Breakpoints are the screen widths where a website changes its layout to fit different devices. This helps websites look good and stay usable on phones, tablets, and computers instead of just one screen size.
These are common ranges used in modern web design, but they are not strict rules. Different websites may adjust them slightly.
Developers don’t usually pick breakpoints based on specific devices. Instead, they design for mobile first and then expand the layout as the screen gets bigger. They add breakpoints where the design starts to look awkward or hard to use.
They also test websites on real devices and look at analytics to see what screen sizes users actually have. This helps them choose breakpoints that match real-world usage instead of guessing.