Anyone who's ever done any construction remodeling or tried to hang a shelf on the wall understands the value of a stud finder. If you can't find a stud in the wall to put your nails into, whatever you're trying to build is just going to fall down.
Not all that long ago, the only stud finders you could find were magnetic. Magnetic stud finders don't really find the studs, rather they find the nails used to hold the drywall to the studs. That means you not only have to find the stud horizontally, but the nail vertically. You could pass one inch above or below that nail and never find it. I remember many a frustrated time looking for a nail that way, but it was still better than tapping on the wall and trying to guess where the stud was hiding.
Modern stud finders are a whole lot better than those old magnetic jobs because they don't just sense the nail, but the stud as well. But they'll go even farther than that, as they sense any solid mass behind the wall thicker than just the drywall.
Some modern sensors also sense plumbing pipe or electrical wires but rarely will a stud sensor find both unless they are right up against the wallboard because they work by different means. Sensing plumbing is usually done by infrared while sensing wiring is done by the voltage going through the wires. Thus, it takes two separate circuits to sense both of them.
There are also new sensors which will sense deeper than just the drywall and what's immediately behind it. Some of them will sense as deep as 4 inches, helping prevent you from putting a nail into a pipe or cutting a wire with a sawzall.
Most of these sensors let you know when they've found a stud or other object by a combination of flashing LEDs and sound. A few have LCDs, but really don't give that much more information via the screen although some will let you know when you're getting close to the stud via the screen. Those that don't have a screen do this by a series of LEDs, which "count down" to the edge.
Any of these best stud finders will do an excellent job for you but each is unique in the features each unit offers. Picking the right one is mostly deciding which will be easier for you to work with, as well as taking into consideration any special needs like locating wires. More expensive units aren't necessarily more sensitive, but may present the information in an easier to use manner.
Franklin's ProSEnsor 710 takes the prize as the easiest stud finder to use. The multiple sensors in this unit instantly locate all studs in its range, lighting up LEDs where the studs are, even if there are multiple studs. Read Full Review
The ProSensor 710 is definitely the easiest stud finder to use available today as it has a series of sensors built in, not just one. This makes it possible for the device to check for studs in multiple locations at the same time. Locations which have a stud or other solid object behind them will show by the lighting of a LED in that location and with the LEDs lighting up in that manner, you not only see where the stud is, but how wide it is as well. This unique system allows the Franklin to find multiple studs at once and if they are located close together. It’s also the only stud finder that works without sliding it across the wall. Differences in texture or drywall mud don't make a difference as the unit is always deep scanning up to 1.5 inches.
Black & Decker makes a really nice unit that is level and stud finder in one. The device auto-levels and puts out laser lines to both sides, providing you with a horizontal line that you can use for anything from hanging pictures to building an addition to the house. Read Full Review
What I like about this model from Black and Decker is that you don't need to carry a bunch of different devices. While one of the functions of this unit is to locate studs, it also provides a built-in level for auto-leveling, allowing you to quickly and easily level the device before sending out a horizontal laser line in both directions. This makes it easy to hang shelves, install suspended ceilings or put in chair rail in your home. The stud sensor works for both wood and metal studs, as well as tracking live electrical wires. So, whether you're doing carpentry or electrical work, this one sensor will help you find what you're looking for.
Zircon is the biggest manufacturer of stud finders, with the widest line of available models. This one will do just about anything you could want, including sensing live electrical lines and copper pipe. Read Full Review
Zircon pretty much invented the electronic stud finder and still has the biggest share of the market, with more models of stud finders than anyone else. This unit is multi-mode, allowing you to use it in edge finding or center finding mode. You can also use to detect live electrical wires up to two inches deep. The unit normally operates in a "shallow mode" of 3/4 of an inch, but can readily be switched over to a 1-1/2 inch deep scan mode. The unit will detect rebar in concrete up to 3 inches deep. An LCD display virtually eliminates the chance of misunderstanding if the unit is sensing the middle or edge of a stud. Built-in auto correcting technology (ACT) automatically corrects common errors, such as when scanning starts over a stud.
Like the Zircon, Bosch's unit detects everything form studs to rebar, via live electrical lines. It has the deepest rebar detection in concrete of any stud finder, ranging 4-3/4" deep. Read Full Review
This sensor from Bosch has every mode of detection you can want. It will detect wood or metal studs, as well as other metal objects such as rebar and metal plumbing pipes. Of all the stud finders on the market, it has the deepest detection range of any for finding rebar in concrete, detecting up to 4-3/4 inches deep. A final mode detects live electrical wiring while a graphical display helps make it easy to understand what the detector has found, as well as pinpointing edges and centers of studs. The automatic center finder feature makes it faster to determine the exact centers of studs.
For those that need a low-cost unit, this edge finding unit from Zircon fits the bill. I've had one of these for five years and it works extremely well, although it doesn't have all the whistles and bells of the more expensive units. Read Full Review
If you're looking for a basic unit or just a lower price, Zircon can help you. I've had one of these units for about five years now, and it works well for all my needs. While it isn't as fancy as some of the more expensive units, it finds studs just fine. This unit is an edge finder, locating the edge of studs for you and indicating their location with a LED and audio tone. It has both shallow and deep modes, with the deep mode operating up to 1-1/2 inches. If you accidentally start your scan over a stud, an indicator warns you, so that you can restart the scan.