f.lux

The program adjusts a computer’s display color temperature according to the local time, making the screen appear warmer after sunset and reverting to a daylight‑like hue during the day. Users input their geographic location and typical lighting conditions, and the software automatically transitions the color balance to match indoor lighting at night and natural sunlight in the morning.

It targets anyone who spends time in front of a screen and wants to reduce eye strain or improve sleep quality by minimizing blue‑light exposure in the evening. The tool is offered as free software for personal use on macOS, Windows, and Linux, with separate corporate licensing options.

What distinguishes it is the automatic, time‑based color adaptation that runs in the background after an initial setup, requiring no further user interaction unless the lighting environment changes. The application also includes links to related sleep‑ and lighting‑information resources.