Oven temperature converter
British recipes give a gas mark, American ones Fahrenheit, and your fan oven needs a lower temperature than the one written down. The conversion puts them side by side.
The fan rule: drop 20°C from the conventional temperature and check the dish ten minutes early. Home ovens routinely run 15–20°C off their display — a cheap oven thermometer settles the question for good.
Frequently asked questions
Why drop 20 degrees for a fan oven?
The fan moves hot air and transfers heat more efficiently, so the same displayed temperature cooks harder.
What is gas mark 4?
About 180°C, or 350°F. Each extra mark adds roughly 14°C.
Does shelf position matter?
Yes. In a conventional oven the top is 15–25°C hotter than the bottom. In a fan oven the difference is much smaller.