Understanding Email Bounce Rates

Email Bounce Rate is the percentage of emails you send that don’t reach the recipient’s inbox (including the spam folder) and are returned as undeliverable. Bounce rates are an important indicator of your email deliverability and contact list health. When emails can’t be delivered, they are considered “bounced.”

Understanding why bounces happen and how to manage them can help protect your sender reputation and improve overall email performance.

What is an Email Bounce?

When an email message can't be delivered, it's returned to the sender as a bounce. When you use an email marketing application, the bounce messages are sent to the application. There are two types of bounces: soft and hard.

Soft Bounces	Hard Bounces
Temporarily prevent email delivery due to short-term problems with the recipient’s inbox. Soft-bounced emails will still be listed as active contacts in your list.	Permanently reject email delivery due to a permanent failure with the inbox or email address. Hard Bounce emails are not considered active contacts.
Common causes may include: Mailbox is full The recipient server is temporarily unavailable.	Common causes include: Invalid or non-existent email address Domain does not exist The recipient server has permanently rejected the message
What to expect:	What to expect:
Soft bounces will remain as active contacts. They will only appear as soft bounces in the email report, where they were temporarily bounced.	When an email hard bounces, its status becomes inactive, and it can no longer receive emails. Hard bounces are not counted in your active contact count.
No action is needed.	Deleting the bounce email does not reactivate the sending status.

Similar to physical mail, if an email can't be delivered, it is returned to the original sender.

You may have seen a bounce message in your personal inbox when sending an email to an invalid address.

Benchmark Bounce Rate Policy

To prevent emails from being filtered, protect your sending reputation, and comply with ISPs and Spam regulations, we have a set of thresholds that will automatically pause sending if an account's bounce rate becomes too high.

Bounce rate should consistently remain below 5%. If the bounce rate exceeds 5%, all email sending is paused. During this phase, our email delivery team will contact you.

The Reports page provides your account's bounce rate for a 30-, 60-, or 90-day period.

How Bounces Impact Sending Reputation

High bounce rates negatively impact sending reputation by signaling to inbox providers that the sender's email practices are unreliable.

Over time, this can lead to:

Emails filtered as spam
Delivered less frequently, or blocked entirely.
As a sender's reputation declines, even valid contacts may stop receiving emails in their inboxes.

Managing your bounce rate is essential to maintaining strong email deliverability and a positive sending reputation. Keeping your bounce rate low ensures your messages continue to reach the audience that wants to hear from you.

Managing and Reducing Bounces

Maintaining an up-to-date contact list can help keep bounces low and can prevent your email delivery from being affected.

Here are some strategies for effectively managing and reducing bounce rates.

List Hygiene

Regularly remove contacts who are not engaging with your emails. A common guideline is to remove subscribers who haven’t opened your emails in a certain timeframe; the timeframe should align with how often you send.

For example:

Daily senders: consider removing contacts who haven’t opened in ~30 days
Weekly senders: ~6 months of inactivity
Biweekly senders: ~9 months of inactivity
Monthly senders: ~12 months of inactivity

These timeframes are based on giving contacts multiple chances to engage before being considered inactive.

Keep in mind, this is a general guideline, not a hard rule. Your ideal timeframe may vary depending on:

How frequently you send emails
The size and quality of your contact list
The type of content you send (promotional vs. informational)
Your contact's typical engagement behavior

Verify Contacts

A third-party verification service can help reduce hard bounces by identifying questionable email addresses before you send.

These services can detect:

Invalid emails (incorrect format or non-existent addresses)
Role-based emails (e.g., info@, support@)
- Usually belong to multiple people, impacting the open and abuse rate.
Risky emails (temporary, disposable, or low-quality addresses)

Verification services cannot identify everything. For example:

Spam traps cannot be reliably detected, as they are intentionally hidden and not publicly known
Engagement level (whether a contact will open or interact) cannot be predicted.

Verification should be a part of a broader list management strategy, not a complete solution.

Permission-Based Lists

Always use permission-based lists. This means your contacts have clearly agreed to receive emails from you.

Permission isn’t only collected through signup forms, it can also be established through direct interactions, such as:

A customer making a purchase
A client email conversation where they request information
A user signing up for a service or account

No Purchased Lists

Avoid using purchased or harvested email lists. While they may seem like a quick way to grow your audience, these contacts have not given you permission and are far more likely to:

Mark your emails as spam
Ignore your messages
Harm your sender's reputation and deliverability
Contain invalid emails

SUMMARY ✅

Keep your list healthy by removing inactive contacts, verifying email addresses, and sending only to people who have given permission. Avoid purchased lists, as they can lead to bounces, spam complaints, and poor deliverability.