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Smartphone design secrets: Why shape, materials, and balance matter

By Aleksandar Anastasov

Published: Jan 18, 2025, 6:10 AM

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Editorials

This article may contain personal views and opinion from the author.

A hand touching a phone with the symbol of an atom displayed on its screen.

Have you ever wondered why some smartphones feel better in your hand, while others seem awkward to use? Or whether the small changes manufacturers make actually make a difference? Every design choice—from the shape to the materials used—is shaped by choices based on physics, with the goal of balancing practicality with style.

Smartphone manufacturers don’t just prioritize aesthetics; they carefully balance functionality and durability. The materials, shape, weight distribution, and even the thickness of your device are all dictated by physics. Manufacturers have to juggle all of these elements perfectly to ensure the phone is not only comfortable to use, but also resilient against wear and tear, as well as efficient in its performance. But we all know there’s no perfect phone, so there are always some trade-offs, which we’ll talk about in detail.

As someone who has used a good number of phones over the years, I’ve often noticed how the design can directly affect my daily experience. For instance, I remember vividly when I transitioned from my Galaxy S3 to the iPhone 6s. It felt like I was holding a completely different device. It was so much thinner and easy to work with, enough for me to even change how I hold my phone—I was much more dexterous with it, not to mention I could barely feel it in my pocket.

Shape and form: square vs. rounded designs

Man holding the Galaxy S24 Ultra and S23 Ultra spread like a fan.

The Galaxy S23 Ultra was round all over, with very curved display and sides. It was comfortable, but there's a good reason Samsung stepped away from that approach with the next generation. | Image by PhoneArena

The shape of a smartphone is one of the first things users notice. We might not want to read a book by its cover, but many often make their purchase decision largely based on how a product looks. And while looks affect how stylish a phone is, they also come with their own quirky shape that has unique physical characteristics, impacting durability and ergonomics.
These days, we’ve gone from oval and curved phones to rectangular, sharp-edged ones. Of course, there’s proper reasoning behind both approaches.

Phones with flatter sides, like the iPhone 14 series, offer better durability. Stress distributes more evenly across square frames, reducing the likelihood of structural deformation. Additionally, flat sides create more internal space for components like batteries and larger sensors.

However, these designs can feel less comfortable during extended use due to sharper edges. For example, I found the iPhone 14’s flat edges stylish but not particularly pleasant during long gaming sessions as it would create dents into my palms, which could sometimes even hurt. Frankly, that probably means I should reduce my time on the phone, but then again that’s one of the reasons cases exist.

On the other hand, curved edges, like those on the Galaxy S23 Ultra, provide better ergonomics by contouring to the shape of your hand. However, they’re more prone to damage during drops, as the curved surfaces concentrate impact forces. I’ve had a couple of friends with curve-edged Galaxy phones that have ended up breaking them rather easily. They are also pretty difficult to protect even with a case.

But it seems that in the past couple of years, manufacturers have found the right shape that balances comfort and durability. By giving their phones flat sides with tapered edges the device can have good structural integrity while also being comfortable to hold. Apple made the transition to such an approach with the iPhone 15 series, which initially looked exactly the same as its predecessor, but after I held it I was instantly convinced how much better it felt in the hand. I had a similar experience when I held the OnePlus 13, which dropped the rounded corners of the OnePlus 12.

Shape will always change, especially with the introduction of new technology, but for now I really feel like phones have reached an optimal form that strikes the perfect balance. It is no coincidence that most modern phones look the same, with every major phone manufacturer favouring a similar design in terms of form.

Material choices: glass, metal, and plastic

Hands gently holding the Motorola Edge 2023, back facing camera.

Motorola's vegan leather is one of my favorite back panel materials in terms of feel, looks, and durability, but it has its downsides. | Image by PhoneArena

Shape is but only one element of a phone’s design. Materials are becoming a more significant area of focus each year. Apple and Samsung, for example, have gone the premium route and introduced a more high-end material for their best phones—titanium. Others, like Motorola, have doubled down on their creativity and continue to release phones with vegan leather back panels that are less prone to cracks, fingerprints and slips.

