Ranking the World’s Thinnest Phones: Why a 10-Year-Old Record Still Hasn’t Been Broken
The pursuit of the impossibly thin smartphone has undeniably become one of 2025’s most compelling design narratives. This was not a subtle shift; the industry’s pivot towards extreme slimness has been a clear and deliberate trend, a collective re-evaluation of what constitutes premium design after years focused on camera bumps and battery heft. With whispers of an iPhone “Air” variant potentially gracing our screens on September 9th, the question looms: is this a confident stride into a new era of sleekness, or a touch of hubris that might revive haunting memories of bendgate? Either way, the race is on, and the current contenders are pushing the boundaries of what we thought possible.
Measuring thinness, however, becomes an intriguing challenge when foldables enter the arena. While a traditional candybar phone presents a single, static dimension, a foldable offers two: its folded state and its dramatically thinner unfolded state. For this list, we embrace the most impressive measurement a device can achieve, celebrating the engineering marvel that allows a phone to stretch into an almost paper-thin profile. This article is about the absolute thinnest a phone can be, plain and simple. And yes, that does make the comparison between candybars and foldables unfair in certain regards, but we’ll try to thread that needle with millimeter precision, so to speak. That being said, stick around till the end to see how a phone from 2014 still holds the ‘thinnest smartphone’ record even after a decade!
Huawei Mate XT Ultimate – 3.6mm unfolded (2025)
Huawei’s approach to thinness is a masterclass in extremes. The Mate XT Ultimate is not just a foldable; it is a tri-foldable, a wild piece of kit that unfolds twice to reveal a sprawling 10.2-inch display. When it is fully unfurled, the device measures a frankly unbelievable 3.6mm at its thinnest point. This is thinner than most USB-C ports, thinner than any tablet, and thinner than any phone ever made. It feels less like a consumer electronic device and more like a sheet of futuristic, flexible glass. For a company to even attempt this kind of engineering is bold, but to actually ship it is a statement that pushes the entire industry forward.
Of course, this radical design comes with a significant trade-off. When fully folded into its 6.4-inch candybar form, the Mate XT is a chunky 12.8mm thick, a necessity of stacking three screen layers. Despite this, Huawei did not skimp on the internals, packing a massive 5,600mAh battery, up to 16GB of RAM, and a flagship-grade triple camera system. It is a device of fascinating contradictions, achieving the world’s thinnest unfolded profile while still delivering heavyweight performance. The Mate XT proves that the pursuit of slimness can coexist with a refusal to compromise on power, even if it requires a completely new form factor to do so.
Honor Magic V5 – 4.1mm unfolded (2025)
Before Huawei’s tri-fold took the ultimate prize, the Honor Magic V5 was the undisputed champion of slim foldables. When unfolded, it measures an astonishing 4.1mm, a figure that makes most traditional slab phones look bulky. Its real magic, however, is its folded thickness of just 8.8mm. This was a groundbreaking achievement because it was the first time a book-style foldable felt less like a niche gadget and more like a normal, everyday smartphone when closed. It sits comfortably in a pocket and can be used one-handed without feeling cumbersome, solving one of the biggest usability hurdles for the form factor.
Honor achieved this feat through meticulous engineering, from a custom super-light titanium hinge to the implementation of a high-density silicon-carbon battery. This allowed them to fit a huge 5,820mAh cell into a chassis that is thinner than many competitors with smaller batteries. The Magic V5 was the phone that proved a large-screen foldable did not have to come with a penalty in portability. It set a new benchmark for the entire category and directly triggered the slim-down we are seeing from its rivals, including Samsung.
Samsung Galaxy Z Fold 7 – 4.2mm unfolded (2025)
Samsung’s response to Honor’s challenge is the Galaxy Z Fold 7, a device that shows how seriously the company is taking the thinness wars. At 4.2mm unfolded and around 8.9mm folded, its dimensions are within a hair’s breadth of the Magic V5, signaling a direct and fierce competition. This is Samsung demonstrating that it can match its rivals millimeter for millimeter while bringing its own expertise in durability and software polish to the table. The near-imperceptible difference in thickness between the two devices highlights just how optimized the engineering has become at the highest level of the foldable market.
