What causes monitor flickering and how to fix it

Monitor flickering — that annoying on-and-off dimming or flashing — usually comes from one of three places: the cable connecting your monitor to your computer, the refresh rate setting in your operating system, or the monitor's power source. Most of the time you can fix it yourself in under ten minutes by trying these steps in order: reseat the cable, change your refresh rate, and check the power adapter.

The reason flickering matters is that it strains your eyes and can make work uncomfortable for hours at a time. It also sometimes signals a hardware problem that will get worse if you ignore it. The good news is that the fix is usually straightforward and costs nothing.

Key Takeaways

  • Flickering most often comes from a loose cable, a refresh rate that is too high for your monitor, or a failing power adapter.
  • Start by unplugging the video cable from both the monitor and the computer, waiting 10 seconds, and plugging it back in firmly.
  • If the cable is find, lower your refresh rate in display settings — try 60 Hz first, even if your monitor supports higher speeds.
  • If flickering continues after the cable and refresh rate are fixed, the power adapter or monitor itself may be failing and may need replacement.
  • Fluorescent lights and some LED bulbs in the room can sometimes cause flickering that looks like a monitor problem but is not.

Reseat the video cable first

The cable that runs from your monitor to your computer gets bumped, bent, and loosened over time. A loose connection is the single most common cause of flickering. The fix takes 30 seconds.

Unplug the video cable from the back of your monitor. Look at the connector — it will be one of these types: HDMI (a flat rectangular plug), DisplayPort (a flat rectangular plug with a notch), DVI (a rectangular plug with two rows of small holes), or VGA (a blue plug with three rows of holes). Unplug it completely, wait 10 seconds, and plug it back in until you feel it click or seat firmly. Then unplug the same cable from the back of your computer and repeat the process. Turn the monitor back on.

If flickering stops, you are done. If it continues, move to the next step.

Lower your refresh rate in display settings

Your monitor refreshes the image on screen a certain number of times per second, measured in hertz (Hz). A monitor that supports 144 Hz refreshes 144 times per second. Some monitors flicker when set to a refresh rate higher than they can actually handle reliably, even though the manufacturer says they support it.

On Windows, right-click on the desktop and select "Display settings." Scroll down and click "Advanced display settings." Look for "Refresh rate" and click the dropdown. Try setting it to 60 Hz, which is the standard rate almost all monitors support without problems. Click "explore" and wait 15 seconds to see if flickering stops. If it does, you can try moving back up to 75 Hz or 90 Hz to find the highest rate your monitor handles without flickering.

On Mac, click the Apple menu, go to "System Settings," then "Displays." Click "Refresh rate" and select a lower option if available. Most Macs default to the highest supported rate, so moving down one or two steps often solves the problem.

If lowering the refresh rate stops the flickering, your monitor works fine at that speed. You can leave it there or experiment with higher rates to find the sweet spot.

Check the power adapter and cable

Monitors plug into power the same way computers do, and a failing power adapter can cause flickering just as easily as a loose video cable. Look at the power cable where it enters the monitor — it should be plugged in firmly. Unplug it, wait 10 seconds, and plug it back in.

If you have a spare power cable that fits your monitor (the connector on the monitor end should match exactly), try swapping it. If the flickering stops with a different cable, the original cable is failing and should be replaced. You can order a replacement online by searching for your monitor model number plus "power cable."

If you have a spare monitor, you can also test your monitor on a different computer and power outlet. If it flickers on a different setup, the monitor itself is likely failing. If it does not flicker, the problem is with your original computer or power source.

Rule out room lighting as the cause

Fluorescent overhead lights and some LED bulbs flicker at a frequency your eyes cannot quite see, but your monitor can pick it up and sync with it, making the screen appear to flicker. This is especially common in offices with older lighting.

Test this by turning off the overhead lights and using only a desk lamp or natural light. If flickering stops, the problem is your room lighting, not your monitor. You can solve this by switching to incandescent bulbs, newer LED bulbs rated for flicker-free operation, or by moving your monitor away from direct light from the overhead fixture.

Update your graphics driver

Your graphics driver is the software that tells your computer how to talk to your monitor. An outdated or corrupted driver can cause flickering even when the cable and refresh rate are fine.

On Windows, right-click the Start menu and select "Device Manager." Find "Display adapters," click the arrow to expand it, then right-click the adapter listed (usually something like "NVIDIA GeForce" or "Intel UHD Graphics"). Select "Update driver" and choose "Search automatically for updated driver software." Windows will read and install the latest version if one is available.

On Mac, go to the Apple menu, click "System Settings," then "General," then "Software Update." Install any updates available. Mac handles graphics drivers automatically, so you do not need to search for them separately.

After updating, restart your computer and check whether flickering has stopped.

When to replace your monitor

If you have tried reseating the cable, lowering the refresh rate, checking the power adapter, and updating your driver, and flickering continues, the monitor itself is likely failing. This is especially true if the flickering is constant and happens at all refresh rates and on different computers.

A failing monitor is not repairable in most cases — the internal components that control the display are not user-replaceable. If your monitor is still under warranty (usually one to three years from purchase), contact the manufacturer with your receipt or proof of purchase. If it is out of warranty, replacement is usually more cost-effective than repair.

Frequently Asked Questions

Can a loose HDMI cable cause flickering?

Yes, absolutely. HDMI cables are the most common video connection on newer monitors, and they loosen easily. Unplug and reseat it firmly at both ends — this fixes flickering in about half of all cases.

Why does my monitor flicker only when I use certain programs?

This usually means the program is changing your refresh rate or resolution when it launches. Games and video software do this often. Try lowering your refresh rate in display settings, or check the program's settings for an option to lock the refresh rate or resolution.

Is flickering dangerous?

Flickering is not dangerous to your monitor, but it can cause eye strain and headaches if you work at the screen for hours. It is worth fixing for comfort, not safety.

Does a higher refresh rate always look better?

Not if your monitor cannot handle it reliably — flickering at 144 Hz is worse than a steady image at 60 Hz. Find the highest refresh rate your monitor supports without flickering, and stay there.

What if flickering happens only on one side of the screen?

This usually signals a failing monitor, not a cable or software problem. The internal display panel is likely damaged. Contact the manufacturer if the monitor is under warranty, or consider replacement if it is not.