Keep the tab visible and place the browser window fully on the display you want to test. Fullscreen is optional, but avoid placing the window across two displays.
What does this refresh rate test measure?
Refresh rate is how many times a display updates its image each second. A 144Hz mode can present up to 144 display updates per second.
This page checks the refresh rate reaching this browser window and lets you compare it with the mode selected in Windows or macOS. It does not read the monitor model or its maximum supported rate.
For example, a monitor may support up to 240Hz while Windows is currently set to 144Hz. If Raw Hz is about 143.8Hz and the run is stable, ScreenDetect presents a 144Hz result. The useful comparison is 144Hz, the selected mode, not 240Hz, the monitor capability.
How to read your refresh rate result
Displayed refresh rate
This is the familiar result shown most prominently. Use it when comparing the reading with the mode selected in your operating system.
Raw Hz
This is the underlying timing value. A result such as 143.8Hz can be normal when the displayed rate is 144Hz and confidence is not low.
Confidence
This tells you whether the browser run collected a steady enough sample to interpret. A low-confidence run should be repeated before you decide that a setting or connection is wrong.
Frame pacing
This describes whether browser frame timing was smooth, uneven, or interrupted during this run. It helps distinguish a steady lower result from a reading that changes during the run.
Interrupted samples
A hidden tab, lost focus, or long pause can interrupt the run. That affects the browser measurement, but it does not identify a hardware fault.
Repeat a low-confidence or interrupted run before changing display settings, cables, adapters, or hardware.
This test measures browser frame timing, not game FPS or pixel response time.
Is your monitor running at the selected refresh rate?
Compare the result with the refresh rate selected in Windows or macOS, not only the monitor’s advertised maximum.
Start with confidence. A stable lower reading and an interrupted run need different next steps.
Swipe sideways to compare columns.Scroll table to view all columns.
| Result pattern | What it usually means | What to do |
|---|---|---|
| Displayed result matches the selected mode | The refresh rate reaching this browser window broadly matches the selected setting. | No change is needed for this browser check. |
| Raw value is slightly below the familiar rate | Small timing differences are common when the displayed result still matches. | Use the displayed result and confidence before treating it as a problem. |
| Stable result near 60Hz when a higher mode is selected | The browser is receiving a lower, steady rate than expected. | Use the 60Hz checks below. |
| Stable intermediate result, such as 144Hz when 240Hz is selected | This is a real lower mode, not the same as a 60Hz cap or an unreliable run. | Check the selected rate and resolution first, then the monitor mode and connection. |
| Large movement, interruptions, or low confidence | The run is not yet reliable enough to diagnose. | Keep the tab focused, reduce distractions, and run the test again. |
Why is my 144Hz monitor showing 60Hz?
First check whether Windows or macOS offers the expected rate for the display. The same process applies to 120Hz, 165Hz, 240Hz, 360Hz, and other high-refresh modes.
Windows or macOS only offers 60Hz
When the higher option is missing in display settings, start with the selected display and its available modes. The browser cannot make an unavailable operating-system mode appear.
- Select the correct display. In a multi-monitor setup, make sure the refresh-rate menu is showing the screen you intend to test.
- Check the resolution and refresh-rate combination. Some displays only offer their faster modes at particular resolutions or display modes.
- Check the monitor’s on-screen menu for a high-refresh, performance, or overclock setting where that option applies. Some monitors do not expose every mode until it is enabled there.
- Check the connection from the computer to the monitor: use the intended dedicated GPU output where applicable, then review the dock or adapter, cable, monitor input, and selected input mode.
- If the higher mode is still unavailable, check mirrored displays and current graphics-driver guidance. Change one meaningful condition, then return to display settings and test again.
A browser result can show that the expected rate is not reaching this window. It cannot identify the exact cable, port, dock, adapter, or component that limits an available mode.
The system is set higher, but the browser still shows 60Hz
If Windows or macOS is already set to the higher rate, keep the next checks close to the browser session before changing the connection.
- Put the browser window fully on the target display. A window shared between displays can give you the wrong comparison.
- Keep the tab visible and focused through the measurement. Background or hidden tabs can pause browser animation timing.
- Restart the browser after changing the operating-system refresh rate. It may keep an earlier display state until it is reopened.
- Temporarily compare the result without battery-saving or Low Power behavior. On supported laptops and mobile devices, power settings can change the refresh behavior available to the browser.
- Use a normal browser window instead of an embedded webview or saved web app. If relevant, confirm that browser hardware acceleration is enabled.
Run the test again after each meaningful change, using the same display, window placement, and power state. Safari can vary with operating-system and browser version, so start with display settings and power state rather than experimental browser flags.
