You’ve crafted the perfect email campaign.
The copy is sharp, the design is on point, the subject line is irresistible, and you hit “Send.”
Out of 5,000 emails, 800 bounce.
They don’t land in the inbox. They don’t even make it to spam. They’re just… gone.
That’s the impact of a high bounce rate.
Email marketing remains one of the most effective channels for connecting with your audience, but it only works if your emails reach the inbox. One major obstacle to successful email delivery is the bounce rate. Despite being a critical performance metric, email bounce rate is often overlooked or misunderstood by marketers and developers alike.
In this in-depth guide, we’ll explore everything you need to know to understand, diagnose, and reduce your bounce rate. Whether you're running a newsletter, a sales campaign, or transactional emails, this resource will help you take control of your sender reputation and improve your overall deliverability.
What Is Email Bounce Rate?
Email bounce rate refers to the percentage of emails that are rejected by the recipient's mail server and never reach the inbox. This typically happens when an email address is invalid, temporarily unavailable, or blocked for some reason.
There are two types of bounces you need to know:
- Hard bounces are permanent failures. These usually happen when the email address doesn’t exist or the domain is invalid.
- Soft bounces are temporary issues, like a full inbox or a server timeout. These might resolve on a future send.
For example, if you send 5,000 emails and 100 bounce, your bounce rate is 2%.
Understanding this formula is crucial to properly measuring campaign performance. If you want a more hands-on approach, we’ve created a free worksheet to help you calculate your rate using real campaign data. You can explore that and more in our guide on the email bounce rate formula.
Why Email Bounce Rate Matters
Bounce rate is more than just a performance indicator, it’s a signal to inbox providers like Gmail, Outlook, and Yahoo about your email practices. A consistently high bounce rate can have cascading effects on your ability to communicate:
Lower deliverability
When too many emails bounce, Internet Service Providers (ISPs) start to see your domain as risky. They may throttle or block future messages, even to valid addresses.
If 20% of your emails bounce in a single campaign, Gmail or Outlook might delay or reject your next send altogether, hurting even your best-performing segments.
Reduced open rates
Fewer emails reaching the inbox means fewer chances to get seen, opened, or clicked. Even small increases in bounce rate can skew your campaign metrics and mask what’s working.
You might think a subject line is underperforming, when in reality, only 70% of your list received the email.
Damaged sender reputation
Your sender reputation is like a credit score for your domain. The more bounces you rack up, the more you erode that trust. Eventually, you may be flagged by spam filters, or blacklisted entirely.
A blacklisted domain could land all your emails in spam folders, even for recipients who previously engaged with your brand.
Wasted budget
Sending to bad addresses means you're paying for emails that go nowhere. At scale, this adds up, especially if you’re running cold outreach or nurturing large lists.
Sending 100,000 emails with a 10% bounce rate means 10,000 messages wasted. That’s money lost on ESP fees, creative work, and missed conversions.
This is why having a bounce rate reduction strategy is a core part of every email program. It affects your engagement metrics, ROI, and your ability to scale reliably.
Common Causes of High Bounce Rates
If your bounce rate is creeping above the 2% threshold, the first step is to identify what’s going wrong. Here are the most frequent causes:
1. Invalid or outdated emails
Email addresses go stale fast, especially in the B2B world, where job changes are frequent. Even a high-quality list can decay by 20–30% per year.For example, someone who signed up last year may have left the company, and their inbox is now deactivated, triggering a hard bounce.
2. Poor list hygiene
Using old, scraped, or purchased lists often leads to fake, misspelled, or recycled addresses. These lists may inflate your reach, but they hurt performance and sender reputation. "johndoe@gmial.com" instead of "gmail.com" looks harmless, but it's a guaranteed bounce. Multiply that by hundreds of typos, and it adds up quickly.
3. Spam traps or fake sign-ups
Spam traps are email addresses set up to catch bad actors. Even one trap hit can tank your deliverability and fake sign-ups from bots can flood your list if you don’t validate new addresses. This can happen for example if a bot signs up 50 fake users with throwaway emails. You blast them with a welcome campaign, and suddenly, your bounce rate spikes and you get flagged by ISPs.
4. Catch-all or unverified domains
Some domains are configured to accept all email traffic, only to silently discard or bounce it later. If you’re unsure how these domains behave, we recommend reading our breakdown of acceptable email bounce rate by industry. Example: You send to "info@company.com" on a catch-all domain. It accepts the message but never delivers it to an inbox.
5. Technical issues
Even if your list is clean, poor domain authentication can cause ISPs to reject your emails. These technical records prove your emails are legit and without them, your messages can bounce or go straight to spam. Missing a proper DKIM signature might cause Outlook to flag your email as spoofed, even if the recipient is valid and opted in.
Diagnosing the Problem: Hard vs Soft Bounces
It’s essential to differentiate between soft and hard bounces because they require different handling. You can learn how to approach each in our guide on soft vs hard bounce handling, but here’s a quick breakdown:
- Hard bounces: Must be removed from your list immediately. These indicate permanent issues.
- Soft bounces: May be retried up to 3 times. If they persist, remove or segment the address.
