Redmi K40 Pro+ Review: Build Quality, Software and Daily Speed

The Redmi K40 Pro+ arrived in China in early 2021 as the top version of the Redmi K40 series, with a flagship chipset, a high refresh rate screen and a 108MP main camera, at a price well below most flagship phones of that year. Announced on 25 February 2021 and released on 4 March 2021, it was aimed at buyers who wanted flagship-level speed at a mid-range price without paying for a larger camera system or a curved display. This article looks at the Redmi K40 Pro+ review build quality and daily performance in detail, from the frame and screen to software, cameras and battery, using the published specifications as the basis for every claim.

On paper, the Redmi K40 Pro+ specs are strong for the price: a Qualcomm Snapdragon 888 5G chipset, 12GB of RAM, 256GB of UFS 3.1 storage, a 6.67-inch 120Hz Super AMOLED display and a 4520mAh battery with 33W wired charging. The Redmi K40 Pro+ price was listed at about 470 EUR, which placed it against upper mid-range phones rather than true flagships, even though its processor matched the fastest Android phones of 2021. That gap between price and processor is the main reason the phone still attracts attention years later, and it is also the reason its trade-offs deserve a close look.

Design and Build Quality

The Redmi K40 Pro+ design uses a glass front and back with a plastic frame, a combination that keeps the weight down while keeping the phone looking like a flagship from the front. At 163.7 x 76.4 x 7.8 mm and 196 g, it is tall and fairly wide, but the 7.8 mm thickness keeps it from feeling bulky in a pocket. The Redmi K40 Pro+ design and build quality with Gorilla Glass 5 on the front gives the screen a reasonable level of scratch protection, while the rear glass adds a smooth, reflective finish in Black, White and Aurora. The Redmi K40 Pro+ colors are Black, White and Aurora, and the Aurora finish is the most distinctive of the three, shifting colour as the light changes. The overall look is a clean and practical design with a rectangular camera module in the top left corner and a centred punch-hole camera on the front.

Materials, Size and Grip

Redmi K40 Pro+ weight and grip comfort during long use are reasonable for a 6.67-inch phone, although one-handed use near the top of the screen still needs a shift in grip. The Redmi K40 Pro+ weight is 196 g, which is neither light nor heavy for its size, and the flat sides of the frame help the phone sit securely in the hand. The side-mounted fingerprint sensor sits in the power button on the right edge, within easy reach of the thumb, and the volume rocker sits just above it. There is no curved glass to catch stray touches, which suits long reading and browsing sessions.

Everyday Handling and Grip

In daily handling, the flat display and slim profile matter more than the choice of materials. The phone slides into a pocket without catching, the buttons are easy to find without looking, and the glass back is grippy enough when clean, although a case is still a sensible addition because glass can be slippery. The Redmi K40 Pro+ durability is helped by the Gorilla Glass 5 front and the solid fit of the frame, but the phone is not built for drops onto hard surfaces, so a case and a screen protector remain the practical choice for most owners.

Display Protection and Splash Resistance

The front glass is Corning Gorilla Glass 5, which protects against scratches from keys and coins in normal use, although it is not a guarantee against cracks from a hard drop. The Redmi K40 Pro+ IP53 splash resistance and durability in daily use means the phone is protected against dust and vertical water sprays, such as light rain, but it is not rated for submersion, so it should not be used in a pool or shower. The dual Nano-SIM tray, USB Type-C port and speaker grille are the usual openings to keep dry, and the IP53 rating is a useful safety net rather than a feature to rely on every day.

Display and Audio

The Redmi K40 Pro+ display measures 6.67 inches, uses a Super AMOLED panel with a 120Hz refresh rate, HDR10+ support and a peak brightness of 1300 nits, and it is one of the strongest parts of the phone for its price. The Redmi K40 Pro+ AMOLED panel is bright, colourful and sharp at 1080 x 2400 pixels, with a 20:9 aspect ratio and about 395 pixels per inch. The Redmi K40 Pro+ screen is protected by Gorilla Glass 5, and the punch-hole selfie camera sits in the centre at the top, keeping the bezels slim on all four sides.

120Hz AMOLED in Daily Use

The Redmi K40 Pro+ 120Hz AMOLED display quality and brightness stand out in scrolling, animations and video, where the higher refresh rate makes motion look smoother than on a standard 60Hz panel. The Redmi K40 Pro+ screen on time with 120Hz refresh rate enabled is shorter than with 60Hz, because the display draws more power, but the phone allows the refresh rate to be changed, so owners can choose smoothness or longer battery life. Colours are vivid in the default mode, blacks are deep because each pixel produces its own light, and HDR10+ video looks noticeably better than standard video on supported apps. For reading, the panel stays comfortable at low brightness, and the 120Hz mode makes long web pages and social feeds feel more responsive, thanks to a bright 120Hz panel that keeps motion smooth. Readers who want a newer Redmi screen to compare can read Redmi K50 Review: Display, Audio and Overall Experience for a later take on the same ideas.

