On an induction stovetop, only cookware with a magnetic base heats up; the stovetop generates heat not from an electric element directly, but from a magnetic field acting on the base of the pan. Cast iron and enamel-coated steel cookware work very well on induction for this reason, heating quickly and evenly across the base.
Pure aluminium, copper and some types of stainless steel aren't magnetic, so they never heat up on an induction stovetop at all; most units will flash a light or sound an alert when a pan like this is sitting on the surface.
How can you tell if a pot is induction-compatible?
The simplest test is holding an ordinary magnet against the base of the pot; if the magnet sticks, the pot works on induction, and if it doesn't, it won't. Some manufacturers stamp a coiled induction symbol on the base of the pot; if that symbol is there, compatibility is confirmed without needing the magnet test at all.
Compatibility among stainless steel pots depends on how they're made; only pots with a magnetic alloy layer built into the base heat up on induction, while pots made from a single thin layer of stainless steel usually don't.
When doing the magnet test, it helps to touch a few different spots on the base rather than just the centre; on some pots the magnetic layer only covers part of the base, and testing near the middle alone can give a misleadingly negative result.
Can aluminium and copper cookware never be used on induction?
Pure aluminium or copper cookware doesn't work on induction on its own, but versions with a magnetic steel layer added to the base can be used. In cookware like this, heat conduction still benefits from aluminium's or copper's fast heat spread, while the actual heating comes from the induction-compatible base.
Someone wanting to use an uncoated aluminium pan on induction can place an induction adapter plate underneath it; the plate converts the magnetic field into heat and warms the incompatible pan indirectly, though this method is less efficient than using a directly compatible pot.
Why does the base need to be flat for induction?
An induction stovetop only transfers its magnetic field to the base that's actually touching the glass surface; a base that's even slightly warped or bowed can't make full contact with the surface, so heating turns uneven and inefficient. Old, well-used cookware can develop a slight bow in the base over time, and this shows up more noticeably on induction than on other stovetop types.
If a pot's base is significantly smaller than the heating zone underneath it, the stovetop may not detect it at all; each induction zone usually has a minimum base diameter, which is listed in the appliance's manual.
How can existing cookware be adapted for induction?
Rather than replacing every single pot in the kitchen at once, swapping out the few pieces used most often — a large pot and a pan — for induction-compatible models, and using an adapter plate for the rest, is a cheaper middle-ground solution. An adapter plate also makes small-diameter cookware usable on a wide induction zone.
Switching to induction means paying attention not just to the base of a pot but also its handle; some older handle materials are more sensitive to the fast heat induction produces than they are on other stovetop types, and can heat up faster than expected.