Size: upload at 128 by 128 pixels. Discord accepts other sizes and scales them down, but square 128 pixel images look sharpest. File size: up to 256 KB per emoji. Formats: PNG or JPG for static emoji, GIF for animated emoji. PNG is the better choice for static emoji because it supports transparency, so the emoji blends into any theme. Names: at least two characters, using letters, numbers and underscores. If an upload fails with a file size error, the image is almost always an animated GIF with too many frames or colors.

Size: exactly 320 by 320 pixels. File size: up to 512 KB per sticker. Formats: PNG for static stickers and APNG (animated PNG) for animated ones. Discord does not accept GIF files as stickers, so an animated GIF has to be converted to APNG first. Stickers appear much larger than emoji, so they are a good place for detailed artwork, reaction faces and server mascots. Each sticker also needs a name, a related emoji and an optional description, which helps Discord suggest it.

Every server starts with a limited number of slots, and Server Boosts add more. Emoji: 50 static and 50 animated slots with no boosts. Level 1 raises each to 100, Level 2 to 150 and Level 3 to 250. Stickers: 5 slots with no boosts, 15 at Level 1, 30 at Level 2 and 60 at Level 3. Discord occasionally changes these numbers, so check Server Settings → Emoji or Stickers, which always shows how many slots are free.

Discord scales every emoji into a square. A wide image is shrunk to fit the width, which leaves empty space above and below and makes the content tiny. Crop images to a square before uploading, and leave a little padding around the edges so nothing touches the border. Thin lines and small text disappear at emoji size. Use thick outlines, strong contrast and as few details as you can. A good test is to look at the image at 32 pixels wide: if you can still tell what it is, it will work as an emoji.

GIF and APNG files store every frame, so file size grows with frame count, canvas size and the number of colors. To get under the limit: shorten the loop or use fewer frames, reduce the palette (32 or 64 colors is often enough for flat artwork), avoid gradients and photo backgrounds, and use transparency instead of a filled background. Boxtype's Server Emoji Maker does all of this automatically and shows the final size of each file before you download it.

Anyone in a server can use its static custom emoji there. Using custom emoji in other servers, and posting animated emoji anywhere, needs Discord Nitro. Members without Nitro still see them in messages from others. Server stickers can be sent by anyone in that server; sending them in other servers needs Nitro.

For emoji, design on a 128 × 128 canvas, export as PNG for static emoji or GIF for animated ones, and aim for well under 256 KB so you have room to spare. For stickers, the canvas must be exactly 320 × 320; leave about 10 pixels of padding so the sticker doesn't feel cramped, and export PNG for static stickers or APNG for animated ones under 512 KB. If you start from a larger image, scale it down in one step with good resampling. Repeatedly resizing an image softens it each time.

Most operating systems show a file's size in the file browser: right-click the file and choose Properties on Windows or Get Info on a Mac. Remember that 256 KB is 262,144 bytes, so a file shown as 260 KB is already too big. Boxtype's Server Emoji Maker checks every tile against Discord's limits before you export and shows the final size, so you don't have to measure files yourself.

Discord occasionally adjusts slots, upload limits and Nitro perks. The emoji and sticker file limits have been stable for years, but if an upload fails with a size error even though your file fits these numbers, check Discord's Help Center for the current requirements.

Emoji are tiny, so fine detail disappears. Thicken thin lines, raise contrast and crop tightly around the subject before exporting. For pixel art, scale up by whole numbers (2×, 4×) with nearest-neighbor resampling so the pixels stay crisp instead of blurry. For photos, simplify the background or remove it entirely; a face on a transparent background reads far better than a face in a busy room.