· 5 min read
What's a safe bounce rate for cold email?
Hard vs soft bounces, the thresholds that matter, and what to do the moment your bounce rate starts to climb.
A bounce is an email that couldn't be delivered. A few are normal. Too many tell mailbox providers that you're emailing addresses you don't really know, and that's one of the fastest ways to lose the inbox.
Hard and soft bounces
- Hard bounce: the address doesn't exist or the domain refuses mail. It will never work. Remove the address and never send to it again.
- Soft bounce: a temporary problem — a full mailbox, a server that's down, a message that was too large. It may work later.
What matters most for your reputation is the hard-bounce rate.
What's a safe rate?
There is no published limit, but practitioners broadly agree:
| Bounce rate | What it means |
|---|---|
| Under 2% | Healthy |
| 2–5% | A list problem — find it before sending more |
| Over 5% | Stop and clean the list |
Outsquid flags mailboxes with a bounce rate of 2% or more on the Reports page for this reason.
Why lists bounce
- Old data. People change jobs; their work address is closed.
- Guessed addresses.
first.last@patterns that were never checked. - Scraped or bought lists. Often full of dead or trap addresses — and usually against the terms of your email provider.
- Typos from manual entry or a bad CSV export.
What to do when it climbs
- Pause the campaign. Each extra bounce makes things worse.
- Find the source. Is it one list, one import, one domain?
- Remove hard bounces and anything from the same bad source.
- Verify the rest before you resume, or drop the list.
- Resume slowly, with lower daily limits for a few days.
Let the tool catch it
You won't always be watching when a bad list goes out. In Outsquid, the bounce guard pauses a campaign automatically when its bounce rate crosses the threshold and emails you, and every hard bounce is added to your blacklist so no future campaign sends to it. See unsubscribes, the blacklist and bounce protection.