Last updated 7 November 2026. Written by the Clean Smile Home team. We sell all three of these cookers, so we've tried to be clear about what each one can't do. We don't run our own lab tests: timings and test results come from the independent reviewers named in the sources at the end, and specifications come from the manufacturers, our product listings and major UK retailers.
The short answer
If you want stews, beans and tough cuts done in under an hour, buy a pressure cooker: the Instant Pot Classic Mini 3.8L (£55.19) for one or two people, the COSORI 5.7L (£91.99) for a family. If you'd rather brown, slow cook and serve from one pot, the Ninja PossibleCooker 6L (£91.99) is better, but it can't pressure cook.
That last point catches people out. "Multi-cooker" is a loose label. All three of these do several jobs, but only two of them cook under pressure. The Ninja is really a very capable slow cooker and rice cooker with a pot you can sear in and put in the oven. Which you want depends on whether you're short of time in the evening or short of time in the morning.
Pressure cooker vs multi-cooker: what's the difference?
A pressure cooker seals the pot so steam can't escape. Pressure builds up, the boiling point of the water rises above 100°C, and food cooks much faster. That's why a beef stew that takes hours in a casserole dish can be done in well under an hour. Electric pressure cookers like the Instant Pot and the COSORI do this with a locking lid, a pressure valve and a heating element, and they switch to keep warm when they're done.
A multi-cooker is any appliance with several cooking modes in one pot. Most electric pressure cookers are also multi-cookers, because they slow cook, steam, sauté and keep warm as well. But some multi-cookers, like the Ninja PossibleCooker, don't pressure cook at all. They have a normal lid and cook at or below boiling point.
So the useful question isn't "pressure cooker or multi-cooker". It's this: do you want speed, which needs pressure, or do you want long, gentle cooking and an easy one-pot routine, which doesn't?
The three cookers at a glance
| Feature | Instant Pot Classic Mini 3.8L | COSORI 5.7L 9-in-1 | Ninja Foodi PossibleCooker 6L (MC1101UK) |
|---|---|---|---|
| Pressure cooks? | Yes | Yes | No |
| Capacity | 3.8 litres, up to 4 portions | 5.7 litres | 6 litres, up to 6 portions |
| Functions | 7: pressure cook, slow cook, sauté, steam, egg, yogurt, keep warm | 9 functions on our listing; reviewers counted 12 or 13 presets | 8: sear/sauté, slow cook, white rice, brown rice, pasta, porridge, steam, keep warm |
| Power | 800 W (our listing) | 1,100 W (Olive) | 1,400 W (our listing) |
| Inner pot | Stainless steel | Non-stick on our listing; check the listing photos | Non-stick, oven-safe to 240°C |
| Lid | Locking pressure lid | Locking pressure lid, automatic steam release | Glass lid |
| Searing | Sauté mode | Sauté mode | Sear/sauté up to 205°C (Ninja) |
| Delay start | Yes (T3) | Up to 24 hours | Timer up to 12 hours |
| Keep warm | Yes | Up to 12 hours | Up to 12 hours |
| Size (H x W x D) | 25.6 x 35.1 x 31.8 cm | About 32 x 34 x 31.7 cm (Olive) | 28 x 42 x 29 cm |
| Weight | 4.72 kg (John Lewis) | Not confirmed | 5.5 kg |
| Dishwasher-safe parts | Inner pot, lid and accessories | Lid, pot and accessories | Pot, lid and accessories |
| Guarantee | 2 years (John Lewis); T3 says 1 year | 2 years (Olive) | 2 years (Ninja) |
| Typical full price | £79.99 (John Lewis, T3) | £99.99 (T3, Trusted Reviews) | £119.99 (Ideal Home) |
| Price at Clean Smile Home | £55.19 | £91.99 | £91.99 |
Prices checked on 7 November 2026. A few figures differ between sources. We've given both where they do and explain the important ones below.
Who should buy which: the quick version
- You live alone or as a couple and want fast dinners: Instant Pot Classic Mini. It's the cheapest, smallest and quickest to put away.
