Cooking Time Converter
Adjust cooking time and temperature when switching between conventional oven, fan/convection oven, and air fryer.
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How to use this calculator
Fan and convection ovens circulate hot air, cooking food faster at lower temperatures. Air fryers are essentially compact convection ovens with even more aggressive air circulation, reducing both temperature and time further.
- 1
Enter the temperature and cooking time from your original recipe.
- 2
Select the oven type the recipe was written for.
- 3
Select the oven type you are using.
- 4
Read the adjusted temperature and time for perfect results.
Frequently asked questions
What rules does the converter apply?
Moving to a fan or convection oven subtracts 20°C and multiplies the time by 0.90. Moving to an air fryer subtracts 20°C and multiplies the time by 0.775, the midpoint of 0.75 and 0.80. Moving away from them reverses the steps: it adds 20°C and divides the time by 0.90 or 0.775.
How does conversion between two non-conventional types work?
It first converts back to a conventional-oven baseline and then forward again. Fan to air fryer therefore keeps the temperature unchanged, since 20°C is added and then subtracted, and only the time moves: 45 minutes at 170°C in a fan oven becomes 39 minutes at 170°C in an air fryer.
Does it work in Fahrenheit?
The input is in °C, and anything you type is read as Celsius. The result shows both °C and °F, with °F calculated as °C × 9 ÷ 5 + 32 and rounded. If your recipe uses °F, subtract 32 and multiply by 5 ÷ 9 before entering it.
How are temperatures and times rounded?
Both are rounded to whole numbers. This is gentle for 40-minute roasts but coarse for short cooks: 12 minutes at 180°C in a conventional oven becomes 9 minutes at 160°C in an air fryer, where the unrounded figure is 9.3.
What happens with zero or very low values?
A temperature of 0 is replaced by 180°C and a time of 0 by 30 minutes, and a cleared box counts as 0, so it gets the same replacement. There is no lower limit after adjustment, so entering 15°C for an air-fryer conversion shows -5°C. Such results mean the starting values are not real oven temperatures.
Is the fixed 20°C and 90 percent rule exact?
It is a rule of thumb, not a physical constant. Ovens, air fryers and their fans vary, as do food size, how full the basket or tray is, and preheating. Use the converted figures as a starting point, then check doneness by the cues in the original recipe.
What does it do when both oven types are the same?
It returns your temperature and time rounded, with a note that no adjustment is needed. Choose different types in the two dropdowns to see a conversion.
Converting oven temperature and time between conventional, fan and air fryer
Two adjustments with a conventional oven as the reference
The tool treats a conventional oven as the baseline. A fan or convection oven is assumed to cook the same food at 20°C lower in 90 percent of the time. An air fryer also takes 20°C off, but multiplies the time by 0.775, the midpoint of the 0.75 to 0.80 range written into the code. Everything else, including the direction of travel, is derived from those two rules. The temperature is assumed to be in degrees Celsius.
Conversions returned by the tool
The rows below are outputs from the converter. Times and temperatures are rounded to the nearest whole number, and the Fahrenheit value is derived from the rounded Celsius temperature.
| From | To | Original | Result |
|---|---|---|---|
| Conventional | Air fryer | 180°C, 30 min | 160°C / 320°F, 23 min |
| Conventional | Fan / convection | 200°C, 40 min | 180°C / 356°F, 36 min |
| Air fryer | Conventional | 160°C, 25 min | 180°C / 356°F, 32 min |
| Fan / convection | Air fryer | 170°C, 45 min | 170°C / 338°F, 39 min |
| Conventional | Air fryer | 180°C, 12 min | 160°C / 320°F, 9 min |
A 30-minute tray bake in the air fryer
A recipe that says 180°C for 30 minutes in a conventional oven becomes 160°C for 23 minutes in an air fryer. The raw calculation is 30 × 0.775 = 23.25, which the tool rounds down. The result is the point to start checking, not a promise that the food will be done then. Smaller, drier or thinner pieces tend to finish first, so it makes sense to look a few minutes early and again near the end.
Going the other way and short cooks
Reversing the conversion lengthens the time: 25 minutes at 160°C in an air fryer maps to 180°C and 32 minutes in a conventional oven, since 25 ÷ 0.775 is about 32.3. Short cook times are where whole-number rounding matters most. A 12-minute recipe converts to 9 minutes in an air fryer although the unrounded number is 9.3, and a difference of a fraction of a minute may be visible in small foods.
What the rule of thumb does not know
The tool knows nothing about food size, quantity, moisture, oven calibration, tin material or whether the basket is crowded. Preheating practice differs from one appliance to the next, so follow your manual on that. If the recipe offers a visual or texture cue for doneness, trust that over the converted minutes. When the converted temperature looks odd, such as a negative number, recheck that you typed degrees Celsius.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →