What causes monitor flickering and how to fix it

Monitor flickering is usually caused by one of three things: a loose cable, a refresh rate mismatch, or interference from nearby electronics. The fix depends on which one is happening. Start by checking the cable connections at both the monitor and the computer — a cable that has come loose even slightly will cause a visible flicker. If the connections are tight, the problem is almost always your refresh rate setting, which you can change in Windows or macOS in under a minute.

Flickering that happens only when you move your mouse or use certain programs points to a driver issue or a refresh rate that is too low for your monitor. Flickering that happens constantly, regardless of what you are doing, usually means a hardware problem — either the cable itself is damaged or the monitor's power supply is failing. This guide covers the fixes you can do yourself; if none of them work, the monitor may need replacement.

Key Takeaways

  • Check that the video cable (HDMI, DisplayPort, or VGA) is pushed firmly into both the monitor and the computer, because a loose connection is the most common cause of flickering.
  • Adjust your refresh rate in Display Settings to match your monitor's maximum — most modern monitors work best at 60 Hz or higher, and the setting is usually too low by default.
  • Update your graphics card driver through Device Manager or your graphics manufacturer's website, because outdated drivers often cause flicker that appears when you move the mouse or open certain programs.
  • Move wireless devices, phone chargers, and other electronics away from your monitor and cables, because electromagnetic interference can cause flickering that gets worse when these devices are nearby.
  • If flickering persists after trying these steps, the monitor cable may be damaged or the monitor's internal power supply may be failing, and replacement is usually the next step.

Check and reseat your video cable

The video cable that connects your monitor to your computer is the first thing to inspect. Turn off both your monitor and your computer. Look at the cable where it plugs into the back of the monitor — you will see either an HDMI port (rectangular), a DisplayPort (small rectangular with a notch), or a VGA port (blue with three rows of holes). Pull the cable straight out, then push it back in firmly until you hear or feel a click. Do the same at the computer end of the cable.

While the cable is out, look at the connector pins or contacts. If any pins are bent, broken, or corroded, the cable itself is damaged and needs to be replaced — this is not something you can repair. If the pins look intact, push the cable back in, turn both devices back on, and wait 30 seconds to see if the flickering stops. A loose cable is responsible for flickering in roughly half of all cases, so this step solves the problem for many people.

Adjust your refresh rate in Display Settings

Your monitor's refresh rate is how many times per second the image on the screen refreshes. Most monitors are capable of 60 Hz (60 refreshes per second) or higher, but Windows and macOS sometimes default to a lower rate, which causes visible flicker. To check and change this on Windows, right-click on your desktop and select Display settings. Scroll down and click Advanced display settings.

In the Advanced display settings window, scroll down to the bottom and click Refresh rate. A dropdown menu will show you the current setting and the available options. Select the highest number in the list — this is usually 60 Hz, but newer monitors may offer 75 Hz, 144 Hz, or higher. Click explore, then Keep changes when Windows asks you to confirm. The flicker should stop when ready if this was the cause.

On macOS, the process is different. Click the Apple menu, go to System Settings, then Displays. Click Refresh Rate and select the highest option available. macOS will explore the change right away. If you do not see a Refresh Rate option, your monitor may not support variable refresh rates, and you can skip this step.

Update your graphics card driver

Your graphics card driver is the software that tells your computer how to communicate with your monitor. An outdated or corrupted driver often causes flickering that appears when you move the mouse, open a web browser, or use certain programs. On Windows, open Device Manager by right-clicking the Start menu and selecting it from the list. Expand Display adapters by clicking the arrow next to it.

Right-click on your graphics card (it will say NVIDIA, AMD, Intel, or another manufacturer's name) and select Update driver. Choose Search automatically for updated driver software. Windows will search for the latest version and install it if one is found. Restart your computer when the installation finishes. If Windows does not find an update, visit your graphics card manufacturer's website directly — NVIDIA, AMD, and Intel all have driver read pages where you can find the latest version for your specific card and operating system.

On macOS, graphics drivers are usually updated automatically through System Updates, so check System Settings > General > Software Update to see if any updates are pending. If updates are available, install them and restart your computer.

Move electronics away from your monitor and cables

Electromagnetic interference from nearby devices can cause flickering, especially if your cables run close to power cords or wireless devices. Move your monitor at least 12 inches away from your phone, wireless router, cordless phone, or microwave. If your monitor cable runs along the same path as a power cord, separate them — route the monitor cable away from power cables if possible, or wrap them in separate cable sleeves to reduce interference.

Unplug phone chargers and other USB power adapters that are not in use, because even idle chargers emit electromagnetic fields. If you use a wireless mouse or keyboard, move the receiver away from your monitor cable. These changes are straightforward and cost nothing, and they solve flickering in cases where interference is the culprit.

Test with a different cable or port

If you have a spare video cable of the same type (HDMI, DisplayPort, or VGA), swap it in to see if the flickering stops. A cable can look fine on the outside but have internal damage that causes intermittent flicker. If you do not have a spare cable, try connecting your monitor to a different port on your computer if one is available — many computers have multiple HDMI or DisplayPort connections. If the flicker moves to a different monitor when you connect it to your computer, the problem is with your graphics card or its driver, not the monitor itself.

If the flicker stops when you use a different cable or port, you have found the problem: either the cable is damaged and needs replacement, or that particular port on your computer is faulty. Replacement cables are inexpensive and widely available at electronics retailers.

When to replace your monitor

If you have tried all the steps above and the flickering continues, the problem is likely inside the monitor itself. The most common internal failure is a failing power supply capacitor, which causes constant flickering that does not change based on what you are doing on the computer. Monitors are not economical to repair — replacement parts and labor typically cost more than a new monitor.

Before you buy a replacement, confirm that the problem is the monitor and not your computer by connecting the monitor to a different computer if you have access to one. If the flicker follows the monitor to the other computer, the monitor is the problem. If the flicker stays with your original computer, the issue is with your graphics card or driver, and you should revisit the driver update step or contact a computer technician.

Frequently Asked Questions

Why does my monitor flicker only when I move the mouse?

This usually means your graphics card driver is outdated or your refresh rate is set too low. The mouse movement triggers a screen redraw, which exposes the problem. Update your driver first, then check your refresh rate setting. If both are current and set correctly, try a different video cable.

Can a power surge damage my monitor and cause flickering?

Yes. A power surge can damage the monitor's internal power supply, which then causes constant flickering. If flickering started right after a power outage or electrical storm, and the cable and driver are both fine, the monitor's power supply may have been damaged. Replacement is usually the only fix.

Does flickering mean my monitor is about to fail completely?

Not necessarily. Flickering from a loose cable or wrong refresh rate setting can be fixed in minutes and does not indicate any damage. Flickering from a failing power supply inside the monitor will get worse over time, but the monitor may continue to work for weeks or months before it stops entirely.

Is 60 Hz refresh rate good enough, or should I get a higher one?

60 Hz is fine for everyday work like email, web browsing, and document editing. If you play fast-action games or do video editing, a higher refresh rate like 144 Hz or 240 Hz will feel smoother, but it is not necessary for general use. Set your monitor to whatever maximum refresh rate it supports — there is no downside to using the highest available.

What if my monitor flickers only in certain programs?

This usually points to a driver issue or a refresh rate problem. Update your graphics driver first. If the flicker continues only in one program, that program may have a setting that conflicts with your monitor — check the program's display or graphics settings for an option to disable hardware acceleration or change the refresh rate.