How Deep Metal Detectors Can Detect?

There is no definite maximum depth level for metal detectors. This is due to the variety of target objects and metal detectors. Contrary to popular belief, not all metal detectors are created equal.

But many people ask me the same question when they begin their journey of metal detecting, How deep metal detectors can detect? and let me tell you, it varies from metal detector to metal detector.

Metal detectors can identify certain types of metal and may perform better or worse depending on the standards under which they were developed.

Coins, gold leaves, and similar things are made to be found by metal detectors used for finding old objects. The detectors work in different places and can find things at different depths.

To understand the phenomenon of metal detector depth, many people wonder how deep metal detectors can detect.

To help you understand this clearly, the depth level has been studied with various factors. Whatever depth your device offers, it is equipped with preset factors described in this article.

Learn How to make a metal detector go deeper.

Factors That Affect How Deep Metal Detectors Can Detect

Here are a few major factors that significantly impact the depth of metal detectors, explained below.

Composition of Target Metal

The composition of metals varies from one another. The depth of a metal detector depends on its technology and specialty.

The composition of the target also affects the detector’s depth. The device can detect different metals in different ways. 

The likelihood of detection is affected by how conductive the target object is. Metals that are good conductors can be found even at greater depths due to their strong conductivity.

They communicate via strong signals and generate more current, which the device can easily detect. However, bad conductors might not be detectable at greater depths.

Size of Target Object

The size of the object also impacts the metal detector’s depth coverage. If the target object is small, the signal penetration into the ground will be less.

Similarly, in the case of a larger target object size, the device will cover more depth.

The device can find small coins near the surface and larger coins or important objects deeper down. The detector won’t find a coin deep down because coins are small and don’t disturb magnetic fields much.

However, the detector will be able to easily detect signals even at great depths if the target size is larger, such as relics.

Shape of the Target

The detection depth also depends on the shape of the target object. Smooth surfaces are more likely to be detected than uneven objects. Furthermore, rectangular-shaped objects will be simpler to identify at maximum depth. 

However, it is difficult to detect thin targets because they have less surface area for waves to disrupt.

It will be challenging to collect signals from nails at depth because of their thin shape. However, chest boxes and relic plates will have the largest surface area for signal capturing.

Target Orientation

Deeper detection of a horizontal target is easier than that of a vertical target. This is because there is a greater surface area to interfere with the detector’s EM field.

 A vertical target has a smaller surface area to deal with and is therefore more challenging to find. If a sword is lying flat on the ground, it will make it easier to find with a metal detector.

On the other hand, a sword placed vertically will be difficult to detect at greater depth.

Size of the Coil

The size of the coil is another major factor that determines the depth a metal detector can cover. Coils with a larger size can find deeper metals, while coils with smaller sizes may not provide the same results.

For instance, a coil with a diameter of 10 to 12 inches cannot capture objects at a depth of 4 to 5 meters. At shallow depths, small-size coils will capture small-size items. Similarly, a larger-sized coil will send signals deep down into the earth to detect faraway targets.

Discover the different Types of Metal Detector Sensor/coils available in the market.


The primary distinction between metal detectors is the frequency at which they operate. The operational frequency of a metal detector is how many electromagnetic waves it broadcasts per second. These frequencies are measured in kilohertz (kHz). 

For example, a 7 kHz frequency can send 7,000 EM waves each second, while a 40 kHz frequency can send 40,000 waves each second.

The majority of metal detectors work between 7 kHz and 25 kHz in frequency. Single-frequency and multi-frequency technologies are the two main categories of frequency technologies.

The higher the frequency is lower the depth will be. Similarly, low frequencies can achieve greater depths.

Check out Metal detector frequency for gold and other valuable metals.


The detector’s capacity to find metals at greater depths is increased by its sensitivity feature. Each device has a different level of sensitivity.

Certain devices can increase or decrease sensitivity to reach different depths. Therefore, you must determine the appropriate metal detector sensitivity settings for your device. High sensitivity improves the signals received from metals.

Halo Effect

The halo effect refers to a target that has been oxidized in its most basic form. Anything buried in the earth that decays corrodes, tarnishes, or leaches can produce a halo effect.

Detectorists may find the halo effect frustrating. A good target can suddenly disappear. The detector can make small objects appear bigger by sending out misleading signals. This happens because of the halo effect mechanism.

 It is a common misconception that items left in one location for a long time have a depth twice as great as their original depth. Due to the halo effect, objects may appear to have a 10%–25% greater increase in depth. However, it is unlikely that the detector picks up items that are twice as deep as before.

Soil Mineralization

Most soils have small particles that react magnetically to the electric field of the detector’s coil. The minerals in the soil disrupt how electromagnetic waves work, causing metal detectors to detect less deeply.

The depth will be shorter if the soil has a high level of mineralization. Less soil mineralization will lead to greater depth. This type of soil can cause the instrument to malfunction and produce misleading readings.

The detector won’t function at its maximum depth if soil mineralization is at its peak in that location. Heavily mineralized soil provides misleading signals and instability in the detector.

Electrical Interference

Electrical interference can be caused by either above-ground or subsurface electrical wires. It is difficult to use metal detectors near high-voltage cables due to electrical interference near the transformer.

Metal gadgets lack sensitivity, so in some places, users can’t increase the device’s sensitivity, which impairs its depth function. Consequently, the instrument won’t detect metal at a great depth.

How deep do most metal detectors go?

The depth at which a metal detector can go depends on a number of factors which are mentioned above.

However, to give you an idea of the max depth a detector can achieve up till now is 4-5 meters or 13 to 16 feet. If you find a device claiming more than this depth you should do proper research about that particular device.


The functioning of metal detectors for deep detection is a topic of general discussion. The answer is different for each device and depends on many things, like metal, size, and frequency. We have mentioned all the factors that can affect how deep metal detectors can detec.

Not all metal detectors are made for 1 objective in mind. While the end result is finding and detecting metal underground, their approach as to how they will detect is different from one another.

That is precisely why choosing the right metal detector is monumental in your success of finding treasure or relics.


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