Foldables: what the spec sheet does not tell you

Folding phones have been on sale for several years and are now reliable enough to recommend without heavy caveats about early-generation failures. They still involve trade-offs that a specification table records poorly or not at all. This page collects them, because we would rather you buy one knowing than return one disappointed.

The two shapes

Clamshells fold along the short edge — a normal-sized phone that halves into something pocketable, with a cover display on the outside. The Motorola Razr in our catalog is one. Book-style foldables open along the long edge into a small tablet, and are larger and more expensive.

The two solve different problems. A clamshell makes a phone smaller. A book-style foldable makes a screen bigger. Being clear about which you want eliminates half the market immediately.

The crease

Every folding phone currently sold has a visible crease across the inner display where it bends. Manufacturers have reduced it substantially and none have eliminated it.

You see it at an angle and in reflected light, and you feel it as a shallow trough when your finger passes over. Most owners report they stop noticing within weeks. It never actually goes away, and no specification sheet mentions it. If it would bother you, go and look at one in a shop.

The inner screen is plastic

The inner display is a plastic-topped laminate, not glass, because glass thin enough to fold repeatedly is not yet practical at consumer prices.

It is softer, marks more easily, and should not be pressed hard or cleaned with anything abrasive. It usually ships with a factory-applied protective layer that is part of the display assembly and must not be peeled off — people have damaged phones removing what they took for shipping film. Long fingernails and grit are genuine hazards in a way they are not on a glass panel.

The hinge is a mechanical part

Hinges are rated for a large number of cycles, usually a number in the hundreds of thousands, and those ratings are laboratory tests under controlled conditions. A hinge wears, can develop play over time, and is the most likely component to eventually fail.

The IP rating is where this becomes concrete. Foldables commonly carry IP48 where slab flagships carry IP68. The first digit is dust: a 4 means protection against objects above one millimetre, not dust-tight. Fine grit reaching a hinge or working under the edge of an inner display is a documented failure mode. A beach or a building site is a genuinely worse environment for a foldable than for a sealed slab phone, and that is a real reason not to buy one rather than a footnote.

Battery volume is the hidden cost

A clamshell splits its internal volume across two halves and a hinge, leaving less room for a cell. The Razr 60 Ultra in our catalog carries 4000 mAh — the smallest battery here, against 5000 mAh in the Galaxy S25 Ultra and 6000 mAh in the OnePlus 13, both at similar or lower prices.

Faster charging partly compensates. It does not change the fact that you will charge more often, and that is the trade-off people most often underestimate.

Cameras give up space too

Camera modules need physical depth, and a folding phone has less of it while also spending internal volume on the hinge. Foldables generally carry fewer cameras and smaller sensors than slab phones at the same price. The Razr's two-camera system with no dedicated telephoto is typical: zoom is digital crop.

Repair costs are in a different class

An inner display replacement on a foldable is substantially more expensive than a screen replacement on a slab phone, sometimes approaching a significant fraction of the phone's value. Third-party repair options are limited because the work is specialised, and independent shops that will replace a normal screen often will not touch a folding one.

If you are buying a foldable, price the insurance and the out-of-warranty screen repair before you decide. It is part of the cost of the form factor.

What you get in return

All of that said: a clamshell genuinely fits where a normal phone does not, and a modern cover display large enough to run applications means much of your daily use never requires opening it. A book-style foldable genuinely gives you a tablet-sized screen you were already carrying.

Neither benefit appears on a specification sheet either.

Cases and screen protectors work differently

A foldable needs a case designed for that exact model, because it has to cover two halves without fouling the hinge, and the choice is far narrower than for popular slab phones. Cases are also usually thinner and offer less drop protection, since bulk prevents the phone closing flat.

Do not apply a normal screen protector to the inner display. It already has a factory-applied protective layer that is part of the display assembly, and adding or removing film over it is a common cause of damage. The cover display takes an ordinary protector.

Buying second-hand

Hinge condition is not visible in photographs. If you buy used, open and close the phone many times listening for grinding, check that it sits flat when closed and holds position when partly open, and look along the inner display at an angle in bright light for lifting at the edges of the crease. A hinge with play or a display starting to delaminate is a phone near the end of its life, and the repair costs more than the discount saved you.

If the form factor appeals to you, current foldables are good enough that the compromises are worth making knowingly — which is all we are trying to help you do.