- You cook for a family of four or more, or batch cook: COSORI 5.7L if you want speed, Ninja PossibleCooker if you want slow cooking.
- You want to put dinner on in the morning and come home to it: Ninja PossibleCooker. It's the best slow cooker of the three.
- You cook dried beans, chickpeas and stock from scratch: one of the pressure cookers. This is where pressure makes the biggest difference.
- You want to brown meat properly before it stews: Ninja. It sears at up to 205°C and the pot can go in the oven.
- You eat a lot of rice and pasta: Ninja, which has dedicated white rice, brown rice and pasta modes.
- You're nervous of pressure cookers: Ninja. There's no pressure to release, just a glass lid.
- Your kitchen is tiny: Instant Pot Classic Mini.
Instant Pot Classic Mini 3.8L: the small, fast one
The Classic Mini is Instant Pot's compact model. It pressure cooks, slow cooks, sautés and steams, has egg and yogurt programmes, and keeps food warm afterwards. It holds 3.8 litres, which Instant Pot and T3 both put at up to four portions.
What it's good at
Speed, for a small household. T3 made meatballs in under 20 minutes, including preheating and releasing the pressure, against about 45 minutes in the oven. It said the pot comes up to pressure very quickly, which is what you'd expect from a smaller volume of food and water. T3 also liked the controls, the price and how easy it is to fit in a small kitchen, and gave it a T3 Recommends badge.
The inner pot is stainless steel, so there's no coating to scratch or wear out. You can use metal utensils in it and it's dishwasher-safe. T3 notes you can save up to four custom presets, plus delay start and manual time and temperature.
Where it falls short
- It's small. T3 said 3.8 litres may not suit batch cooking. Remember that a pressure cooker shouldn't be filled to the brim, so the usable space is less than 3.8 litres.
- Food sticks. T3 found food stuck to the stainless pot, especially on pressure cook. Deglazing after sautéing helps a lot (we explain below).
- The slow cook is weak. T3 found the low setting was only a small step up from keep warm. If slow cooking is your main job, this isn't the one.
- The lid can stick. T3 said it sometimes got stuck in use. With any pressure cooker, the lid won't open until the pressure has dropped, which is a safety feature, but T3's comment suggests it can be awkward even then.
There's one disagreement to flag. John Lewis lists a two-year guarantee for the Classic Mini, while T3's review says one year on non-disposable parts. Keep your receipt and check the paperwork in the box.
For more on cooking for one or two in it, read our Instant Pot Classic Mini guide.
COSORI 5.7L 9-in-1: the family pressure cooker
The COSORI is a full-size electric pressure cooker at 5.7 litres. Our listing describes nine cooking functions, including pressure cook, slow cook, steam, rice, sauté and yogurt, plus delay start up to 24 hours, keep warm up to 12 hours and automatic steam release.
The reviewers counted its buttons differently. T3 listed 13 presets, including porridge, stew, bean and grain, meat and poultry, cake and sous vide. Trusted Reviews and Olive both counted 12. That's because "functions" and "presets" aren't the same thing: several presets are pressure cooking with different default times. Don't read too much into the number.
What it's good at
All three reviews liked it. Olive gave it 4.5 out of 5 and called it great value that does the basics well. T3 called it versatile and efficient with great value for money. Trusted Reviews called it a great-performing multi-cooker for a reasonable price. They praised its sturdy build, its results across modes and the accessories that come with it: T3 and Trusted Reviews list a ladle, spatula, metal trivet and measuring cup.
Trusted Reviews timed several dishes, which gives a good feel for what pressure cooking actually saves:
| Dish (Trusted Reviews) | Cooking time |
|---|---|
| Porridge | 3 minutes |
| Salmon, steamed | 5 minutes |
| Potatoes and cabbage, high pressure | 8 minutes |
| Three chicken breasts | About 15 minutes |
| 1.5 kg gammon | About 1 hour |
| Beef stew, slow cook mode | 6 hours |
Those are cooking times. They don't include the time to come up to pressure, which is the COSORI's main weakness.
