Bounce rate benchmarks
| Bounce rate | Status | What to do |
|---|---|---|
| Under 2% | Healthy | Keep verifying new and old contacts. |
| 2% to 5% | Warning | Clean the list before the next send. |
| Above 5% | Critical | Pause sending to the list and verify it first. |
These bands are common industry guidance rather than a single official rule. Each email provider applies its own thresholds, and cold outreach is judged more strictly than newsletters to opted-in subscribers.
Why bounce rate matters
Mailbox providers such as Gmail and Outlook treat a high bounce rate as a sign that a sender does not maintain its list, a pattern shared by spammers. As bounces rise, more of your mail goes to spam, including mail to valid subscribers. Email service providers watch the same metric and may throttle or suspend accounts that bounce too much.
What causes bounces
- Invalid addresses: typos in sign-up forms, made-up addresses entered to get a download, or addresses from people who left their company.
- Dead domains: companies that shut down or changed domains. An MX lookup shows whether a domain can still receive mail.
- Old lists: B2B lists lose a meaningful share of valid addresses every year as people change jobs.
- Disposable addresses: temporary inboxes that stop working within hours.
- Temporary problems: full mailboxes or busy servers cause soft bounces.
How to bring your bounce rate down
- Verify the whole list before your next campaign and send only to deliverable addresses.
- Remove every hard bounce right after each send.
- Add verification or double opt-in to sign-up forms so bad addresses never enter the list.
- Re-verify segments that have not been mailed for three months or more.
- Treat catch-all and role-based addresses as a separate, lower-priority segment. See how catch-all addresses are handled.