Oven to air fryer

Tell it what the recipe says and it tells you what to set the basket to, with a printable chart that fits on one sheet.

Which way

What the recipe says

Kind of oven

A recipe is written for a conventional oven unless it says otherwise. A fan oven already runs 20 °C below that, so starting from the wrong one swallows the whole conversion.

Temperature

Minutes · optional

Set it to 180°C for 24 min

Start checking at minute 17.

The working

Everything is normalised to a conventional oven first, then the rule is applied once: fan + 20 °C, a gas mark straight off the British table, then −20 °C and a fifth off the time.

The chart, to print

Sheet

Each system keeps the settings its own ovens are marked with rather than one converted into the other: Fahrenheit recipes go in twenty-fives, Celsius ones in tens. It comes out as a PDF carrying its own page geometry, so it will not reflow across two sheets or arrive at 94% the way a printed web table does.

Oven °C	Gas	Air fryer
140 °C	1	120 °C
150 °C	2	130 °C
160 °C	—	140 °C
170 °C	3	150 °C
180 °C	4	160 °C
190 °C	5	170 °C
200 °C	6	180 °C
210 °C	—	190 °C
220 °C	7	200 °C
230 °C	8	210 °C
240 °C	9	220 °C

Oven °F	Air fryer
275 °F	250 °F
300 °F	275 °F
325 °F	300 °F
350 °F	325 °F
375 °F	350 °F
400 °F	375 °F
425 °F	400 °F
450 °F	425 °F

And the minutes

10 → 815 → 1220 → 1625 → 2030 → 2440 → 3245 → 3650 → 4060 → 48

Leave the print dialogue at 100% or "actual size". On "fit to page" the sheet comes out shrunk.

Where this actually goes wrong

It is not the brand. Ninja, Cosori, Tefal or the supermarket one: they all move hot air and the rule is the same. Not one page ranking for this term says so, which is how the internet filled up with per-model charts that are the same chart with a different logo.
It is the basket. In one layer the air gets all the way round the food; piled up it steams instead, and comes out pale and soft. Cook two batches before you drop the temperature.
The two numbers in circulation are not the same number. Everyone says "25 °F less" and everyone metric says "20 °C less", and 25 °F is 13.9 °C. The gap is about 6 °F, which is far less than overfilling the basket will cost you.
Look early. The basket sits close to the element and the failure is dry, not raw.

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An air fryer is a small convection oven with a fast fan and a basket that sits close to the element. That one sentence contains the whole conversion: forced air moves heat into food faster than still air does, so the same result arrives at a lower setting in less time. The figures everybody quotes — about 20 °C or 25 °F lower, and a fifth off the clock — come from exactly that.

What most conversion pages leave out is the step before the arithmetic. A recipe is written for a conventional oven unless it says otherwise, a fan oven is already run below that, and a British gas mark is a conventional temperature wearing a number. Start from the wrong one and the correction you apply is the correction that was already applied. This page normalises to a conventional oven first and then converts once, which is why a fan oven at 180 °C and a conventional oven at 200 °C both come out at the same basket setting.

And it gives you the chart as a PDF rather than a table on a page. Of the eight pages ranking for this term, one offers something printable; the rest print an HTML table, which the print dialogue is free to shrink to 94% or spill onto a second sheet. A PDF carries its own page geometry, so the sheet that comes out is the sheet that was designed, and it fits on the fridge.

Manual

How to use it

1
Say which oven the recipe means

Conventional is the default and the right answer for most recipes. Pick fan only if the recipe explicitly says fan, fan-forced or convection, and pick gas mark if it gives you a number from 1/4 to 9.
2
Type the temperature in the unit you cook in

Switch between °C and °F and the number is converted rather than reinterpreted, so 200 °C becomes 390 °F instead of quietly turning into a much colder oven.
3
Add the minutes if the recipe gives any

Plenty of recipes name a doneness cue instead — golden, risen, pulling away from the tin. Leave the field empty in that case; the temperature stands on its own.
4
Set the basket and note the check time

You get the setting, the converted time, and the minute to start looking. That last one matters more than it sounds: the basket runs hot and the failure mode is dry rather than raw.
5
Go the other way when you need to

An air fryer recipe can be put back into an oven, which is the conversion you want when the batch does not fit in the basket. Choose whether the oven you are moving it to has a fan.
6
Print the chart once and stop looking things up

The PDF has the temperature table, the gas marks, the times and the four things that actually go wrong, on one sheet in A4 or Letter. Leave the print dialogue at 100%.

In depth

Things worth keeping in mind

What the conversion does not know

The arithmetic here is exact and the cooking is not. These are the four things that will move your result further than any rounding on this page:

How full the basket is. One layer with air gaps around each piece is the condition every air fryer time assumes. Crowd it and you are steaming.
Whether it was preheated. Two or three minutes for anything that should crisp; the difference is largest in the first five minutes of cooking.
What the food came out of. Fridge-cold and freezer-cold are not the same starting point, and neither matches a recipe written for room temperature.
The shape of the thing. Thickness decides cooking time far more than weight does, which is why a table of times by food is less useful than it looks.