The browser shows the correct Hz, but a game remains at 60 FPS
Game FPS is a separate measurement. If the test matches the selected refresh rate, the remaining limit may be a game frame cap, display-mode setting, synchronization setting, or performance limit.
This refresh-rate test does not diagnose application FPS.
Why does the test show 143.8Hz instead of 144Hz?
A raw reading such as 143.8Hz is normally consistent with a 144Hz result when the displayed rate matches and confidence is not low.
The same idea applies to 59.9Hz near 60Hz and 119.8Hz near 120Hz. Browser frame timing rarely lands on a perfectly round number, so ScreenDetect keeps Raw Hz visible while showing a familiar rate when the result is close enough to that mode.
A small raw difference is not the same as a different mode. If you selected 240Hz and the result is steadily 144Hz with adequate confidence, investigate the selected mode, resolution, monitor setting, and connection. If the reading swings widely or reports interruptions, repeat the run before changing hardware.
Refresh rate vs FPS, response time, and VRR
A refresh-rate result should not be used as a substitute for a game-performance or panel-response measurement.
Swipe sideways to compare columns.Scroll table to view all columns.
| Term | What it describes | What this test tells you |
|---|---|---|
| Refresh rate | How often the display path updates per second. | The refresh rate reaching this browser window. |
| FPS | How many frames an application or game produces per second. | Nothing about game FPS. A game can remain at 60 FPS while this page reads 165Hz. |
| Response time | How quickly pixels change from one color to another. | Nothing about pixel transition speed, ghosting, or input lag. |
| VRR | A display path that can vary update timing with content or frame delivery. | Variable browser timing does not prove FreeSync, G-Sync, or another VRR technology is active. |
How accurate is a browser refresh rate test?
This test observes browser animation-frame timing after a brief warm-up and uses a usable timing sample to report Raw Hz. The displayed result, confidence, pacing, and interruptions help you decide whether the reading is stable enough to compare with the rate selected in Windows or macOS.
A visible, focused tab matters because browsers can pause or change animation timing when a page is hidden or sent to the background. That is why confidence comes before hardware troubleshooting.
This test can help confirm:
- The refresh rate currently reaching this browser window.
- Whether that result broadly matches the mode selected in your operating system.
- Whether the run looks stable enough to interpret before you make a change.
This test cannot identify:
- The display’s maximum supported rate or an exact limiting cable, port, dock, adapter, or GPU.
- Pixel response time, input lag, ghosting, game FPS, or FreeSync/G-Sync certification.
If the measured refresh rate matches the selected setting but the screen still shows fixed pixels, retained images, or color problems, use the test that matches the symptom. A burn-in test is more useful for a previous image that remains visible.
Sources
- Window: requestAnimationFrame() · MDN Web DocsSupports the relationship between animation-frame callbacks and display refresh rate, and the effect of hidden or background contexts.
- Change the refresh rate on your monitor in Windows · Microsoft SupportSupports selecting a display, checking available refresh rates and resolution-dependent choices, and Dynamic Refresh Rate guidance.
- Change the refresh rate on your MacBook Pro or Apple display · Apple SupportSupports checking and changing refresh rate on supported Mac displays, including listed nominal and fractional rates.
- Use Low Power Mode to save battery life on your iPhone or iPad · Apple SupportSupports the note that Low Power Mode can affect ProMotion refresh behavior on supported iPhone and iPad models.
Refresh Rate Test FAQ
How accurate is this refresh rate test?
It is useful for checking the refresh rate reaching this browser window against the mode selected in Windows or macOS. Keep the tab visible and focused, then use confidence and interruptions to decide whether the run is reliable enough to interpret. It is not direct physical-panel measurement.
Why does it show 59.9Hz or 143.8Hz?
Raw browser timing does not always land on a perfectly round value. If the displayed result matches the selected mode and confidence is not low, 59.9Hz is normally consistent with 60Hz and 143.8Hz is normally consistent with 144Hz.
Why is my 144Hz monitor showing 60Hz?
First check whether Windows or macOS offers 144Hz for the correct display. If it does, check window placement, tab visibility, browser restart, power-saving behavior, and browser context. If it does not, check the selected resolution, monitor mode, and connection.
Does the test work with 120Hz, 165Hz, 240Hz, and higher-refresh displays?
It can report high refresh rates that are reaching this browser window. Compare the result with the rate selected in your operating system. A monitor that supports a higher maximum can still be running at a lower selected mode.
Why does the result change when I move the browser to another monitor?
Different displays can use different refresh rates. Put the browser window fully on the monitor you want to check, keep the tab visible, and run the test again before comparing results.
Can it detect FreeSync, G-Sync, or VRR?
No. Variable timing can have several causes, including browser load, power behavior, and display scheduling. This test does not identify FreeSync, G-Sync, VRR certification, response time, or game FPS.