Magnetic or electronic: how to choose a stud finder

Heavy things belong in wall studs, not just drywall. A stud finder helps you find them. No stud finder is perfect, so the best approach is to find the stud, then confirm before you drill.

Types of stud finders

Type	How it works	Strengths	Weaknesses
Magnetic	Finds the screws or nails holding drywall to studs	Cheap, no batteries, works through many wall types	Slower; you find fasteners, not stud edges
Electronic edge-finding	Senses density changes as you slide it	Affordable, quick	Must be calibrated on a spot with no stud; can give false readings
Electronic center-finding	Uses multiple sensors to show the stud's center	Shows where to drill, often with a display	More expensive
Multi-scanner / wall scanner	Detects wood, metal and live AC wires with deeper scanning modes	Most information	Most expensive; still not foolproof

Drywall vs. plaster

• Drywall works well with most electronic stud finders.
• Plaster and lath walls, common in older homes, are dense and uneven and confuse many electronic finders. Magnetic finders that locate the nails holding the lath often work better.
• Textured walls and wallpaper can affect readings; some finders handle these better than others.

AC detection

Many stud finders warn you when they sense live AC wiring. Treat this as a helpful warning, not a guarantee. It may not detect wires that are deep, shielded, not carrying current, or behind metal. Wires often run vertically along studs and horizontally between outlets and switches, so be careful drilling near them.

Confirm before you drill

Before drilling a large hole, confirm the stud:

1. Mark both edges of the stud if your finder shows them; studs are typically about 1.5 inches wide.
2. Studs are often spaced 16 inches apart center to center (sometimes 24). Check that your marks follow the pattern.
3. Drive a small finishing nail through the mark where it will be hidden. Solid resistance means wood; easy passage means a gap.

Features worth having

• A display showing stud edges and center.
• Deep scan mode for thicker walls.
• Built-in level or laser line for marking.
• Marking notch to mark the wall precisely.

Questions people ask

Why does my stud finder find studs everywhere?

It may need recalibrating: hold it flat on the wall away from studs, turn it on, then slide slowly. Dense walls, plaster and pipes can also cause false readings.

Can a stud finder detect metal studs?

Magnetic finders can locate the screws; some electronic models have a metal-detection mode.

Do stud finders work on ceilings?

Yes, the same principles apply for ceiling joists. Confirm with a small nail before mounting anything heavy overhead.