# What is an email bounce?

> An email bounce is a message that could not be delivered. Hard vs soft bounces, why a high bounce rate hurts inbox placement and how to prevent it.

Source: https://learn.ynteractive.com/content/glossary/email-bounce · Updated 2026-10-13 · Free from Stepthrough (https://learn.ynteractive.com)

[Business](https://learn.ynteractive.com/content/glossary#topic-business) · [AI glossary](https://learn.ynteractive.com/content/glossary)

Quick answer

An email bounce is a message that comes back undelivered. A hard bounce is permanent, such as an address that does not exist or a domain that has expired. A soft bounce is temporary, such as a full mailbox. The bounce rate is the share of a send that bounced, and email services watch it closely.

Last updated October 13, 2026

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Updated October 13, 2026 · By [Robert Breen](https://learn.ynteractive.com/content/about)

## Why it matters for a small business

Bounces are a signal to mailbox providers. If you keep sending to addresses that do not exist, you look like a sender who does not check their list, and providers can respond by sending more of your mail to spam. That is a [deliverability](https://learn.ynteractive.com/content/glossary/email-deliverability) problem, and it affects the good addresses on your list too, not only the dead ones.

It is also a cost problem. Many email services charge by contact, so a list with old addresses costs money every month. And it is a quiet problem: you rarely see a warning until the bounce rate on a report is already high.

## Hard bounce vs soft bounce

| Type | What it means | What to do |
| --- | --- | --- |
| Hard bounce | Permanent: the address does not exist, has a typo or the domain is gone | Remove it from the list and do not send again |
| Soft bounce | Temporary: the mailbox is full or the server is down for a while | Try again later, and remove it if it keeps failing |

Email services set their own bounce limits and warnings, so check your provider's rules instead of relying on a single number.

## In a real lesson: Protect Your Sender Reputation Before a Big Send using no2bounce

In the [no2bounce lesson](https://learn.ynteractive.com/content/no2bounce-clean-email-list-sender-reputation), Nora markets a made-up event space, Lantern Hill Venue. Her open house invitation went to 600 contacts and 54 bounced, which is 9%. The numbers are an illustration, not a benchmark, but they show the problem: the list was built over years from badge scans and old sign-ups.

The lesson checks a 30-row contact list before the next send. The list includes typos such as gmial.com and a .con ending, shared inboxes and a former employee. You upload it, read the Deliverable, Risky and UnDeliverable groups, and download only the confirmed addresses. A message to that file should not hard bounce.

[Try this lesson free](https://learn.ynteractive.com/modules/no2bounce-clean-email-list) or [read the step-by-step guide](https://learn.ynteractive.com/content/no2bounce-clean-email-list-sender-reputation).

## Common confusions

### Bounce vs spam folder

A bounce means the message was refused or could not be delivered. A message in the spam folder was delivered, just not to the inbox.

### Bounce vs unsubscribe

An unsubscribe is a person choosing to stop. A bounce is a technical failure. Honor both, and never send again to either.

## Tips

- Check a list that is more than a few months old before a big send.
- Watch the bounce rate on every report and act early.
- Only email people who have a reason to hear from you, and follow the opt-in and unsubscribe rules where you send.

## Related terms

[Email deliverability](https://learn.ynteractive.com/content/glossary/email-deliverability) · [Cold email](https://learn.ynteractive.com/content/glossary/cold-email) · [Lead nurturing](https://learn.ynteractive.com/content/glossary/lead-nurturing) · [Follow-up email](https://learn.ynteractive.com/content/glossary/follow-up-email)

## More Business terms

[Email open rate and click rate](https://learn.ynteractive.com/content/glossary/email-open-rate) · [Email opt-in](https://learn.ynteractive.com/content/glossary/email-opt-in) · [Employee handbook](https://learn.ynteractive.com/content/glossary/employee-handbook) · [Employee offboarding](https://learn.ynteractive.com/content/glossary/employee-offboarding)

## Where you use it: free lessons

- [Protect Your Sender Reputation Before a Big Send using no2bounce](https://learn.ynteractive.com/content/no2bounce-clean-email-list-sender-reputation) (no2bounce, 8 min)

## Prompt templates that use it

[Email list send decision prompt](https://learn.ynteractive.com/content/prompts/email-list-send-decision-prompt)

## Frequently asked questions

**What is the difference between a hard and a soft bounce?**

A hard bounce is permanent, like an address that does not exist. A soft bounce is temporary, like a full mailbox. Remove hard bounces right away.

**What is a good bounce rate?**

Lower is better. Providers often suggest keeping it low, commonly cited at around 2% or less, but each email service sets its own limits, so check yours.

**How do I reduce email bounces?**

Check your list with an email verifier before a big send, remove hard bounces after each campaign, and collect addresses with a confirmation step.

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