Responsive Viewport Planner

Compare the current viewport with practical responsive sizes and prepare a test plan. The tool does not load, embed or emulate another website.

Runs in your browserNo permanent storage by default

Request scope

Sizes are compared locally in your browser; no external page is loaded or embedded.

Current viewport — read locally

No URL or third-party page is loaded. Only CSS viewport sizes are compared.

Test size

Custom width

Used when “Custom size” is selected.

Custom height

The check starts only after you press the button.

About this check

What the tool checks

Choose representative widths for layout review and carry the plan into browser developer tools and real-device testing.

The selected target ranges are organised into named viewport checks and a repeatable review checklist.

The planner does not load a website or simulate touch, device pixel ratio, browser chrome, network speed or hardware.

The viewport ranges entered or selected by the user; no remote device database is claimed.