Kevlar vs TPU vs Silicone Phone Cases: Which Material Is Best?

Walk down a phone case aisle and every box says roughly the same thing. “Shock-absorbing” silicone. “Military-grade” TPU. Aramid this, carbon that. It all blurs together until you've carried each one around for a few months. Then the differences are obvious: how it feels in your hand, how it looks after a while, and whether it does anything useful when the phone hits the floor.

So here's our take on the five materials you'll run into most: silicone, TPU, polycarbonate, carbon fiber and Kevlar® fiber. We make Kevlar cases, so we're not neutral. But we've used all five, and we'll tell you where each one shines and falls short, ours included.

The short version: Silicone and TPU are cheap, soft and easy to grip, but they're chunky, and clear TPU goes yellow. Polycarbonate is thin and clear but slippery, and on its own it doesn't absorb much of a drop. Carbon fiber is light and stiff and looks the part, but some builds mess with 5G, NFC or wireless charging. Kevlar® gives you strength, low weight, a thin profile and no signal issues. The catch is the price.

Silicone

Silicone is the “soft case” most people picture. It's warm and slightly grippy, so the phone feels planted in your hand and one-handed use is easy. When you drop it, the rubbery body squashes a little and takes some of the hit instead of passing it all to the phone. It's quiet on a table, it won't scratch anything, and it's about the cheapest way to get decent everyday protection.

Live with it for a while and the annoyances show up. It picks up lint and pocket fluff almost instantly. The grip that's nice in your hand is a pain when you're trying to slide the phone into jeans. It wears faster than anything else here: corners loosen, button areas stretch, and light colours pick up stains. And because silicone needs thickness to protect, it turns a slim phone into a not-so-slim phone.

Pros: Good shock absorption; grippy; soft and comfortable; cheap.

Cons: Bulky; lint magnet; stretches and discolours over time; catches on pockets.

TPU (thermoplastic polyurethane)

TPU is the bendy plastic in most budget and mid-range cases, including nearly every clear one. It sits somewhere between rubber and hard plastic: flexible enough to cushion a drop, tough enough to shrug off scuffs, and easy to snap on and off. It holds up to skin oils and abrasion better than silicone, and it's cheap to mould, which is why it's everywhere.

The problems are just as familiar. TPU needs thickness to do much, so the ultra-thin ones are mostly decoration and the rugged ones are bulky. Clear TPU yellows. That's not dirt you can wipe off; it's the plastic itself changing from UV, heat and hand oils. The cushioning also softens with age, and the slightly rubbery feel never quite reads as premium.

Pros: Decent impact absorption; cheap; easy on and off; handles oils and scuffs better than silicone; available for basically every phone.

Cons: Bulky; clear versions yellow; cushioning fades with age; looks and feels generic.

PC (polycarbonate)

Polycarbonate is the hard, clear plastic you find in safety glasses and face shields. In a case it lets you go very thin, and it's the usual pick for clear cases that show off the phone's colour. The hard surface also resists scratches and scuffs better than silicone or TPU.

The weak point is drops. PC is stiff, so instead of absorbing a hit it passes a lot of it straight to the phone's frame. That's why the better clear cases pair a PC back with soft TPU edges or some internal cushioning. Bare PC is also slippery, it can crack in a hard fall, and the cheaper stuff goes cloudy and scuffed after a while.

Pros: Thin and light; very clear; scratch-resistant; keeps its shape; cheap.

Cons: Not much shock absorption; slippery; can crack; cheap versions haze and scuff.

Carbon fiber

Carbon fiber got its reputation in cars and aircraft, where being strong and light matters more than anything. A real carbon fiber case can be remarkably thin, light and stiff, and the woven pattern looks like it belongs on something expensive.

In a phone case, though, there are a few catches. Real carbon fiber conducts electricity, so a full carbon shell can get in the way of things your phone relies on: 5G, GPS, NFC payments, wireless charging. A lot of what's sold as “carbon fiber” is also just plastic with a carbon-look print or laminate on top. You get the pattern without the strength. And carbon fiber is rigid, so like PC it tends to pass impact along rather than soak it up.

Pros: Very strong for its weight; thin and stiff; looks great.

Cons: Can interfere with 5G, GPS, NFC and wireless charging; lots of fakes; limited shock absorption; pricey.

Kevlar® (aramid fiber)

Kevlar® is DuPont's aramid fiber, the same family of material used in protective gear and motorsport parts. Weight for weight it's about five times stronger than steel. Woven into a phone case, it's strong, stiff and very light. Our DURO® cases start at 0.65 mm thick and about 11 grams, which is thin enough that the phone still feels like the phone.

It also feels different from anything else on this list. The fine matte weave gives you grip without the tackiness of silicone. It doesn't collect lint, doesn't yellow and doesn't stretch out. And because aramid doesn't conduct electricity, it stays out of the way of 5G, GPS, NFC, MagSafe and wireless charging.

The main downside is cost. Real Kevlar® and other good aramid fibers cost a lot more than commodity plastic, so these cases sit at the top end of the price range. And to be fair, any case this thin has less edge cushioning than a chunky rugged case. If you drop your phone a lot, our reinforced DURO® Special Edition and DURO® Ring Master are tested to MIL-STD-810H and add more structure around the edges while keeping the aramid benefits.

Pros: About five times stronger than steel by weight; very thin and light, from 0.65 mm and 11 g; no interference with 5G, GPS, NFC, MagSafe or wireless charging; grippy matte texture; doesn't yellow, stretch or collect lint.

Cons: Expensive.

Side by side

So which should you buy?

• On a budget and don't mind some bulk? Silicone if you want grip, TPU if you want it to last a bit longer.
• Want thin and clear? Polycarbonate, ideally with TPU edges so it survives a drop.
  
• Want the most strength for the least bulk? Kevlar®. It's the best balance of protection, weight and signal we've found, which is why we build with it.

Keep reading

• Are Kevlar phone cases worth it?
• DURO® vs Special Edition vs Ring Master

Shop our DuPont™ Kevlar® cases, or take a look at the non-conductive G-10 bumper if you want a bit more edge protection.