For induction cooking, compare the working base with the hob’s requirements, not simply the diameter printed beside the pan’s name. A wide-rimmed frying pan or wok can have a much smaller underside. The pan may be induction compatible as a product yet be a poor match for the zone you planned to use.
Image: AI-generated editorial illustration of generic equipment; not a photograph of a reviewed product.
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Collect the two sets of measurements
Start with the hob manual. Find the permitted cookware sizes for each zone and any special instructions for a flexible or linked cooking area. Copy the stated measurements exactly, including whether they refer to a base or a pan diameter.
Then obtain the pan’s rim diameter, flat base diameter and any separately stated magnetic area. Bosch’s cookware guidance says the ferromagnetic base should correspond to the cooking zone. The relevant comparison is therefore at the underside, rather than between the upper rim and the decorative circle on the glass. Bosch induction cookware advice
If the listing gives only one diameter, ask which part it measures. Guessing the underside from a top-down product photograph can produce a misleading answer, particularly for deeply sloping sides.
Measure a cold pan carefully
Turn a clean, cold pan over on a protected surface. Measure across the flat portion through its centre, avoiding the curved transition into the sides. Note the result as a physical measurement, not a confirmed magnetic diameter if the construction is unclear.
An added disc, patterned plate or exposed ring may need interpretation from the manufacturer. A ruler can show geometry, but it cannot tell you how every visible section responds to the induction field. Keep a clear photograph with the measurement when asking for clarification.
| Measurement | What it describes | Why it matters |
|---|---|---|
| Rim diameter | Width across the top | Food space and lid choice |
| Flat underside | Area resting on the cooking surface | Physical contact and stability |
| Magnetic base area | Manufacturer-identified responsive area | Induction matching |
| Overall width | Body plus handles where applicable | Clearance from other cookware |
Work through a comparison on paper
Suppose a pan is sold as 28cm, while its documented working base is 20cm. The useful number for a zone check is 20cm. The 28cm figure still matters for cooking capacity and neighbouring-pan clearance, but it answers a separate question.
Now imagine two candidate pans with that same 28cm rim: one has a 20cm base, the other 23cm. They are not interchangeable merely because their lids might share a nominal size. Compare both documented bases with the actual limits in your hob manual; do not substitute a universal minimum from a shopping guide.
These figures are an illustrative measurement exercise, not specifications for a named product. The purpose is to make the comparison before spending money, not to predict a cooking result from diameter alone.
Consider the whole meal
Lay out your usual combination of cookware on a cold hob. A large pan may occupy a suitable zone while its sides or handles obstruct the neighbouring saucepan. A linked zone may also have particular placement instructions that differ from an ordinary circular zone.
Write down the combination you need most often, such as one frying pan and two saucepans. Prioritise that arrangement over a theoretical maximum vessel you rarely use. Check access to controls and clear lifting space as part of the plan.
If the pan is not recognised
Follow the appliance’s documented cookware check and troubleshooting sequence. Record the zone and any displayed code. Avoid treating an empty pan at maximum power as a diagnostic tool; Bosch expressly warns against heating empty cookware in its guidance.
Ask the pan maker about an unclear base and the hob maker about zone requirements. Give each the other model number. Once the dimensions and compatibility are confirmed, choose the pan that fits the relevant zone and the rest of your cooking routine. That is a more reliable selection method than buying the largest rim that fits inside the cupboard.