Outdoor Visibility and Brightness

The Redmi K40 Pro+ display outdoor visibility under bright sunlight is good for a phone of its age, thanks to the 1300-nit peak brightness on HDR content and strong brightness in normal outdoor use. Text stays readable in direct sun, although the glossy glass can reflect light at some angles, so shading the screen with a hand still helps on the brightest days. The automatic brightness sensor reacts quickly when moving between indoors and outdoors, and the panel keeps its colours stable rather than washing out as the brightness rises.

Stereo Speakers and Sound

The Redmi K40 Pro+ stereo speakers sound quality and volume are solid for videos, games and speakerphone calls, with one speaker at the bottom and a second speaker in the earpiece. The Redmi K40 Pro+ speakers are stereo, and they produce a wider sound than a single bottom speaker, although bass is limited, as it is on almost every slim phone. The Redmi K40 Pro+ audio comes from stereo speakers with 24-bit/192kHz Hi-Res audio support, and there is no 3.5mm headphone jack, so wired headphones need a USB Type-C adapter or a wireless connection. The Redmi K40 Pro+ no headphone jack and USB Type C audio setup will suit owners who already use wireless earphones, but buyers with wired headphones should budget for an adapter. For a later Redmi flagship with its own take on cameras and battery, see Redmi K50 Ultra Review: Cameras, Performance and Battery Life.

Performance and Gaming

The Redmi K40 Pro+ performance comes from the Qualcomm SM8350 Snapdragon 888 5G chipset, built on a 5 nm process, with an octa-core CPU and Adreno 660 graphics. The Redmi K40 Pro+ Snapdragon 888 performance in everyday use covers app opening, web browsing, photo editing and switching between apps without delay, and the 12GB of RAM keeps more apps in memory than the 8GB versions of many rivals. The Redmi K40 Pro+ RAM is 12GB, paired with 256GB of UFS 3.1 storage, and the Redmi K40 Pro+ storage is fixed at 256GB with no microSD card slot, so buyers cannot expand it later. The Redmi K40 Pro+ 256GB storage with 12GB RAM performance is therefore important to judge as a fixed package: it is generous for apps, photos and games, but owners who keep large offline video libraries will need to manage space.

Snapdragon 888 in Everyday Tasks

The Redmi K40 Pro+ app opening speed and multitasking with 12GB RAM are the clearest benefits of the flagship chipset in normal use. Apps open quickly, the camera starts without a long wait, and switching back to a game or a browser with many tabs rarely forces a reload. The CPU uses one 2.84 GHz Cortex-X1 prime core, three 2.42 GHz Cortex-A78 cores and four 1.80 GHz Cortex-A55 efficiency cores, a layout that gives fast bursts for demanding tasks and lower power use for light tasks. In practice, the phone feels fast in the tasks most owners repeat every day, from messaging and maps to streaming and light photo editing.

Gaming, Heat and Sustained Speed

The Redmi K40 Pro+ gaming performance with Snapdragon 888 chipset is strong for demanding titles at high settings, and the Adreno 660 GPU handles 3D games with smooth frame rates on the 120Hz display. The Redmi K40 Pro+ gaming experience benefits from the large display and stereo speakers, although long sessions can warm the upper part of the phone, as the Snapdragon 888 is known for running hot under sustained load. The Redmi K40 Pro+ heating issue during gaming and heavy use is therefore worth knowing about: short bursts stay fast, but very long sessions may see the phone reduce speed to control temperature. A case that traps heat can make this worse, so removing the case during long gaming sessions and keeping the phone out of direct sun are simple ways to keep performance steadier. Readers weighing a gaming-focused Redmi can compare with Redmi K50 Gaming Review: Strengths, Trade-Offs and Everyday Use.

Multitasking with 12GB RAM

With 12GB of RAM, the phone keeps many apps open at once, from a browser and a music app to a map and a messaging app, without closing them in the background. Split-screen use is comfortable on the 6.67-inch display, and returning to an app after an hour usually finds it in the same state. The UFS 3.1 storage also speeds up installing large games and copying files, which matters when the phone is used as a daily driver for both work and play.

Software and MIUI Experience

The Redmi K40 Pro+ software shipped with Android 11 and MIUI 12, the Xiaomi interface of its time, with a large set of customisation options, themes, gestures and system apps. The Redmi K40 Pro+ MIUI 12 software experience on Android 11 is colourful and feature-rich, with a control centre, floating windows, a second space for separate profiles and many settings for the display, sound and battery. Some owners like the number of options, while others find the number of pre-installed apps and notifications takes time to tidy up after the first setup. Redmi K40 Pro+ connectivity covers 5G, Wi-Fi 6E, Bluetooth 5.2, NFC, GPS and an infrared port, and the software settings bring those connections together in one place.

