SSL Certificate Checker

Check SSL certificates – validity, issuer, expiry date and more

Enter domain (without https://)

Check & understand SSL certificates

A valid SSL/TLS certificate is mandatory for every modern website — it encrypts the connection between browser and server and has been a direct Google ranking factor since 2014. The checker shows all relevant certificate data at a glance: issuer, validity period, SAN entries and TLS version.

Particularly critical: an expired certificate triggers browser warnings that immediately deter visitors. Renewal is recommended at least 30 days before expiry — for Let's Encrypt certificates ideally automated via Certbot.

Current browsers only support TLS 1.2 and TLS 1.3. Older versions (TLS 1.0, 1.1, SSL 3.0) are considered insecure and are blocked. The checker shows you which TLS version your server is using.

Frequently Asked Questions

What does the SSL Certificate Checker verify? +

The checker shows the issuer, validity period, expiry date, SAN entries, TLS version, cipher suite, public key algorithm and key size. This lets you quickly check whether a certificate is valid and correctly configured.

Why is a valid SSL certificate important for SEO? +

Google has used HTTPS as a ranking factor since 2014. Pages without a valid SSL certificate are marked as "Not secure" in Chrome, which increases the bounce rate. HTTPS is also a prerequisite for HTTP/2 and many modern browser features.

How far in advance should I renew an SSL certificate? +

Renewal is recommended at least 30 days before expiry. Let's Encrypt certificates expire after 90 days and should ideally be renewed automatically via Certbot. An expired certificate causes browser warnings and loss of trust.

What is TLS and how does it differ from SSL? +

TLS (Transport Layer Security) is the successor to SSL (Secure Sockets Layer). Both terms are often used interchangeably, but SSL is outdated and insecure. Modern servers use TLS 1.2 or TLS 1.3 — older versions are no longer supported by current browsers.

Is the SSL Certificate Checker free? +

Yes, the SSL Checker is 100% free and usable without registration. Enter a domain, check, done.

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