Coil and circuitry design determine the overall ability of any metal detector to find targets. During the design phase of any detector, the engineers decide which features to include. The things that they consider are the type of hunting and who will be using it. A beginner's model may not have the bells and whistles of the more professional models, but it will be easier to use. The more specific a metal detector's design, the narrower set of features it will have. Some detectors designed for ultimate depth will be hard for a beginner to use or may be too sensitive to use in trashy areas. Coil size will affect the depth of the metal detector but may not be suited for a particular type of hunting.

Environmental factors include just about everything except the detector and coil. Just a few of the things to take into consideration are the following: size and shape of the target, soil conditions, orientation of the target in the ground, content of the target, and any outside interference, such as electrical wires and radio or cell phone traffic. Weather conditions, such as rain-soaked ground or even an incoming thunderstorm, may also play a part in the depth and sensitivity of any detector.

With all that being said, an average metal detector using a stock coil in moderate ground should see the following targets with these ranges:

Knowing your metal detector and using it properly are the two most important things that you can do to get the best depth and sensitivity out of any machine.