Creating a custom emoji takes two minutes and requires only an image file

You can add a custom emoji to your Slack workspace in three steps: upload an image, name it, and save. The image should be square, at least 128 pixels wide, and in PNG, GIF, JPG, or BMP format. Once uploaded, the emoji appears in your emoji picker alongside Slack's built-in set and is available to everyone in your workspace.

Only workspace owners and admins can add custom emoji by default, though some workspaces let all members do it. If you do not have permission, ask your workspace admin to add it for you or to change your role.

Key Takeaways

  • Custom emoji must be square images at least 128 pixels wide in PNG, GIF, JPG, or BMP format.
  • Go to your workspace name in the top left, select Customize Slack, then choose Emoji to upload and name your image.
  • Only workspace owners and admins can add custom emoji unless your workspace has changed that permission.
  • Once uploaded, your custom emoji shows up in the emoji picker for all workspace members to use in messages and reactions.

Step-by-step: uploading your emoji

Start by preparing your image. It should be square — 128 pixels by 128 pixels is the minimum, but 256 by 256 works better on high-resolution screens. Save it as PNG, GIF, JPG, or BMP. Transparent backgrounds work fine and often look better than solid colors.

Open Slack and click your workspace name in the top left corner. A menu drops down. Select Customize Slack. You will land on your workspace settings page in a browser. Click Emoji in the left sidebar. You will see a button labeled Add Custom Emoji — click it.

A dialog box opens. Click Select an image and browse to your file. Once you choose it, Slack shows you a preview. The image will be cropped to a square if it is not already one. Review the preview and click Save Custom Emoji if it looks right.

Naming your emoji so others can find it

After you click Save, a text field appears asking for the emoji name. This is what people type when they search for it in the emoji picker. Keep it short and descriptive — thumbsup_custom, team_logo, or coffee_break are all clear choices.

You can add aliases — alternate names that also trigger the same emoji. If your emoji is called tada, you could add celebrate as an alias so people can find it either way. Separate multiple aliases with commas. Once you are happy with the name and aliases, click Save.

The emoji now appears in your workspace's emoji picker. Members can find it by typing its name in the search box or scrolling through the custom section.

What to do if you do not have permission to add emoji

If you click Customize Slack and do not see the Emoji option, or if the Add Custom Emoji button is grayed out, you do not have permission. Only workspace owners and admins can add custom emoji by default in most workspaces.

Contact your workspace admin and ask them to add the emoji for you, or ask them to change the permission so members can add their own. Some workspaces do allow all members to create custom emoji — your admin can enable this in the workspace settings under Permissions.

Image size and format guidelines

Slack accepts PNG, GIF, JPG, and BMP files. PNG is usually the best choice because it supports transparency and compresses well. The minimum size is 128 pixels by 128 pixels, but Slack recommends 256 by 256 for clarity on modern screens.

Your image will be displayed at different sizes depending on where it appears — small in message reactions, larger in the emoji picker. Test your emoji after uploading by using it in a message and seeing how it looks at different sizes. If it is hard to read, you may want to simplify the design or increase the contrast.

Slack will crop any non-square image to a square, so if you upload a rectangle, the sides will be cut off. Make your image square before uploading to avoid surprises.

Editing or removing a custom emoji

To edit a custom emoji you have already created, go back to Customize Slack and click Emoji. Find the emoji in the list and click the pencil icon next to it. You can change the name and aliases, but you cannot change the image itself — you have to delete it and upload a new one.

To remove an emoji, click the trash icon next to it. The emoji will no longer appear in the picker, and people will not be able to use it in new messages. Existing reactions using that emoji will show a broken image in older messages.

Using your custom emoji in messages and reactions

Once your emoji is uploaded, use it the same way you use any other emoji. Type a colon followed by the emoji name — :coffee_break: — and it will appear in your message. You can also click the emoji picker icon in the message box and search for your custom emoji by name.

To react to a message with your custom emoji, hover over the message and click the emoji reaction icon. Search for your emoji by name in the picker that opens. Your custom emoji will show up in the custom section at the top of the picker for quick access.

Frequently Asked Questions

Can I use an emoji from another workspace in my workspace?

No. Custom emoji are specific to each workspace. If you want the same emoji in multiple workspaces, you have to upload it separately to each one. You can download an emoji from another workspace if you have access to it, then upload that image file to your own workspace.

What happens if I upload an emoji with the same name as an existing one?

Slack will not let you save it. You will get an error message saying the name is already taken. Choose a different name or delete the old emoji first if you want to replace it.

Can I make an emoji that is animated?

Yes, if you upload a GIF file instead of a static image. Slack will play the animation when the emoji is used in messages and reactions. Keep the file size reasonable — very large GIFs may slow down the workspace.

Do all workspace members see my custom emoji?

Yes. Once you upload a custom emoji, it is available to everyone in the workspace. Members cannot opt out of seeing it, but they do not have to use it.

Is there a limit to how many custom emoji I can add?

Slack does not publish a hard limit, but workspaces with thousands of custom emoji may experience slower performance in the emoji picker. Most workspaces stay well below any practical limit.