Does Cast Iron Work on Induction?

1. Why Cast Iron Works on Induction, and Works Well

An induction hob does not get hot and pass heat upward. A copper coil under the glass carries a rapidly alternating current, which creates an alternating magnetic field just above the surface. Put something ferromagnetic in that field and two things happen inside the metal itself: eddy currents swirl through the base and meet electrical resistance, and the magnetic domains in the iron flip back and forth every cycle and lose a little energy each time. Both effects turn into heat, and they happen in the pan, not in the hob.

Cast iron is close to the ideal material for that process. It is iron with a few percent carbon, so it is strongly magnetic, and it has relatively high electrical resistance compared with aluminium or copper, which means the induced currents generate heat rather than flowing through freely. The field also concentrates in a thin layer near the bottom surface of a magnetic pan, so the energy lands exactly where the food is. Iron stays magnetic up to its Curie point of roughly 770°C, far beyond any cooking temperature, so there is no point at which a hot pan stops working.

The quick check is the same one we recommend for every pan in our induction cookware guide: hold a fridge magnet against the base. On bare or enameled cast iron it snaps on and holds hard, which is as strong a result as the test gives. If you are sorting through a whole cupboard of mixed pans, our companion guide on what pans work on induction goes material by material, but cast iron is never the one in doubt.

Coupling is only half of why cast iron suits induction. The other half is mass. Induction is fast and responsive, but at low settings many hobs regulate power by cycling the coil on and off, and a thin pan follows that cycling, so a simmer pulses rather than holds. A heavy cast iron base absorbs those pulses and releases heat steadily. The same mass means a steak dropped into a preheated skillet barely dents the surface temperature, which is the difference between a crust and a grey, steamed exterior.

That second number is the catch, and most of this article flows from it. Cast iron couples brilliantly but conducts heat poorly, roughly a quarter as well as aluminium. On gas, flame wraps the base and partly hides that weakness. On induction, heat is generated in a ring above the coil and has to travel sideways through a slow metal to reach the rim. Every real problem with cast iron on induction is either that heat pattern, or the fact that the pan is heavy, rough and sitting on glass.

2. Will Cast Iron Scratch an Induction Cooktop?

It can, and the cause is almost always movement rather than the pan itself. The top of an induction hob is glass-ceramic, which is hard and heat-tolerant but not scratch-proof. A cast iron skillet set down and lifted off will not mark it. The same skillet slid across the surface while you shake a pan of potatoes, or dragged from one zone to another, grinds whatever is between the two surfaces into the glass. Lodge and Le Creuset give the same instruction in their care guidance: lift, never slide.

The villain is usually grit. A grain of salt, a crumb of burnt seasoning or a speck of sand from a vegetable gets trapped under several pounds of iron and acts like sandpaper. New Lodge castings also have a slightly pebbled texture and occasionally a small burr on the base or the rim of the bottom, which a sweep with fine sandpaper or a quick pass with a file will knock down. Vintage skillets with machined, glassy-smooth bottoms are kinder to glass, which is one reason they have a following among induction owners.

Not every mark is a scratch. Grey or silvery streaks after cooking are often metal or carbon transferred from the pan base onto the glass, and a ceramic cooktop cleaner and a soft pad will remove them. Run a fingernail across the mark: if it catches, the glass is scratched and that is permanent; if it does not, it is surface residue and will clean off. Scratches are cosmetic in nearly every case, but a deep gouge or a chip at the edge of the glass is a different matter and is worth having looked at.

The paper towel and silicone mat trick, and its limits

Because the magnetic field passes straight through non-metallic material, you can put a sheet of paper towel or parchment between the pan and the glass and the hob will still heat the pan. It catches splatter and stops a sliding pan from grinding grit into the surface. Purpose-made silicone induction mats do the same job more durably and also stop a heavy pan from shifting. The idea is sound for gentle cooking; the limit is temperature.

The pan base gets as hot as the cooking surface, and paper scorches and can ignite at temperatures cast iron reaches easily when searing. Silicone mats are commonly rated to around 450°F to 480°F depending on the maker, and a preheated cast iron skillet for a steak can exceed that. A mat also lifts the pan slightly away from the glass, which can confuse the hob's temperature sensor under the zone and slightly weaken coupling. Use either trick for eggs, braises and simmering. For a hard sear, take it out, keep the glass clean and lift the pan.

3. Warped Bases, Rocking Pans and Pan-Size Detection

Induction cares about flatness far more than gas does. The field is strongest right at the glass and weakens quickly with distance, so a base that touches the hob only in the middle, or only around the rim, heats slowly and unevenly. Set the pan on the cold hob and press each side of the rim. If it rocks or spins on a centre point, the base is convex; if it sits on the rim with a gap in the middle, it is concave. A slight concavity is common in new skillets and is mostly harmless, because the base often relaxes flat as it heats.

