What It Is
A breakpoint is a set screen width where a website’s design shifts to a different layout. Designers write CSS rules that say, in effect, "when the screen is at least this wide, show the menu across the top instead of behind an icon." Most sites use a few breakpoints, roughly matching phones, tablets and larger screens. Think of it like a folding table that has a few set positions rather than infinite ones.
Why It Matters for Your Business
Breakpoints decide how your site behaves on the devices your customers really use. If they are set poorly, you get awkward in-between sizes, such as a tablet view where a photo crowds out the text or buttons overlap. For a contractor showing project photos, that can make the work look sloppy even when the craftsmanship is excellent.
Good to Know
When you review a new design, slowly drag the edge of your desktop browser window narrower and wider and watch for anything that breaks, overlaps or disappears. Also check a tablet held both ways. Small fixes at a breakpoint are usually quick for a designer, but only if someone notices them before launch.