Bounce Rate
Email bounce rate is the percentage of emails that were rejected by the receiving server before reaching the recipient. It is a key indicator of list health and data quality.
(Total Bounces / Total Emails Sent) × 100Definition
Bounce rate measures the percentage of emails that could not be delivered because the receiving server rejected them. Bounces fall into two categories that require different responses.
Hard bounces occur when the email address is invalid, does not exist, or the domain is not configured to receive email. These addresses should be removed from your list immediately. Soft bounces occur when the email address is temporarily unreachable due to a full inbox, server timeout, or out-of-office auto-reply.
Formula
Bounce rate is calculated using total bounces (hard + soft) divided by total emails sent.
Bounce Rate = (Total Bounces / Total Emails Sent) × 100
| Variable | Description |
|---|---|
| Total Bounces | Hard bounces + soft bounces |
| Total Emails Sent | Number of emails you attempted to send |
Average Benchmark
| Bounce Type | Acceptable Rate |
|---|---|
| Total bounce rate | Below 3% |
| Hard bounce rate | Below 1% |
| Soft bounce rate | Below 2% |
A total bounce rate above 5% indicates list quality issues. If your hard bounce rate exceeds 2%, mailbox providers may flag your sending reputation.
How to Improve Bounce Rate
- Use double opt-in: Confirmed opt-in ensures every subscriber entered a valid email address before joining your list.
- Validate emails at point of capture: Use real-time email validation to catch typos, invalid domains, and disposable email addresses during sign-up.
- Remove hard bounces immediately: Never retry sending to an address that hard bounced. Most email platforms automatically suppress hard bounces.
- Handle soft bounces with limits: Retry soft bounces 2-3 times over several days. If an address soft bounces consistently across multiple campaigns, move it to a suppression list.
- Monitor for role-based addresses: Addresses like admin@, info@, or support@ have higher bounce rates. Consider excluding them from acquisition.
- Prune engaged segments quarterly: Pull a list of subscribers who have not opened or clicked in 180 days and gradually remove them.
Example Calculation
If you send a campaign to 15,000 subscribers and receive 135 hard bounces and 210 soft bounces:
Total Bounces = 135 + 210 = 345
Bounce Rate = (345 / 15,000) × 100 = 2.3%
A total bounce rate of 2.3% is within the acceptable range. The hard bounce rate component (135/15,000 = 0.9%) is also below the 1% threshold.
Related Tools
- Email Bounce Rate Calculator: Calculate your bounce rate at email bounce rate calculator
- List Growth Rate Calculator: Track how quickly your list is growing at list growth rate calculator
Frequently Asked Questions
What is the difference between hard bounce and soft bounce?
A hard bounce means the email address is permanently invalid — the address does not exist, the domain is wrong, or the mail server rejects all mail. Hard bounces should be removed immediately. A soft bounce means the email was temporarily undeliverable — the inbox is full, the server is down, or the message was too large. Soft bounces can be retried later.
How many bounces are normal?
A healthy email list should have a bounce rate below 3%. Hard bounce rates should stay below 1%. If your bounce rate exceeds 5%, your list acquisition or hygiene process needs attention. High bounce rates damage sender reputation with email providers.
Do bounces affect deliverability?
Yes, especially hard bounces. Sending to too many invalid addresses signals to mailbox providers that you do not maintain your list, which can hurt your sender reputation and inbox placement. The effect is more significant on shared IPs where your reputation is also influenced by other senders.
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