StopBouncingHow to Reduce Your Email Bounce Rate
A high bounce rate damages your sender reputation, triggers spam filters, and can get your sending account suspended. This guide covers the causes of email bounces and six proven strategies to keep your bounce rate below the 2% threshold.
What Causes Email Bounces
| Cause | % of bounces |
|---|---|
| Invalid addresses | 40–60% |
| Domain not found | 10–20% |
| Mailbox full | 5–10% |
| Server-side block | 10–20% |
| Other | 5–15% |
6 Strategies to Reduce Your Bounce Rate
Verify your list before every send
Email verification is the single most effective action. A full SMTP check removes invalid, disposable, and undeliverable addresses before they reach your sending infrastructure. Clean lists have bounce rates under 0.5%.
Use double opt-in on all signup forms
Double opt-in (confirmed opt-in) sends a confirmation email after signup. Only users who click the confirmation link are added to your list. This eliminates mistyped addresses, fake signups, and disposable emails in one step.
Remove hard bounces immediately
Hard bounces (permanent failures) must be suppressed after the first occurrence. Resending to a hard bounce address signals to inbox providers that you don't maintain your list, which damages your sender reputation further.
Re-engage or remove inactive subscribers
Inactive subscribers (no opens in 6–12 months) are more likely to have abandoned addresses. Send a re-engagement campaign first, then remove those who don't respond before your next major send.
Never buy email lists
Purchased lists have the highest bounce rates in the industry — often 30–50%. They consist of addresses collected without consent, many of which are invalid, outdated, or spam traps. A single blast to a purchased list can permanently damage your sending domain.
Verify new emails at the point of capture
Integrate email verification into your signup forms via the API. Block addresses with invalid syntax, MX failures, or disposable domains before they enter your database — not after.
Bounce Rate Limits by Email Platform
These are the thresholds major platforms enforce. Exceeding them can result in account suspension.
| Provider | Bounce rate limit |
|---|---|
| Google Workspace (Gmail) | < 2% hard bounce recommended |
| Mailchimp | Accounts suspended above 2% bounce rate |
| Klaviyo | < 0.5% recommended, accounts reviewed above 2% |
| SendGrid | < 5% — accounts suspended above this threshold |
| Amazon SES | < 5% — accounts suspended at 10% hard bounce |
| Postmark | < 2% — accounts suspended above |
Note: Thresholds may change. Refer to your email provider's official documentation for current limits.
Bounce Rate FAQ
What is a good email bounce rate?
A good email bounce rate is below 2% for hard bounces. Most email service providers will warn or suspend accounts that exceed this threshold. The best senders keep their hard bounce rate below 0.5% by verifying lists before every campaign.
What is the difference between a hard bounce and a soft bounce?
A hard bounce is a permanent delivery failure — the address doesn't exist, the domain has no mail server, or the server permanently rejected the message. A soft bounce is a temporary failure — the mailbox is full, the server is temporarily unavailable, or a policy-based rejection that may succeed on retry.
Can email verification prevent all bounces?
Email verification can eliminate the vast majority of hard bounces caused by invalid addresses. However, it cannot prevent every bounce: some mail servers temporarily block verification (making addresses appear Unknown), and some valid addresses become invalid between verification and sending time. The goal is to reduce bounces, not eliminate them entirely.
How often should I clean my email list?
For active lists, verify before every major campaign or quarterly at minimum. For lists that haven't been mailed in 6+ months, always verify before re-engaging — address quality degrades quickly, and inactive lists have the highest bounce rates.
Clean Your List. Reduce Bounces Today.
Most customers reduce their bounce rate by over 90% after their first verification run.