Glass, for example, has long been associated with premium phones, as seen in the iPhone and Galaxy series. Gorilla Glass or similar technologies offer scratch resistance and a premium feel. However, glass is inherently fragile, and even tempered variants can shatter under high impact. One thing I personally find annoying is that I have to be extra careful if I don’t want any scratches on my display or back, so as most people, I resort to protectors and cases.

It’s worth mentioning, however, that during our time with the Galaxy S24 Ultra we have noticed considerably less display damage than all other phones we have handled so far, probably thanks to Samsung’s Gorilla Armor glass created in collaboration with Corning.

Metal is also a predominantly used material in phones, even lower tier ones. Aluminum is the most common choice for frames, while nowadays titanium seems to have replaced stainless steel when it comes to the premium options. The more obvious use for metal in this case is the sturdiness it offers, but it is also the best material as far as heat dissipation. Unfortunately, since wireless charging is not possible with metal backs, we don’t see phones like this anymore.

Of course, there’s also plastic. While often associated with budget devices, polycarbonate offers excellent impact resistance and flexibility. It’s also lighter than glass and metal, making phones more comfortable to handle. For example, the Motorola Edge (2023) features a plastic back that balances durability with affordability, making it a great choice for those who want a lightweight, sturdy phone without compromising on style. In fact, I’d argue that Motorola produces one of the most stylish phones in recent years. But the biggest issue I have with this material is that it is much harder to recycle and reuse compared to glass and metal, and sustainability is a factor that’s more important for manufacturers than ever before.

Weight distribution and ergonomics

A bald man showing the Vivo X200 Pro&#039;s back to the camera.

Many large phones have an issue with weight distribution, but the Vivo X200 Pro takes the cake in that regard. | Image by PhoneArena

Ever picked up a phone that felt heavier than it looked? That’s usually due to uneven weight distribution. Phones with well-balanced internal components feel lighter and more comfortable, even if their actual weight is significant.

Designers strategically place elements like batteries, processors, and camera modules to avoid a top-heavy or bottom-heavy feel. Tiny details like this can affect your experience with the phone without you even realizing it.

One good example of a top-heavy phone is the Vivo X200 Pro. Because of its rather large camera module centered at the top, the phone’s weight distribution feels extremely uneven. In comparison, something like the iPhone 15 Pro Max feels more comfortable to hold.

Protruding camera bumps have become the norm, and they can easily be a nuisance. Larger camera sensors require more depth to capture better images, necessitating a thicker module. Funnily enough, though, they can also help with a phone’s ergonomics. The uniform camera bar on the Pixel series eliminates wobble while the phone is placed on a flat surface, and it can even help the user hold onto the phone by resting their fingers on the bottom edge of the camera module.

Foldable phones have the most room for improvement when it comes to weight distribution and ergonomics, as one side can be significantly heavier or lighter than the other. Thankfully, some of the more recent models like the Honor Magic V3 have thoughtful designs that tackle weight distribution well, which makes them feel more comfortable to hold in comparison to other models on the market.

Final thoughts

Smartphone design is a delicate balance of aesthetics, functionality, and practicality. Every curve, material, and component placement serves a purpose—whether it’s improving durability, enhancing ergonomics, or optimizing performance. From the switch to flat edges for strength to the adoption of materials like titanium and vegan leather, every choice affects how we interact with our devices.

I’ve personally experienced these changes—switching to an iPhone 6s years ago made me realize how much a thinner, well-balanced phone could transform daily use. Details like weight distribution, camera placement, and even the feel of the edges influence comfort in ways we often take for granted.

As technology evolves, innovations like flexible displays and personalized designs are on the horizon. But no matter how advanced smartphones become, their design will always reflect the principles of physics and the needs of users. By understanding these details, we can better appreciate the thoughtfulness behind the devices we use every day.

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Aleksandar is a tech enthusiast with a broad range of interests, from smartphones to space exploration. His curiosity extends to hands-on DIY experiments with his gadgets, and he enjoys switching between different brands to experience the latest innovations. Prior to joining PhoneArena, Aleksandar worked on the Google Art Project, digitizing valuable artworks and gaining diverse perspectives on technology. When he's not immersed in tech, Aleksandar is an outdoorsman who enjoys mountain hikes, wildlife photography, and nature conservation. His interests also extend to martial arts, running, and snowboarding, reflecting his dynamic approach to life and technology.