A healthy total bounce rate sits below 2%. Anything above 5% will quickly damage your sender reputation, and many ESPs will throttle or suspend accounts that breach it on repeat sends. Hard bounces in particular should be vanishingly rare.
Hard bounces vs soft bounces
A hard bounce is a permanent failure: the address does not exist, the domain does not exist, or the receiving server has flatly refused. A soft bounce is temporary: a full mailbox, a server outage, a deferral. Hard bounces must be suppressed at once. Repeated soft bounces (typically three to five sends) should be treated as hard.
Benchmark ranges
- Healthy: total bounce rate below 2%, hard bounces below 0.5%.
- Watch: total 2 to 5%, hard 0.5 to 2%. Investigate immediately.
- Danger: anything above 5% total or 2% hard. ESPs will throttle or suspend.
Why bounce rates spike
- An old segment is mailed for the first time in months, surfacing dead addresses.
- A list import or form has not been verified, letting typos and bots through.
- A purchased or rented list is added (do not do this).
- A domain has stopped accepting mail to its full range of addresses.
How to keep bounces low
Verify any list before its first send. Honour suppression every time. Re-verify large or dormant segments before reactivating them. Use double opt-in for new subscribers. None of this is glamorous; all of it works.
Frequently asked questions
What is considered a high email bounce rate?
Above 5% total, or above 2% hard, is a red zone. Most ESPs will throttle or suspend accounts that maintain those rates across consecutive sends.
Do soft bounces hurt sender reputation?
A few will not. Repeated soft bounces to the same address signal poor list hygiene and start to damage reputation, which is why they should be promoted to hard after a few attempts.
How can I reduce bounces on a large old list?
Run a verification pass, suppress every invalid result, then warm the remaining list back gradually starting with the most recently engaged contacts.