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Free SSL Certificate Checker

Check if a website has a valid SSL/TLS certificate. Get instant links to professional SSL analysis tools for detailed certificate information.

Why external tools? Browser security policies prevent JavaScript from directly reading SSL certificate details of other domains. The tools below provide comprehensive certificate analysis from their servers.

Check SSL for:

🔐SSL Labs (Qualys)
In-depth analysis with A-F grade, protocol support, and vulnerabilities🔎SSL Shopper Checker
Quick check for certificate validity, issuer, and expiration date📜crt.sh (Certificate Search)
Search Certificate Transparency logs for all certificates issued for a domain🌐Visit Site (HTTPS)
Open the domain in a new tab — click the padlock icon in your browser to view the certificate

Tip: You can also check SSL directly in your browser — click the padlock icon in the address bar, then click "Certificate" or "Connection is secure" to view details.

What Is an SSL Certificate?

An SSL (Secure Sockets Layer) certificate — more accurately called a TLS (Transport Layer Security) certificate — is a digital certificate that authenticates a website's identity and enables an encrypted connection. When you see a padlock icon and "https://" in your browser's address bar, the site is using an SSL/TLS certificate.

SSL certificates contain the domain name, the certificate authority (CA) that issued it, the CA's digital signature, the associated public key, the issue and expiration dates, and the certificate's serial number. They are essential for protecting sensitive data in transit, such as login credentials, payment information, and personal data.

Why Client-Side SSL Checking Is Limited

Browsers enforce strict security policies that prevent JavaScript from accessing SSL certificate details of other domains. This is a fundamental security feature — if scripts could read certificate data, malicious websites could fingerprint and profile your browsing. Full SSL analysis requires server-side tools that can establish direct TLS connections to the target domain.

The external tools linked above (SSL Labs, SSL Shopper) connect to the target domain from their own servers, perform a complete TLS handshake, and analyze the full certificate chain, supported protocols, cipher suites, and known vulnerabilities.

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Frequently Asked Questions

Why can't this tool check SSL certificates directly?
Browser security policies (CORS and the same-origin policy) prevent JavaScript from reading SSL certificate details of other domains. This is a security feature, not a limitation of this tool. Full SSL analysis requires a server-side connection to the target domain, which is what the linked tools provide.
What does an SSL Labs grade mean?
SSL Labs grades range from A+ (best) to F (worst). An A+ rating means the server uses strong protocols, secure cipher suites, and has features like HSTS. Common reasons for lower grades include supporting outdated protocols (TLS 1.0/1.1), weak cipher suites, or missing security headers.
How often should I check my SSL certificate?
Check your certificate at least monthly and set up automated monitoring for expiration. Most certificates are valid for 90 days (Let's Encrypt) or 1 year. An expired certificate will cause browser warnings that can drive away visitors and harm your SEO rankings.
What is Certificate Transparency?
Certificate Transparency (CT) is a framework where Certificate Authorities must publicly log every certificate they issue. The crt.sh tool searches these logs, allowing you to see every certificate ever issued for your domain — useful for detecting unauthorized certificates.
Is HTTPS enough to make a website secure?
HTTPS encrypts data in transit but does not guarantee the website itself is safe. A phishing site can have a valid SSL certificate. HTTPS protects against eavesdropping and tampering during transmission, but you should still verify you are on the correct domain and the site is legitimate.