The bounce rate measures how many of your emails "bounced": the recipient's mail server rejected them, and they never arrived. In web analytics, the same term is used to refer to something else (visits that end without any interaction), but here we're talking about email bounces. There are two main types:

• Hard bounce: a persistent problem, such as a nonexistent email address or an invalid domain.
• Soft bounce: a temporary issue, such as a full inbox or a down server.

Why does it matter?

Every bounce is a message that didn't reach its destination, but the impact goes beyond that. A high bounce rate is a red flag for email providers and can harm your deliverability, causing even emails sent to valid customers to end up in the spam folder. That's why you should stop sending to hard-bounced addresses and keep an eye on those that soft-bounce repeatedly.

How is it calculated?

Formula: Bounce rate = (bounced emails ÷ emails sent) × 100

For example, if you send 20,000 emails and 400 bounce, the bounce rate is 400 ÷ 20,000 × 100 = 2%. If 300 of those 400 are hard bounces, those addresses should be excluded from your future mailings.

Story mode

An online sports store combines the email addresses from its brick-and-mortar store, its e-commerce site, and an old contest. Many contain typos, such as “gmial,” or are duplicates. In the first campaign, the bounce rate skyrockets. The team cleans up the database, consolidates the records, and resends the email. Lucía, who had two addresses on file, now receives a single email at the address she actually uses.

How to Use It with Data4Sales

A low bounce rate starts with organized data. With Data4Sales:

• You consolidate purchases from brick-and-mortar stores, e-commerce sites, ERP systems, and marketplaces into a 360° customer profile.
• Identity Resolution merges duplicate records based on document, email, or phone number into a single customer record.
• Segment by activity and life cycle so you don't send messages to your entire list indiscriminately.

Related terms

• Deliverability
• Email marketing
• Data Quality
• Opening rate