While the numbers are impressive, Samsung’s focus with the Z Fold 7 is on refining the complete user experience. The phone feels more rigid and durable than previous generations, with a stronger hinge and better screen protection. This focus on practical usability, combined with its class-leading software and multitasking features in One UI, makes the Z Fold 7 a formidable contender. It represents a mature and polished vision for what a slim, powerful foldable can be, proving that extreme thinness can be achieved without sacrificing the reliability that mainstream users expect.
Samsung Galaxy S25 Edge – 5.8mm (2025)
Samsung’s Galaxy S25 Edge is a flagship entry that proudly claims the title of the thinnest slab phone from a major global brand in 2025, measuring a uniform 5.8mm. This is a deliberate design choice, positioning the Edge as the ultimate style statement within the S25 lineup. Crafted with a premium titanium frame and protected by Gorilla Glass Ceramic 2, it feels incredibly solid despite its featherlight 163-gram weight. The S25 Edge is a masterclass in minimalist design, exuding an aura of understated luxury.
To achieve this extreme thinness, Samsung made strategic decisions, including equipping it with the smallest battery among the S25 series and omitting a dedicated telephoto lens. These choices highlight its focus as a design-first device, appealing to users who prioritize sleek aesthetics and a comfortable in-hand feel above all else. The S25 Edge is a clear signal that Samsung believes there is a strong market for phones that are as much about their physical presence as their internal capabilities.
ZTE nubia Air – 5.9mm at thinnest point (2025)
Nubia’s Air enters the fray with an overall thickness of 6.7mm, but its design tapers to an impressive 5.9mm at its thinnest point along the frame. This makes it a serious contender in the ultra-slim candybar category, especially when considering its other remarkable features. The Nubia Air stands out by pairing its slender profile with an IP69K rating, offering exceptional dust and high-pressure water resistance. This level of ruggedness is almost unheard of in such a thin device, showcasing a sophisticated balance of form and function.
Beyond its durability, the Nubia Air surprises with a substantial 5,000mAh battery, defying the expectation that thin phones must compromise on power. It also features a vibrant 6.78-inch AMOLED display, ensuring a premium visual experience. Nubia has engineered a phone that not only looks incredibly sleek but also offers the resilience and endurance needed for everyday use. It is a thought-provoking blend of delicate aesthetics and robust construction, proving that a thin phone can indeed be built to last.
Tecno Spark Slim – 5.93mm (2025)
Tecno’s strategy in the thinness race appears to be a two-pronged attack unleashed at IFA 2025, with the Spark Slim representing the purist’s choice. At 5.93mm, it is the absolute thinnest modern candybar phone you can buy today, period. There is a beautiful simplicity to this device; its primary reason for being is to achieve that single, headline-grabbing number. The design is flat, clean, and minimalist, leaning into the aesthetic that makes thin devices feel so satisfying to hold. This is not a phone weighed down by excessive features; it is a focused exercise in industrial design.
By stripping back the complexity, Tecno has created a device that makes a singular, powerful statement. The Spark Slim is for the consumer who is captivated by the raw appeal of an incredibly thin object. It democratizes this design-first philosophy, bringing an obsessive level of slimness to a market segment that rarely sees such engineering focus. In a world of do-everything gadgets, there is something refreshing about a phone that unabashedly prioritizes form to this degree, proving that sometimes, the spec sheet’s most important number is the one with “mm” next to it.
Tecno Pova Slim 5G – 5.95mm (2025)
If the Spark Slim is the purist, the Pova Slim is the pragmatist. It is only two-hundredths of a millimeter thicker at 5.95mm, a difference that is functionally imperceptible. What you get for that negligible trade-off, however, is a suite of modern, premium features that make it a more well-rounded device. The Pova Slim boasts a gorgeous curved AMOLED display and 5G connectivity, elevating it from a simple design statement to a genuinely competitive mid-range smartphone. It is Tecno’s way of saying that you do not have to give up contemporary features to get a super-slim phone.