MIUI 12 on Android 11

The Redmi K40 Pro+ software is based on MIUI 12, which adds its own animations, icons and system tools on top of Android 11. The interface supports dark mode, always-on display options, gesture navigation and a full-screen mode that hides the navigation bar, and the settings menu covers the 120Hz refresh rate, the fingerprint sensor and the battery saver in one place. The Redmi K40 Pro+ fingerprint sensor and face unlock speed are both quick in daily use, with the side sensor unlocking the phone as the thumb rests on the power button, and face unlock working well in good light. The Redmi K40 Pro+ side mounted fingerprint sensor accuracy and speed are good in daily use, unlocking quickly with a registered thumb and rarely needing a second attempt. Notifications, permissions and background app behaviour can all be adjusted, although new owners should spend a few minutes turning off the notifications they do not want.

Updates and Long-Term Software Support

The Redmi K40 Pro+ software update to MIUI 13 and Android 12 arrived for the phone after launch, bringing a newer interface and a newer Android version, and later updates continued the MIUI line for the K40 series. A Redmi K40 Pro+ update to MIUI 13 changes the look of widgets and the control centre, and it also brings the security patches and system improvements that came with that release. The Redmi K40 Pro+ WiFi 6E Bluetooth 5.2 and NFC connectivity features include Wi-Fi 802.11 a/b/g/n/ac/6e, Bluetooth 5.2 with A2DP and LE, NFC for payments, an infrared port and GPS with several satellite systems. Even so, buyers in 2026 should check the exact software version on the unit they are buying, because update support for a 2021 phone is limited, and the newest Android features will not all be available.

Cameras

The Redmi K40 Pro+ camera system uses a triple rear camera: a 108MP wide camera, an 8MP ultrawide camera and a 5MP macro camera, with a 20MP front camera for selfies and video calls. The Redmi K40 Pro+ camera is built around the high-resolution main sensor, which uses pixel binning to produce detailed 12MP photos in normal mode and full 108MP photos when that mode is selected. Video reaches 8K at 30 frames per second and 4K at 30 or 60 frames per second, with gyro-EIS stabilisation and HDR10+ recording, which is a strong video specification for a phone at this price.

Main 108MP Camera in Daylight and Low Light

The Redmi K40 Pro+ 108MP camera photo quality in daylight is detailed and sharp, with good colour and a wide dynamic range in bright scenes, and the large 1/1.52-inch sensor helps keep noise low in good light. The Redmi K40 Pro+ night mode camera performance in low light is weaker than in daylight, as night mode needs a steady hand and a few seconds to combine frames, but it still produces usable photos in street light and indoor light, with brighter shadows than the standard mode. The main camera uses an f/1.8 aperture and phase detection autofocus, and the colour spectrum sensor helps with white balance, so photos in mixed light look more natural than on phones without that sensor.

Ultrawide, Macro and Selfie Cameras

The Redmi K40 Pro+ ultrawide camera photo quality and distortion control are reasonable for landscapes and group photos, with a 119-degree field of view that fits much more into the frame than the main camera, although fine detail is lower than on the 108MP sensor and the edges can show some softness. The Redmi K40 Pro+ macro camera close up photo quality review notes that the 5MP macro lens focuses at close range and can capture small subjects such as flowers and textures, but it needs good light and a steady hand to get a sharp result. The Redmi K40 Pro+ selfie camera quality for video calls and portraits is good in daylight, with the 20MP front camera producing clear photos and 1080p video, although low-light selfies show more noise. The Redmi K40 Pro+ selfie camera also supports HDR, which helps when the background is brighter than the face. The Redmi K40 Pro+ 8K video recording quality and stabilisation features include gyro-EIS and HDR10+ video, and 8K footage is best used in bright light on a tripod or a stable surface, because the files are large and the phone can warm up during long recordings. For a later Redmi camera comparison, see Redmi K60 Ultra Review: Camera Quality, Battery and Value.

Battery Life and Charging

The Redmi K40 Pro+ battery is a 4520mAh Li-Po cell, which is a typical size for a 2021 flagship, although it is smaller than the 5000mAh batteries found in some rivals. The Redmi K40 Pro+ battery life with 4520mAh and 33W charging depends on the refresh rate, brightness and use, with the 120Hz mode and 5G both drawing more power than 60Hz and Wi-Fi. The Redmi K40 Pro+ charging is rated at 33W wired, with PD3.0 and QC3 support, and the published figure is a full charge in 52 minutes. There is no wireless charging, which is one of the trade-offs at this price, so owners should keep the supplied cable and charger handy.

