Air fryer listings love a litre figure. 2L, 4.7L, 6.2L, 9.5L. The trouble is that the number on the box tells you surprisingly little about how much food you can actually cook at once, and the “serves 2-4” line next to it is often even less help. If you’ve ever bought a machine that looked big enough on paper and then found yourself doing chips in two batches, this is why. Below we explain what air fryer capacity really means, how to work out the size you need, and take a proper look at one popular mid-size model, the Ninja 4.7L Air Fryer Pro (AF140UK), as a real-world example.

At a glance

  • The short answer: the litre figure is the volume of the drawer, not the amount of food that will cook well in it. Floor space matters more, because most food crisps best in a single layer
  • The product: Ninja 4.7L Air Fryer Pro (AF140UK), a single-drawer, 2,000W air fryer with four functions: Air Fry, Roast, Reheat and Dehydrate
  • What Ninja says fits: a whole 1kg chicken or up to 500g of fries, and it’s pitched as right for up to two people
  • Footprint: 26.5cm high, 28.5cm wide and 36cm deep
  • Best for: one or two people in a small kitchen who want room to spread food out rather than pile it up
  • Think twice if: you regularly cook for three or more, or your socket is a stretch from where it would sit (the cable is short and fixed)
  • Owner rating: 4.8 out of 5 from over 900 ratings on Amazon UK at the time of writing

What the litre number actually measures

When a brand says 4.7L, it means the volume of the drawer or basket. Picture filling it to the brim with water. That’s a useful number for comparing two models from the same range, but it hides two things.

First, you can’t fill an air fryer to the top. Hot air needs space to move around the food, and most manuals mark a maximum fill line well below the rim. Pack the drawer full and you get steamed, pale chips on the inside of the pile and burnt ones on top.

Second, shape matters. A tall, narrow drawer and a wide, shallow one can have the same volume, but the wide one gives you far more floor space. For things like chicken thighs, fish fillets, halloumi or a tray of veg, the floor is what counts, because you want everything in one layer.

Ninja’s own listings show how slippery the figures are. Its smaller 3.8L model (AF100UK) is described on Amazon as fitting a 1.35kg chicken or 900g of fries and suiting two to four people, while the bigger 4.7L Pro is described as fitting a 1kg chicken or up to 500g of fries for up to two people. On paper the smaller drawer holds more. In reality the two descriptions are just measuring different things in different ways, and Ninja’s own comparison chart on the same listings puts both at one to two people. The lesson: don’t compare air fryers on litres or “people” claims alone, especially across brands.

How to work out the size you need

Forget the people count on the box and think about the biggest thing you cook regularly.

  • Mostly cooking for one, small portions: around 2L to 3L can be enough. Our Cosori 2L review looks at how far a really small drawer can stretch
  • One hungry person, or two people sharing sides: somewhere around 4L to 5L gives you room to spread chips out or cook two things side by side
  • A family of three or four: look at 6L and above, or a two-drawer model so the main and the sides can cook at once
  • Two drawers: check the size of each drawer, not just the total. A 9.5L dual model is usually two drawers of under 5L each, so neither will take a large chicken. Our look at the Ninja Double Stack XL goes into this

Treat those bands as a loose guide, not a rule. A couple who mostly reheat leftovers will be fine with less. Anyone who wants to do a whole chicken or a full bag of frozen chips in one go needs more.

Then measure your counter. Check the depth especially, since many air fryers are deeper than they are wide, and you’ll need clearance behind and above for the hot air coming out of the vent.

The Ninja 4.7L Air Fryer Pro as a real example

The AF140UK is a good test case because it sits right in the middle of the range. On the outside it’s compact: shorter than a lot of air fryers, and narrow enough to tuck into a corner. Several owners say the same thing in their reviews, that it looks smaller than expected on the worktop but the drawer is roomier than they thought it would be. One single owner who’d considered a 3L model said the 4.7L let chips spread out easily and left space for a second item, which is exactly the floor-space point above.

It has four modes (Air Fry, Roast, Reheat and Dehydrate), a temperature range that tops out at 210°C, and a non-stick drawer with a removable crisper plate. The controls are a simple set of buttons for temperature, time and mode. It’s rated at 2,000W, which is on the higher side for its size and part of why owners describe it heating up quickly.