When not to convert at all

Some things are better cooked in the oven, and knowing which saves a wasted dinner. Anything with a wet batter will be blown around before it sets. Anything taller than the basket has clearance for will scorch on top. Large joints of meat do not fit the geometry — the outside is much closer to the element than in an oven, so you get a dark crust over an undercooked middle. And leafy or very light items get lifted into the element by the fan, which is a genuine smoke hazard rather than a matter of taste.

History

A patent about doughnuts, and a name that stuck to the wrong thing

The engineering is much older than the appliance. Convection ovens were sold to commercial kitchens from the 1960s, on exactly the reasoning above: a fan let a baker run a lower temperature, fit more trays and finish sooner. The domestic version arrived slowly and was mostly bought by people who wanted a second oven.

What turned it into a countertop machine was a patent filed in 2005 by Turbochef for rapid-cook technology, and Philips' decision in 2010 to build a small chamber around a fast fan and sell it as the Airfryer. The design point was doughnuts and chips — food people wanted to make without a pan of hot oil — and the name was a marketing decision rather than a description. Nothing in the machine fries anything.

The category then grew faster than almost any small appliance before it. By the early 2020s air fryers were in a substantial share of kitchens in the UK, the US and Australia, helped along by a run of high domestic energy prices: heating a two-litre chamber for twenty minutes uses a fraction of what heating a sixty-litre oven does, and that argument sold a great many machines that the crisping argument alone would not have.

Which is why this conversion is a question at all. Millions of people acquired a new appliance and kept every recipe they already owned, all of them written for something else. The search volume for "oven to air fryer conversion" is essentially a measure of that mismatch.

2010: Philips launches the first Airfryer
1960s: convection ovens reach commercial kitchens
−20 °C: the rule everyone settled on
×0.8: and what it does to the clock

How it works

Why moving air cooks faster, and what the rule is really approximating

Food in a still oven sits inside a thin envelope of air it has already cooled — the boundary layer. Heat has to cross that envelope by conduction, which is slow, so a lot of the oven's energy never reaches the food. A fan strips the envelope away and keeps replacing it with air at full temperature. The oven does not get hotter; the food simply receives more of what the oven is already producing.

An air fryer takes that further than a fan oven does. The chamber is small, the fan is fast relative to the volume, and the basket is perforated so the stream reaches the underside too. Nothing about it is frying: there is no oil bath, and the crisping is the Maillard reaction and moisture leaving the surface, which is what a very hot dry oven has always done.

So the rule of thumb is really a correction for efficiency, not for temperature. Dropping the dial by 20 °C compensates for the surface receiving heat faster than it would in a still oven, which is what stops the outside finishing long before the middle. Taking a fifth off the time compensates for the same thing in the other direction.

The two figures in circulation do not agree, and it is worth knowing why. The imperial rule is "25 °F less" and the metric rule is "20 °C less", but 25 °F is 13.9 °C — so the metric rule is the more aggressive of the two by about 6 °F. Both are rounded numbers chosen to be memorable. This page keeps each kitchen's own version rather than converting one into the other, because a chart that told a British cook to set 186 °C would be precise about the wrong thing.

By hand

Doing it on paper

Three steps, and the first is the one that gets skipped. Worth walking through once: after that you will not need the page for a temperature you already know.

1

If the recipe says fan, add 20 °C (or 36 °F). If it gives a gas mark, look it up: gas 4 is 180 °C, gas 6 is 200 °C, gas 7 is 220 °C. If it says nothing, it already is conventional and there is nothing to do.
2

Subtract 20 °C, or 25 °F if you are working in Fahrenheit. A conventional 200 °C becomes 180 °C; a conventional 400 °F becomes 375 °F. Round to whatever your dial can actually be set to — most go in steps of five.
3

Multiply the minutes by 0.8: 30 minutes becomes 24. Then plan to open the basket at about 70% of that — around minute 17 — because you can always put it back and you cannot undo dry chicken.

Diagnosis

If something is not working

Symptom:The outside is dark but the middle is still cold

Likely cause:: The basket sits much closer to the heating element than an oven shelf does, so the surface gets ahead of the interior. Usually a piece that is too thick for the setting.
What to do:: Drop another 10 °C and add a few minutes, or cut the food thinner. For a joint or a whole bird, cover the top with foil once the colour is where you want it and let the middle catch up.

Symptom:It came out pale and soggy

Likely cause:: An overcrowded basket. The food is steaming in its own moisture instead of drying and browning.
What to do:: Cook in two batches with one layer each and a gap around every piece. Do not lower the temperature to compensate — that keeps the food wet for longer and makes it worse.

