Bounce rate: the website version, the email version, and what to fix

Hard and soft, the two ways an email bounces

A hard bounce is permanent. The address was mistyped, the mailbox closed, or the domain doesn't exist. A soft bounce is temporary: a full inbox, a server having a bad morning, a message too large to accept. Klaviyo's help centre says it suppresses an address after one hard bounce, or after a run of soft bounces in a row.

Bounces do quiet damage. Mailbox providers read a sender with lots of dead addresses as one that doesn't look after its list, and that opinion follows the next send to the people who did want it.

Where bounced addresses come from, and how to stop them at the door

• Typos at sign-up, which a confirmation email or a check on the form catches early
• Old imports from a previous platform that nobody has mailed since
• Competition and giveaway entries, full of throwaway addresses
• Bought lists, which you shouldn't have, and which bounce like nothing else

If one send suddenly bounces far more than usual, stop and look before the next. Google's sender guidelines tell senders to cut volume when bounces or deferrals start, until the errors fall. A big send to addresses nobody has mailed in a year is the classic cause.

Website bounce rate, and when a high one is fine

Google Analytics changed the definition. A bounce used to be a single-page visit. Now it's a session that wasn't engaged: ten seconds or less, one page and no key event. Shopify reports a bounce rate too, and changed how it counts sessions in late September 2026, so compare either side of that date with care.

A high rate isn't automatically bad. A blog post that answers the question in one read can bounce plenty and still do its job. A product page bouncing visitors from a paid campaign is different. Often the ad promised one thing and the page showed another, and that's conversion rate optimisation work, not a reason to buy more traffic.