Pros

  • The drawer is wide and shallow enough to cook a proper single layer, which is what you want for crisp results
  • Small footprint for the capacity, with several owners mentioning it fits a small kitchen or even a cupboard shelf
  • The crisper plate comes out, so you can clean the grease that collects underneath it rather than working around it
  • Very simple controls that most owners say they used without reading the manual
  • Strong owner feedback overall, with performance, ease of cleaning and size the most praised points

Cons

  • The power cable is short and can’t be removed, which one owner marked it down for. If your sockets are awkwardly placed, measure before you buy, and remember air fryer manuals generally advise against extension leads
  • Only four functions, and no dedicated bake setting. Fine for most air fryer cooking, but rivals offer more modes
  • The temperature tops out at 210°C, where some competitors go to 230°C
  • Owners say it’s the right size for two, but bigger appetites or a third person will push you into cooking in batches. A whole pizza won’t go in without cutting it
  • A few owners found it noisier than other air fryers they’d used, and one felt the included recipes and online guidance were thin

Who it’s for

This size makes most sense for one person who cooks proper meals rather than just snacks, or a couple who want a main and a side in the drawer at the same time. It suits flats and small kitchens because it doesn’t eat much counter space for what it holds.

If it’s just you and you mainly do quick bits, a smaller machine will save space. Our guide to the best air fryers for one person covers a few. For a family, go bigger or go dual-drawer. And if you want something in a similar size class to compare against, our Tower Vortx 4.2L review is a sensible place to look.

How to get the most out of the space

  • Cook in a single layer wherever you can. If food overlaps, give the drawer a good shake halfway through
  • Don’t fill above the max line, even if it looks like there’s room
  • Cut big items down. Halving a jacket potato or splitting a pizza is quicker than doing two rounds
  • Use the removable crisper plate for chips and anything you want crisp all over, and take it out when you want food sitting in the drawer to catch juices
  • Do sides first and the main last, then give the sides a quick blast on Reheat while the main rests

Cleaning and safety

Ninja describes the drawer and crisper plate as non-stick. Let them cool, then wash them in warm soapy water with a soft sponge, and pop the crisper plate out so you can get at the fat underneath. Skip metal scourers and metal utensils, which will damage the coating. Our guide to cleaning an air fryer basket without scratching it has more on this.

Leave space around the machine, especially behind it where the hot air comes out, and keep it away from the edge of the worktop and from cupboards above. A new air fryer can give off a faint smell the first few times it’s used. If that bothers you, our piece on why air fryers smell like plastic explains what’s going on and what to do.

FAQ

Is a 4.7L air fryer big enough for two people?

For most couples, yes. That’s how Ninja pitches the AF140UK, and it’s what most owners report. You’ll have room for a main and a side or a decent portion of chips. If either of you has a big appetite, or you want to do a large chicken regularly, look at 6L or more.

Why does a bigger air fryer sometimes claim to fit less food?

Because brands measure and describe capacity differently, even within the same range. Drawer shape, the fill line and whether the claim is for fresh or frozen food all change the figure. Compare floor size and the biggest item you actually cook, not just the litres.

Can I fill an air fryer to the top?

No. Air needs space to circulate, so stick to the max line in the manual. Overfilling is one of the most common reasons for soggy, uneven results.

Is a dual-drawer air fryer better than one big drawer?

It depends what you cook. Two drawers let you cook two things at different settings, which is great for families. But each drawer is smaller than the total suggests, so a single large drawer is better for a whole chicken or a big tray of wings.

The verdict

Air fryer capacity is one of those specs that sounds precise and isn’t. The litre figure is a rough guide to drawer volume, and the “serves” claim is even rougher. Work out the biggest thing you cook, think in terms of floor space, and measure your counter. For one or two people, the Ninja 4.7L Air Fryer Pro shows what a well-shaped mid-size drawer looks like: compact outside, roomy enough inside, and easy to clean. Just be honest with yourself about portion sizes, and check where your socket is, before you commit.

You can check the current listing for the Ninja 4.7L Air Fryer Pro on Amazon UK here: Ninja 4.7L Air Fryer Pro (AF140UK).