Bounce rate is the percentage of emails that fail to reach recipients. Learn how bounce rate is calculated and how to reduce hard and soft bounces.
Bounce rate measures the percentage of sent emails that were not delivered and were returned by the receiving mail server. It’s a key indicator of list quality and sending health because it reflects how many addresses are unreachable or rejecting your mail.
A high hard-bounce rate often signals poor list hygiene, outdated contacts, or purchased lists. Soft-bounce spikes can indicate volume issues, temporary blocks, or infrastructure instability on either side.
To reduce bounce rate, validate addresses before sending, remove hard bounces immediately, and warm up new domains or IPs gradually. Also monitor authentication and reputation signals, since blocks and filtering can look like bounces at the server level.