Bounce rate (BR)
Email bounce rate is the percentage of sent emails that were rejected by the receiving mail server and returned as undeliverable. It is calculated by dividing the total number of bounced emails (hard and soft combined) by the total number of emails sent, then multiplying by 100. Most email platforms report overall bounce rate as well as split breakdowns by bounce type. A healthy overall bounce rate is generally considered to be below 2 percent. Hard bounce rate specifically should ideally be below 0.5 percent.
Bounce rate is a leading indicator of list quality. A high bounce rate means your list contains a significant proportion of invalid, outdated, or inactive addresses. This is often the result of not using email verification at the point of data collection, importing old or purchased contact lists, or failing to regularly clean and suppress unengaged or bounced contacts. The older a contact database, the more significant the decay: business email addresses change frequently as people move jobs, companies are acquired, or roles are reorganised.
Monitoring bounce rate trends over time is as important as the absolute number. A sudden spike in bounce rate after a campaign to a previously clean list might indicate that a batch of imported contacts was of poor quality, or that your sending IP has been blacklisted by specific mail servers. A gradual increase over months usually signals natural list decay that needs to be addressed through re-engagement or suppression of long-inactive contacts.
Complete guide to managing email bounce rates
Learn what drives high bounce rates, how to measure them accurately, and how to reduce them through better list hygiene and data collection practices.
What is a good email bounce rate?
An overall bounce rate below 2 percent is generally considered healthy. Hard bounce rates specifically should be kept below 0.5 percent. For well-maintained, permission-based B2B lists with regular hygiene, achieving bounce rates of 0.5 to 1 percent overall is realistic. If your bounce rate is above 5 percent, your list has a significant quality issue that needs addressing before you run further campaigns, as continued sending will compound the damage to your sender reputation.
Does a high bounce rate affect my ability to send emails?
Yes. Most email service providers monitor sender bounce rates and have thresholds that trigger account review or automated pausing of sends when bounce rates exceed safe levels. Inbox providers and blacklist operators also use bounce rates as signals of irresponsible sending behaviour. Consistently high bounce rates can result in your sending IP or domain being flagged or blacklisted, which affects delivery across your entire email programme, not just the sends that triggered the issue.
How is email bounce rate different from website bounce rate?
They measure entirely different things and should not be confused. Email bounce rate measures the percentage of sent emails that could not be delivered to the recipient’s mail server. Website bounce rate measures the percentage of website visitors who leave after viewing only a single page without taking any further action. The term ‘bounce’ is used in both contexts but refers to completely unrelated phenomena.