Responsive Viewport Tester
See which responsive breakpoints your current viewport supports.
Breakpoint Support
Responsive Design Breakpoints
Responsive web design adapts layouts to different screen sizes using CSS breakpoints. This tool shows which common breakpoints your current viewport supports, helping you understand how websites adapt to your screen.
As you resize your browser, breakpoints become active or inactive. This visual feedback helps developers understand responsive behavior without diving into code.
Why Breakpoints Matter
Each breakpoint represents a design change point. Layouts shift from single columns on mobile to multi-column on desktop. Navigation may change from hamburger menus to visible links. Content priority can be reordered.
Choosing Breakpoints
Base breakpoints on content needs, not specific devices. Content should dictate when layout changes are necessary. Test at all sizes, not just exact breakpoint values.
Common Breakpoint Values
320px catches small phones. 768px is the classic tablet breakpoint. 1024px targets laptops. 1440px covers large monitors. These values cover most real-world devices effectively.
Fluid vs Fixed Layouts
Between breakpoints, use fluid (percentage-based) widths for smooth scaling. Fixed widths at extremes prevent overly wide content. Combining both approaches creates polished responsive experiences.