How do emojis appear in subject lines?
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So you're thinking about adding 🎉 or 🚀 to your subject line. Will it actually display as an emoji, or will your readers see a mess of gibberish?
Here's the short version: it depends on the email client. Most modern inboxes (Gmail, Outlook, Apple Mail, Yahoo) render emojis just fine. Older clients or stripped-down versions might show a blank box, question mark, or just skip the character entirely.
Behind the scenes, your emoji is encoded as UTF-8 (the same character standard that lets you write in any language), then wrapped in MIME encoding so older mail systems don't choke on it. When the email client receives your subject line, it decodes the MIME wrapper, reads the UTF-8 bytes, and either renders the emoji or... doesn't.
What you actually need to know: test before sending. If you're using Mailchimp, Brevo, Klaviyo, or most ESPs, they'll let you send a preview to your own inbox. Open it on desktop Gmail, mobile iOS Mail, and Outlook. If the emoji displays on all three, you're probably safe for 95% of readers.
A few gotchas: some emojis are newer (like the melting face 🫠 added in 2021) and won't display on older phones or Windows 10. Stick to the classics (🎉, 🚀, 💌, ✨) if you want widest compatibility. And keep it to one or two emojis max. Three or more starts to look spammy, and spam filters notice.
One more thing: emojis can boost open rates by 5-10% in some tests, but only if they're used sparingly and match your brand voice. A law firm putting 🔥 in every subject line? Probably not the move. A DTC brand celebrating a product launch? Go for it.
If you want to check how your subject line looks across different clients before you hit send, our free Subject Line Tester can help you spot potential rendering issues.
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