How Deep Do Metal Detectors Go? The Honest Physics (2026)

How deep does a metal detector really go? For a coin-sized target, a quality VLF detector reaches roughly 20 to 35 centimetres in mild ground. A pulse-induction gold machine hears multi-gram nuggets well past half a metre. And for large buried objects — a metal box, a cache, a cluster of tools — one-metre frame coils and two-box configurations reach one to three metres and beyond. There is no single number, because depth is not a property of the detector alone: it is the product of target size, coil size, ground mineralisation and the technology inside the control box. This guide gives you the honest physics and realistic figures you can plan around, whether you work the goldfields of Sudan, Mali and Mauritania or search old village sites anywhere in Africa and the Middle East.

The four factors that actually decide depth

Every detection is an exchange of energy. The coil transmits an electromagnetic field, buried metal distorts that field, and the detector listens for the faint distortion coming back. Four things govern how far down this exchange works. First, target size: a bigger piece of metal disturbs more of the field and can be heard from further away. Second, coil size: a larger coil projects a broader, deeper field. Third, ground mineralisation: iron oxides and salts answer the coil themselves, burying quiet targets in noise. Fourth, technology: how the machine transmits, and how cleverly it separates ground signal from metal signal. Change any one of these and the same detector's depth can double — or halve. That is why the question on the box is never how deep does it go, but how deep does it go on what, and in which ground.

Realistic depth numbers you can trust

Coin-sized target, VLF detector: roughly 20–35 cm in mild ground. A useful rule of thumb: a coin is detectable at about the diameter of the coil.
Sub-gram gold nuggets, dedicated gold VLF or PI: from a few centimetres to roughly 20–30 cm, depending on nugget size and ground.
Multi-gram nuggets, pulse induction like the GPX 6000 or Garrett Axiom: commonly 30–60 cm as a field guide, deeper again for ounce-class pieces.
Drink-can-sized object, large PI coil: around one metre — Lorenz rates the Deepmax with its 45 cm coil at over 1 m on a can-sized target.
Large objects such as a metal chest or a cluster of tools, with 1 m frame coils or two-box setups: one to three metres, the deepest rated configurations approaching 4 m.
No hand-held detector on the market sees tens of metres. Any brochure promising 20, 30 or 50 m of depth is describing physics that does not exist.

Target size and orientation: the biggest lever

The single biggest variable is not the machine — it is what you are looking for. The returned signal collapses extremely fast with distance, which is why a detector that hears a buried chest at two metres can walk straight over a gold ring at forty centimetres. Orientation matters too: a coin lying flat presents its whole face to the coil and rings out clearly, while the same coin standing on edge presents only a sliver of metal and can lose a large share of its detectable depth. Time in the ground adds a small bonus: over decades, buried metal leaches ions into the surrounding soil and builds a halo that makes the target appear slightly larger to the detector than it really is — one reason old, undisturbed targets often sound better than freshly buried test pieces.

Ground mineralisation: the silent depth killer

In the lateritic, iron-rich soils that dominate the goldfields of Sudan, Mali, Burkina Faso and Niger, the ground itself answers the coil. Iron oxides, hot rocks and salty patches all produce signals, and the detector must subtract that ground response before it can hear metal at all. In quiet European-style loam a mid-range VLF may be impressively deep; drop the same machine onto Sahel laterite and its usable depth can fall by half, with constant false signals as a bonus. This is why ground balance is the most important control on any serious detector, and why pulse-induction and ZVT machines — which are far less disturbed by iron mineralisation — dominate African prospecting even though good VLF machines cost so much less. Depth figures measured in air, with no soil involved, are the most optimistic numbers a detector will ever produce.

Why a bigger coil is not always better

It is tempting to think the largest coil wins every time, but coil choice is a trade, not an upgrade. A big coil pushes its field deeper and covers more ground per sweep — on large, deep targets it is clearly the right tool. But the field it projects is less dense near the surface, so tiny nuggets and thin coins fade into the background; it also averages more ground per pass, so in mineralised soil it collects more ground noise; and it is heavier on the arm hour after hour. A small coil concentrates energy near the surface, hears the sub-gram gold a big coil misses, and pinpoints precisely between rocks. That is exactly why machines like the GPX 6000 ship with two coils: swing the small one on shallow, patchy gold, and mount the big one when the goal is deep targets under clean ground.

