Mastodon header size
1500 × 500 px · 3:1 · banner
1500 × 500
The details
Profile header image, downscaled by the server to 1500×500 (3:1). WEBP, PNG, GIF or JPG up to 2MB by default; since your avatar covers part of the lower-left, decorative imagery works better than text.
Safe area: The avatar overlaps the lower-left of the header on profile pages — keep important content up and to the right.
Source: docs.joinmastodon.org · checked 2026-07-04