An air fryer is a small oven with a powerful fan. It blows hot air around the food, which browns and crisps the outside quickly. A normal oven does the same job more slowly and in a much bigger box. So the real question for a beginner is not "which is healthier?" but "which one will I actually use on a Tuesday evening?"
The appliance does not make a meal healthier. The food and the amount of oil do.
Fat provides 9 kcal per gram, compared with 4 kcal for carbohydrate and protein (NHS). A teaspoon of cooking oil is roughly 4–5 g, so about 40 kcal. A tablespoon is about 120 kcal. That is why "air fried" often means fewer calories than deep fried: you add a teaspoon or two instead of a pan full. But an oven tray of roast vegetables with a teaspoon of oil is just as light.
Use the calculator to see what your oil adds. It is an estimate: oils differ slightly and some oil stays in the bottom of the tray.
Because an air fryer is small, it heats up fast and wastes little energy. The Energy Saving Trust compared cooking the same 600 g chicken breast and found the air fryer cheaper to run than an electric oven. They also note that ovens come into their own when you cook a lot at once, because the heat is shared across many portions. Exact savings depend on your energy price and your oven, so treat any figure as a rough guide.
| Job | Air fryer | Oven |
|---|---|---|
| 1–2 portions | Quick, little preheating | Slow to heat for a small meal |
| Crisp potatoes, veg, chicken pieces | Very good | Good, a little slower |
| Family batch or a whole roast | Basket fills up | Better |
| Cakes, bread, big trays | Limited by size | Better |
Starchy foods such as potatoes and bread form a substance called acrylamide when cooked at high heat, and it is considered a possible carcinogen. This happens in any appliance. Public health advice, including the UK Food Standards Agency's "Go for Gold" campaign, is to aim for golden yellow rather than dark brown, and to avoid storing raw potatoes in the fridge. You cannot avoid it completely, and a varied diet with plenty of vegetables matters more.
You do not need one to eat well. If you already have an oven you like, keep using it. An air fryer is simply convenient if you cook small portions often. As with any change in how you eat: if you have a medical condition, are pregnant or breastfeeding, have or had an eating disorder, or take medication, talk to your doctor or a dietitian first. This is general information, not medical advice.