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Slack Emoji Resizer

Resize custom emoji to Slack's size limits.

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Drop an image here or click to browse

Everything runs in your browser — your image is never uploaded to a server.

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What Is Slack Emoji Resizer?

The Slack Emoji Resizer squares your artwork to one of the sizes Slack works best with, from a lightweight 64 px up to a retina-sharp 512 px. With 128 px marked as the Slack recommended default, you can pick a size that suits your workspace rather than guessing. A target in KB keeps the upload inside Slack 128 KB custom emoji limit.

Who Uses the Slack Emoji Resizer?

Workspace admins, team leads, community managers and designers use it to add a full set of branded custom emoji that stay sharp on high-DPI screens without hitting the size ceiling.

How to Use the Slack Emoji Resizer

  1. Drop the emoji image into the resizer.
  2. Choose a square size - 64 px small, 128 px Slack recommended, 256 px retina sharp, or 512 px large if your workspace allows it.
  3. Set the target size in KB to stay under the 128 KB limit, pick PNG, JPG or WebP, then press Resize for Slack and download.

Why Choose Our Slack Emoji Resizer?

  • Covers the sizes Slack recommends, with 128 px as the safe default for most workspaces
  • 256 px and 512 px options keep emoji crisp on high-DPI and retina displays
  • PNG output preserves transparency, so circular and cut-out emoji keep clean edges
  • Runs in the browser, so the emoji file never goes to a server

Try the Slack Emoji Resizer above — it is free, fast, and works on any device. Bookmark this page to return whenever you need it.