← Glossary
Bounce Rate
The percentage of emails that could not be delivered to the recipient's mailbox.
Bounce rate is (Bounced Emails ÷ Sent Emails) × 100. Hard bounces indicate permanent failures (invalid address, domain doesn't exist) and should be removed immediately. Soft bounces are temporary (full mailbox, server down) and may resolve on retry. A bounce rate above 2% suggests list quality problems. High bounce rates damage sender reputation and trigger ESP throttling or suspension.