A pronounced rock is a real problem. Beyond slow heating, a pan that spins on a centre point is easy to knock, and it slides about while you stir. Cast iron rarely warps in ordinary use because it is thick, but it can after a hard thermal shock, such as cold water poured into a very hot pan, or after being blasted on a high-power zone that is much smaller than its base. A warped bare cast iron pan cannot practically be flattened at home. A machine shop can resurface one, but for a standard skillet buying a new one is usually cheaper.

Vintage skillets add one wrinkle. Many older American pans have a raised heat ring on the underside, a lip near the outer edge from the era of wood and coal stoves. On induction, that ring holds the flat base slightly off the glass. The hob usually still detects the pan, but heating is weaker and slower, and the pan can sit at an angle if the ring is uneven. Smooth-bottomed vintage pans are fine; ringed ones are better kept for gas or the oven.

Pan detection is the other half of the story. An induction zone checks whether enough magnetic material is sitting over the coil, and if the base is too small or too far off-centre it flashes a no-pan symbol and refuses to heat. Your hob's manual lists a minimum base diameter for each zone, and a small cast iron pan on a large zone can fall short. The reverse problem is quieter: a 12-inch skillet has a base of roughly 10 inches, and on a 7-inch zone it heats only the middle while the outer band stays cool.

Match the pan to the biggest zone it fits, and keep it centred. If you regularly cook in large skillets or a long griddle, a hob with a bridge or flex zone that links two coils is worth prioritising when you buy, which is one of the practical differences we cover in induction vs gas cooktop.

4. Heat-Up, Hot Spots and Thermal Shock

Here is the mistake almost every new induction owner makes with cast iron: put an empty skillet on the largest zone, hit boost, and wait for it to smoke. Induction will happily do that, and very fast, but it heats a ring directly over the coil while the rest of the pan lags behind. Because cast iron conducts slowly, the centre can be scorching while the rim is still lukewarm. That temperature difference is exactly what stresses the metal, and it is the main way cast iron cracks or warps on induction.

Lodge's guidance is to start on low and work up to medium or medium-high, and Le Creuset advises heating gradually and says medium or low heat gives the best results, including for frying and searing. That is not timidity. A gradual preheat gives heat time to spread from the coil ring across the whole base, so when the food goes in the pan is evenly hot instead of hot in a donut shape. On gas the flame spreads heat for you; on induction, time does that job.

A practical routine for a 10 to 12-inch skillet is a few minutes on a low-to-medium setting, then a few more at the cooking setting, with a thin film of oil in the pan so you can watch it shimmer. Expect to spend longer preheating than you would with clad stainless, but far less than on a radiant electric hob. If you need even heat all the way to the rim, for a big batch of pancakes or cornbread, preheat the skillet in the oven first and then move it to the hob; the oven heats it evenly from every side.

Those times are starting points rather than measurements, because hob power, zone size and pan thickness all vary. The tell is the oil: a shimmer across the whole surface, not just in a ring, means the pan is ready. Infrared thermometers are cheap and settle the question if you want numbers, and checking the rim against the centre once is an eye-opener for anyone who has been preheating on boost.

The other half of thermal shock happens at the end of cooking. Running cold water into a hot skillet, or setting a hot pan straight onto a cold wet surface, creates a sharp temperature gradient that can crack cast iron or warp carbon steel. Let the pan cool for a few minutes before washing, and use hot water. It is the same rule on any hob, but induction makes a very hot pan easy to reach quickly, so it comes up more often. If you are still choosing between hob types, the heat-control differences are laid out in our induction vs gas comparison.

5. Enameled Cast Iron: Le Creuset, Staub and the Rest

Enameled cast iron works on induction for the same reason bare cast iron does: underneath the glassy coating is a thick iron body that couples strongly with the field. Le Creuset lists induction among the heat sources its cast iron can be used on, and Staub's cast iron is likewise sold as induction compatible. The enameled Dutch oven is the one piece our best induction cookware guide tells nearly everyone to spend real money on, because cast iron mass and a wide flat base make it close to ideal for braises, soups and bread on an induction hob.

The enamel changes two things. The base is usually smoother than raw cast iron, so it is kinder to the glass, although it is still heavy enough to grind grit and still needs lifting rather than sliding. And the enamel itself is the vulnerable part. It is a layer of glass fused to iron, and the two expand at different rates, so rapid heating of an empty pot can craze or chip the coating. Le Creuset's care guidance is explicit: do not heat the pan empty, and allow it to heat gradually.

In practice that means adding oil, butter or liquid before switching on, starting on low or medium, and treating the boost button as off-limits for enameled pieces. Once the pot is up to temperature, Le Creuset notes that almost all cooking can continue on lower settings, and on induction the mass of a Dutch oven holds a simmer extremely well on a low number. Many people turn the power down further than they expect once they switch from gas.

