Why is my stud finder all over the place?

Try a strong magnet, moving it slowly across the wall. It can catch drywall screws or nails, which often mark where a stud is. Find a few fasteners in a vertical line rather than relying on one spot. That gives you a likely stud line, but check the exact mounting point with a small pilot hole before using the mount screws.

Electronic finders can be thrown off by insulation, foil layers, thick or uneven walls, or a low battery. If you try it again, check the battery and follow its calibration instructions. Scan from both directions, mark the edges it detects, then use the midpoint as a lead, not proof. Stud spacing varies, so measurements from an outlet or another stud are only clues.

If the magnet and finder still disagree, the wall may have unusual framing or a different material behind the surface. You can use an existing small opening to inspect carefully with a borescope or feel sideways with a bent wire, but don’t push blindly. Before drilling for a TV mount, check for wiring and pipes, identify whether the wall is wood, metal framing, or masonry, and use a mounting method rated for that construction and load.