Does the base of the pot or pan have to be exactly the same size as the hob?

The hob or cooking zone and the base of the pot/pan do not have to be exactly the same size, but should at least be of a similar size.

For example, if the base of a 28 cm pan (upper inner diameter) has an outer diameter of 22 cm (i.e. the surface that stands on the hob), a hotplate with a diameter of 20-22 cm would be ideal, but an 18 cm size will also do in a pinch.

Hotplate smaller than the base yes, larger no

So it's not so bad if the hob / cooking zone is slightly smaller than the base. But the difference in size should not be extreme. For base diameters up to around 25 cm, the difference should not be more than 1-2 cm on each side, i.e. 2-4 cm in diameter. For larger bottom diameters, the difference should not be more than 2-3 cm on each side, i.e. 3 to a maximum of 6 cm in diameter.

However, it should not be the other way around: The hob should not be significantly larger than the base of the cookware! A hotplate that is too large can cause heat damage to the outer coating of the cookware, excessive heating or even melting (plastic handles) or charring (wooden handles) of handles.

With gas stoves in particular, always make sure that the gas flame does not reach beyond the base.

The special case of induction

As induction hobs do not radiate heat but generate it directly in the base of the pot or pan, it is generally not a problem if the cooking zone is slightly larger than the base of the cookware. In the case of cooking zones consisting of several coils, the control electronics of the cooktop do not even switch on those coils above which there is no or insufficient magnetizable material.

Please note that the markings on the glass ceramic surface of induction cooktops do not necessarily represent the size of the induction coils underneath. Particularly with inexpensive cooktops, the coil underneath the glass ceramic may be significantly smaller than the circle marking at the top. You can recognize this when boiling water by the fact that steam bubbles rise mainly in the smaller area of the coil.

The sizes are not standardized

When looking at different hobs or when changing to a new hob, you may have noticed that the sizes of the cooking zones / hotplates differ slightly from hob to hob.

The base diameters of cookware are also not standardized and depend mainly on the shape of the cookware.

It is therefore not always easy to find the perfect hotplate / cooking zone for a pot or pan.

The consequences of different stovetop and pan base sizes

So, a good fit between the size of the hob / cooking zone and the base of the pot / pan has advantages, but is often impossible to achieve in everyday life. So what can you expect if the hob is a little smaller than the base of the cookware?

First of all, the base temperature of the pot or pan can of course never be as high outside the area of the hob as directly above the hob, even with the best heat conduction of the base. It can therefore be useful, especially when frying, to occasionally reposition the food in the pan, from the edge to the center and vice versa, so that everything browns more or less evenly. When cooking, the water distributes the heat introduced from the stove, so a difference in size does not have a negative effect in this respect.

A more important possible consequence of a hob that is too small can be the stability of the base of the cookware: If the heat is only applied to a smaller part of the base, i.e. if the base is at very different temperatures, the metal of the cookware will also expand to different degrees. In extreme cases, this can lead to permanent warping of the base. Pans are affected more often than pots because pots are usually used for cooking and the water ensures a certain temperature equalization.

Attention, cooktop rim!

If your glass ceramic hob has a stainless steel rim, please note that this determines the maximum base size of the cookware if it is to be placed in the middle of the cooking zone! So if in doubt, first measure the diameter of the cooking zone and then the smallest distance from the cooking zone to the rim. This distance times two plus the cooking zone diameter is your maximum possible base diameter. The base must not be positioned above any touch control panel. (Please follow the hob manufacturer's instructions).

Recommendation

If the base diameter of your cookware is larger than the hob, we recommend that you handle the cookware with even more care:

Make sure that the cookware is always positioned as exactly centered as possible on the cooktop.
Do not switch to full heat, especially with pans, even when heating up, but heat the cookware slightly first and then gradually increase the heat so that the heat can be better distributed in the base.
Do not overheat the cookware during further operation. Never exceed 60-70% of the hob's maximum power when frying. Only use the hob at full power when boiling large quantities of water; this also applies particularly to induction; never use the power/booster function when frying, otherwise there is a risk of damage to the base and/or coating!