Metal Detector Colors: What Lights & Displays Mean

Updated 4 November 2026 · Standard formula, shown below

Metal detector displays and indicator lights are not just for show; they convey real-time information about a target’s conductivity, depth, and likely metal type. The color coding on a display or a target ID number tells you whether the detector has found ferrous metal (like iron) or non-ferrous metal (like gold, silver, or copper), helping you decide whether to dig. This article explains what the colors and numbers on common metal detector displays actually mean, how to interpret them, and why they are not always perfectly accurate.

How Metal Detectors Classify Metals

Metal detectors work by generating an electromagnetic field and measuring the response of a metallic object to that field. The key measurement is the conductivity of the target. Different metals have different electrical conductivity, which affects the phase shift of the reflected signal. The detector’s circuitry analyzes this phase shift and assigns a numerical value or a color to the target.

Here is a basic breakdown of how conductivity maps to metal types:

Ferrous (Iron/Steel): Low conductivity, high magnetic permeability. These usually produce low target ID numbers and are often shown as red or black on color displays.
Non-ferrous (Gold, Silver, Copper): High conductivity. These produce higher target ID numbers and are shown as yellow, green, or blue on color displays.
Aluminum (foil, cans, pull tabs): Medium-high conductivity, but often produces a range of IDs depending on the shape and thickness.
Lead (sinkers, bullets): Medium conductivity, often ID in the mid-range.

It is important to note that the conductivity of an alloy is different from its pure metal. For example, a gold ring (14k) has lower conductivity than a pure silver coin, so it may show a lower ID number than you might expect.

What the Colors on a Display Mean

Many modern metal detectors, especially those with color LCD screens, use a color scale to visually represent the target ID. While the exact color mapping varies by brand and model, the following is a common general scheme:

Red or Black: Ferrous targets (iron, steel, nails). Most detectors allow you to “notch out” or discriminate against these, meaning they will not sound an alert.
Yellow or Orange: Low-conductivity non-ferrous metals, often including small gold nuggets, lead, and some aluminum foil.
Green or Blue: High-conductivity non-ferrous metals, such as copper, silver, and large aluminum objects.
White or Gray: Often used to indicate a target that is too deep to be accurately identified, or a target that falls outside the selected discrimination range.

These colors are usually paired with a numerical target ID (e.g., 0-99 or -10 to +40). The color is essentially a visual shortcut for the number range. For instance, on a detector with a 0-99 scale, iron might be 0-10 (red), foil 10-20 (yellow), pull tabs 20-30 (orange), and coins 30-99 (green/blue). Always check your detector’s manual for the specific color-to-number mapping, as it is not universal.

Target ID Numbers and Conductivity

The target ID number is a more precise way to gauge a target than color alone. It is a numerical representation of the phase shift, which correlates with conductivity. A higher number generally means higher conductivity. Here is a typical scale for a detector with a 0-99 scale:

0-10: Iron, steel, nails.
10-20: Aluminum foil, small lead objects, some gold rings (low karat).
20-30: Pull tabs, screw caps, some gold rings (higher karat), zinc pennies.
30-40: Aluminum cans, copper coins, silver coins (dime, quarter), brass.
40-60: Large silver coins, copper pipe, aluminum bottle caps.
60-99: Very high conductivity targets, often large silver or copper objects.

Keep in mind that the shape and depth of a target affect its ID. A deeply buried coin may read lower than the same coin near the surface. A bent nail might read higher than a straight one. The ground mineralization can also shift the ID. Therefore, the target ID is a guide, not a guarantee.

Interpreting the Depth Indicator

Most detectors also display a depth estimate, often as a bar graph or a number in inches or centimeters. This is calculated based on the strength of the received signal. The depth reading is most accurate for coin-sized objects. For larger objects, the detector may underestimate depth, and for very small objects, it may overestimate. The depth indicator is useful for deciding whether to dig, but it is not a precise measurement. A common mistake is to assume the depth reading is exact; it is an estimate based on signal strength, which can be affected by ground conditions and target orientation.

Discrimination and Notching

The color display and target ID are essential for using discrimination and notching features. Discrimination allows you to ignore certain ranges of conductivity (e.g., iron) so that the detector does not beep on them. Notching is a more precise form of discrimination where you can select specific target ID numbers to accept or reject. For example, you might notch out pull tabs (ID 20-25) but accept nickels (ID 26-30). The color display makes it easy to see which ranges are active. When a target is rejected, the detector may still show the ID on the screen but will not produce an audio tone. When a target is accepted, you will hear a tone and see the ID.

Common Misconceptions

One common misconception is that a metal detector can tell you exactly what a target is (e.g., “this is a gold ring”). It cannot. It measures conductivity, which is an indirect indicator. A gold ring and a pull tab can have similar conductivity, so they may show the same ID. Similarly, a corroded copper coin may read as iron. Another misconception is that all iron is junk; some historical artifacts are iron, and some detectors allow you to “ferrous check” to hear the iron tone and decide if you want to dig it.

Another common question is why the same coin gives different IDs at different angles. The orientation of a coin in the ground affects the eddy currents and thus the phase shift. A coin on edge will typically read lower than a coin lying flat. This is normal and not a malfunction.

How to Choose a Detector Based on Display

When choosing a metal detector, consider the display features that matter for your type of hunting:

For coin and jewelry hunting: A display with a clear target ID number and a color scale (green for high-conductivity coins) is helpful.
For gold prospecting: Look for a detector with a high-frequency coil and a display that distinguishes between small gold and iron. Some gold-specific detectors have a “ferrous/non-ferrous” bar graph rather than a numeric scale.
For relic hunting: You may want a detector that allows you to see all targets, including iron, and has a ferrous/conductive audio tone option.

Entry-level detectors often have simple 0-99 ID numbers and a few color zones. Advanced detectors offer multi-frequency, target trace, and customizable color palettes. The display is not the only factor; audio tones are often more informative than the screen, as they convey subtle changes in the signal.

Frequently Asked Questions

Why does my metal detector show a different color for the same coin?

The color is based on the target ID number, which can vary with depth, angle, ground mineralization, and the coin’s condition. A coin that is deeply buried or on edge may produce a lower conductivity reading, shifting its color down the scale. This is normal behavior.

Can I trust the target ID to tell me if it’s gold?

No. Target ID indicates conductivity, not the specific metal. Gold alloys have a wide range of conductivity. A gold ring can ID anywhere from 20 to 40 on a 0-99 scale, overlapping with pull tabs and foil. You must dig all signals in a range to find gold.

What does “notch” mean on a metal detector?

Notching is a discrimination setting that lets you accept or reject specific target ID numbers. For example, you can notch out iron (ID 0-10) but accept everything else. The display will show which ranges are active, usually with a color or a line.

Why does my detector beep on iron even when I have iron discriminated?

Discrimination is not perfect. Large iron objects, like a big piece of steel, can overload the detector and cause it to beep. Also, iron that is heavily corroded can have a different conductivity signature and may not be fully rejected. Ground mineralization can also cause false signals.

What is the best color to see on a metal detector?

There is no “best” color; it depends on what you are hunting. For coin shooters, green or blue (high conductivity) is usually the target. For gold prospectors, yellow or orange (low conductivity) might be more interesting. The color is just a visual aid for the numeric ID.

Do all metal detectors have color displays?

No. Many entry-level and some professional detectors have monochrome LCD or LED displays. They still show target ID numbers and depth, but not in color. Color is a convenience, not a necessity for successful detecting.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.