Cast Iron on Glass, Induction, Electric and Gas: Heat Source Compatibility Table
Yes, with three conditions: lift the pan rather than sliding it, keep the setting at or below medium-high, and check the base is flat within about 0.5 mm across its diameter. On glass-ceramic the failure mode is a damaged cooktop rather than a damaged pan, and gate-marked or heat-ringed vintage pans are the ones that scratch, because only a raised ring or scar touches the glass.
By the Cast Iron FAQ Editorial Team
You can, and millions of people do it daily without incident. The three rules that make it safe are boring and non-negotiable: lift the pan on and off instead of sliding it, stay at or below about medium-high, and make sure the base is flat and free of raised features before it ever touches the glass.
The reason this question generates so much anxiety is that the failure mode is asymmetric. On gas, a bad pairing gives you an unevenly cooked dinner. On glass-ceramic, a bad pairing gives you a scratched or cracked cooktop, which is a repair bill rather than a lesson. The pan is essentially never the casualty.
Base geometry is what decides it, and that varies enormously by era — which is where most of the bad advice comes from, because "cast iron on glass" is not one question when the pans span 150 years of casting practice.
The compatibility matrix
Eight heat sources against a 10-inch-class skillet of about 5.5 lb. Preheat times assume a pan at room temperature reaching a 400°F surface reading. Weight limits are what cooktop manufacturers typically publish; check your own manual, because a few say nothing at all and a few are stricter than the range given.
Heat source Usable? Max recommended setting Preheat to 400°F Base-flatness tolerance Weight guidance Warp risk Scratch / crack risk Required precaution Gas burner Yes, unrestricted High is fine, but medium reaches temperature almost as fast 7-9 min Irrelevant — grates carry the load No practical limit Low; rises if a small burner heats a large pan hard None to the hob Rotate the pan 90° twice during preheat if the burner is much smaller than the base Electric coil Yes Medium-high, 7 of 10 8-11 min Rocking is tolerated; contact is through the coil ring No practical limit Low None to the hob; the coil can mark a soft base finish Match coil diameter to pan floor within about 2 in Glass-ceramic radiant Yes, with care Medium-high, 6-7 of 10 9-12 min Under about 0.5 mm gap across the base, no rock Most manuals publish a ceiling between 25 and 50 lb for the cooktop Low High if slid, high with a raised gate scar or heat ring Lift on, lift off. Wipe grit off the glass and the base before every use Induction Yes — cast iron is the ideal load Medium-high; avoid boost or power settings on an empty pan 4-6 min Under about 1 mm; the field tolerates a gap, the temperature sensor does not Same published ceiling as radiant glass Moderate — the fastest heating of the eight and the least forgiving of an empty pan Same glass surface, same rules Never preheat empty on boost; add a film of oil or food before the pan gets going Oven Yes, unrestricted Up to about 650°F before seasoning degrades; enamel is capped near 500°F 15-20 min at 450°F to equalise Irrelevant Check the rack rating for anything over about 15 lb loaded Very low — the most even heating available None Use both hands and a dry glove; a wet glove steams instantly Broiler / grill element Yes for bare iron Full, at 4-6 in from the element 5-8 min Irrelevant Rack rating applies Low for cast iron; real for thin carbon steel None Enamelled pans do not go under a broiler — knob rating and crazing Charcoal or gas grill grate Yes Direct heat is fine; the pan will exceed hob temperatures 8-12 min Irrelevant Check the grate, not the pan Moderate if one side sits over coals and the other does not None Spread the fire so the whole base is over heat; rotate every few minutes Open campfire and coals Yes — bare iron only No limit that matters; the pan will go past 700°F and lose seasoning 10-15 min Irrelevant None Highest of the eight — point contact with logs is the classic warp cause None Cook over coals rather than flame, and never quench a hot pan in a stream Find your hob, note the max setting and the precaution column, and treat those two cells as rules rather than suggestions. Everything else in the row is context. The setting column surprises people. Running a glass-ceramic hob on maximum under a heat-retaining pan is not the fast route to a hot pan — the element cycles on a thermostat, and a 5.5 lb slab of iron holding heat against the glass makes that cycling worse rather than better. Medium-high for nine minutes beats maximum for six, and it is easier on the hob.
