This translation has not been editorially reviewed yet. The German version is authoritative. Deutsche Fassung →
Which devices get checked — and why shrinking the window isn't enough
Measurement happens across three profiles: smartphone at 390 pixels, tablet at 768, and desktop at 1440 — each in a real browser with the matching device identifier, screen density, and touch capability. That's different from just narrowing a desktop window.
- The difference isn't theoretical: many pages deliver different content when they detect a phone, and CSS queries for pointer precision or touch don't apply at all in a shrunk desktop window.
- The higher screen density of the phone profile is also part of the measurement — it helps decide which image gets loaded and how sharp it appears.
- Every profile is assessed independently. A good desktop value doesn't make up for a poor phone result.
FAQ
Why exactly these three widths?
They cover the common classes: a narrow phone, a tablet in portrait orientation, and a typical desktop screen. The report states the values, so a result stays traceable.
Is it enough to just narrow the browser window?
For a first look, yes; for a check, no. The device identifier, touch capability, and screen density stay the desktop's — exactly the traits many pages base their behaviour on.