Verify expiry, issuer & covered domains for any HTTPS site
Our SSL Certificate Checker connects directly to the server hosting your domain and retrieves the full SSL/TLS certificate presented during the TLS handshake. It then parses the certificate to extract critical details including the issuer (Certificate Authority), validity dates, Subject Alternative Names (SANs), public key algorithm, and the SHA-256 fingerprint. This gives you a complete snapshot of the certificate protecting any HTTPS website.
SSL certificates are the foundation of secure communication on the web. They encrypt data in transit between your browser and the server, verify the identity of the website, and establish trust with visitors. An expired or misconfigured certificate triggers browser warnings that drive users away and can harm search engine rankings. Regularly checking your certificates helps you avoid downtime and maintain trust.
To use the tool, enter any domain name (for example, google.com) and click Check. The results will show whether the certificate is valid, how many days remain until expiry, which Certificate Authority issued it, all domains covered by the certificate, and the cryptographic key details. You can use this information to verify your own sites or audit third-party domains before integrating with them.
An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates a website's identity and enables an encrypted connection between a web server and a browser. Modern certificates actually use the newer TLS (Transport Layer Security) protocol, but the term “SSL” is still widely used. Without a valid certificate, browsers display “Not Secure” warnings to visitors.
The checker displays the certificate issuer (e.g., Let's Encrypt, DigiCert), the exact issue and expiry dates, the number of days remaining until expiration, all Subject Alternative Names (additional domains covered), the public key type and size, and the certificate's SHA-256 fingerprint for verification purposes.
The certificate chain (or chain of trust) is the sequence of certificates from your domain's certificate up to a trusted root Certificate Authority. It typically includes the end-entity certificate (your domain), one or more intermediate certificates, and a root certificate that browsers inherently trust. A broken chain causes browser warnings even if the certificate itself is valid.
To fix an expired certificate, you need to renew it through your Certificate Authority or hosting provider. If you use Let's Encrypt, renewal can be automated with Certbot. After obtaining the renewed certificate, install it on your web server and restart the server process. Most CAs recommend renewing at least 30 days before expiry to avoid any gaps in coverage.
Domain Validation (DV) certificates only verify that you control the domain and are the fastest and cheapest to obtain. Organization Validation (OV) certificates additionally verify your organization's identity through business registration checks. Extended Validation (EV) certificates require the most rigorous vetting process, including legal and physical verification of the organization. All three provide the same level of encryption, but OV and EV offer higher levels of identity assurance.
