Is a 3% bounce rate bad?

It is below most published enforcement lines but above Brevo's 2% suspension line. Treat anything over 2% as a list-quality problem to fix before the next send.

What should I do when bounces spike mid-campaign?

Pause the campaign, export the bounced addresses, suppress them, verify the rest of the list, and resume with a smaller batch.

SimpleVerifier Team · Reviewed October 23, 2026

How many bounces are too many?

Aim to keep hard bounces under 2% of each send. Published enforcement lines are higher, but they are where sending stops: Brevo can suspend above 2%, HubSpot and Amazon SES review accounts at 5%, and SES may pause sending at 10%. Mailchimp and Mailgun enforce thresholds they do not publish.

or test one address on this page

The published lines

These come from each vendor's own help pages, read on 1 October 2026. A benchmark is advice; an enforcement line is where sending actually stops.

Brevo: hard bounce rate above 2% can lead to suspension.
HubSpot: a hard bounce rate of 5% in a month can lead to suspension.
Amazon SES: 5% puts an account under review; 10% or more may pause sending.
Postmark: bounce rate must stay below 10%.
Instantly: campaigns auto-pause at 5% by default after 200 or more sends (adjustable).

Why a 2% target

A sender is judged on the whole stream, so one bad segment can push the total over a line. Keeping the overall target at 2% leaves room for a segment that bounces at 5% or more. Count hard bounces (permanent failures such as an unknown mailbox) separately from soft bounces, which are temporary.

Sources

Figures marked as ours come from SimpleVerifier’s own dated tests on made-up addresses, published with their data on the research page. No customer data is used, and we publish no accuracy percentage because we have no independent measurement to back one.

Do it now

Test it on a real address first

Type any address. It gets the same check the paid plans run: syntax, the domain’s mail servers and, where the provider allows it, a live mailbox check. Nothing is sent to the address.

Email address

Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.

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