Free SSL Certificate Checker Online

Check SSL certificate validity free online. View certificate details, expiry dates. Instant results, browser-based, no registration, security check.

Free SSL Certificate Checker Online

Verify SSL certificate details, expiration, and validity for any domain

Complete SSL Analysis

Verify certificate validity and configuration at a glance

Certificate Details

See the certificate issuer, subject, serial number, and signature algorithm used for the SSL certificate.

Expiration Monitoring

Check the exact issue and expiration dates to ensure your certificate is current and plan renewals.

Validity Status

Get an instant pass or fail assessment of the certificate validity including chain verification.

About This Tool

This tool inspects the SSL/TLS certificate a website presents, reporting who it was issued to, who issued it, and when it expires. That certificate is what enables the padlock and HTTPS: it proves the site's identity and encrypts traffic between the browser and the server.

The most common real-world problem it catches is an expired or soon-to-expire certificate, which makes browsers show a security warning and can take a site offline for cautious visitors. The checker also flags mismatched domains and incomplete certificate chains, both of which break trust even when the certificate itself is valid.

How to Use It

  1. Enter the domain to inspect.
  2. Review the certificate's issuer, subject, and validity dates.
  3. Act on any warning about expiry, domain mismatch, or an incomplete chain.

References

  1. RFC 8446: The Transport Layer Security (TLS) Protocol Version 1.3 - IETF
  2. RFC 5280: Internet X.509 Public Key Infrastructure Certificate - IETF
  3. Transport Layer Security (TLS) - MDN
  4. Transport Layer Security - Wikipedia