What litres actually mean, and why they mislead

Questions this answers

• What size air fryer do I need?
• What does litre capacity actually measure?
• Is a 5 litre air fryer enough for a family of four?
• Does a 9 litre dual basket hold twice as much as a 4.5 litre?
• Why does my air fryer hold less than I expected?

Litres measures the box

The figure on the packaging is the volume of the drawer. It is measured the way any container is measured, and it includes every part of the drawer — including the headroom above the food, which is not usable capacity but the space the air has to move in.

An air fryer crisps by moving fast air over every surface of the food. Food stacked on food defeats that, which means the amount a machine can cook WELL is set by the area available for one layer, not by the volume of the drawer. Fill the volume and you have not increased the capacity; you have made a small steamer.

So the useful number is the base area, and here is the problem this page exists for: across the twenty-nine models in this catalogue, not one manufacturer publishes it. Most do not publish internal dimensions either. Litres is the number they give you and it is not the number you need.

Why two identical litre figures cook different amounts

Because volume is area times depth, and the same volume can be a tall narrow drawer or a shallow wide one. The shallow one has more base and therefore more single-layer area; the tall one has more headroom you must not fill.

This is not a small effect. A deep five-litre drawer and a shallow five-litre drawer can differ substantially in how many chips come out crisp, and nothing on either box tells you which you are looking at.

The practical move, if you can see the appliance: ignore the litre figure and look at the base. If you are buying online, treat litres as a rough ordering — an 8-litre machine is bigger than a 4-litre one — and not as a quantity you can plan a meal around.

Dual-zone litres are two numbers pretending to be one

A 9.5-litre dual-zone machine is not a 9.5-litre space. It is two drawers of under five litres each, and no single item larger than one drawer will fit in it. The headline number is the sum, and the sum is the one figure that describes nothing you can actually cook.

What two drawers buy is independence — two foods at two temperatures — rather than capacity. Each individual drawer is often slightly smaller than a comparable single-basket machine's, which is the trade: variety in exchange for the biggest single space.

One machine in this catalogue makes the point by itself. A dual-drawer model publishes different maximum loads for its two drawers — 1,400g in one and 800g in the other for the same food — which is a split no single capacity figure can express.

A flex-drawer machine is the third answer: one large space with a removable divider, so it can be either. It trades some independence for the ability to cook one big thing.

So what size do you need?

AirfryerHQ is not going to give you the table you came for — 'two people need 4 litres, four people need 8' — because it would be invented. Those tables are everywhere, they contradict each other, and none of them rests on a measurement of usable area, because that measurement is not published.

What can be said honestly is the shape of the decision. A machine holding one single layer of food feeds the number of people that layer feeds, and everything beyond that is a second batch. If you routinely cook for four and want one run, you are looking for the largest single-layer area you can fit on the worktop — which usually means a large single basket or an oven-style machine rather than a dual-zone one.

If you cook two different things more often than you cook a lot of one thing, that is the dual-zone case, and the litre figure is beside the point.

And a machine that is too big is a real cost rather than a free margin: it takes worktop you do not get back, and on a small load it heats space you are not using.

What we would need to do better

A useful size selector needs base dimensions or a usable-area figure per model. AirfryerHQ has looked for both across every model in this catalogue and holds neither for any of them, which is why there is no size selector on this site and why the compatibility checker for accessories is also blocked.

It is recorded as a gap rather than worked around. Deriving an internal area from external dimensions would produce a number indistinguishable from a measured one and would be wrong by an unknown margin — the walls, the insulation and the drawer mechanism are all in between.

Where a manufacturer does publish a maximum load for a food, this catalogue records it on that model's page. Those are the only capacity figures here that mean anything concrete.

What AirfryerHQ has not established

The usable cooking area of any model in this catalogue. Not published by any manufacturer, not measured by us, and not derivable from the figures that are published.

Any litres-to-household mapping. Every version of that table in circulation is an assertion, and this page declines to add another.

How much difference drawer shape makes, quantitatively. The direction is certain from the mechanism; the magnitude would need measuring across machines nobody here has.

Evidence and confidence

Cooking pages this relates to

• Frozen chips
• Roast potatoes

Appliances

• Basket air fryer
• Dual-basket air fryer
• Flex-drawer air fryer
• Oven-style air fryer