How Long the 4520mAh Battery Lasts

The Redmi K40 Pro+ screen on time with 120Hz refresh rate enabled is shorter than with the standard refresh rate, so owners who want the longest battery life can switch to 60Hz for a day of heavy use. With mixed use, including messaging, browsing, video and some gaming, the phone is best described as a one-day phone, with a charge needed by the evening on busy days and a comfortable margin on lighter days. The Redmi K40 Pro+ 5G connectivity speed and network performance also affect battery life, because 5G can draw more power than 4G in areas with a weak signal, so switching to 4G in a poor 5G area can save power. The battery saver in MIUI can extend the day further by limiting background activity and reducing the refresh rate.

33W Charging in Practice

The Redmi K40 Pro+ charging time from zero to full with 33W is listed at 52 minutes, which is fast enough to top up the phone during a meal or a short break, although it is slower than the 65W and 120W charging found on some later phones. A fast 33W wired charging top-up of 15 to 20 minutes adds a useful amount of power for several hours of light use, and the phone supports PD3.0 and QC3, so compatible chargers can also be used. Charging is wired only, through USB Type-C 2.0 with OTG support, and the phone does not support wireless charging. For a later Redmi model with a different balance of battery and charging, read Redmi K50 Pro Review: Gaming, Multitasking and Battery Life.

Full Specifications

The table below lists the Redmi K40 Pro+ specs in full, based on the published specification sheet. Announced on 25 February 2021 and released on 4 March 2021, the phone is also known as the Xiaomi Redmi K40 Pro Plus and the Xiaomi Redmi K40 Ultra, and the model number is M2012K11C.

Pros and Cons

The Redmi K40 Pro+ value in 2026 depends on the price of the unit and the condition of the battery, because the phone is no longer new and its software support is limited. The Redmi K40 Pro+ price and value for money in 2026 are strongest when the phone is bought at a clear discount to newer mid-range phones, because the Snapdragon 888 still delivers fast daily speed, while the 120Hz display and 108MP camera remain useful. Buyers should weigh that value against the smaller battery, the lack of wireless charging and the absence of a headphone jack before deciding.

Pros

• Snapdragon 888 flagship performance with 12GB of RAM
• Bright 120Hz Super AMOLED display with HDR10+ and 1300 nits peak brightness
• 108MP main camera with 8K video recording
• 256GB of fast UFS 3.1 storage
• Stereo speakers, 5G, Wi-Fi 6E, NFC and an infrared port
• Slim 7.8 mm body with Gorilla Glass 5 protection

Cons

• 4520mAh battery is smaller than many rivals
• 33W charging with no wireless charging
• No microSD card slot and no 3.5mm headphone jack
• IP53 splash resistance only, not full water resistance
• Snapdragon 888 can run warm under sustained load
• Software support is limited years after launch

FAQ

Is the Redmi K40 Pro+ good for gaming?

Yes, for most games. The Redmi K40 Pro+ gaming performance is strong because of the Snapdragon 888 chipset and Adreno 660 graphics, and the 120Hz display and stereo speakers help in fast games. Very long sessions can warm the phone, so short breaks and a case-free session help keep frame rates steadier.

Does the Redmi K40 Pro+ support 5G?

Yes. The phone supports 5G on bands 1, 3, 28, 41, 77 and 78 with SA and NSA, along with 4G LTE, Wi-Fi 6E, Bluetooth 5.2 and NFC. Actual 5G speed depends on the network and the coverage in the area where the phone is used.

How fast is Redmi K40 Pro+ charging?

The phone charges at 33W wired, with a published full charge time of 52 minutes from zero to full. It supports PD3.0 and QC3, but it does not support wireless charging.

Does the Redmi K40 Pro+ have a headphone jack?

No. There is no 3.5mm headphone jack, so wired headphones need a USB Type-C adapter, or owners can use Bluetooth earphones. The phone also has stereo speakers and Hi-Res audio support.

Is the Redmi K40 Pro+ still worth buying in 2026?

It can be worth buying at the right price, as a second-hand or discounted phone, because the Snapdragon 888, 120Hz display and 108MP camera still cover daily use well. The Redmi K40 Pro+ long term durability after years of daily use depends on the battery condition and the software version, so buyers should check both before paying. The phone is best suited to buyers who want flagship speed on a budget and who accept the smaller battery and limited update support.

Taken as a whole, the Redmi K40 Pro+ is a phone that trades battery size, wireless charging and a headphone jack for flagship speed, a bright high refresh rate display and a high-resolution camera at a lower price. That trade still makes sense for buyers who value speed and screen quality above all else, and who are comfortable with the limits of a 2021 flagship in 2026.