Privacy screen protectors: do they work, and which kind to get
A privacy screen protector is a thin filter that darkens your screen for anyone looking from the side. It does not stop someone behind you, and it dims the screen for you too.
Yes, privacy screen protectors work against people beside you. Tiny louvers in the film block light leaving the screen at an angle, so anyone outside a cone of about 30 degrees either side of center sees a dark screen. They do nothing against someone standing directly behind you, and they make the screen dimmer for you too. Get a 4-way filter if you turn your phone sideways for video or maps, and a 2-way filter if you only use it upright.
How a privacy screen works
A privacy filter is a sheet of microscopic vertical slats, called microlouvers, sandwiched in clear film. Light heading straight out of the screen passes between the slats, and light heading out at a steep angle hits a slat and stops. The screen looks normal to you and black to someone at your elbow.
Makers state the cutoff as a viewing angle. Belkin says its iPhone privacy glass narrows viewing to 30 degrees with the phone upright. StarTech describes its filters as blacking out everything outside a 60-degree cone, 30 degrees either side of center. 3M quotes the same 60-degree cutoff for its Bright Screen laptop filters.
2-way vs 4-way privacy
A 2-way filter has slats running in one direction, so it blocks the people to your left and right while you hold the phone upright. Belkin's support page says that once you rotate the phone sideways, anyone can view the screen.
A 4-way filter blocks in both directions, so it keeps working whether the phone is upright or sideways. StarTech sells 4-way iPhone filters that hold the same 30-degree cutoff either way you hold the phone.
| 2-way | 4-way | |
|---|---|---|
| Blocks people beside you, phone upright | Yes | Yes |
| Blocks people beside you, phone sideways | No | Yes |
| Blocks someone looking down from above, phone upright | No | Yes |
| Screen brightness for you | Dimmer | Dimmer |
| Pick it if | You mostly read and type upright | You watch video, use maps sideways, or sit where people stand over you |
How much light gets through varies by product, so check the maker's light transmission figure if it publishes one.
The trade-offs
- Your screen gets dimmer. 3M says its Bright Screen filter passes an average of 85% of the screen's brightness and is up to 25% brighter than other black privacy filters on the market, so a standard black filter lets through less.
- Someone directly behind you sees everything. The filter only cuts off angles, so a person or camera inside the viewing cone has the same view you do.
- Image quality off-axis gets worse for you too. Tilt the phone while reading in bed and the screen fades.
- Face ID and touch need a compatible filter. Belkin says its UltraGlass 2 Privacy glass is engineered to pass Apple's tests for Face ID, which is the kind of claim to look for on any phone filter.
The Samsung Galaxy S26 Ultra has one built in
Samsung's Galaxy S26 Ultra, from $1,299.99 before trade-in, is the phone Samsung calls the world's first with a privacy display built in. Samsung says the pixels change how they disperse light, so the screen dims for anyone at an angle when the feature is on and looks normal from every direction when it is off. You get privacy without a permanent dimming film. The S26 and S26+ do not have it.
You can switch Privacy Display on from the Quick Panel, set a double press of the Side button in Settings > Advanced features, or have it turn on by itself for selected apps and when you enter a PIN, pattern, or password in Settings, the lock screen, or Secure Folder (not in third-party apps). A partial mode hides only incoming notifications. Samsung's own footnote warns that some information may still be visible depending on angle and brightness.
Laptop privacy screens
Laptop filters use the same louver idea, sized to your screen. Measure the screen diagonally and check the aspect ratio before you order. StarTech, for example, sells versions that attach with built-in magnetic strips, flip up out of the way when you want to share the screen, or hang over a monitor. Thin ones let the laptop lid close with the filter still attached. StarTech's black filters and 3M's Bright Screen filters are reversible, with a matte side and a glossy side.
How to choose a privacy screen protector
- 1If you hold the phone sideways for video or maps, buy 4-way. If you don't, 2-way is enough.
- 2Buy the filter made for your exact model. Phone filters are cut around each model's cameras and sensors.
- 3Check that the maker says it works with Face ID or your phone's fingerprint reader.
- 4Look for a stated viewing angle and, ideally, a light transmission figure. Without either, you have nothing to compare.
- 5After you apply it, hold the phone at arm's length and tilt it slowly. The screen should go dark at roughly the angle the maker claims.
Where a privacy screen protects your bitcoin
A thief who watches you type your passcode and then takes the phone can open your email, and any exchange app that does not ask for its own login. Apple's Stolen Device Protection is meant to stop someone who has stolen your iPhone and knows your passcode from making critical changes. Turn it on in iOS 17.3 or later, and put a privacy filter on the phone you unlock in public.
A filter on your phone does nothing for a hardware wallet, though. When a wallet shows your seed phrase during setup, it shows it on its own small screen. Do that at home, in a room with no windows facing the street and no cameras pointed at the desk. My seed phrase guide covers what to do once the words are on the screen.
Frequently asked questions
Do privacy screen protectors really work?
Yes, against people to the side. The louvers block light leaving the screen at an angle, so anyone outside a cone of about 30 degrees either side of center sees a dark screen. Someone standing directly behind you still sees it.
What is the difference between a 2-way and 4-way privacy screen?
A 2-way filter blocks side views only while the phone is upright. Belkin notes that once you turn the phone sideways, anyone can view the screen. A 4-way filter blocks either way you hold it.
Do privacy screens work with Face ID?
Ones designed for it do. Belkin, for example, says its UltraGlass 2 Privacy glass is engineered to pass Apple's tests for Face ID. Check the product page for your exact iPhone model before you buy.
Do privacy screens make your phone dimmer?
Yes. The louvers block some of the light, so you will turn up brightness to compensate. 3M's Bright Screen filters let through an average of 85% of the screen's brightness, and 3M says they are up to 25% brighter than other black privacy filters, so standard filters let through less.
Which phone has a built-in privacy screen?
The Samsung Galaxy S26 Ultra. Its Privacy Display can be switched on from the Quick Panel or set to turn on automatically for chosen apps, notifications, and PIN or password entry. The S26 and S26+ do not have it.