Tracking these types through your ESP (email service provider) is the first step toward actionable remediation.
The 5-Step Plan to Reduce Your Email Bounce Rate
High bounce rates aren’t just a tech issue, they’re a signal that your email program needs attention. Here’s a step-by-step plan to protect your deliverability, improve performance, and build long-term trust with your audience.
Step 1: Use Confirmed Opt-In (a.k.a. Double Opt-In)
Getting a new subscriber is great, but not if they mistype their email or sign up with a fake one.
Double opt-in means that after someone signs up, they must confirm their address by clicking a link in a follow-up email. It adds one extra step, but ensures you’re only emailing real people who actually want to hear from you.
Why it matters:
- Reduces fake or miss typed addresses
- Improves list quality from the start
- Boosts engagement (because your list wants your emails)
Example: Someone signs up as “jane.doe@gnail.com” a typo. With double opt-in, that email never gets added to your list because the confirmation link was never clicked.
Step 2: Bulk Clean Your Email List
Even if your list was once clean, emails go stale over time. People change jobs, abandon accounts, or mistype addresses. Regular bulk validation helps keep your list healthy and bounce rates low.
Use a reliable email verification tool to remove:
- ❌ Invalid or fake addresses
- ⏳ Temporary or disposable emails
- ⚠️ Spam traps that damage reputation
- 🧩 Duplicates or malformed entries
- 🎯 Catch-all domains that accept everything but silently drop or bounce your messages
Catch-all tip: These domains look like they’re working, but they’re risky. Validation tools like Email Awesome flag catch-alls so you can decide how to handle them, either segment them or verify manually.
Start cleaning with our Bulk Validator. First 1,000 checks are free every month.
Step 3: Monitor Bounce Metrics Regularly
Don’t just send and forget. Bounce tracking is essential for spotting issues early and acting fast.
Set up reporting in your email service provider (ESP) and understand the difference between bounce types:
- Soft bounces are temporary (e.g. full inbox, server down). Retry them a few times.
- Hard bounces are permanent (e.g. invalid address). Suppress them immediately to protect your reputation.
Tip: Track bounce rates by campaign and segment. If one group suddenly spikes, dig deeper. It could be a sign of a bad source or list issue.
Step 4: Authenticate Your Sending Domain
ISPs want to know your emails are legit. That’s why SPF, DKIM, and DMARC records matter. They verify that your domain is authorized to send emails and protect you from spoofing.
Without proper authentication, even valid emails can bounce or land in spam.
What to do:
- Set up SPF to define which servers can send on your behalf
- Add DKIM to sign your emails with a digital signature
- Configure DMARC to tell ISPs what to do if something looks suspicious
Example: If you use a third-party email platform (like Mailchimp, HubSpot, or your own ESP) and don’t update your domain’s DNS records, your emails could be flagged, even if your list is clean.
Step 5: Segment and Warm Up New Lists
Never blast a cold list all at once. Even if you’ve cleaned it, ISPs are cautious with sudden surges in sending volume.
Instead:
- Break your list into smaller segments
- Send a small test batch and monitor bounce and engagement rates
- Gradually increase volume over days or weeks
This “warm-up” approach helps build trust with ISPs and gives you room to detect and fix issues before they scale.Segment out risky addresses like catch-alls or unverified emails into separate sends. That way, they don’t pull down your overall reputation if something goes wrong.
Long-Term List Health Tactics
Keeping your bounce rate low is not a one-time fix, it’s an ongoing practice. Some long-term strategies include:
- Real-time email validation at sign-up
- Remove disengaged users after 60–90 days
- Avoid purchased lists altogether
- Use CAPTCHA or email verification tools to block bots
- Check for duplicates and formatting errors before importing lists
How Often Should You Clean Your List?
The frequency depends on how active your list is. As a general rule:
- Clean your list quarterly if you send weekly campaigns
- Run a validation before major sends (like Black Friday or product launches)
- Validate new sign-ups in real time, especially for high-volume forms
A high bounce rate means your emails aren’t reaching inboxes and that hurts your deliverability, open rates, and sender reputation. Common causes include invalid or outdated emails, spam traps, catch-all domains, and missing domain authentication (like SPF, DKIM, and DMARC).
To fix it, use double opt-in to catch typos and fake sign-ups, clean your list regularly with a validator, monitor bounce metrics, authenticate your domain, and slowly warm up new lists. Healthy email lists don’t just perform better, they protect your ability to reach your audience.
Ready to clean your list? Try Email Awesome, your first 1,000 verifications are free.
Mini FAQ
What’s a bad bounce rate?
Anything over 2% is considered high and could negatively impact your domain.
Can soft bounces be fixed?
Sometimes. Retry the message a few times. If the soft bounce persists, consider removing or segmenting the contact.
Are catch-all domains safe to email?
They’re risky. Use a validator with catch-all detection to score their likelihood of bouncing.
Can my content affect bounce rate?
Not directly. However, spammy formatting or blacklisted links can cause deliverability problems which sometimes result in bounces.
How does bounce rate impact open rate?
A poor bounce rate affects sender reputation, which in turn may reduce inbox placement and thus open rates.