Ninja AF400UK vs AF300UK: Which Dual Zone Wins?
Last updated: 2026-07 · Built from real UK owner discussions — sources linked throughout.
The AF400UK is the bigger machine and the right default: 9.5L across two 4.75L drawers, 2,470W, £150–£220. The AF300UK is the same appliance one size down — 7.6L across two 3.8L drawers, 2,400W, £120–£180. Functions, controls and the sync feature are identical, so this is a capacity-and-price decision and nothing else.
It is also the most-argued air fryer question in UK communities. A dedicated hotukdeals thread exists purely to help buyers choose between the two, and Mumsnet threads on the same pairing run for pages. That is unusual for two models from one brand, and it happens because the AF300UK is frequently discounted into territory where the price gap looks trivial — right up until the drawers turn out to be too small.
Below: the spec difference in full, what 1.9 extra litres actually buys, whether the extra 70W matters, how the two compare on price and running cost, where the AF500UK and Double Stack XL fit, and which one owners recommend. If you are not yet sure which capacity band you are in, start with which capacity suits your household.
What is the difference between the AF400UK and AF300UK?
Capacity and power, nothing else. The AF400UK holds 9.5L in two 4.75L drawers and draws 2,470W; the AF300UK holds 7.6L in two 3.8L drawers and draws 2,400W. Both have the same six cooking functions, the same Sync and Match features, and dishwasher-safe baskets and crisper plates.
That shared feature set is why the comparison comes down to litres. Air fry, max crisp, roast, bake, reheat and dehydrate appear on both. Sync finishes two drawers cooking different things at the same moment on both. Neither model gives you a capability the other lacks.
Each AF400UK drawer is 25% larger than an AF300UK drawer — 4.75L against 3.8L — which is the number that matters more than the 9.5L versus 7.6L headline. Because the drawers are sealed compartments, the largest single item you can cook is capped by one drawer, not by the total.
| Specification | Ninja AF400UK | Ninja AF300UK |
|---|---|---|
| Total capacity | 9.5L | 7.6L |
| Per drawer | 4.75L | 3.8L |
| Power draw | 2,470W | 2,400W |
| Cooking functions | Six (air fry, max crisp, roast, bake, reheat, dehydrate) | Six (identical) |
| Sync and Match | Yes | Yes |
| Price range | £150–£220 | £120–£180 |
| Cost per hour at 24.67p/kWh | 60.9p | 59.2p |
| Suits | Families of four or more | One to three people |
How much bigger is the AF400UK in practice?
1.9 litres in total, but 25% per drawer — and that is what changes the cooking. The AF300UK handles a weeknight meal for two or three; the AF400UK handles four. The extra drawer depth also makes baking practical, which owners cite more often than portion counts.
The practical test is a full meal for four in one pass: chips in one drawer, chicken in the other, synced to finish together. Two 4.75L drawers do it. Two 3.8L drawers do it for three people and start rationing at four, which is exactly where the regret threads come from.
The less obvious gain is height. Mumsnet users who compared the two repeatedly point to what the deeper drawers allow beyond larger portions — cakes and individual crumbles in pots, which the AF300UK simply cannot accommodate. Neither model takes a large whole chicken comfortably, though: both have drawers that are deep rather than wide.
“The AF400 gives you more space in the drawers to do things like cakes and individual crumbles in little pots (paraphrased)”
Does the extra 70W change cooking times?
No. The AF400UK's 2,470W against the AF300UK's 2,400W is a 2.9% difference in power for 25% more drawer volume, so the larger machine is marginally less power-dense. Heat-up and cooking times are effectively identical, and Ninja's programme times are the same on both.
The 70W is worth knowing about for one reason only: running cost. At the 2026 price-cap rate of 24.67p per kWh, 70W costs 0.07kW × 24.67p = 1.7p per hour of cooking. Over an hour a day for a year that is £6.30 — a rounding error next to the price difference between the machines.
Both models sit well above the 1,500W figure that generic running-cost calculators assume for air fryers, which is why we work the arithmetic out on the real wattages in our guide to what an air fryer costs per hour at 2,470W. The AF400UK costs 60.9p an hour to run at full draw against 59.2p for the AF300UK.
- Power difference: 70W, or 2.9%
- Capacity difference: 1.9L total, 25% per drawer
- Running-cost difference: 1.7p per hour of cooking at 24.67p per kWh
- Cooking-time difference: none in practice — identical functions and programmes
Which is better value at current UK prices?
The AF400UK, whenever the gap is under about £40. It sells for £150–£220 against the AF300UK's £120–£180, so the ranges overlap: a discounted AF400UK regularly costs less than an AF300UK at full price. Buy on the price you can find, not the RRP difference.
