Mastodon Header Size (2026)
Upload a 1500×500 px header (3:1). Keep content centered — your avatar overlaps the bottom-left; max file size 2 MB.
| Placement | Pixels | Ratio | |
|---|---|---|---|
| Header (recommended) — 3:1 Downscaled to 1500×500 across the profile top |
1500×500 | 3:1 | |
| Avatar overlap zone Your rounded avatar sits over the lower-left |
~bottom-left | — | |
| Max file size WEBP, PNG, GIF or JPG |
~2 MB | — |
Upload 1500×500 for a clean 3:1 header
Mastodon shows the profile header as a 3:1 strip and downscales uploads to 1500×500 px. Uploading at that exact size avoids any upscaling and keeps the header sharp.
Mind the avatar and the crop
Your rounded-square avatar overlaps the bottom-left of the header, and edges can crop on mobile. Keep logos and text centered with padding.
Format and file size
Headers accept WEBP, PNG, GIF or JPG up to 2 MB.
FAQ
What is the Mastodon header size in 2026?
1500×500 px, a 3:1 aspect ratio. Mastodon downscales uploads to this size.
What is the maximum Mastodon header file size?
2 MB. Accepted formats are WEBP, PNG, GIF and JPG.
Where does the avatar sit on a Mastodon header?
The rounded-square avatar overlaps the bottom-left corner, so keep that area clear.