The Ninja CRISPi 4-in-1 Portable Glass FN101UKST is a compact air fryer designed to handle everyday meals without taking over your worktop. With a 3.8-litre capacity and two glass containers, it’s aimed at smaller households that still want flexible, healthier cooking.
Ninja has a strong reputation in the air fryer space, and this model leans on that experience with straightforward controls, a clear display and four core functions: air fry, roast, keep warm and recrisp. It’s not the biggest or most feature-packed fryer Ninja makes, but it focuses on practicality, ease of use and visibility through the glass bowls.
With an average user rating of 4.6 out of 5 from over 80 reviews, it’s clearly well liked by owners, especially for its size, performance and simple clean-up.
The Ninja CRISPi FN101UKST is best suited to singles, couples or smaller families who want the benefits of an air fryer without a bulky appliance permanently living on the counter. Its 3.8-litre main container is enough for a couple of chicken breasts, chips for two to three people or a side dish for a family meal.
If you’re moving from oven-only cooking or a basic air fryer, this is a good mid-range step. You get Ninja’s reliable performance, a clear digital display and automatic programmes, but without the complexity or cost of the largest dual-zone models.
Health-conscious cooks who want to cut down on oil will appreciate the air fry and roast modes, which promise up to 75% less fat than traditional frying. The recrisp function is ideal if you often end up with leftover chips or pizza that need reviving, while the keep warm setting suits anyone juggling different elements of a meal.
It’s less ideal for big batch cooking or large families who regularly cook multiple components at once. If you often cater for four or more hungry adults, you may prefer a larger-capacity or dual-drawer air fryer.
The compact footprint and 3.8-litre capacity strike a good balance between space-saving and practicality, making it easy to leave on the worktop or tuck away in a cupboard.
Two glass containers – a 3.8-litre and a smaller 1.4-litre – are a standout feature. Being able to see your food as it cooks helps avoid overcooking, and the smaller container is ideal for sides and snacks.
The 4-in-1 functionality (air fry, roast, keep warm, recrisp) covers most day-to-day needs without overcomplicating things. Recrisp is particularly useful for bringing leftovers back to life instead of binning them.
Dishwasher-safe components and a non-stick finish make cleaning far less of a chore. You can simply lift out the bowls and crisper plates and pop them in the dishwasher.
Features like non-slip, heat-resistant feet and auto power-off add reassurance, protecting your worktops and giving peace of mind if you forget to switch it off.
With a single basket and relatively modest 3.8-litre capacity, this model won’t suit larger families or those who like to cook protein and sides at the same time in separate zones.
There’s no dedicated grill plate or baking tray included, which limits some cooking styles compared with more fully accessorised air fryers.
An anti-odour filter is missing, so while air fryers are generally less smelly than deep-fat fryers, very aromatic foods may still linger a little in smaller kitchens.
Despite being glass-based, the unit isn’t rated as fully dishwasher proof as a whole appliance – only the removable parts are, so the main body still needs wiping down carefully.
Day to day, the Ninja CRISPi FN101UKST is designed to be straightforward. The button-based controls and built-in display are easy to understand, even if you’ve never owned an air fryer before. Automatic cooking programmes help you get consistent results without too much guesswork.
The relatively small footprint (around 29 cm high and under 30 cm wide) means it fits comfortably on most worktops, and the heat-resistant, non-slip feet keep it stable while protecting your surfaces from heat.
Loading food is simple: place it in the glass container with the appropriate crisper plate, select the function and temperature, and you’re away. The glass bowls make it easy to see how crispy things are getting without opening the unit and losing heat.
Cleaning is one of the stronger points. The non-stick interior and dishwasher-safe containers and crisper plates make post-dinner clean-up quick. You’ll still need to wipe the exterior and control panel, but there are no awkward nooks or complex parts to dismantle.
The 0.89 m power cord is adequate for most kitchen layouts, though you may need to think about placement if your sockets are limited.
Powered by a 1500-watt heating system, the Ninja CRISPi offers brisk preheating and fast cooking times for its size. It’s well suited to mid-week meals where you want food on the table quickly, and air frying helps you achieve crisp results with far less oil than deep frying.
The 3.8-litre main glass container is the workhorse, handling mains and family sides, while the 1.4-litre container is perfect for smaller portions, reheating leftovers or cooking for one. Both use crisper plates to promote air circulation underneath the food, helping chips, nuggets and veg come out evenly browned.
Four power levels and automatic cooking programmes give you enough control without being overwhelming. Air fry and roast cover most recipes you’d typically move from an oven, while the bake capability adds versatility for simple traybakes or small desserts.
The keep warm function is genuinely useful if one part of the meal finishes early or someone is late home. It stops food sitting and cooling on the counter, and avoids having to reheat in the microwave. The recrisp mode is similarly handy; it focuses on restoring crunch to previously cooked food without drying it out.
Useful safety and convenience touches round out the package: auto power-off reduces the risk of accidental overcooking, the ready indicator lets you know when it’s at temperature, and the non-slip, heat-resistant feet ensure stability during use.
At around £129, the Ninja CRISPi FN101UKST sits in the mid-range for single-basket air fryers. You’re paying a little extra for the glass-container design and Ninja’s build quality, but you’re not into the premium bracket of large dual-zone models.
The feature set is focused rather than flashy, but covers the key jobs most people want an air fryer for, and the inclusion of both a large and small glass container adds flexibility that many rivals at this price don’t offer.
The strong user rating of 4.6 out of 5 from more than 80 reviews suggests owners feel they’ve had good value, particularly around performance and ease of cleaning. If you regularly use it in place of your main oven, you may also see some savings on energy bills over time.
If you need to cook for a big household or want more advanced functions and accessories, you may find better value in a larger-capacity model. For smaller homes looking for a reliable, neat, glass-based air fryer, though, the price feels fair.
The Ninja CRISPi 4-in-1 Portable Glass FN101UKST is a well-judged compact air fryer that focuses on everyday practicality. Its combination of clear glass containers, simple controls and genuinely useful modes like keep warm and recrisp make it easy to integrate into daily cooking.
It’s not the largest or most feature-packed option in Ninja’s range, and the single 3.8-litre basket will be limiting if you routinely cook for a crowd. The lack of grill plate and anti-odour filter are minor compromises at this price point.
For singles, couples and smaller families who want a smart-looking, easy-to-clean air fryer from a trusted brand, this model is a strong choice. If capacity is your priority, look at larger or dual-zone fryers; if you value compact size, glass visibility and hassle-free use, the Ninja CRISPi earns its place on the worktop.
