Mastodon profile picture size
400 × 400px
Aspect ratio
1:1
Mastodon avatars are 400 × 400 px — official docs confirm uploads up to 2 MB are downscaled to exactly that square.
Last verified June 2026
Like the header, the Mastodon avatar has an officially documented spec: uploads (WEBP, PNG, GIF, or JPG, up to 2 MB) are downscaled to 400 × 400 px. The wrinkle is display: the official apps round the corners but some clients show full circles and others near-squares, so the safe design treats the corners as expendable. Your avatar federates everywhere your posts do — it’s your face on every server in the network.
| Variant | Dimensions | Ratio |
|---|---|---|
| Stored size (official) | 400 × 400 pxPer docs.joinmastodon.org — uploads are downscaled to this. | 1:1 |
| Recommended upload | 800 × 800 pxDownscales cleanly; reuses your cross-platform avatar master. | 1:1 |
| Display shape | variesRounded square in official apps; circular in several third-party clients. | 1:1 |
Because some fediverse clients crop avatars to circles and others to rounded squares, design for the harshest case: keep the subject inside the central circle with roughly 12–15% padding from every edge. Timeline renderings run small — often 40–48 px — so contrast and simplicity beat detail. A bold mark on a solid field reads everywhere; a busy photo becomes noise at boost-notification size.
The only region visible in every client is the inscribed circle of your 400 × 400 square. Center the face or logo inside it, and treat the corners as background. If your current cross-platform avatar already obeys circular-crop rules (most do, since Instagram and X enforce circles), upload the same master here and you’re done — consistency across networks is worth more than per-platform tweaks.
When you change your avatar, remote servers that cache your profile may keep showing the old one for a while. That’s federation working as designed, not a bug. Plan rebrands accordingly: update the avatar, then keep posting normally — each post nudges remote servers to refresh their copy of your profile.
GIF avatars are a charming Mastodon-culture artifact, and for personal accounts they can be memorable. For brands they mostly read as noise, render as static frames in half the clients, and burn the 2 MB budget fast. A clean static mark performs consistently everywhere — boring is correct here.
400 × 400 px — officially documented: uploads up to 2 MB in WEBP, PNG, GIF, or JPG are downscaled to that square. Uploading 800 × 800 gives the downscaler clean source material.
Both, depending on the client — official apps use rounded squares, several popular third-party apps use circles. Design for the inscribed circle and the avatar works in every app.
On many servers, yes — it’s an accepted format. But some servers and clients display only the first frame, so make sure frame one stands alone as a static avatar.
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