1 · Your phone
Checking this screen…
Use Display Zoom or a larger display size? Still pick your real model — the ruler reads the screen width the browser reports, so it stays true.
2 · Check it with a card
Hold any bank, ID or loyalty card (85.6 × 54 mm) flat against the screen. Its outline should match the outer edge of the box. If it doesn't, nudge the size until it does and save.