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Add your signature in Outlook

Step by step for Outlook on Windows, Outlook for Mac and Outlook on the web, including what to do when the pasted signature comes out oversized.

Outlook is the client most signatures break in, because Outlook on Windows renders mail through Microsoft Word rather than a browser engine. These steps assume a signature built in Pinned Signature, which is already table-based markup Word can render.

Outlook on Windows

  1. In the builder, press Copy signature.
  2. In Outlook, open File → Options → Mail → Signatures.
  3. Click New and give it a name.
  4. Click into the large edit box and press Ctrl + V.
  5. On the right, set the signature as the default for New messages and for Replies/forwards.
  6. Click OK, then send yourself a test message.
If the logo arrives enormous, the paste has lost the image's width and height attributes. Use Download .htm instead and save the file into %APPDATA%\Microsoft\Signatures, then pick it from the Signature menu. The downloaded file keeps the attributes and the Word-specific pixel-density hint that stops the resize.

Outlook for Mac

  1. Press Copy signature in the builder.
  2. Open Outlook → Settings → Signatures.
  3. Click +, name it, click into the body and press Cmd + V.
  4. Under Choose default signature, set it for new messages and replies.

Outlook on the web

  1. Press Copy signature in the builder.
  2. Open Settings (the gear) → Mail → Compose and reply.
  3. Click into the signature box and paste.
  4. Tick both boxes so it appears on new messages and on replies, then Save.

Animated logos in Outlook

Outlook on Windows does not animate. A recipient there sees the first frame of your GIF and nothing else, on every message. If you use an animated logo, make sure the first frame reads as a finished logo by itself. The builder shows you that frame next to the animation for this reason.

Why the same signature looks different in Outlook

Word does not support flexbox, CSS grid, external stylesheets or max-width. It also sizes an image from the file's own pixel dimensions unless the <img> tag carries both a width and a height attribute, not just CSS. A signature that relies on any of those will look correct in a browser preview and wrong in the inbox.

Need a signature to install? Build one free, no account needed.

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Last updated 2026-08-31.