Facebook displays your cover photo at 820 × 312 on desktop but crops the sides on mobile, showing roughly 640 × 312. Design for the overlap.
The safe zone
Keep text and faces within the central 640 pixels so nothing important is lost on phones. BannerCrop AI's Facebook Cover preset draws this zone for you.
- Desktop: 820 × 312
- Mobile: ~640 × 312 visible
- Upload at 2× (1640 × 624) for retina sharpness