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SSL Certificate Checker Tool: Check Certificate Validity Online

This free SSL certificate checker tool lets you check certificate validity online. It reads the certificate a public website presents and reports when it expires, who issued it, and whether the name and trust chain verify. Enter a public web address, confirm you may check it, and read the result in one place. The check runs from outside, takes at most four minutes and often finishes sooner. It looks at one public HTTPS address and does not audit your whole server configuration.

  • Free
  • No account needed
  • Public websites only
  • Up to 4 minutes

SSL Certificate Checker

Confirm permission to check .

Free public snapshot · Maximum 4 minutes Results may finish sooner. Unchecked areas are never treated as clean.

No account needed · Public targets only · No passwords, private addresses or network ranges

Quick-check results expire after 30 minutes and may reuse a result checked within the last 10 minutes. They are not automatically saved to an account. Sanitized target addresses and check activity are retained for 35 days for operations and the administrator daily summary. Addresses omit query strings and fragments; login details are not accepted. Advisory and network lookups may use public data services.

How to check certificate validity online

  1. 1Enter the addressType a public website address. Only ports 80 and 443 are supported.
  2. 2Confirm permissionTick the box to confirm you own the target or have permission to check it.
  3. 3Read the resultSee the expiry, issuer, name match, trust chain and the names on the certificate.

What the SSL certificate checker tool reports

Run the SSL certificate checker online and the result starts with a verdict: certificate verified, certificate expires soon, or certificate verification failed. Below it the checker lists the details you need to act on the result.

  • Read the website name and the issuer of the certificate.
  • Check the valid-from and expiry dates and the number of days remaining.
  • Confirm whether the name and the trust chain were verified, and read the verification issue if one is reported.
  • Note the TLS protocol negotiated during the test.
  • Review the names listed on the certificate.

SSL certificate checks this page covers

One check reads the certificate and the connection together. These are the four parts of the result you can act on.

Certificate expiry check

The result shows the valid-from date, the expiry date and the days remaining. A certificate close to expiry is reported as expires soon, so you can renew before visitors see a browser warning.

Name match check

The result lists the names on the certificate, known as Subject Alternative Names (SANs). The address you check, including any www or subdomain, must appear in that list for the name to verify.

Trust chain check

The result reports whether the X.509 certificate chains to a trusted certificate authority (CA) through its intermediate certificates. A missing intermediate certificate is a common reason the chain fails on some devices. Name and trust chain are reported together as one verification result.

TLS protocol check

The result notes the TLS version that the test connection negotiated. It shows what this connection used, not every protocol your server supports.

SSL certificate check or TLS vulnerability scan?

People search for two different things. A certificate check, which this tool does, confirms that the certificate installed on your server is valid, matches the name and chains correctly. A TLS vulnerability scan audits the server configuration: supported protocol versions, cipher suites and known flaws such as Heartbleed or POODLE. This tool does not run that audit.

  • Use this checker when a browser shows a certificate warning or before a certificate expires.
  • Use a TLS configuration test when you need to review protocol versions and cipher suites.
  • Use the website vulnerability scanner to check the website and application behind the certificate.
  • Use the security headers checker to review HTTPS-related headers such as HSTS.

What this check does not cover

The checker tests one public HTTPS address from outside and reports the fields listed above. It does not grade your cipher suites, list every protocol your server supports, scan for TLS vulnerabilities or check certificates on other services such as mail servers. It cannot reach private addresses, internal hosts or ScanTitan domains, and it supports ports 80 and 443 only. Where something could not be checked, the result says so, because unchecked areas are never treated as clean. A valid certificate also does not mean the website behind it is secure, since the application, plugins and server can still carry vulnerabilities.

How to fix common certificate problems

  • Renew an expired or expiring certificate with your certificate authority or hosting panel, then reload the web server so it serves the new file.
  • Reissue the certificate when the name does not match. The exact domain you use, including www or a subdomain, must appear in the certificate names.
  • Install the intermediate certificates when the chain fails to verify, and serve the full chain, not only the leaf file.
  • Automate renewal with your host or an ACME client such as Certbot, so expiry never depends on a calendar reminder.
  • Recheck after every change, from outside your own network.

Other ways to check an SSL certificate

The checker above is the quickest way to check certificate validity online. You can also inspect a certificate yourself.

  • Browser: click the padlock beside the address, then open the certificate details to see the issuer and the expiry date.
  • Command line: run the command below to print the dates, issuer and subject.
echo | openssl s_client -connect example.com:443 -servername example.com 2>/dev/null | openssl x509 -noout -dates -issuer -subject

Replace example.com with your domain. Only run it against hosts you own or are allowed to test.

What a free account adds

The SSL certificate checker is free and needs no account. Create a free account to protect one website, with a dashboard for your checks and reports. The Free plan includes one website security scan, plus basic malware and uptime monitoring, with the TLS certificate and domain expiry checked daily. Compare paid plans on the pricing page.

Frequently asked questions

What does an SSL certificate checker tool do?An SSL certificate checker tool connects to a public HTTPS address and reads the certificate it presents. It reports who issued the certificate, when it expires, whether the name matches the website and whether the trust chain validates, so you can fix problems before visitors see a browser warning.
Do I need an account to use it?No. The check is free and needs no account. You confirm that you own the target or have permission to check it, and the check runs for at most four minutes.
Why does the result say verification failed?Verification fails when the certificate has expired, the name does not match the address, or the server does not send the intermediate certificates needed to build the trust chain. The result shows the verification issue when one is reported. Fix the cause, then run the check again.
Can I check a staging site or an internal server?No. The checker only works for public websites on ports 80 and 443. Private addresses, internal hosts and ScanTitan domains are blocked.
Does a valid certificate mean my website is secure?No. A valid certificate means the connection to the site is encrypted and the site identity checks out. It says nothing about vulnerabilities in the application, plugins or server behind it.
How do I check when my SSL certificate expires?Enter your public web address in the checker above. The result shows the expiry date and the days remaining, and flags a certificate that expires soon. You can also open the certificate from the padlock in your browser or run the openssl command shown on this page.
What is the difference between an SSL certificate checker and a TLS vulnerability scanner?A certificate checker confirms that the installed certificate is valid, matches the name and chains to a trusted authority. A TLS vulnerability scanner audits the server configuration, such as supported protocols, cipher suites and known flaws. This checker does the first and does not audit server configuration.
What is a certificate chain?A certificate chain links your site certificate to a trusted root authority through one or more intermediate certificates. If the server does not send the intermediate certificates, some browsers and devices cannot build the chain and show a warning.
Is SSL the same as TLS?TLS is the current protocol and SSL is its older predecessor. People still say SSL certificate for the certificates used with TLS. The test connection reports the TLS version it negotiated.
Is this SSL certificate checker free?Yes. This SSL certificate checker is free, needs no account and runs online in your browser. Enter a public web address, confirm you may check it and read the result.
How do I check certificate validity online?Open the SSL certificate checker online, enter your public web address and confirm permission. The result shows whether the certificate verified, when it expires, who issued it and whether the name and trust chain verify.

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A valid certificate does not mean the site is free of vulnerabilities. Check the application behind it.

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A free tool by ScanTitan. Guidance only, not a guarantee of security. Last reviewed October 2026.