Oven Temperature Offset Calculator

Use an oven thermometer (available from most kitchen shops for a few pounds). Place it in the centre of the oven, set the oven to a known temperature (e.g., 180°C), wait 20 minutes for it to fully heat, then read the thermometer. The difference between the set temperature and the actual reading is your offset.

Yes, it is very common. Most domestic ovens are off by 10-25°C, and the offset can increase with age. Even new ovens may not match their dial exactly. Regular calibration with an oven thermometer helps ensure consistent baking results.

Not always. Some ovens are more accurate at lower temperatures and less accurate at higher ones, or vice versa. Ideally, test at 2-3 different temperatures (e.g., 150°C, 180°C, 220°C) to see if the offset is consistent. This calculator assumes a constant offset.

Fan ovens are typically 20°C lower than conventional ovens for the same cooking effect, because the fan circulates hot air more efficiently. So if a recipe says 200°C conventional, use 180°C fan. This calculator uses a default 20°C offset which you can adjust in the advanced options.