Free Email Bounce Checker —
Stop Hard Bounces Before They Happen.
Identify and remove invalid email addresses before you hit send. Our free bounce checker runs SMTP-level verification to catch the addresses that will hard-bounce — protecting your sender score and keeping your ESP account safe.
Check a single address for bounce risk:
Need to check thousands of emails? Use the bulk email verifier →
Understanding Email Bounces
Not all bounces are equal. Knowing the difference helps you target the right problem.
Hard Bounces — Must Remove
A hard bounce is a permanent delivery failure. The address doesn't exist, the domain is gone, or the server has blocked you. These must be removed immediately — ESPs track them closely and will suspend accounts with high hard-bounce rates.
Causes: invalid address · deleted mailbox · non-existent domain
Soft Bounces — Monitor & Retry
A soft bounce is a temporary failure — the server was overloaded, the mailbox was full, or the message was too large. Most ESPs retry soft bounces automatically, but repeated soft bounces on the same address should be flagged for removal.
Causes: full inbox · server timeout · message size limit
Catch-All Addresses — Flag as Risky
Some mail servers accept all incoming email regardless of whether the specific mailbox exists. These "catch-all" addresses can't be fully verified via SMTP — they're a bounce risk that only shows up after sending. Our checker flags them as risky.
Often found on corporate domains and small business servers
Disposable Addresses — Remove Proactively
Disposable email addresses (from services like Mailinator) are designed to expire. Sending to them after expiry results in a hard bounce. Our checker detects these from a live list of disposable providers and removes them upfront.
Auto-detected against 3,000+ known disposable domains
Why high bounce rates are so dangerous
Hard bounce rate that triggers ESP warnings and reduced deliverability
Bounce rate that can result in account suspension on major ESPs
Average percentage of email lists that contain invalid or undeliverable addresses
Email Bounce Checker — FAQ
What is a hard bounce in email marketing?
A hard bounce is a permanent email delivery failure. It means the address doesn't exist, the domain is invalid, or the receiving server has permanently rejected delivery. Hard bounces must be removed from your list immediately.
How do I remove hard bounces from my email list for free?
Upload your list to ListEmailCheck. Our SMTP verifier identifies the addresses that will hard-bounce and separates them into an 'invalid' export file that you can then permanently remove from your database.
What is a safe bounce rate for email campaigns?
Most ESPs consider anything above 2% a warning sign. Above 5% risks account suspension. Regular list cleaning keeps you well below both thresholds.
What is a catch-all email verifier?
A catch-all email verifier detects domains that accept all incoming mail regardless of whether the specific mailbox exists. These addresses can't be confirmed as valid via SMTP, so they're flagged as 'risky' for you to decide on.
How often should I check my email list for bounces?
Best practice is to verify your list before every major send, and to suppress any address that hard-bounced in a previous campaign. For actively-growing lists, run a full verification monthly.
Does bounce checking work for cold email outreach?
Yes — it's especially important for cold email. Cold outreach typically has no prior relationship with recipients, so invalid addresses are common. High bounce rates on cold campaigns can get your domain blacklisted.
Reduce your bounce rate starting today
Free plan: 100 verifications/day. No credit card. Bulk CSV upload included.
Start Free — No Card NeededAlso see: Free Email Validator · Improve Deliverability