Symptom:Smoke is coming out of it

Likely cause:: Usually fat dripping onto the element or the drawer base, most often with bacon, sausages or anything marinaded in oil. Occasionally it is a light item that the fan has lifted onto the element.
What to do:: Stop it, let it cool, and put a tablespoon of water in the bottom of the drawer to stop fat from smoking. Weigh down anything light with a piece of food. Clean the drawer between fatty batches rather than at the end of the week.

Symptom:One side is done and the other is not

Likely cause:: The airflow is not symmetrical, and whatever is nearest the fan gets the most of it.
What to do:: Shake the basket or turn the pieces at the halfway point — this is the one instruction almost every air fryer recipe includes and it is the reason. For a large flat item, turn it over rather than shaking.

Symptom:It finished far sooner than the converted time

Likely cause:: A small chamber and a strong fan; the conversion is a starting point calibrated to a middling load.
What to do:: Trust the check time rather than the end time. Once you know your machine runs fast, take the reduction from the time rather than the temperature — a fifth is an average, not a law.

Trivia

Things worth knowing

Nothing in it fries

There is no oil bath and no immersion. The name was chosen in 2010 to sell the machine against the deep fat fryer it was meant to replace, and it describes the outcome people wanted rather than the mechanism they got. "Small convection oven" is accurate and would have sold rather fewer.

Gas marks are not a linear scale

Gas 1/4 to 1 climb in 10 °C steps and everything above that in 20 °C steps, a legacy of the Regulo thermostat that British gas ovens were built around from the 1920s. It is why the conversion has to be a lookup table rather than a formula.

The two rules of thumb disagree by about 6 °F

Everyone says "25 °F less"; everyone metric says "20 °C less". They are not the same reduction — 25 °F is 13.9 °C — and both survive because they are easy to remember. The gap is smaller than the error from loading the basket badly, which is why nobody has ever had to settle it.

The energy argument did more selling than the crisping did

Bringing a two-litre chamber up to temperature takes a small fraction of what a sixty-litre oven takes, and it gets there in two or three minutes rather than fifteen. During the energy price rises of the early 2020s that became the headline reason to own one, which is also why so many households ended up converting recipes.

The basket is perforated for a reason you can taste

Air reaching the underside is what stops food sitting in its own released moisture. It is also why a solid tin inside an air fryer behaves much more like a small oven than like an air fryer: block the airflow underneath and you have removed the thing that makes it different.

Questions

Frequently asked questions

Does the conversion change for a Ninja, a Cosori or a Tefal?

No. They all move hot air through a small chamber, and the rule follows from that rather than from the badge. Per-model charts are almost always the same chart with a different logo on it. What genuinely varies between machines is basket size, which changes how many batches you cook, not what you set the dial to.

My recipe says fan oven. Do I still take 20 °C off?

Not from the fan number. A fan oven is already run about 20 °C below a conventional one, so you add that back first to recover what the recipe would have been in a static oven, and then take the air fryer reduction off that. In practice a fan oven at 180 °C and an air fryer at 180 °C are the same instruction, which surprises people.

Do I need to preheat?

For anything that wants a crisp surface — chips, chicken, anything breaded — yes, two or three minutes, because a cold chamber lets the surface dry out before it browns. For a bake that spends twenty-five minutes in there it makes very little difference. Note that the times here assume a preheated basket, as oven times assume a preheated oven.

Why does my food come out pale and soft instead of crisp?

Almost always an overcrowded basket. Piled-up food traps its own steam, the surface never dries, and steaming is what you get instead of browning. One layer with gaps, or two batches. Dropping the temperature is the instinctive fix and it is the wrong one — it makes the food sit in its own moisture for longer.

Can I convert baking, or only chips and chicken?

Cakes and bread convert, with two caveats. The fan is strong enough to move a loose batter around before it sets, so a cake can come out lopsided; and the small chamber means the top of a tin sits much closer to the element than it would in an oven, so it browns early. Cover the top with foil once the colour is right and finish it as usual.

What about frozen food that already has air fryer instructions?

Use those and ignore this page. The manufacturer tested that specific product in that specific state, which is better information than any conversion. This page is for the recipes that only give you oven instructions.

Why is there no chart of cooking times per food?

Because an honest one cannot be short. How long a chicken thigh takes depends on its thickness, whether it went in from the fridge or the freezer, how full the basket is and whether the machine was preheated — and a table that ignores all four is a guess printed in a grid. What this page will do is convert the numbers from a recipe that did account for them.

Is the printable chart really going to come out the right size?

It is a PDF with its own page geometry, so as long as you leave the print dialogue at 100% or "actual size" rather than "fit to page", yes. That is exactly why it is not an HTML table with a print stylesheet: those are at the mercy of the scale box, and a chart that lands across two sheets is no use on a fridge door.