Where it falls short
- Slow to preheat. Every reviewer mentioned it. Trusted Reviews said preheating was well over 10 minutes for salmon and porridge, and T3 said over 10 minutes for some dishes. So the "3 minute porridge" is more like a quarter of an hour from switching on.
- Rice came out a little dry for T3 and Trusted Reviews. Adding a splash more water usually fixes this.
- It's bulky. Olive and T3 both mentioned the size. Measure your cupboard.
- No air fry. Olive noted this. If you want one appliance that pressure cooks and air fries, this isn't it. Our air fryer buying guide covers the separate options.
A note on the inner pot. Our listing describes a non-stick pot. Some reviewers describe the COSORI's materials as stainless steel, and COSORI has sold versions of its 5.7 litre cooker with different pot finishes. If the pot material matters to you, check the photos on our listing for the exact version and accessories supplied. If it's non-stick, use wooden or silicone utensils.
For more on the brand, see our COSORI brand guide.
Ninja Foodi PossibleCooker 6L: the one-pot slow cooker
The PossibleCooker is a different kind of appliance. Ninja calls it an 8-mode rice and slow cooker. Its modes are slow cook, steam, sear/sauté, keep warm, white rice, brown rice, porridge and pasta. There's no pressure function on Ninja's page or in any review we read.
What it's good at
Searing. Ninja says the pot reaches up to 205°C on sear/sauté, and Ideal Home said it was excellent and heated up very quickly. That's much hotter than a pressure cooker's sauté mode tends to get, and it's what gives stews and chilli their deep, browned flavour.
The pot. It's non-stick and oven-safe up to 240°C, so you can brown, slow cook, then put it in the oven to crisp a topping or finish a pie lid, and bring it to the table. Ideal Home found this worked well.
Rice and pasta. Ideal Home cooked white rice in under 30 minutes and liked the pasta mode. Ninja says the pot takes up to 800 g of rice, 500 g of pasta or a 1.8 kg joint.
Slow cooking. It does this properly, with a timer up to 12 hours and keep warm for up to 12 hours after. Ideal Home made a soup on low for six hours and a chicken dish on high for three hours. Its verdict was that it's a fantastic buy if you want a slow cooker with a rice mode that you can also use as a second hob.
Where it falls short
- It's not fast. No pressure means no shortcuts. A stew still takes hours.
- No metal utensils. Ideal Home pointed out that metal tools can damage the non-stick, which also means you can't use a stick blender in the pot to blend soup.
- It can boil over on high. Ideal Home found this. Don't overfill, and leave the lid slightly ajar for starchy food like pasta.
- It's wide. At 42 cm across it takes more worktop than either pressure cooker.
- Heat settings are simple. Ideal Home described high and low for slow cooking and was inconsistent about whether there was a medium setting, so check the manual if you rely on a middle setting.
You'll see other reviews of a "Ninja PossibleCooker" from Tech Advisor and Expert Reviews. Those cover an earlier, larger 8 litre model with different modes, such as bake, braise and prove, and no rice or pasta settings. Their findings don't all apply to the 6 litre MC1101UK we sell, so we haven't used their test results here.
Our guide to searing, slow cooking and serving from the PossibleCooker has recipe ideas.
Head to head: which wins at each job?
| Job | Best of the three | Why |
|---|---|---|
| Weeknight stew or curry in under an hour | COSORI or Instant Pot | Pressure is the only way to soften tough meat fast |
| Dried beans and chickpeas from scratch | COSORI or Instant Pot | Pressure cuts hours to minutes, and gets beans hot enough (see safety below) |
| Stock and bone broth | COSORI | Bigger pot, pressure speeds extraction |
| All-day slow cook while you're at work | Ninja | Proper slow cook settings, 12-hour timer and keep warm |
| Browning meat before cooking | Ninja | Sears up to 205°C |
| Rice | Ninja | Dedicated white and brown rice modes; reviewers found the COSORI's rice a bit dry |
| Pasta in one pot | Ninja | Dedicated pasta mode |
| Porridge | Any | All three have a setting for it |
| Yogurt | COSORI or Instant Pot | Both have a yogurt programme; the Ninja doesn't |
| Hard-boiled eggs in batches | Instant Pot | Egg programme and steam rack |
| Finishing in the oven | Ninja | Pot is oven-safe to 240°C |
| Cooking for one or two | Instant Pot | Smallest and cheapest |
| Batch cooking for the freezer | COSORI or Ninja | 5.7 and 6 litres |
How much time does pressure cooking really save?