Size matters more with Dutch ovens than with skillets, because the base is wide and the walls are tall. A 5.5-quart round pot has a base that suits a large zone well; an oval pot on a round zone heats the middle and leaves the ends behind, which is fine for a braise that will spend most of its time in the oven anyway. Cheaper enameled brands also work on induction, since the iron is the same, but quality varies more in the enamel than in the casting, so chipping risk is where the money tends to show.

Cleaning is easier than with bare iron. Le Creuset rates its enameled cast iron as dishwasher safe, though hand washing keeps the exterior finish looking better for longer, and if you are weighing a machine for heavy cookware loads our best dishwasher picks note which racks handle big pots. Bare cast iron and carbon steel never go in a dishwasher; the detergent strips the seasoning and the pan comes out rusted.

6. Carbon Steel on Induction: Same Physics, Different Weak Spots

Carbon steel is cast iron's lighter cousin. It is mostly iron with a small amount of carbon, rolled into sheet rather than poured into a mould, so it is just as magnetic and couples just as well, but a 12-inch carbon steel skillet is usually noticeably lighter than its cast iron equivalent. It seasons the same way, it builds the same slick surface over time, and it reacts faster to power changes because there is less metal to heat and cool.

The weak spot is warping. Carbon steel pans are thin, often a few millimetres, and a thin disc heated hard in a ring and left cool at the rim can bow. A carbon steel pan that has domed slightly will spin on induction, which is worse than useless on a slippery glass top. de Buyer, one of the best-known carbon steel makers, advises heating its pans gradually, and the same advice applies to every brand. Medium heat, then step up, and never put a cold carbon steel pan on boost.

Woks are the special case. A traditional round-bottomed wok touches a flat induction top at a single point and most hobs will not detect it, or will heat only a tiny spot. A flat-bottomed carbon steel wok works properly, with the caveat that only the flat base is heated and the sloped sides rely on conduction. Dedicated induction wok burners with a curved coil exist, but on a normal flat hob the flat-bottomed wok is the realistic choice.

Which is better on induction is a matter of what you cook. Cast iron's mass makes it more forgiving of induction's ring-shaped heating and better for sustained searing; carbon steel's lightness makes it better for anything you toss or move. Neither replaces a fully clad stainless pan for sauces, where even heat up the walls matters, which is why the induction cookware roundup puts a clad skillet first and a Lodge cast iron skillet alongside it rather than instead of it. For the materials that do not work at all, see which pans work on induction.

7. Weight on the Glass, Seasoning and Daily Care

Weight worries people more than it should. A 12-inch Lodge skillet weighs about 8 pounds, and retailers list a 5.5-quart Le Creuset round Dutch oven at roughly 11 to 13 pounds depending on the listing and whether the lid is included. Add a few quarts of stew and you are well into the teens. Induction glass-ceramic is designed to carry loaded pots, and a full stockpot of water weighs more than any skillet, so resting weight is not the realistic risk.

Impact is. Dropping a cast iron pan onto the glass from a few inches, or catching the hob edge with the rim of a heavy pot, is how glass-ceramic tops crack, and the edges and corners are the most vulnerable points. Set heavy pans down with both hands where you can, use the helper handle on a large skillet, and never stack cookware on the hob for storage. Do not use the cold hob as a counter for a cast iron pan that has just come out of the oven either, because the zone sensors are not designed for that.

Seasoning behaves the same on induction as anywhere else, with one difference: the hot ring over the coil can scorch seasoning in a circle if you repeatedly preheat on high, leaving a visible ring of darker or flaking seasoning. Gradual preheating avoids it. If a neglected skillet has gone rusty, scrub the rust off with steel wool, wash, dry on a low zone, and re-season. Do not reach for a chemical rust converter; those products leave a coating meant for tools and steel, not food surfaces, which is the point our rust converter vs rust remover comparison makes about where each belongs.

Clean the glass after each cooking session once it has cooled, because cast iron leaves more residue than stainless: seasoning flakes, oil rings and the odd grey metal mark. A ceramic cooktop cleaner and a soft cloth handle most of it, and a razor scraper held at a low angle shifts anything baked on. Wipe the pan base before it goes back on the hob, since a crust of burnt oil on the bottom of a skillet is both a scratch risk and a smoke source.

The handle is the last thing induction changes. Because induction heats the pan quickly and the iron handle is part of the same casting, a skillet handle gets dangerously hot faster than many cooks expect from gas, where the handle often sits outside the flame. Keep a silicone handle cover or a folded towel by the hob, and expect that any cast iron or carbon steel handle is as hot as the pan within a few minutes of preheating.