Your phone’s marketing sheet says 120Hz. That doesn’t mean it’s running at 120Hz right now. Adaptive displays, battery saver mode, and per-app rate caps can each cut that number without showing you a warning. You feel it in scrolling and in games before you can name it. Here’s how to confirm the real number in under a minute.
The spec and the reality
Phones with adaptive refresh switch Hz on the fly. Hold the screen still on a static page and the OS might drop to 30 or even 10Hz to save battery. Swipe across the home screen and it jumps back to 120. That’s by design, but it means the displayed refresh rate changes constantly based on what you’re doing and what power state the phone is in.
Battery saver caps the display the moment you enable it, usually at 60Hz regardless of the rated maximum. Some apps explicitly request 60Hz from the OS because they don’t handle higher frame pacing. A third-party launcher or browser extension can also lock the rate without advertising it.
Method 1: Run the browser test
Open your phone browser and run the refresh rate test. It uses the same frame-timing interface the browser exposes and reads what the display is actually delivering, not what the OS thinks it’s set to. No download, no signup.
Hit Start, scroll a little to give the display something to react to, and wait about five seconds. If your phone is rated for 120Hz but the test reads 60, it’s throttled, not broken. Disable battery saver, then rerun.
The mechanic is identical on a monitor or a phone: the browser samples how often it can paint a new frame, and the display caps that rate.
Method 2: Android live overlay
Android’s Developer Options can show a live Hz counter in the corner of the screen, visible in every app including games.
- Open Settings > About phone and tap Build number seven times until you see “You are now a developer.”
- Go to Settings > System > Developer options (on Samsung, it sits directly in Settings; on OnePlus, look under Additional settings).
- Find Show refresh rate and enable it.
A small number appears at the top of the display and updates in real time. Open a game and watch what happens during a fast scene. Watch what it drops to on a static settings screen. That range tells you your adaptive refresh is working and what floor the phone falls to at rest.
Samsung labels the equivalent option GPU rendering mode > Show GPU view updates on some older OneUI builds. If you can’t find Show refresh rate, search Developer options by keyword.
Method 3: iPhone
Apple doesn’t expose a live Hz overlay in Settings. The browser test is your fastest option: open Safari and run the refresh rate test. iPhone 13 Pro and later support ProMotion up to 120Hz. Earlier models top out at a fixed 60Hz, so the test confirms what the hardware can do.
If you have Xcode and a Mac, Instruments has a Core Animation profiler that shows frame timing in detail. For most people the browser test is enough.
When the number is wrong
If the test reads far below rated and disabling battery saver doesn’t fix it, work through this list.
- Enable the maximum refresh rate. Go to Settings > Display > Motion smoothness (or Screen refresh rate, depending on the brand) and pick the highest fixed option. Some phones default to 60Hz out of the box to save battery.
- Check Game mode or performance settings. Samsung Game Booster and similar tools sometimes apply per-app frame limits. Check whether your game is listed.
- Reboot the phone. A background service can occasionally latch onto a low rate after a crash or a deep sleep. A clean boot clears it.
Check the rest of your display
A correct refresh rate doesn’t mean the panel is healthy. Dead pixels, stuck pixels, and backlight issues are separate problems. Open the dead pixel test and cycle the solid color fields, then run the monitor test for uniformity and backlight bleed. Both work in a mobile browser exactly as they do on a desktop.