What is a good email bounce rate?

Bounce rate is bounced ÷ sent × 100. A campaign of 10,000 messages with 420 bounces has a bounce rate of 4.2%. The bounce rate calculator does it for you, which is the least interesting part of this page.

The more useful split is by class. A hard-bounce rate — 5xx failures for mailboxes that do not exist — says something about how the list was built. A soft-bounce rate says something about the receiving servers on the day. Reporting them as one number hides the only distinction that tells you what to fix.

No mailbox provider publishes a bounce-rate threshold. Not Google, not Yahoo, not Microsoft. The figures quoted everywhere — under 2% is healthy, over 5% is dangerous — are email-service-provider suspension thresholds and industry rules of thumb. Your ESP may well enforce them under its own acceptable-use policy, and that is a real consequence. It is just not the rule the receiving side is applying.

What Google does publish is a spam-complaint rate. Its sender guidelines ask senders to "keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching a spam rate of 0.30% or higher". Those are the numbers with a source behind them, and they are two orders of magnitude smaller than the bounce figures they get confused with.

Google also defines when its bulk-sender requirements apply: "If you send more than 5,000 messages per day to Gmail accounts, follow the Requirements for sending 5,000 or more messages per day." That is a volume trigger, not a quality threshold, and it is the other number in this area worth knowing exactly. Both were checked on 2026-09-11.

None of this makes a high bounce rate safe. Bounces are a direct signal about how a list was built and they feed the reputation judgement that decides inbox placement. It means the honest sentence is "keep it low because it reflects list quality", not "keep it under 5% because Gmail says so". Gmail does not say so.

Verify before the send, and close to it. Suppress every hard bounce permanently the first time, rather than retrying it. Stop buying lists — a purchased list is a list nobody consented to and nobody maintained. Segment catch-all and unknown addresses away from confirmed deliverables so a bad batch cannot contaminate a good send.

And watch the complaint rate as well as the bounce rate, since that is the one with a published threshold behind it.

Your email-service provider’s acceptable-use policy, not a mailbox provider’s. The thresholds vary by ESP and are published in their own terms — read yours rather than the industry average. What is common to all of them is that a single send with a high hard-bounce rate is treated as evidence about the list rather than an accident, because that is what it is.