Metal Detector Target IDs: Model Scales, Gold & Calibration

A metal detector's target ID estimates a target's response; it does not tell you with certainty what is buried. Gold, aluminum and other targets can produce overlapping numbers. Start with your exact detector model, then build a small reference from known objects and your own recovered finds.

What a target ID actually means

Target IDs are numbers derived from the detector's interpretation of a target's electrical response. Manufacturers use them to suggest conductivity or ferrous/non-ferrous character. “VDI” is another term used for this kind of display. A high number is not a measure of value, and it is not a laboratory test of metal composition.

Target-ID scales by detector model

This is a reference to manufacturer scales, not a universal coin chart or a set of LuckyFind field measurements. Follow the source for the exact model and software version.

On a small screen, scroll the table sideways to read every column.

What about nickels, silver coins and pull tabs?

The ACE 300 manual includes a visual sample chart on printed page 8. It illustrates overlapping categories, including jewelry and common rubbish, and warns that size, thickness and mineralized soil can alter readings. Use that chart as a starting point for an ACE 300, not an exact-number promise for every coin or another machine.

For a coin you want to recognize, identify its denomination, year and composition first. Label that exact sample on your worksheet. “Penny” or “ring” alone is too vague for a useful comparison. Leave a blank when you do not have a verified sample rather than copying a number from an unrelated chart.

Why the same target can read differently

The LEGEND manual lists depth, orientation, corrosion, soil mineralization and sweep direction among the factors behind changing IDs. It also notes that a small or weak target can be detected without a displayed ID. Changing conditions can therefore change the display without changing the object.

When recording an observation, include the detector, coil, mode, settings and test conditions. That context makes a later comparison meaningful. A number copied without those details is difficult to evaluate.

A steady signal is still an estimate

A repeatable response is useful for comparing passes, but it does not prove that a target is a valuable coin. A jumpy response is not proof that it is rubbish. Where recovery is authorized, compare the observed response with the actual recovered object and record both. That is how you learn which guesses were wrong.

Do not turn a signal-quality judgment into permission to dig. Local access, recovery and artifact-protection rules still apply; see where you can metal detect.

Tones, target IDs and discrimination

Audio and the number display need to be read together with your current settings. On the ACE 300, for example, the target cursor can display a response while the selected discrimination pattern suppresses its audio. Record the pattern you used rather than assuming silence means there is no metal. Check the model's manual before changing a notch or tone setting.

Do not convert numbers between models

“42” is not a standardized metal label. Even models from the same manufacturer can have different scales. Check the exact product name, not just the brand, and note the software version where relevant. These examples were chosen because their official documentation establishes the scales clearly; they are not a ranking of detector quality.

Build a personal calibration sheet

Download the printable target-ID calibration sheet (PDF). It has space for your setup, known sample, test conditions, readings from two directions and the recovered object. Blank rows are deliberate: this is your record, not invented test data.

1. Name the setup. Record model, software if known, coil, search mode, discrimination and ground-balance setting.
2. Use known samples. Choose a few identified coins and common rubbish objects. Start where testing and any recovery are permitted; keep track of every sample.
3. Record observations. Note the test type, distance or depth, orientation, soil/sand condition and displayed range. Mark an air test as an air test; do not treat it as a buried-target guarantee.
4. Repeat consistently. Compare passes from two directions with a level coil and consistent height. Change one condition at a time and note it.
5. Add actual recoveries. Record what the target turned out to be, including mistakes and empty recoveries. Keep those observations separate from predictions.

Log your finds, see your patterns

Get LuckyFind for iPhone or Android to record your hunts and finds. Review the app guidance before your next trip.