Free SSL Certificate Checker
Verify SSL certificate validity, expiry date, issuer chain, and TLS version for any domain. Instant results, no signup required.
What it checks: certificate expiry date, issuing CA, full chain validity, TLS protocol version, and whether the certificate matches the domain — the same checks that cause a browser security warning if something's wrong.
Frequently Asked Questions
Enter your domain in the SSL Checker above and click Check. The tool will connect to your server on port 443, retrieve the certificate, and show you the validity dates, issuer, subject alternative names, and whether the certificate is trusted by major browsers.
SSL/TLS certificates have an expiry date — typically 90 days (Let's Encrypt) or 1–2 years. After expiry, browsers show a security warning and visitors cannot reach your site safely. Use our SSL Checker to see exactly how many days remain on your certificate.
A certificate chain is the sequence of certificates from your site's certificate up to a trusted root certificate authority (CA). For a certificate to be trusted by browsers, the full chain must be valid and properly installed. Missing intermediate certificates are a common cause of SSL errors.
Your server should support TLS 1.2 and TLS 1.3 only. TLS 1.0 and 1.1 are deprecated and considered insecure. Our SSL Checker shows which TLS version your server is using so you can identify outdated configurations.
To fix an expired SSL certificate: 1) Contact your certificate provider or hosting company, 2) Renew the certificate through your control panel, 3) If using Let's Encrypt, run certbot renew on your server, 4) Verify the new certificate is installed correctly using this SSL checker tool, 5) Check that your server is serving the new certificate on port 443.
SSL certificates can appear invalid for several reasons: incomplete certificate chain (missing intermediate certificates), the domain does not match the certificate (check for www vs non-www), the certificate has expired, or the server is not properly configured. Use this tool to see the full certificate chain and identify the specific issue.