What is a good email bounce rate, and what counts as too high?

Last updated May 19, 2026Deliverability

Bounce rate is the percentage of messages that failed to deliver. ISPs use it as a direct signal of list quality. The thresholds are universal across providers. Gmail, Microsoft, Yahoo, and the others all agree on roughly the same numbers.

The thresholds

Bounce rate	Status	What it means
0–2%	Healthy	Your list is well-maintained. Keep doing what you are doing.
2–5%	Caution	Sender reputation is starting to degrade. Investigate. Probably some address decay since the last verification.
5–10%	Red flag	Reputation is actively being damaged. Some sends already going to spam. Stop and clean before next send.
Above 10%	Critical	ISPs will rapidly demote your domain. Many platforms (Mailchimp, Klaviyo, etc.) auto-pause accounts that hit this. Cease sending immediately.

Hard vs. soft bounces

Both count toward your bounce rate, but they signal different problems:

Hard bounce — permanent failure. Address does not exist, domain has no MX, mailbox was deactivated. Almost always the result of stale or unverified lists. Address should be removed from your list immediately.
Soft bounce — temporary failure. Mailbox full, server temporarily down, recipient blocked you. Worth a retry; if the same address soft-bounces 3+ times, treat it as hard and remove.

Why cold lists are so bad

Email addresses decay at roughly 2–3% per month even on opt-in lists. After 12 months without contact, 25–35% of addresses are stale (closed accounts, job changes, abandoned mailboxes). Send to a 12-month-old list without verification first and your bounce rate sits in the 15–30% range — well into the "critical" tier.

Purchased lists are even worse: 30–60% bounce rates are common, plus a high probability of hitting spam traps.

How verification controls bounce rate

Verifying before send is the single largest lever:

Removes invalid addresses (definite bounces) before they hit your ESP.
Flags catch_all addresses so you can test small batches first.
Flags disposable and disabled addresses so you can drop them.
Catches spamtrap hits before they damage your reputation.

A clean send to a freshly verified list typically produces a 1–3% bounce rate on safe-marked addresses, comfortably inside the healthy zone.

When the rate is still high after verification

If bounce rate stays high even after verification:

Time gap between verification and send is too long. Address decay continues after verification.
Sending domain reputation is already damaged, so even valid addresses bounce because the receiving server is blocking you upstream of validity checks.
List was generated through scraping or buying. Verification catches obvious garbage but cannot detect everything.