TL;DR
- The rule: drop the temperature by 20C (or 25F) and cut the time by about 20%.
- Then check early. At 70% of the new time, look. Air fryers run faster than the maths predicts.
- Halve the oil. Recipes written for an oven assume a tray. A basket needs a fraction of that.
- Cook in one layer. A recipe that fills an oven tray will need two rounds in a basket.
- Some things do not convert. Anything wet, loose batter or a full roast belongs in the oven.
Table of Contents
An air fryer is a small convection oven with a strong fan. Moving air strips heat into food far quicker than still air does, so oven settings overcook the outside long before the middle is ready. The fix is a simple adjustment you can do in your head.
The conversion
| Step | What to do | Why |
|---|---|---|
| 1. Temperature | Subtract 20C or 25F | The fan makes a given temperature hit harder than in a still oven |
| 2. Time | Subtract about 20% | Less air to heat, and it moves faster |
| 3. Oil | Halve it, or less | A basket needs a light coat, not a greased tray |
| 4. Quantity | Single layer only | Stacked food steams instead of browning |
| 5. Check | Look at 70% of the new time | The maths gets you close, not exact |
Worked examples
| Oven recipe says | Air fryer setting | New time |
|---|---|---|
| 200C / 400F for 25 min | 180C / 360F | 20 min |
| 180C / 360F for 30 min | 160C / 320F | 24 min |
| 220C / 425F for 20 min | 200C / 400F | 16 min |
| 160C / 320F for 40 min | 140C / 285F | 32 min |
| 200C / 400F for 45 min | 180C / 360F | 36 min |
If the recipe already says fan or convection, the temperature has been adjusted once already. Do not subtract again. Keep the stated temperature and just cut the time by 20%.
What converts well
Anything you would roast, and anything you want crisp. Chips, wedges, chicken pieces, sausages, firm vegetables, halloumi and most frozen food all move across without complaint, and usually come out better than the oven version because the fan is stronger.
Small bakes work too if you drop the heat further. Cakes and brownies want 160C or lower, since a strong fan will set the crust while the centre is still raw. Our banana bread recipe is a good example of the slower approach.
What does not convert
| Dish | Why it fails | Do this instead |
|---|---|---|
| Loose batter | The fan blows it off the food before it sets | Use a dry breadcrumb coating |
| Anything in liquid | Casseroles and stews need still, wet heat | Keep it in the oven |
| Large roasting joints | The outside burns before the middle reaches temperature | Oven, or an air fryer oven on a low setting |
| Full trays of one thing | Will not fit in one layer | Split into rounds, or use an air fryer oven |
| Delicate pastry | Direct fan pressure collapses the layers | Lower temperature and shield the top |
| Cheese on its own | Melts through the basket holes | Use a tin or a liner |
Adjust for your machine, not just the recipe
Two air fryers set to the same number will not cook at the same speed. Fan strength and basket geometry vary far more between air fryers than between ovens, which is why our test method scores browning rather than trusting the dial.
A deep basket like the Ninja Air Crisp 5 QT concentrates airflow and runs fast. A wide air fryer oven such as the Cosori 13 QT spreads that air over more space and behaves more like a conventional fan oven, so oven times convert almost directly.
Cook the same recipe twice and you will know your machine. Note what worked on the page. After a fortnight you will stop doing the maths at all.
Skip the maths entirely
For common foods you do not need to convert anything, because we have already timed them. The air fryer cooking times chart lists temperatures and times for around 50 foods, and every one of our 51 recipes was written for an air fryer from the start.
Frequently asked questions
How do I convert oven temperature to air fryer?
Subtract 20C, or 25F, from whatever the recipe says, and cut the time by roughly 20%. So an oven recipe at 200C for 25 minutes becomes 180C for 20 minutes in an air fryer. Check the food at about 70% of the new time, because air fryers usually run faster than the calculation suggests.
Is the 25 degree rule accurate?
Close enough to start with, not close enough to trust blindly. The rule assumes an average fan, and fan strength varies a lot between models. Treat it as a first guess, check the food early, then write the real number on the recipe for next time.
Do I need to change the temperature if my recipe already says fan oven?
No. A fan oven temperature has already been reduced from the conventional figure, so subtracting another 20C would leave the food undercooked. Keep the stated temperature and only cut the time, by about 20%.
How much oil should I use compared to an oven recipe?
About half, and often less. Oven recipes assume oil spread across a tray to stop sticking. An air fryer basket needs just enough to help the surface brown, which is roughly half a teaspoon per portion. Too much oil pools in the drawer and starts smoking.
Why did my converted recipe burn on the outside and stay raw inside?
The temperature was too high for the thickness of the food. A fan drives heat into the surface fast, so a thick piece browns long before the centre catches up. Drop another 10 to 20 degrees and add time. For anything thicker than about 4 cm, the oven is usually the better tool.
Can I convert baking recipes to an air fryer?
Small ones, yes, with a bigger temperature drop. Go 30 to 40 degrees below the oven figure rather than 20, because the fan sets the crust while the middle is still batter. Cakes, brownies and cookies all work. Anything that needs to rise gently, like a large sponge, is better left in the oven.
Does the 20% time reduction work for frozen food?
Frozen food usually comes with air fryer instructions on the packet now, so use those first. If it only lists oven times, the same rule applies, though frozen food tends to need slightly less reduction because it starts far colder. Cut 15% rather than 20% and check early.