Induction is the odd row out in the other direction. It is genuinely the best hob for cast iron, because it puts energy into the iron itself rather than heating the surface underneath it. It also gets a pan to 400°F in a third of the time gas takes, which is exactly why the empty-preheat warning is there.
Why glass-ceramic is the one that breaks
Glass-ceramic is strong in compression and unforgiving of point loads and scratches. A scratch is a stress concentrator, and a cooktop that has been scratched across the heat zone is materially weaker there than it was, particularly under thermal cycling. That is the actual mechanism behind most cracked cooktops — not one dramatic impact, but a scratch plus months of heating and cooling.
Cast iron interacts badly with that in two specific ways. Sand-cast bases carry a texture measurably harder than the glass, so any sliding movement grinds. And a trapped grain of salt or sugar between the base and the glass turns the whole weight of the pan into a cutting tool the moment it moves an inch.
Weight alone is rarely the problem. A stationary 8 lb pan sitting flat on a clean glass surface distributes its load across the whole base and is comfortably inside what the material handles. The same pan set down hard, or slid six inches to reach the front burner, is a different event entirely.
Manufacturers publish weight ceilings, usually somewhere between 25 and 50 lb, and those figures are about the cooktop overall rather than any single pan. A No. 14 skillet at 13 lb loaded with a roast is nowhere near it. Standing on the cooktop to reach a cupboard, which people genuinely do, is.
Base flatness: the test
Two tools, thirty seconds, and it settles the question for any pan you own. Lay a steel rule or any known-straight edge across the base, hold the pan up to a window, and look for light under the rule. Repeat at 90 degrees and across both diagonals.
No visible light anywhere means the base is flat enough for anything. A sliver of light at the centre means the base is slightly concave, which is the more common of the two warps and the more benign — the pan rests on its rim and heats slightly more slowly in the middle. A sliver at the edges means convex, the pan will rock, and on glass that rock concentrates the entire mass onto a moving contact patch. That is the one to worry about.
For a number: a feeler gauge under the rule tells you the gap. Under 0.5 mm across a 10-inch base is fine on glass. Between 0.5 and 1 mm is usable on gas and coil, marginal on glass, and will heat unevenly everywhere. Over 1 mm and the pan rocks visibly, which you will have already noticed.
There is a second test that takes no tools. Set the pan on the cooktop and press down on the rim at four points around the clock. Any movement, any click, any rock — that pan does not go on glass until the base is addressed.
Pan class on glass and induction
This is where era matters more than anything else on the page. The base of a pre-1890 pan and the base of a Lodge made last year are different objects with different contact geometry, and generic advice about "cast iron on glass" ignores that entirely.
Pan class Base feature Contact with the glass Glass-ceramic verdict Induction verdict Fix Pre-1890 gate-marked Raised gate scar across the base from the sprue A single raised line takes the entire load Do not use. This is the classic cooktop scratcher Poor — heats unevenly and the scar still contacts the glass Grind the scar flush, or keep the pan for gas and oven only Heat-ring vintage (raised outer ring) Raised ring around the base perimeter, sized for a stove eye Ring only; the centre of the base floats above the glass Usable but poor — ring contact concentrates load and conducts badly Works, because the field does not need contact, but the hob's temperature sensor reads low Use it on gas. If you must use glass, treat the setting as one notch lower than the dial says Flat-bottom machined vintage Fully flat, machined base Full-face contact, smooth Excellent — better contact than most modern pans Excellent None needed; check for warp and get on with it Modern sand-cast domestic (Lodge and equivalents) Flat, as-cast, textured Full-face contact with a coarse texture harder than the glass Fine if lifted, damaging if slid Excellent Lift, never slide. Wipe both surfaces before setting the pan down Modern machined (Field, Stargazer, Smithey) Flat, machined base Full-face contact, smooth Excellent — the safest bare pans for glass Excellent None Enamelled with an unglazed base ring Bare iron ring, glazed elsewhere Ring contact of bare, slightly rough iron Usable; the unglazed ring is the abrasive part Good Lift only, and check the ring for casting flash Enamelled, fully glazed base Smooth glass on glass Full-face, glass to glass Excellent — the gentlest option on the whole list Good, though some fully glazed bases have marginal induction response None Warped convex base Base bows downward, pan rocks A single moving contact patch under full pan weight Do not use. This is how cooktops crack Poor — hot spot at the contact point Machine the base flat, or retire the pan to gas and oven Warped concave base Base bows upward, rests on the rim Rim contact, centre floating Usable, heats slowly and unevenly in the middle Fair — a visible cool spot at the centre Accept it, or have the base ground flat Identify your pan's class before deciding, not after. Two rows here are hard no's on glass, and both are pans people commonly inherit and assume are fine. The heat-ring row is the one that catches people out, because the pan looks perfectly flat sitting on a worktop. It is resting on a ring 8 or 9 inches across with a millimetre of air under the middle, and on a radiant hob that means the centre of the pan is heated by trapped air rather than by contact. Anyone convinced their vintage skillet has a permanent cold spot on a glass hob has probably found this rather than a defect.
