Heat Retention & Preheat Calculator
Heat retention is the property everyone claims for iron and nobody quantifies. This does the arithmetic: how much energy your pan stores per degree, how long your burner needs to get it there, and how far the surface temperature falls the instant a cold load goes in. Run two pans through it and the case for mass stops being folklore and starts being a number.
Bare and dry, straight off the kitchen scale.
Share of rated power that lands in the iron: induction 85%, electric radiant 70%, gas 40%.
Rated input, not output. A single ring is usually 1,500–2,400 W.
Room temperature in most kitchens.
About 200 °C for a hard sear, nearer 160 °C for eggs.
Whatever goes into the pan once it is up to temperature.
Fridge cold is about 5 °C; tempered on the counter is nearer 18 °C.