SSL Certificate Expiration Checker
Check any website's SSL certificate expiration date and days until expiry, plus the issuer, key size, signature algorithm, version, serial number, and full Subject Alternative Name list. One click, fetched live over port 443, no signup.
How to Check an SSL Certificate Expiration Date
Enter the Domain
Type any domain name, like example.com or a subdomain, into the box. No https or paths needed.
Run the Check
Click Check. The tool connects over port 443 and reads the live SSL certificate in seconds.
Read the Expiry and Details
See the expiration date, days remaining, issuer, key size, algorithm, serial, and the full SAN list.
Check Your SSL Certificate Expiration Date Before It Breaks Your Site
An expired SSL certificate throws a full-page security warning, blocks checkout, and drags down search rankings, and it almost always happens on the one domain nobody was watching. This SSL certificate expiration checker tells you exactly when a certificate expires and how many days are left, so a renewal never catches you off guard. Enter any domain and it connects live over port 443, reads the X.509 certificate, and shows the expiry date in one click.
You also get the issuer, key size, signature algorithm, serial number, certificate version, and the full Subject Alternative Name (SAN) list, so you can confirm the certificate actually covers every hostname it should, including the www and any subdomains. To check an SSL certificate expiration date the manual way you would run an OpenSSL command or dig through the browser padlock. This does the same read instantly, with nothing to install. Run it on every domain you own once a month, and set a reminder 30 days before the closest expiry date.
Why Use This SSL Certificate Expiration Checker?
Expiry Date and Days Left
See the exact SSL certificate expiration date and the number of days remaining, so you can renew before the certificate lapses and breaks the site.
Issuer and Certificate Details
Get the issuing authority, key size, signature algorithm, certificate version, and serial number, the full technical picture in one scan.
Full SAN List
View every Subject Alternative Name on the certificate to confirm it covers the root domain, www, and all subdomains you expect.
Live Check, No Signup
Enter a domain and get a live TLS handshake result in seconds. No account, no rate limits, and nothing to install.
Any Domain or Subdomain
Check your own sites or any public domain, including subdomains, exactly as a real browser would see the certificate.
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Frequently Asked Questions
Expiration dates, SAN, and how the check works, answered.
How do I check when my SSL certificate expires?
Enter your domain in the SSL certificate expiration checker above and click Check. It connects to your server over port 443, reads the live certificate, and shows the exact expiration date along with the number of days remaining, with no signup.
How many days until my SSL certificate expires?
The checker shows the days remaining next to the expiration date. Most certificates are valid for 90 days (Let's Encrypt) or up to about 398 days, so checking monthly and renewing 30 days before expiry keeps you safe.
How do I check the SAN on an SSL certificate?
Run the check and look at the Subject Alternative Name (SAN) list in the results. It lists every hostname the certificate covers, so you can confirm it includes your root domain, www, and any subdomains.
Can I check an SSL certificate expiration date without a browser?
Yes. This tool reads the certificate over a direct port 443 connection, the same data OpenSSL returns, so you get the expiry date, issuer, and SAN list without opening the site or clicking the browser padlock.
Does it work for expired, self-signed, or subdomain certificates?
Yes. The checker reports the details of whatever certificate the server presents, including expired and self-signed ones, and it works on subdomains. An expired or mismatched certificate is shown clearly so you can fix it.
Is the SSL certificate checker free with any limits?
It is completely free with no signup and no rate limits. Check a single domain or run it across every site you operate as often as you need, at no cost.