How this monitor refresh rate test works
Your browser draws a new frame each time the screen refreshes. The test times hundreds of those frames and turns the typical gap between them into Hz: 16.7 ms per frame is 60 Hz, 8.3 ms is 120 Hz, 6.9 ms is 144 Hz. Within a few seconds it shows the rate and the nearest standard value. Keep the tab in front and don't scroll while it measures.
| Refresh rate | Time per frame | Typical device |
|---|---|---|
| 60 Hz | 16.7 ms | Most office monitors, TVs, older laptops and phones |
| 90 Hz | 11.1 ms | Many mid-range Android phones |
| 120 Hz | 8.3 ms | Flagship phones, MacBook Pro, newer TVs and laptops |
| 144 Hz | 6.9 ms | Common gaming monitors |
| 165 Hz | 6.1 ms | Gaming laptops and monitors |
| 240 Hz | 4.2 ms | Competitive gaming monitors |
Screen refresh rate test showing too low? Fix it
- Windows: Settings → System → Display → Advanced display → Choose a refresh rate. Pick the highest value. If it isn't listed, check the cable and port first.
- Mac: System Settings → Displays → Refresh rate.
- Cable and port: many monitors only reach 144 Hz and above over DisplayPort or a recent HDMI port. Use the cable that came with the monitor and plug it into the graphics card, not the motherboard.
- Power saving: laptops often drop to 60 Hz on battery. Plug in, or turn off "dynamic refresh rate" and battery saver to test the full rate.
- Two monitors: move the browser window to the screen you want to test. With mixed refresh rates, some browsers follow the main monitor.
- Android: look for Motion smoothness (Samsung) or Smooth display (Pixel) in display settings and choose the high setting.
120Hz refresh rate test on phones
Android phones with 90 Hz or 120 Hz screens usually show their full rate in Chrome once the high setting is on. iPhones and iPads with ProMotion are different: Safari limits web pages to about 60 frames per second by default to save battery, so a 120hz refresh rate test in Safari reads 60 Hz even though apps and scrolling run at 120 Hz. Low Power Mode on any iPhone also caps the screen at 60 Hz.
Reading the frame strip and motion check
The frame strip lights one block per refresh. On a healthy screen the bright band sweeps smoothly; a dark gap means a frame was skipped. The motion check moves a block at a steady speed: at 144 Hz it looks noticeably smoother and sharper than at 60 Hz, and visible jumps mean dropped frames. Some smearing behind the block at high speed is normal on LCD screens and is about pixel response time, not refresh rate.
Seeing stuck or dark pixels instead? Use the dead pixel test. Glow around the edges of a dark screen is covered by the backlight bleed test.
How we tested this tool
We fed the measurement code simulated frame timings at 60, 144 and 240 Hz, including random jitter and occasional skipped frames, and checked that it reported the right rate, the matching standard value and the number of slow frames. We also ran it in a desktop browser and at a 375 px phone width. We haven't yet run it across a range of real high-refresh monitors; if your result looks wrong, tell us what screen you have.
Frequently asked questions
Why does my 144 Hz monitor show 60 Hz?
Usually because Windows or macOS is still set to 60 Hz, the cable or port can't carry a higher rate, or the browser window is on another monitor. Set the refresh rate in display settings, use DisplayPort or the cable that came with the monitor, and drag the browser to the screen you want to test.
Why does my 120 Hz iPhone show 60 Hz?
Safari limits web pages to about 60 frames per second on ProMotion iPhones and iPads by default to save battery, so a browser test reads 60 Hz even though the screen can do 120 Hz in apps. Low Power Mode also caps the display at 60 Hz.
Is the refresh rate the same as FPS?
No. The refresh rate is how many times per second the screen redraws. FPS is how many new frames your game or app produces. To see 144 smooth frames per second you need both a 144 Hz screen and a computer that renders 144 FPS.
What do slow frames mean?
A slow frame took noticeably longer than the others, so the screen showed the same image twice. A few are normal when the computer is busy. Many in a row point to background load, power saving, or a browser that isn't using hardware acceleration.
How accurate is this screen refresh rate test?
On a normal desktop or laptop it reads the rate the browser is drawing at, which matches the display in most setups. It can read lower if the browser is throttled by power saving, and with variable refresh rate (G-Sync, FreeSync) the number can float.