Every bounced email is a message that never arrived — and a small ding to your credibility with mailbox providers. Keeping bounce rate low is one of the simplest ways to protect deliverability.

How is bounce rate calculated?

Bounce rate = (bounced emails ÷ emails sent) × 100. Bounces split into two types: hard bounces (permanent failures, like an invalid address) and soft bounces (temporary issues, like a full mailbox).

Why does bounce rate matter?

Mailbox providers watch bounce rates closely. A spike suggests you're mailing bad or purchased addresses, which can route your legitimate mail to spam. Aim to keep bounces well under 2%.

How do you reduce bounce rate?

Use double opt-in, validate addresses at signup, remove hard bounces immediately, and never buy lists. Regular list hygiene keeps your bounce rate — and reputation — healthy.