Induction behaves differently from everything else
Induction does not heat the cooktop and then heat the pan. It generates an alternating magnetic field that induces eddy currents inside the ferrous base, so the iron itself becomes the heating element. Cast iron is close to a perfect load for that — high permeability, high resistivity, plenty of mass.
Three consequences follow. Heating is dramatically faster: 4 to 6 minutes to a 400°F surface against 9 to 12 on radiant glass. A small gap between the base and the glass does not stop it working, because the field does not need contact. And the pan gets hot from the inside of the metal outward, which is why an empty pan on a boost setting can reach a genuinely alarming temperature in under two minutes.
That last point is the real induction warning and it has nothing to do with the glass. An empty cast iron pan on full induction power will blow past 700°F, burn the seasoning off in patches and, on a thin vintage pan, introduce enough thermal stress to matter. Put oil or food in before you turn it up.
One genuine limitation: the cooktop's temperature sensor lives under the glass and reads the glass, not the pan. With a heat-ringed or warped pan the sensor reads low, so any automatic temperature-hold function will overshoot. On those pans, ignore the auto modes and drive the hob manually.
The precautions that actually matter
Ranked by how much damage they prevent, rather than by how often they get repeated.
- Lift, never slide. This single habit prevents the overwhelming majority of cooktop scratches. Two hands on a pan over 6 lb, and put it down where you want it rather than adjusting.
- Wipe both surfaces first. A grain of salt under the base is the actual cutting tool in most scratch cases, not the iron.
- Cap the dial at medium-high on glass. It gets you there nearly as fast, and it stops the hob's thermal cut-out cycling against a heat-retaining pan.
- Never set a hot pan on a wet surface, and never run cold water into a hot pan. Thermal shock cracks pans and can craze enamel; it is the leading cause of genuinely dead cast iron.
- Check for rock before every first use of a pan on a new hob, and after any drop.
- Leave the pan on the hob to cool rather than moving it hot. A cooling pan is doing nothing to the glass; a hot pan being carried across a kitchen is a hazard to you.
- Do not preheat empty on induction boost. Thirty seconds is fine; two minutes is not.
- Keep enamelled pans away from the broiler and away from coals, whatever the pan is capable of on a hob.
Already scratched?
Cosmetic scratches in the surface of a glass-ceramic cooktop — the fine grey marks that look like metal transfer — are usually exactly that: metal smeared onto the glass rather than glass removed. A cooktop cleaning cream with a mild abrasive and a razor scraper held flat will take most of them off, and the glass underneath is intact.
Genuine scratches, the kind you can catch a fingernail in, are permanent. They do not immediately mean a failed cooktop, but they are stress concentrators, so it is worth changing habits around that zone and keeping heavy pans on a different ring where the layout allows.
A crack is the end. Any crack through the glass means the cooktop is unsafe to use — the element is live under a compromised surface and spills can reach the wiring. That is a replacement job, not a repair.
If a pan caused it, work out which pan and check its base against the class table above. In almost every case the answer is a gate scar, a heat ring or a convex warp, and the pan has a long future on a gas hob or in an oven where none of it matters.