Hold a kitchen magnet against the bottom of the pan. If it grips firmly, the pan will work on an induction hob. If it barely holds or slides off, it will not. That test is not a rough approximation — it is a direct measurement of the property induction depends on.
What follows is why, and the handful of cases where a pan passes the magnet test and still performs badly.
Why induction needs a magnetic base
An induction hob is an electromagnet. A coil beneath the glass carries a rapidly alternating current, which produces a rapidly changing magnetic field. Place a ferromagnetic material in that field and two things happen: circulating eddy currents are induced in the metal, and the material’s magnetic domains are repeatedly flipped. Both dissipate energy as heat, directly in the pan.
The hob surface itself stays relatively cool. The pan is the heating element, which is why induction is fast and why the hob responds instantly when you change the setting.
A non-ferromagnetic pan does not couple with the field in any useful way. Little energy is transferred, the hob’s detection circuit sees no load, and most hobs simply refuse to start and show an error. It is not inefficiency — it is a missing mechanism.
Which materials work, and which do not
| Material | Induction? | Why |
|---|---|---|
| Cast iron | Yes | Strongly ferromagnetic. The ideal induction material. |
| Carbon steel | Yes | Ferromagnetic. Works excellently. |
| Enameled cast iron | Yes | The enamel is only a surface coating; the iron underneath couples normally. |
| Ferritic stainless (18/0, 430) | Yes | Ferritic structure is magnetic. |
| Austenitic stainless (18/10, 18/8, 304) | No, by itself | Austenitic structure is essentially non-magnetic. |
| Aluminum | No | Not ferromagnetic. |
| Copper | No | Not ferromagnetic. |
| Glass, ceramic, stoneware | No | Not metal. |
The 18/10 problem, and how manufacturers solve it
This is the detail that confuses people, because \”stainless steel\” is treated as one thing when it is not.
The numbers in 18/10 and 18/8 are the chromium and nickel percentages. Nickel at that level stabilizes an austenitic crystal structure, which is corrosion-resistant, tough, attractive — and essentially non-magnetic. Those grades are chosen for cooking surfaces precisely because they are inert and durable, and their non-magnetic character is a side effect of that choice.
18/0 stainless has effectively no nickel and a ferritic structure, which is magnetic. It is less corrosion-resistant than 18/10, which is why it tends to appear on the outside of a pan rather than the inside.
So a clad pan is usually built with the grades doing different jobs: 18/10 austenitic inside for the food-contact surface, an aluminum or copper core for heat conduction, and a ferritic magnetic layer on the base exterior so an induction hob can couple with it. Three layers, three purposes.
This is also why a pan can be excellent on gas and useless on induction despite being made of \”stainless steel\”. The question is never what the pan is made of in general — it is what the bottom exterior layer is made of.
When a pan passes the magnet test and still disappoints
Five cases, in rough order of how often they catch people out.
A weak magnetic grip. If the magnet holds only lightly, the ferritic layer may be thin or sparse. The pan will probably work, but it will couple less efficiently and heat more slowly than a cast iron pan on the same setting. A firm, unmistakable grip is what you want.
A base smaller than the hob’s minimum. Induction hobs detect a pan by its load, and most specify a minimum base diameter per zone. A small milk pan or a narrow saucepan may be ignored entirely by a large zone. Check your hob’s manual for the minimum; it is usually printed per zone.
A base that is not flat. Induction coupling falls off quickly with distance, so a warped or domed base heats unevenly and inefficiently. Lay a straight edge across the bottom. This is the usual reason an older pan that once worked well on induction now performs badly.
A magnetic ring smaller than the pan. Some pans have a magnetic disc covering only part of the base. Heat is generated in the disc and then has to spread outward through whatever is above it, so a small disc under a wide pan gives you a hot center and cool edges. Test the magnet at the edge of the base as well as the center.
A wok with a round bottom. Only the small area in contact with the glass couples, so a round-bottomed wok performs poorly. Flat-bottomed woks exist for induction, and dedicated induction wok hobs with a concave zone exist too.
About induction adapter discs
An adapter disc is a ferromagnetic plate that sits between the hob and a non-magnetic pan. The hob heats the disc, and the disc heats the pan by conduction.
It works, in the sense that the food gets hot. But it discards the reasons you would choose induction in the first place: the response is now slow, because you are heating a plate and then heating the pan through it; efficiency falls; the glass gets hot under the disc; and heat distribution depends on contact between two flat surfaces that are rarely perfectly flat.
Reasonable as a stopgap for one much-loved pan. Not a reason to buy non-induction cookware for an induction kitchen.
Reading the labels
\”Induction ready\”, \”induction compatible\”, \”suitable for all hob types\” — these are generally reliable, and the magnet test confirms them in two seconds.
A coil symbol — four or five horizontal loops, sometimes with the word \”induction\” — is the conventional marking, usually stamped on the base.
\”18/10 stainless steel\” with no induction claim — treat as not compatible until the magnet says otherwise. That phrase describes the cooking surface, not the base.
\”Works on all cooktops\” on old stock or a vague listing — check. The claim predates induction on some product lines.
Buying for an induction kitchen
- Carry a magnet when buying in person. A fridge magnet in a pocket settles every question on the shop floor.
- Buying online, look for the coil symbol or an explicit induction statement, and test it when it arrives.
- Check your hob’s minimum base diameter before buying small pans.
- Prefer a magnetic layer across the full base, not a central disc.
- Consider cast iron and carbon steel — they couple strongly and need no special construction, and they are the materials induction suits best.
- Avoid thin, cheap clad pans. Fast, intense, localized heating is hard on a thin base, and warping is what ends an induction pan’s life.
One useful consequence of how induction works: because the heat is generated in the base rather than applied from below by a flame, induction is more forgiving of a pan with mediocre lateral conductivity than gas is. The base heats more uniformly to begin with. It is less forgiving of flatness, which is the trade you are making.
Related guides
- Cookware materials explained
- Stainless steel: what tri-ply and 18/10 really tell you
- Cast iron vs carbon steel
- Which pans you actually need
The physics of induction heating, the magnetic behavior of austenitic and ferritic stainless grades, and the composition of 18/10, 18/8 and 18/0 stainless are established metallurgy. Minimum base diameters and hob behavior vary by appliance — take those figures from your own hob’s manual.