Oven guide
Is Your Oven Running Hot?
How to check your oven’s real temperature with a thermometer, and what to do if it’s off.
Updated October 2026
Cakes that dome and crack, biscuits that burn at the edges, roasts that take far longer than the recipe says: these often mean the oven isn’t at the temperature on the dial. It’s common, and you can check it in under an hour with an inexpensive oven thermometer.
Signs your oven may be off
- Bakes regularly take noticeably longer or shorter than the recipe says.
- Cakes brown on top before the middle is cooked, or rise to a peak and crack.
- Food on one side of the tray is consistently darker.
- Results changed when you moved house or replaced the oven, using the same recipes.
How to check your oven temperature
- Put an oven thermometer in the centre of the middle shelf. Hang or stand it where you can read it through the door.
- Set the oven to 180°C (350°F) on the conventional setting, not fan, so the reading isn’t affected by moving air.
- Wait 20 minutes after the preheat signal. Many ovens signal “ready” before the whole cavity has settled.
- Take several readings over 20–30 minutes without opening the door. The temperature rises and falls as the thermostat cycles, so note the highs and lows.
- Work out the average and compare it with the setting. Repeat at 200–220°C (400–425°F) if you bake hot, since the error isn’t always the same at every temperature.
Example: set to 180°C, the thermometer swings between 185°C and 199°C, so the average is about 192°C. Your oven runs about 10–12°C hot at this setting.
What to do if it’s off
1. Adjust the dial yourself
The simplest fix: if your oven runs 10°C hot, set it 10°C lower than the recipe says. Write the offset on a sticky note inside a cupboard door. Use the converter to work out the dial setting in your oven’s units.
2. Use the oven’s calibration setting
Many digital ovens let you adjust the thermostat offset from the settings menu. Others have an adjustment behind the temperature knob. The method and range differ by make and model, so follow your oven’s manual. Search for “temperature calibration” or “offset”.
3. Get it repaired
A failing thermostat or temperature sensor, a worn door seal or an element that doesn’t heat fully can all cause big or erratic errors. If the temperature swings far more than usual or won’t reach the setting, have it looked at. Gas ovens should only be repaired by a qualified engineer (in the UK, Gas Safe registered).
Fan ovens and gas ovens
Fan ovens are usually more even, but the fan setting is meant to run hotter in effect, not on the dial. Test on the conventional setting first. Then, if you like, test on fan to see how fast it recovers after the door has been opened. Gas ovens are hotter at the top. Test on the middle shelf, which is what the gas mark refers to.
Common questions
How accurate should an oven be?
No oven holds one exact temperature. The thermostat switches the heat on and off, so the temperature rises and falls around the setting. What matters is the average. If it is consistently well above or below the dial, adjust for it.
Can I trust my oven’s built-in display?
The display shows what the oven’s own sensor reads, and that sensor sits in one spot. A separate thermometer on the middle shelf tells you what your food actually experiences.
My oven is hotter at the back. Is that normal?
Some unevenness is normal, especially in conventional and gas ovens. Turning trays halfway through baking evens things out.
When should I call an engineer?
Call one if the temperature swings wildly, the oven won’t reach temperature, or a gas oven shows any sign of a fault. In the UK, gas appliances must be worked on by a Gas Safe registered engineer.