Ask what information is missing
An experienced DIYer may already find plasterboard screws with a strong magnet but tire of moving it point by point. The missing information might be speed, a suggested edge/centre, or warnings about metal and energised wiring. An electronic tool is useful only when its current manual states that it provides that information for the wall being scanned.
Do not buy the word “electronic”. Some models focus on density changes, some on metal/live cables, and others disclose several material modes. The Bosch Truvo scope comparison is a good reminder: Bosch’s current Truvo page names metal and live cables, not wooden studs. A familiar brand or screen cannot change the target list.
Likewise, a magnet is not a stud detector in the literal sense. It reacts to ferrous metal. The object could be a board screw, nail, corner bead, protector plate, pipework or another fitting. Interpretation comes from the pattern and the wall context.
Compare the methods without creating a fake winner
| Decision field | Magnetic method | Electronic method |
|---|---|---|
| Directly senses | Magnetic attraction to ferrous metal | Only the targets/modes named for that model |
| Typical useful output | A fastener/object point | Signal region, edge/centre suggestion or target warning |
| Power/manual | No battery; technique still matters | Battery, start/calibration and handling instructions matter |
| Main ambiguity | The metal’s identity and relationship to framing | The signal’s material identity and wall-condition effects |
| Hidden services | Cannot rule them out | Only adds warnings within documented limits; cannot rule them out |
| Difficult plaster | May trace metal fasteners, but mesh can saturate the clue | Irregular density can create unstable or false indications |
Cost belongs at the end of this table. A low-cost magnet remains valuable as a second method. An electronic detector earns its place when its additional documented information changes a real decision repeatedly—not because it has a large mode count.
Use a combined workflow on ordinary plasterboard
First map the proposed fixing area and nearby sockets, switches, taps, lights and reverse-wall fittings. Read the electronic model’s manual. Begin and calibrate as directed, then scan across the whole area from left and right at more than one height. Mark repeatable signal edges and any metal/live warnings.
Next move the magnet slowly across the same zone and mark strong attraction points. Search above and below a point to see whether there is a coherent vertical fastener series. Compare that line with the electronic edge region. Agreement supports—but does not prove—a framing hypothesis.
If the methods disagree, do not vote two passes against one. Check battery, hand position, wall finish and calibration conditions in the manual; widen the scan; and reassess the wall type. If uncertainty persists, use a competent inspection or choose a fixing strategy designed by an installer for the confirmed substrate.
Change method for lath, mesh and metal framing
Period lath-and-plaster is not ordinary plasterboard. Irregular density can trigger electronic stud indications, whilst the repeated nails fixing horizontal laths can create useful metal clues. The dedicated lath-and-plaster guide explains how to look for a vertical nail pattern and why metal mesh can make even that method inconclusive.
Metal framing changes the interpretation too. A continuous metal response may be framing, a service protector or another object, and fixing design differs from timber. Do not convert a metal line into a timber screw plan. Foil-backed board, insulation, moisture and textured finishes may also affect tools; follow the model’s stated limits.
For television mounting, continue with the bracket-specific wall check. Finding a likely line is only one part of matching the bracket and fixing to the substrate.
Keep hidden-service safety outside the method contest
Neither a magnet nor an electronic stud indication can clear a drill point. HSE’s pre-drilling guidance says to inspect both wall faces, seek plans, look at nearby equipment and use a suitable detector if competent. It also warns that some cable detectors will not find a wire carrying a small current.
Therefore a socket route, pipe clue or unresolved warning overrides apparent agreement about a stud. Mark it, move the planned fixing only within the item manufacturer’s approved pattern, or stop for a competent electrician/plumber/installer. A clear-looking patch is not evidence that services take a convenient route around it.
A two-method comparison you can repeat
- Identify the wall family and the information needed from the scan.
- Map visible service clues on both sides before using either method.
- Read the electronic model’s target list and operating limits.
- Scan the whole area from both directions and mark repeatable edges/warnings.
- Use the magnet to map individual metal points above and below each other.
- Compare patterns without assuming every metal point is a board fastener.
- Recheck operation if methods disagree; do not cherry-pick the preferred pass.
- Stop when the wall, service route or structural fixing remains uncertain.
Questions people ask
Is a magnet more accurate than an electronic stud finder?
They sense different things, so a universal accuracy comparison is misleading. A magnet finds ferrous metal; an electronic model responds only to its documented targets and conditions.
Can a magnet find the centre of a wooden stud?
No. A fastener pattern may support the location of framing, but the magnet does not directly show the stud’s edges, material, condition or centre.
Should both methods always agree?
No. Disagreement may reveal different targets, wall effects or operating errors. Recheck the instructions and wall, and treat persistent disagreement as unresolved.
Do I still need a cable check?
Yes. Neither a magnetic fastener clue nor a stud-mode response rules out hidden electrical or plumbing services.
Sources and scope
- HSE — Work near electricity — pre-drill inspection, competence and low-current warning
- Zircon — How to Find Studs in Lath and Plaster Walls — density and metal-fastener method limits
- WOEAOZY — live product detail — current public product name, price and URL only
Sources were checked on 20 July 2026. Manufacturer specifications describe their named products only. General guidance cannot identify what is inside a particular wall.