Less than the cooking times on the box suggest, and more than sceptics think.
Every pressure cook has three stages. First the cooker heats up and builds pressure. Then it cooks for the set time. Then the pressure has to come down before you can open the lid, either slowly on its own (natural release) or quickly by opening the valve (quick release). Recipes often quote only the middle stage.
The COSORI shows why this matters. Trusted Reviews' porridge took 3 minutes to cook, but preheating took well over 10. T3's Instant Pot meatballs, on the other hand, took under 20 minutes from start to finish, including preheat and release.
Where pressure cooking really pays off is anything that normally takes hours: beef shin, lamb shoulder, pulled pork, dried beans, chickpeas, stock. Trusted Reviews' 1.5 kg gammon took about an hour. In a pan that would usually be longer, and you'd be watching it. For quick things like steamed vegetables or salmon, a pressure cooker isn't much faster than a pan, once you count the heat-up time.
Running costs over three years
All three are cheap to run compared with a conventional oven, but we couldn't find independent UK measurements of how much electricity each one uses for a typical meal. So rather than invent figures, here's a ceiling you can work from.
A cooker's rated wattage is the most it can draw. It only draws that while heating up. Once it's at pressure or at temperature, the element switches on and off to hold it, so the real use is lower. At Ofgem's price cap for October to December 2026, electricity averages 26.32p per kWh on a direct debit standard variable tariff.
| Cooker | Rated power | Most it could cost for 1 hour at full power |
|---|---|---|
| Instant Pot Classic Mini | 800 W | About 21p |
| COSORI 5.7L | 1,100 W | About 29p |
| Ninja PossibleCooker | 1,400 W | About 37p |
In practice a pressure-cooked stew runs at full power only for the heat-up, so it will cost well under these figures. A slow cooker runs for longer, but on low it uses a small share of its rated power for most of that time. The honest answer is that for any of these three, a meal costs pennies, and the difference between them is unlikely to be more than a few pounds a year. If you're comparing with the oven, our air fryer vs oven energy guide explains why small appliances usually win.
Over three years, the bigger costs are the purchase price and parts:
| Three-year cost | Instant Pot Classic Mini | COSORI 5.7L | Ninja PossibleCooker |
|---|---|---|---|
| Price at Clean Smile Home | £55.19 | £91.99 | £91.99 |
| Parts that wear | Silicone sealing ring | Silicone sealing ring; non-stick pot if yours has one | Non-stick pot |
| Cost per month of ownership (cooker only) | About £1.53 | About £2.56 | About £2.56 |
Pressure cooker sealing rings pick up smells and harden with age, and most owners replace them now and then. Prices vary, so check before you buy. A non-stick coating lasts longest if you avoid metal utensils and harsh scourers.
Safety: what you need to know
Pressure cookers
Modern electric pressure cookers have several safety features. The lid locks while there's pressure inside, and won't open until it drops. Instant Pot describes an easy-seal locking lid and a steam release switch, and our COSORI listing mentions an anti-scald lid, overheat protection and automatic steam release. Even so:
- Never force the lid open.
- Keep your hands and face away from the valve during a quick release. The steam is very hot.
- Don't fill above the maximum line, and fill less for food that foams, like beans, grains and porridge.
- Check the sealing ring is fitted properly and the valve is clear before each use.
Slow cookers and red kidney beans
This is the big one for the Ninja. Dried red kidney beans contain a natural toxin that's destroyed by proper boiling but not by gentle cooking. The Food Safety Information Council says to soak dried kidney beans for at least five hours, then boil them briskly in fresh water for at least 10 minutes, and not to cook them at a low temperature such as in a slow cooker. It also says undercooked beans can be more toxic than raw ones. Tinned kidney beans are already cooked and are fine to add to a slow cooker.