This device is arguably the more compelling of the two for the average buyer. It successfully blends its headline thinness with the practicalities of a modern smartphone, including a substantial 5,160mAh battery. The Pova Slim challenges the very notion of compromise, offering a sleek, premium-feeling device that does not skimp on screen quality, battery life, or connectivity. It is a testament to clever component packaging and a sign that the benefits of the thinness trend are finally trickling down to phones that balance form and function beautifully.
Oppo R5 – 4.85mm (2014)
Now for a trip back in time. In 2014, Oppo released the R5, a phone so shockingly thin that it sent ripples through the entire industry. At just 4.85mm, it was a marvel of miniaturization, featuring a hand-polished steel frame and a beautiful AMOLED display. To put that into perspective, it is a full millimeter thinner than today’s slimmest candybar phones. The R5 was a bold declaration of engineering prowess and a testament to how far a company would go in the pursuit of a design record. It felt futuristic at the time, and its thinness is still impressive even by today’s standards.
The R5 is also famous for a major compromise it made to achieve its slimness: it was one of the first mainstream phones to remove the 3.5mm headphone jack. This decision was highly controversial back then, but it proved to be incredibly prescient, foreshadowing a trend that would become the industry standard years later. The Oppo R5 remains a landmark device, a beautiful and divisive piece of tech that pushed the boundaries of what was possible and gave us a glimpse into the future of smartphone design, for better or worse.
vivo X5 Max – 4.75mm (2014)
Just when the world thought 4.85mm was the absolute limit, vivo arrived weeks later in 2014 and dropped a bombshell: the X5 Max. Measuring an almost unbelievable 4.75mm, it officially became, and still remains, the thinnest slab smartphone ever created. To achieve this, vivo’s engineers redesigned and stacked internal components with microscopic precision, creating a motherboard that was just 1.7mm thick. The result was a device that felt less like a phone and more like a thin sliver of metal and glass, a true “razor-thin” gadget.
What makes the vivo X5 Max’s achievement even more legendary is that it managed to do what the Oppo R5 could not: it included a 3.5mm headphone jack. This was a direct and brilliant feat of engineering, proving that even at the absolute bleeding edge of thinness, user-friendly features did not have to be sacrificed. The fact that no candybar phone in the decade since has managed to surpass this record speaks volumes. The X5 Max is not just a thin phone; it is a monument to a time when the race for thinness produced one of the most remarkable engineering achievements in mobile history.
Apple iPhone Air (Rumored – thickness TBD)
Apple’s rumored iPhone Air represents perhaps the most significant wildcard in this entire discussion. While concrete specifications remain under wraps, industry whispers suggest Apple is preparing to enter the ultra-thin smartphone arena in a major way, potentially targeting sub-6mm territory. This would mark a dramatic philosophical shift for a company that has spent recent years prioritizing camera capabilities and battery life over extreme slimness. The timing feels deliberate, arriving just as competitors have proven that modern thin phones can maintain flagship performance and reasonable battery life. If the rumors prove accurate, Apple’s entry could legitimize the thin phone trend for mainstream consumers in a way that no other manufacturer can match.
The elephant in the room, however, is whether Apple has truly moved past the bendgate controversies that plagued the iPhone 6 and 6 Plus. Those incidents created a lasting association between Apple and structural fragility in thin designs, a reputation the company has worked hard to overcome. An iPhone Air would represent either supreme confidence in their materials engineering or a calculated risk that the market’s appetite for thinness outweighs durability concerns. Given Apple’s typical approach to product launches, we can expect them to address this history head-on, likely showcasing rigorous stress testing and premium materials. The success or failure of an iPhone Air could determine whether the industry’s current obsession with thinness becomes a lasting trend or a cautionary tale.
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