Email Bounce Rate
Quick definition
Email bounce rate is the percentage of sent emails that were rejected by the recipient's mail server and not delivered.
Formula
Email Bounce Rate = Bounced Emails ÷ Emails Sent × 100
Formula variables
- Bounced Emails
- Emails that were not delivered.
- Emails Sent
- All emails sent in the campaign.
Worked example
- Emails sent
- 10,000
- Bounced
- 200
200 ÷ 10,000 × 100
Result: 2%
Two in every 100 sent emails were not delivered. The figures are illustrative, not a benchmark.
How definitions differ
- Hard and soft bounces
- A hard bounce is a permanent failure, such as an address that does not exist. A soft bounce is a temporary one, such as a full mailbox. Platforms report them separately and may handle them differently.
- Not the website metric
- Email bounce rate has nothing to do with website bounce rate, which measures sessions on a website.
How to interpret it
Bounces show list quality and affect sender reputation. A rise often traces to old addresses, purchased lists or typing errors in forms.
Removing addresses that hard-bounce is standard list hygiene.
When it is useful
- Monitoring list quality.
- Finding data-collection problems at signup.
- Deciding when to clean a list.
Limitations
- Categorisation of bounces differs by platform.
- Soft bounces may resolve on retry.
- It does not capture emails that arrive in spam folders.
Common mistakes
- Confusing it with website bounce rate.
- Continuing to send to hard-bounced addresses.
- Ignoring soft bounces that repeat.