So if you make chilli in the PossibleCooker with dried beans, soak them and boil them first on a hob, or use tinned. In a pressure cooker, the beans reach well above boiling point, but follow the manual's bean programme and soaking advice.
Tips for getting the best from each
- Brown first. All three can sauté. Browning meat and onions before you pressure or slow cook gives far more flavour. The Ninja does this best.
- Deglaze after sautéing. On the pressure cookers, pour in a splash of stock and scrape the bottom before you seal the lid. It stops food sticking and burning, which can stop the cooker reaching pressure.
- Use enough liquid. Pressure cookers need liquid to make steam. Follow the manual's minimum.
- Use less liquid when slow cooking. Very little evaporates under a lid, so slow cooker recipes need less than a hob recipe.
- Thicken at the end. Use sauté mode or the Ninja's sear setting to reduce a sauce once the lid is off.
- Add delicate things later. Peas, spinach, cream and fresh herbs go in at the end.
- Let meat release naturally. A slow, natural pressure release keeps meat more tender than a quick one.
- Keep the sealing ring fresh. Wash it after strong-smelling dishes. Some people keep one ring for curries and one for sweet dishes.
- Don't cook dried kidney beans in a slow cooker. See the safety section above.
Common problems and how to fix them
"My pressure cooker is taking ages to start counting down"
It's still building pressure. Reviewers found the COSORI takes over 10 minutes for some dishes. Starting with hot liquid, or sautéing first so the pot is already warm, shortens the wait.
"My pressure cooker never reaches pressure"
Check the sealing ring is seated properly, the valve is set to seal rather than vent, and there's enough thin liquid in the pot. Thick sauces and food stuck to the bottom can also stop it.
"Food is stuck to the bottom of my Instant Pot"
T3 found this too. Deglaze after sautéing, add liquid before thick ingredients like tomato purée, and soak the pot in warm water before scrubbing.
"The Instant Pot lid won't come off"
If there's still pressure inside, it's locked for safety. Wait, or carefully use the steam release. T3 found the lid could stick even in normal use, so twist gently and don't force it.
"My COSORI rice is dry"
T3 and Trusted Reviews both found this. Add a little more water than the manual suggests and let it rest on keep warm for a few minutes.
"My Ninja PossibleCooker boiled over"
Ideal Home saw this on high. Don't fill too high with starchy food, and turn down to low once it's simmering.
"My slow cooker stew is watery"
Use less liquid next time. To rescue it, take the lid off and reduce it on sear/sauté for a few minutes.
"The sealing ring smells of last night's curry"
Wash it in warm soapy water and let it air dry off the lid. If the smell won't shift, a replacement ring is the fix.
Our verdict
If you're short of time in the evening, buy a pressure cooker. The Instant Pot Classic Mini is the one we'd pick for one or two people. At £55.19 it's the cheapest of the three, it fits a small kitchen and T3 found it quick. Its slow cook is weak and food can stick, but that's not why you'd buy it.
For a family, the COSORI 5.7L is a well-reviewed full-size pressure cooker at £91.99. Accept that it's slow to preheat and you'll get dinners that would otherwise take hours.
If you're short of time in the morning and like to come home to dinner, the Ninja PossibleCooker is the better appliance, and the best of the three at searing, rice and pasta. Just go in knowing it isn't a pressure cooker, and don't put dried kidney beans in it.
If you can only have one and you're not sure, ask yourself how often you'll cook dried beans or a tough cut on a weeknight. Often? Pressure cooker. Rarely? The Ninja will probably get more use.
Frequently asked questions
What is the difference between a pressure cooker and a multi-cooker?
A pressure cooker seals the pot so pressure builds up and food cooks above 100°C, much faster. A multi-cooker is any appliance with several modes in one pot. Most electric pressure cookers are multi-cookers too, but some multi-cookers, like the Ninja PossibleCooker, don't pressure cook at all.
Is the Ninja PossibleCooker a pressure cooker?
No. The MC1101UK's eight modes are slow cook, steam, sear/sauté, keep warm, white rice, brown rice, porridge and pasta. It has a glass lid and cooks at normal pressure. If you want to pressure cook, look at the Instant Pot or COSORI.
