Refresh rate changed after turning on night mode?

After turning on night mode, one screen may look warmer, seem less smooth, or report a different refresh rate. These symptoms do not always have the same cause. Night mode usually changes color temperature, while refresh rate is controlled separately for each display.

Check the screens and their refresh behavior before changing settings. TooLab's Screens tool identifies connected displays, and the Display Test checks screen colors and refresh rate in your browser.

Check the refresh rate on each screen

1. Open Screens and note how many displays appear, along with each screen's resolution and scale. This gives you a way to tell the screens apart.
2. Open the Display Test on the screen you want to check. Read the refresh-rate result and note which display the browser window is on.
3. Move the browser window to another connected screen, then run the check again. Compare the readings, rather than assuming every screen uses the same rate.
4. Check the selected refresh rate in your operating system for each display. Compare it with the test result, then toggle night mode off and on once while keeping other settings unchanged.

Keep the browser window on the screen being tested. If a browser test result changes between runs, repeat it with other demanding tabs and apps closed. Variable refresh rate, browser rendering, and animations can affect what a browser measures.

What the result means

The refresh rate is the same with night mode on and off

Night mode probably changed the color tone, not the display's refresh setting. A warmer white can make a screen feel dimmer or less crisp, which may be mistaken for slower motion. Check the operating system's refresh-rate setting if scrolling or animation still looks choppy.

One screen has a lower rate than the others

Refresh rates are set per display. A laptop panel might run at 120 Hz while an external monitor runs at 60 Hz, or the external display may be limited by its cable, adapter, resolution, or selected mode. A difference by itself does not show that night mode caused it.

The operating system and browser test disagree

The operating system setting shows the selected display mode. A browser test observes how updates reach the page, so it can be affected by the browser, other work on the computer, and changing refresh behavior. Treat the test as a comparison, not proof that a screen is faulty.

The image looks different, but movement looks normal

This points to a color or brightness change rather than a refresh-rate problem. Night mode shifts whites toward warmer colors. It can make a screen appear less bright, but it does not normally select a different refresh rate.

How to fix a refresh rate that changed

1. Select the correct display. On Windows 11, open Settings › System › Display › Advanced display, then select the screen you are checking. On macOS, open System Settings › Displays and select the display if the settings show more than one.
2. Choose a supported refresh rate. In Windows 11, use the refresh rate menu under Settings › System › Display › Advanced display. On macOS, open System Settings › Displays and choose a rate from the Refresh rate menu if it is available. Use a rate supported by that screen at its current resolution.
3. Compare night mode separately. On Windows 11, go to Settings › System › Display › Night light and switch Night light off briefly to compare. On macOS, open System Settings › Displays › Night Shift and turn it off for a short comparison. If the selected refresh rate does not change, the color filter was not the cause.
4. Check the cable and adapter. If a monitor is stuck at a lower rate, connect it directly to the computer if possible. Try another port or a cable rated for the monitor's resolution and refresh rate. Some docks and adapters limit the available modes.
5. Restore the monitor's usual resolution. A high resolution can reduce the refresh rates available over a particular connection. In Windows 11, check Settings › System › Display. On macOS, check System Settings › Displays. Select the display's recommended resolution, then check the available rates again.
6. Restart the browser and computer. Close the browser, reconnect an external display, and reopen the test. If the operating system still omits a rate the display should support, restart the computer and check for graphics or display driver updates from the computer or display manufacturer.

Why screens can look less smooth without changing refresh rate

A refresh rate is the number of times a display can update each second, measured in hertz (Hz). A 60 Hz screen can update up to 60 times per second, while a 120 Hz screen can update up to 120 times per second. Night mode adjusts the color balance of the image, not this setting.

Some displays also adjust their refresh behavior dynamically to save power or match on-screen content. A browser test may not report a perfectly steady result in those conditions. If motion looks smooth and the operating system shows the intended rate for each display, a small difference in browser readings is not enough to diagnose a display fault.

If one screen continues to show the wrong rate after checking its mode and connection, test it with another compatible cable or computer before arranging a repair.