Phone Refresh Rate Test

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

Run the test above. 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.

Tap your phone’s rated Hz, hit Start, scroll a little to give the display something to react to, and wait about five seconds. An Android phone rated for 120Hz that reads 60 is throttled, not broken. Turn off battery saver and run it again. An iPhone or iPad reads about 60 for a different reason: Safari holds pages near 60 fps by default. Method 3 shows how to switch that off.

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.

1. Open Settings > About phone and tap Build number seven times until you see “You are now a developer.”
2. Go to Settings > System > Developer options (on Samsung, it sits directly in Settings; on OnePlus, look under Additional settings).
3. 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. That leaves the browser test, and on an iPhone it needs one Safari flag switched off before it can show more than 60. Out of the box, Safari renders web pages near 60 fps, even on a 120Hz ProMotion screen. Chrome and Firefox on iPhone use Apple’s WebKit engine too, so every iPhone browser reads about 60, whatever the display is doing.

To measure the real rate, open Settings > Apps > Safari > Advanced > Feature Flags and turn off Prefer Page Rendering Updates near 60fps. Close Safari fully, reopen it, and run the test above. A model with ProMotion should now read close to 120, and one without it stays at 60. The same switch works on an iPad. Turn the flag back on afterward if you’d rather save battery.

If you have Xcode and a Mac, Instruments has a Core Animation profiler that shows frame timing in detail.

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. Run the phone dead pixel test and cycle the solid color fields, then run the phone backlight bleed test for uniformity and bleed.