Is the Instant Pot Classic Mini big enough for a family?
Usually not. It holds 3.8 litres, which Instant Pot and T3 put at up to four portions, and T3 said it may not suit batch cooking. For a family of four or more, a 5.7 or 6 litre cooker is more practical.
Which is better, Instant Pot or COSORI?
They suit different households. The Instant Pot Classic Mini is smaller, cheaper and comes up to pressure quickly, according to T3. The COSORI 5.7L is a full-size family cooker with more presets, rated 4.5 out of 5 by Olive, but every reviewer found it slow to preheat.
Can you slow cook in an Instant Pot?
Yes, it has a slow cook mode. T3 found the low setting was only a small step up from keep warm, so it's not as good at slow cooking as a dedicated slow cooker like the Ninja PossibleCooker.
Does pressure cooking save electricity?
Usually, compared with an oven or a long simmer on the hob, because it cooks faster in a small insulated pot. We couldn't find independent UK measurements for these models, but at the current price cap even an hour at full power costs between about 21p and 37p for these three.
How long does the COSORI pressure cooker take to preheat?
Over 10 minutes for some dishes, according to both T3 and Trusted Reviews. That's on top of the cooking time, so 3-minute porridge is more like 15 minutes from switching on.
Can you cook rice in a pressure cooker?
Yes. The COSORI has a rice programme and the Instant Pot can pressure cook rice. Reviewers found the COSORI's rice slightly dry, so add a little extra water. The Ninja PossibleCooker has dedicated white and brown rice modes and cooked white rice in under 30 minutes for Ideal Home.
Can I put the Ninja PossibleCooker pot in the oven?
Yes. Ninja says the removable pot is oven-safe up to 240°C. That means you can sear, slow cook and then finish a dish in the oven in the same pot.
Can you cook dried kidney beans in a slow cooker?
Not from raw. The Food Safety Information Council says to soak dried kidney beans for at least five hours and boil them briskly for at least 10 minutes, and not to cook them at low temperature in a slow cooker. Tinned kidney beans are already cooked and are fine.
Are electric pressure cookers safe?
Modern electric pressure cookers have locking lids that won't open under pressure, plus pressure valves and overheat protection. Follow the manual, don't overfill, check the sealing ring before use and keep your face away from the steam during a quick release.
Which multi-cooker is best for one person?
The Instant Pot Classic Mini 3.8L. It's the smallest and cheapest of the three at £55.19, cooks up to four portions, and pressure cooks quickly, so you can make a portion for tonight and one for tomorrow.
Can I use metal utensils in these cookers?
In the Instant Pot's stainless steel pot, yes. The Ninja PossibleCooker has a non-stick pot, and Ideal Home warned that metal tools can damage it. Our COSORI listing describes a non-stick pot, so use wooden or silicone utensils unless your version's pot is stainless.
Shop the cookers in this guide
- Instant Pot Classic Mini 3.8L 7-in-1 Multi-Cooker, Sea Salt White, £55.19
- COSORI 5.7L 9-in-1 Electric Pressure Cooker, Stainless Steel, £91.99
- Ninja Foodi 8-in-1 PossibleCooker 6L MC1101UK, £91.99
For more on the brands, read our Instant Pot brand guide, COSORI brand guide and Ninja brand guide. If you're timing a purchase, see our Black Friday kitchen deals guide.
Sources
- T3: Instant Pot Classic Mini 3.8L review
- John Lewis: Instant Pot Classic Mini Multi Cooker
- Trusted Reviews: COSORI 5.7L Pressure Cooker review
- T3: COSORI 5.7L Electric Pressure Cooker review
- Olive: COSORI 9-in-1 Electric 5.7L Multi-Cooker review
- Ninja UK: Foodi 8-Mode 6L PossibleCooker MC1101UK
- Ideal Home: Ninja Foodi 8-Mode 6L PossibleCooker MC1101UK review
- Ofgem: energy price cap, 1 October to 31 December 2026
- Food Safety Information Council: kidney beans
