"Cooks with little or no oil" is the headline claim on every air fryer box. It is partly true, and the part that is true is easy to measure: oil is the most calorie-dense thing in most kitchens, so the less of it that ends up on your plate, the fewer calories come with the meal.
The size of the saving depends on what you are comparing it with and on how much oil you use. Pick a food below and see the oil, in teaspoons and in calories, for four ways of cooking it.
What are you cooking?
How heavy is your hand with oil? (pan, oven and air fryer)
Portion of raw food:
Times a week:
Fat provides about 9 kcal per gram, roughly double the 4 kcal per gram from carbohydrate or protein. A single tablespoon of cooking oil is around 120 kcal, and you barely see it on the plate. The NHS names the "oil on chips" as an example of how added fat raises the calories in starchy food.
That does not make oil bad. A small amount of vegetable or olive oil is a normal part of eating well, and fat carries flavour and helps you absorb some vitamins. The point is only that oil is easy to add without noticing, and the cooking method decides how much goes in.
Studies that cook the same food both ways find that air-fried food ends up with far less fat than deep-fried food. A 2015 study in the Journal of Food Science that compared French fries and potato chips made by deep-fat frying and by hot-air frying reported a substantially lower fat content for the air-fried versions. Later reviews put the reduction anywhere from about half to around four-fifths, depending on the food and the method, so treat any single number with care.
There is a catch. Those comparisons are against deep frying, where food soaks up oil from a bath. Against a tray in a hot oven with a spoonful of oil, the difference is much smaller, as the bars above show. The research is also mostly about oil content and texture, not long-term health outcomes, so "less oil" is the claim that holds up, not "healthy".
An air fryer saves oil mainly compared with deep frying. If you already use a teaspoon on an oven tray, the gain is small.
The food still counts. Chips cooked in an air fryer are still chips; the potato brings its own calories and the oil is only part of the story. Many ready-made breaded or "oven" foods already contain oil in the coating, so adding more or cooking them in a machine does not remove it.
Sauces and sides add up as well, and so does portion size: a full basket is not one portion. If you want a quick way to judge a portion, try the hand-portion guide. One more tip for starchy foods such as potatoes and bread: the UK Food Standards Agency advises aiming for a golden yellow colour rather than dark brown, because heavy browning creates more acrylamide, a compound formed in starchy foods at high heat.
If you have a medical condition, are pregnant or breastfeeding, have or had an eating disorder, or take medication, or if you have been told to manage your fat or cholesterol intake, talk to a doctor or dietitian before changing how you eat. This guide is general information, not medical advice.
Prices vary a lot, from around €50 for compact single-basket models to around €200 for large dual-drawer ones. Spending more buys size and convenience, not less oil.
The oil amounts per method in the calculator are illustrative assumptions for a typical home cook, not measured values.