A depth figure without a target size next to it is marketing, not measurement.

The technology ladder: VLF, PI, ZVT and two-box

Ranked purely by achievable depth on suitable targets, the ladder runs VLF, then pulse induction, then ZVT, then two-box and frame systems. VLF machines transmit a continuous wave and read tiny phase shifts — superb sensitivity and target ID, but the same mechanism reads mineralised ground loudly, which caps depth. Pulse induction, as in the Minelab GPX 6000 and the Garrett Axiom, fires powerful pulses and listens in the silence between them, largely ignoring iron mineralisation — the Axiom's Ultra-Pulse engine still responds to gold as small as one or two grains. ZVT, exclusive to the Minelab GPZ series, drives the coil with a constant alternating field; Minelab rates it up to 40% deeper than previous GPX machines on gold. At the top, two-box and frame systems like the Lorenz Deepmax Z1 with its one-metre frames — or the classic Depth Multiplier attachment for the Garrett GTI 2500 — deliberately ignore anything smaller than about 7 cm, which is precisely how they reach metres of depth without ringing on every nail.

What about detectors that claim 10, 25 or 50 metres?

Physics is firm on this point. The field from a hand-held coil weakens so quickly with distance that no signal-processing trick can recover a small target tens of metres down; the energy simply is not there to be read. Devices marketed as long-range locators, molecular-frequency scanners or ionic field detectors have never passed a controlled test, and we have published a full, separate debunk of that industry on this blog. The honest routes to more depth are the ones in this article: a larger coil or frame, a technology suited to your ground, a bigger target, and patient, disciplined sweeping. Every genuine manufacturer — Minelab, Garrett, XP, Lorenz — publishes depth claims in centimetres and metres, not in fantasy tens of metres, and that restraint is itself a mark of legitimacy.

How deep can a metal detector find gold?

It depends almost entirely on the size of the gold. Sub-gram nuggets are surface-zone targets: expect a few centimetres to roughly 20–30 cm with a dedicated gold machine. Multi-gram nuggets are commonly heard at 30–60 cm by pulse-induction detectors in real mineralised ground. Ounce-class and larger pieces go deeper still, and this is where ZVT machines like the GPZ 7000 justify their reputation. A reef or accumulation big enough to behave like a large object crosses into metre territory — but single small nuggets at those depths are beyond any honest machine.

Can a metal detector find gold one metre underground?

A single small nugget at one metre — realistically, no. A gold object with real mass, or a concentrated cache of metal at one metre — yes: this is exactly the job of large pulse-induction coils, frame antennas and two-box configurations. The Lorenz Deepmax Z1 with a 45 cm coil is rated at over a metre on a can-sized object, and its frame coils reach considerably further on larger masses. If a seller promises you a device that hears a coin or a small nugget at one metre and beyond, you are looking at a claim the physics cannot support.

How can I increase my detector's depth?

Start with the free gains. Ground balance properly and rebalance whenever the soil changes — an unbalanced machine wastes its depth fighting the ground. Run a noise cancel away from power lines and phones. Sweep slowly, keep the coil low and level to the very end of each swing, and overlap your passes. Use fresh or fully charged batteries. Dig the faint, repeatable whispers — the deepest targets never sound like shallow ones. Then, if your targets justify it, fit the largest coil your ground allows, and only after all of that consider stepping up the technology ladder from VLF to PI or ZVT. A disciplined operator with a modest machine consistently out-digs a careless operator with a flagship.

Detectors built for real depth

The right question is never which detector is deepest — it is which detector is deepest on your targets, in your ground. Tell us what you are searching for and where, and we will match the machine to the physics honestly. Message us on WhatsApp for advice or a current quote — we answer in Arabic, English and French, and shipping is free across Africa and the Middle East.