Under 2% is the number to aim for. If your bounce rate is below 2%, your list is in decent shape. Below 1% and you're doing well.
Anything above 2% is a signal worth acting on. Above 5%, mailbox providers start treating you like a risk, and your delivery to the good addresses on your list suffers too.
That last part is the piece most people miss. Bounces don't just waste sends. They drag down everything else.
What a bounce actually is
A bounce is an email that couldn't be delivered. The receiving mail server rejected it and sent back a notice.
There are two kinds, and they mean very different things.
Hard bounces are permanent. The address doesn't exist, the domain is dead, or the mailbox was deleted. Someone typed "gmial.com" at your signup form. An employee left the company and IT wiped the account.
Soft bounces are temporary. The inbox is full. The server was down for maintenance. The message was too big. These often deliver fine on the next send.
Most email tools, including Constant Contact, separate the two in your reporting. Look at that split before you panic. A 3% bounce rate made up almost entirely of soft bounces from one bad send day is a different problem than 3% hard bounces.
The benchmarks, plainly
Here's how to read your number:
- Under 1%, healthy. Keep doing what you're doing.
- 1% to 2%, normal, especially if you've added a lot of new contacts recently.
- 2% to 5%, something's off. Check where those addresses came from.
- Over 5%, treat it as urgent. Your sender reputation is taking damage.
One caveat on brand-new lists. Your first send to a list you just imported will almost always bounce higher than your steady-state number. That's the cleanup send. Judge yourself on send number three, not send number one.
Why your bounce rate is high
Nearly every high bounce rate traces back to one of these.
You bought or rented a list
Purchased lists are full of dead addresses and spam traps. Even the "verified" ones. There's no version of this that ends well, and no cleanup process that fixes it. Delete the list.
You haven't emailed in months
Email addresses decay. People change jobs, abandon old accounts, switch providers. A list that sat untouched for a year can bounce 10% or worse on the first send back.
If this is you, don't blast the whole list. Start with the people who opened something in the last six months, then work outward in small batches.
Your signup form has no safety net
Typos happen. "yahho.com" and "gmail.con" go straight into your list and straight to a hard bounce. A confirmation step, even a simple double opt-in, catches most of it.
You're importing from places you shouldn't
Business card stacks. Old spreadsheets. A conference attendee list someone handed you. These addresses are stale and often weren't permission-based to begin with.
Your own sending setup has problems
Sometimes the bounce isn't about the address. It's about you. Missing SPF or DKIM records, a domain with no sending history, or content that trips filters can all produce rejections that show up as bounces.
Our Spam Score Checker flags content-level issues before you send. It won't check your DNS records, but it catches the stuff you wrote.
How to fix it
Remove hard bounces immediately
Most platforms do this automatically after one hard bounce. Don't override it. Don't re-import an address that already bounced hard. It won't magically start working.
Watch soft bounces across sends
One soft bounce is nothing. The same address soft-bouncing three or four sends in a row is effectively dead. Pull it.
Clean before you send, not after
If your list has been sitting for a while, run it through a verification service before the next campaign. It costs a few dollars per thousand addresses and saves you from a reputation hit that takes months to recover from.
Fix the front door
Add a confirmation email to your signup flow. Yes, you'll lose a few subscribers who never confirm. Those were mostly bad addresses anyway.
Set your form field to validate the email format at minimum. It catches missing @ symbols and obviously broken domains.
Send more consistently
This is the boring fix that works. Lists that get regular mail stay clean, because bad addresses get caught and removed a handful at a time instead of all at once. Our Email Frequency Calculator can help you pick a cadence you'll actually stick to.
Segment your way out of a mess
If you're staring at a list you're afraid to email, here's the sequence.
- Sort by recent engagement. Anyone who opened or clicked in the last 90 days goes in group one.
- Send to group one first. Small batch, normal campaign. Watch the bounce rate.
- If it's clean, expand. Add the 90-to-180-day group next. Send again. Watch again.
- Stop when bounces spike. The group where your rate jumps is where your list goes stale. Everything older than that needs verification or removal.
This takes a few weeks. It's slower than one big send, and it protects your ability to reach the people who actually want to hear from you.
What to check in your reports
Every send, glance at three numbers:
- Bounce rate, is it trending up?
- Hard vs. soft split, hard bounces mean list quality, soft bounces often mean timing or content size.
- Unsubscribes and complaints, a rising bounce rate paired with rising complaints means your list source is the problem, not your cleanup.
If you want a structured way to look at all of this, run your recent campaigns through the Performance Audit and see what stands out.
The short version
Aim for under 2%. Investigate anything over that. Never buy a list, never let a hard bounce stay on your list, and email consistently enough that your list cleans itself.
A clean list of 800 people beats a messy list of 5,000 every single time.