Glossary
What is an email bounce rate?
Email bounce rate is the share of sent emails that could not be delivered and came back with an error. A hard bounce means the address does not exist or will never accept mail. A soft bounce is temporary, such as a full mailbox. A high bounce rate signals a poor list and damages sender reputation.
Published by Sellinger AI. Numbers and settings checked on 24 October 2026 against the fact register. Report an error.
How do you calculate it?
Bounce rate = bounced emails / emails sent x 100. An example with made up numbers: 400 emails sent, 12 bounced, a bounce rate of 3%. Count hard and soft bounces separately, because they need different actions.
What is the difference between hard and soft bounces?
| Type | Typical cause | What to do |
|---|---|---|
| Hard | Address does not exist, domain does not exist, receiver blocks you permanently | Remove the address and never send to it again |
| Soft | Mailbox full, server busy, message too large | Retry later; remove after repeated soft bounces |
| Block | Your sender or content was refused | Stop and check your reputation and setup before sending more |
Why does a high bounce rate hurt?
Mailbox providers read a high bounce rate as a sign that you send to addresses you did not collect carefully, which is how spammers behave. It lowers your sender reputation, and that pushes even your good emails toward spam. Cold lists bounce more than opt in lists, because addresses go stale as people change jobs. That is why verifying a list before sending matters; see email verification before you send.
How Sellinger handles it
Sellinger does not publish a bounce rate benchmark. Contact lookups use a database of 700M+ contacts, which returns verified emails where it finds them, and you can import your own list. Automatic replies from helpdesks, no reply senders, satisfaction surveys and empty messages are marked as machine mail. They never count as a human reply, the agent does not answer them, and the lead is sent to a person with a named reason.
Every connected account has daily limits that the agent cannot exceed, set per account. LinkedIn defaults are 20 invitations a day and 150 a week. Email defaults to 50 sends a day per mailbox, with an optional warm up that starts at 5 a day and doubles every 3 days up to the limit. Keeping volume per mailbox low limits the damage a bad batch can do.
Common questions
What is a good bounce rate for cold email?
Should I retry a soft bounce?
Do bounces count as replies?
Sources and method
Formula and example are illustrative. Sellinger behaviour from the fact register, checked 24 October 2026.
Related: Sender reputation, Catch all email address, Email deliverability, Email verification before you send.
