Mastodon · Image size

Mastodon Profile Picture Size

Mastodon shows your avatar as a circle or rounded square on timelines and profiles. Export a clear 800×800 square, keep the face inside the guide, then download in your browser.

Crop to this size View all specs

Last verified 2026-08-20 · Based on Mastodon UI as of 2026-08-20. Exact crops and pixels can shift—preview before you publish.

800×800 square upload. The circle is what people see—corners are cut.

Browser crop · stays on your device

Crop your Mastodon profile picture

800 × 800

Add a photo to crop

Upload a headshot or logo—or try the sample—then keep the subject inside the circle guide before you download.

Size specs

Always start from a square. Timelines show a tiny circle or rounded tile—eyes and marks must live inside the guide, not in the corners.

Publish

Export this for Mastodon upload.

Clearer upload

Recommended

800×800 1:1

Clearer source before the instance processes it. Mastodon docs still downscale avatars to 400×400 for display.

Use in tool

Asset	Pixels	Ratio	Notes	Action
Clearer upload Recommended	800×800	1:1	Clearer source before the instance processes it. Mastodon docs still downscale avatars to 400×400 for display.	Use in tool

What Mastodon shows

Reference sizes and crops—not always separate upload files.

Docs downscale target

400×400 1:1

Mastodon documentation cites 400×400 as the processed avatar size. Prefer the clearer 800×800 upload when your source allows it.

Use in tool

Asset	Pixels	Ratio	Notes	Action
Docs downscale target	400×400	1:1	Mastodon documentation cites 400×400 as the processed avatar size. Prefer the clearer 800×800 upload when your source allows it.	Use in tool

Mastodon avatars are small circles—and every instance can tweak limits

You upload a square, but Mastodon almost never shows the full square. Home timelines, notifications, and profile headers draw a circle or rounded square—often very small. Anything in the four corners disappears when the mask applies.

Mastodon’s own documentation describes downscaling avatars to 400×400. That is a processing target, not an excuse to ship a soft 120×120 upscale. Prefer a clearer 800×800 upload when the photo allows it, then keep the face or mark bold inside the safe zone.

Default media limits are commonly around 2MB for images, but federated instances can raise or lower upload caps, change allowed formats, or restyle the avatar chrome. Always check your home instance’s about or settings page if a file is rejected.

The header banner and the post attachment are different jobs. Do not stretch a 1500×500 header into this square, and do not treat a landscape post still as an avatar.

Good vs weak crop

Same circle mask—corners disappear; design for the tiny comment-size icon.

Reads in the timeline

Face centered in the guide
True 800×800 square when possible
Bold mark that survives tiny timeline size

Soft blob or cut corners

Only branding in the cut-off corners
Header strip stretched into a square
Soft tiny upscale next to HD posts

Before you upload

Tick these off against your crop preview—nothing is saved.

Face or mark sits inside the circular / rounded guide—not in the cut-off corners.
Export a square sRGB file at 800×800 when the source allows it (400×400 is the docs downscale target).
No critical detail only in the corners the mask removes.
Looks clear at timeline thumbnail size, not only on the large profile header.
File weight stays within your instance’s limit (often ~2MB by default).
You did not stretch a header strip or post landscape into a fake square.

Related surfaces compared

Similar-looking slots often use different ratios—do not reuse one export for all of them.

Profile picture / avatar

800 × 800 (try)

This page. Circle or rounded square on timelines and profiles.

Header / banner

1500 × 500

Wide 3:1 profile header—separate export.

Post attachment

Often 1920 × 1080

Timeline media—different upload; limits vary by instance.

Surface	Typical size	Note
Profile picture / avatar	800 × 800 (try)	This page. Circle or rounded square on timelines and profiles.
Header / banner	1500 × 500	Wide 3:1 profile header—separate export.
Post attachment	Often 1920 × 1080	Timeline media—different upload; limits vary by instance.

Design for the circle (or rounded square), not the full square

Themes and clients may use a full circle or a rounded square, but corners still fail. Keep eyes or the logo center inside the guide. Leave rim detail out—busy edges look chopped in notifications.

Center the subject before you export.
Test at timeline size: if you cannot tell who it is, simplify.
Coordinate color with the header, but export two files.

Instance differences are real

Mastodon is federated. Your home server’s max upload size, allowed MIME types, and even avatar chrome can differ from mastodon.social. Treat ~2MB as a common default, not a universal guarantee.

If upload fails, check your instance about / admin limits.
Prefer sRGB JPG or PNG; avoid exotic formats unless the instance documents them.
Re-verify framing after each theme or client update.

File requirements

JPG suits photographs. PNG suits flat marks. Prefer sRGB. Instances may recompress after upload—bold geometry survives better than film grain.

Clearer upload: 800 × 800 px square
Docs downscale target: 400 × 400 px
Display: Circle or rounded square (theme-dependent)
Typical file limit: ~2MB (instance may differ)
Formats: JPG or PNG (sRGB)
Not this slot: 1500×500 header, post attachments

Common mistakes

Uploading a landscape header crop as the avatar.
Putting the only logo in a corner the circle removes.
Shipping a soft tiny file and blaming Mastodon compression.
Ignoring instance limits after a rejected ~3MB upload.

How to use the crop tool

Upload a photo, choose Clearer upload (800×800), drag until the face clears the circle guide, then download. Processing stays in your browser.

Zoom until the face fills most of the guide.
Prefer PNG for a flat logo; JPG for a headshot.
After you publish, judge the avatar beside a timeline post—not only on Edit profile.

After you download

From this download to a live upload in a few minutes.

1
Download the 800×800 JPG (photos) or PNG (flat logos) from the tool.
2
On your Mastodon instance, open Preferences → Profile and update the avatar.
3
Save, then check the profile and a home-timeline row on phone and desktop.
4
If the face sits off-center in the circle, re-crop here and upload again.

Frequently asked questions

What size is a Mastodon profile picture in 2026?

Upload a square. Prefer 800×800 for a clearer source. Mastodon docs describe downscaling avatars to 400×400—keep the face centered for the circle or rounded mask.

Is every Mastodon instance the same?

No. Upload limits, themes, and processing can differ. ~2MB is a common default image cap—confirm on your home instance if a file is rejected.

Is the profile picture the same as the header?

No. The header is a wide 1500×500 (3:1) banner. The profile picture is a square circle crop. Export them separately.

JPG or PNG for a Mastodon avatar?

JPG for photographs, PNG for flat logos. Export sRGB either way.

Can I crop Mastodon sizes in the browser?

Yes. This guide includes an in-browser crop—files stay on your device until you download and upload to your instance yourself.