All tools
Viewport size reference

Browser Size Cheat Sheet

Use common browser viewport sizes for practical desktop, tablet, and mobile QA coverage.

A small set of well-chosen browser sizes can catch most responsive issues before release. Use this sheet as a baseline, then add product-specific widths where your analytics show traffic.

Recommended baseline sizes

These widths cover common layout transitions without turning every release into an exhaustive device lab.

360x740 for compact mobile

390x844 for common iPhone-class mobile

768x1024 for tablet portrait

1280x800 and 1440x900 for desktop

When to add more sizes

Add sizes when a product has important traffic or known risk in a specific band: dashboards, data tables, sidebars, embedded widgets, and checkout pages often need extra coverage.

Add 320px for dense consumer pages

Add 1024px for sidebar handoffs

Add ultrawide only for canvas-heavy tools

Add height variants for sticky footer or CTA issues

Release checklist

Keep one shared viewport matrix for release screenshots.

Add analytics-driven sizes for high-value traffic bands.

Retest pages with tables, sidebars, and sticky CTAs separately.

Document any supported minimum viewport width.