finder in the Everyday Toolkit.
- Hold the phone flat against the wall and tap Start.
- Move slowly in a horizontal line for 10 seconds.
- Read the baseline µT, the peak readings and the signal strength.
- Mark the peak with a pencil and repeat 30 cm higher and lower to confirm a vertical line.
Studs are commonly spaced at regular intervals (often about 400 or 600 mm centres, or 16 inches in the US). Once you find one, measure across to find the next.
Find the stud before you drill.
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4-day free trial on Google Play. Cancel any time.
Other ways to confirm a stud
- Knock test: a hollow sound between studs, a duller solid sound over one
- Look for clues: skirting board nails, sockets and switches are usually fixed to a stud
- Tiny pilot hole: a thin drill bit in a spot that will be hidden confirms wood behind
- Corners: there is almost always a stud at internal corners and beside door frames
What a phone stud finder cannot do
- It does not detect wood directly, only metal fixings or metal studs
- It does not detect copper or plastic pipes, or non-ferrous metals
- It cannot tell a screw from a steel pipe or cable conduit
That last point matters most. A strong signal in an unexpected place could be a pipe or cable. Avoid drilling directly above, below or beside sockets and switches, where cables usually run, and use a dedicated cable and pipe detector if in doubt. Stud Finder reports what it senses; it does not confirm what is behind the wall.
Why it works offline
Stud Finder reads your phone's sensor directly, so it runs fully on the device with no internet, ideal for a new-build or a basement with no signal. The same magnetometer powers EMF Health. For more home jobs, see why is my washing machine making noise? and the top SI toolkit.
Find the stud before you drill.
CEMP Life puts 20+ SI tools in one app: calorie counter, food and allergen scanner, recipe maker, wellness sensors, crash detection, car diagnosis, contract checker, receipt scanner and a full creator studio. No account needed. Nothing stored.
4-day free trial on Google Play. Cancel any time.