In today’s world, we spend more time on screens than ever before. Between our TVs, phones, tablets, laptops, and gaming consoles, much of our work and play time is spent staring at screens. Our eyes weren’t designed for this, and it can lead to uncomfortable eye strain. While not usually serious, eye strain can cause migraines and other issues for some people.
For many of us, drastically reducing screen time is not an option. The good news is, a free tool can help you adjust the brightness and “warmth” of your computer screen. It is available for Windows, macOS, and Linux.
About f.lux
f.lux is a free tool you can install on Windows, macOS, or Linux that can help control the harshness of your computer screen. It can automatically match your screen tone to the time of day or stay the same tone all day.
After installing f.lux, you can find it on the bottom right of your screen in Windows or the top right on your Mac. If you don’t see the icon 
in Windows, try clicking the up arrow on the toolbar to reveal more icons. Click the icon to open f.lux.
f.lux Options
Manually adjusting f.lux is easy. Use the slider to darken or brighten your screen.
Because I’m extra sensitive to blue light, I leave it on the darker side all of the time. This works for me, so I don’t mess with the options. But let’s take a look at what’s available to adjust.
Custom Colors
In the upper-right of the screen, there is a dropdown menu for custom colors. You can stick with the recommended colors or try one of the other settings to see if it suits you better.
There is another menu on the left side of the screen that contains more options.
Adjust the day and night colors together allows you to set the brightness for different times of day.
If you want your screen to be a certain brightness all the time, set all three sliders to the same spot.
Options and Smart Lighting
Most folks won’t need the options and smart lighting setting, unless you want to set hotkeys, adjust jarring transitions, or connect your home’s smart lighting.
More Color Options
The change current color and effects and extra colors settings are supplemental to the custom colors menu, offering more options:
Got Questions?
When I first started using f.lux, my main question was whether I could use the free version on my work computer. The answer is yes, as long as your IT department has allowed it. A paid license is needed if an organization recommends it to staff or if IT needs control over updates.
If you have questions or need to troubleshoot, check out their Frequently Asked Questions page.
Summary
Avoiding eye strain due to screen use can be difficult. f.lux is here to help ensure your computer’s screen isn’t adding to the problem.