Both models are heavily and frequently discounted, and the AF300UK is discounted harder — which is what makes this decision live rather than obvious. The trap is comparing a sale price on the smaller machine with the RRP of the larger one. Check both prices on the day, and if the AF400UK is within £40, take the capacity.
There is a second value argument owners make, which is that the machine pays for itself in displaced oven use. One PistonHeads member ran the numbers on his own AF400 purchase and counted the professional oven clean he no longer books alongside the electricity saving.
“One member of a long-running PistonHeads air fryer thread said that after spending £180 on a Ninja AF400, the savings on electricity plus no longer paying around £120 a visit for oven cleaning meant it had already paid for itself (paraphrased)”
What about the AF500UK and the Double Stack SL400UK?
Both solve a problem the AF400UK has. The AF500UK FlexDrawer holds 10.4L and its central divider lifts out, giving one big cavity when you need it. The Double Stack XL SL400UK keeps 9.5L but stacks the drawers vertically, making it around 30% slimmer at £200–£270.
The Double Stack is the answer to the AF400UK's most common complaint: worktop width. Two included racks let you cook across four levels for up to eight portions, and it carries the same six functions and sync features as the flagship. You pay a premium for the format, and it is tall — check the clearance under your wall units before ordering.
The AF500UK answers the other limitation, which is that no dual-zone drawer takes a large single item. Its removable divider turns two zones into a single 10.4L space, and it reaches 240°C. If you routinely cook one big thing rather than two smaller ones, it is the more flexible machine.
Both sit above the AF400UK on price, which is why our full air fryer ranking still puts the AF400UK first: it is the model that suits the most households at the lowest price.
| Model | Capacity | Format | Price range | Best for |
|---|---|---|---|---|
| Ninja AF300UK | 7.6L (2 × 3.8L) | Side-by-side drawers | £120–£180 | One to three people |
| Ninja AF400UK | 9.5L (2 × 4.75L) | Side-by-side drawers | £150–£220 | Families of four |
| Ninja Double Stack XL SL400UK | 9.5L stacked | Vertical, four levels | £200–£270 | Narrow worktops |
| Ninja AF500UK FlexDrawer | 10.4L | Removable central divider | Above AF400UK | One large item or two zones |
Which one do UK owners actually recommend?
The AF400UK for anyone cooking for four, the AF300UK for couples and small households. The consistent pattern across Mumsnet and MoneySavingExpert threads is that AF300UK owners with families wish they had bought the bigger drawers, while AF300UK owners cooking for two are happy with it.
That split is the clearest signal in the data. Nobody reports regretting the AF400UK's capacity; a steady stream of owners report regretting the AF300UK's. The only complaints attached to the larger model are worktop footprint and price, and the Double Stack XL exists to solve the first of those.
The wider Ninja verdict is unusually settled too. Owners who commit to the brand report both satisfaction and lower bills, and the recurring MoneySavingExpert advice on cheaper alternatives is to pay for the Ninja badge. If you are still weighing up the appliance itself rather than the model, our owner verdict on whether air fryers are worth it covers the case against as well as for.
“Contributors on a 'which air fryer and are they worth it' thread said their Ninja had been worth the money for regular use, and that their electricity spending had dropped because the household stopped using the oven for simpler meals (paraphrased)”
See both models in our full ranking
The AF400UK and AF300UK sit first and third in our air fryer ranking, alongside the Double Stack XL and the cheaper Instant Vortex Plus. Every pick carries owner evidence linked to its source thread.
See the best air fryers for 2026 →Frequently asked questions
What size air fryer do I need?
3.8L single drawer for one or two people, 7.6L dual for two or three, and 9.5L dual for a family of four or more. Because dual drawers are sealed compartments, judge the largest item you cook against one drawer rather than the total capacity.
How much does it cost to run an air fryer?
The AF400UK costs 60.9p an hour at 24.67p per kWh, or about 30p for a half-hour cook. The AF300UK costs 59.2p an hour. Used 30 minutes a day, that is £111.21 and £108.05 a year respectively — a difference of roughly £3.
How do you clean an air fryer?
Both models have dishwasher-safe baskets and crisper plates, but owners recommend hand-washing the coated parts so the non-stick lasts. A dual-drawer machine means two baskets and two plates after every meal, which is the most-cited practical downside in UK owner threads.
Is it worth getting an air fryer?
Yes if you will use it four or more times a week in place of an electric oven — that frequency is what produces both the speed benefit and the measured bill savings owners report. At twice-weekly use, payback on a £150 machine takes years.