How to Check SSL Certificate: Verify HTTPS Security in 5 Ways
What Is an SSL Certificate?
An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates a website's identity and enables an encrypted connection. When you see https:// and a padlock icon in your browser, it means the site has a valid SSL certificate and your connection is encrypted.
SSL certificates contain important information: the domain name it covers, the certificate authority (CA) that issued it, the validity period, the public key, and any subdomains covered by the certificate. TLS (Transport Layer Security) is the modern successor to SSL, but the term "SSL certificate" remains widely used.
Why You Should Check SSL Certificates
- Security: Ensure your connection to a website is truly encrypted and not compromised
- Compliance: Verify that your own site's certificate is properly configured and not expiring
- Troubleshooting: Diagnose connection errors, mixed content warnings, and trust issues
- Due Diligence: Verify certificates before submitting sensitive information to a website
Check SSL Certificate Online
The quickest way to check an SSL certificate is using an online tool. Our SSL Certificate Checker provides comprehensive certificate analysis:
Enter the Domain
Type the domain name you want to check (e.g., google.com) into the SSL checker.
Review Certificate Details
The tool shows the certificate issuer, validity dates, serial number, and the complete chain of trust from the root CA to the end-entity certificate.
Check Security Configuration
Verify the TLS version, cipher suites, and supported protocols. Modern sites should support TLS 1.2+ and preferably TLS 1.3.
Check SSL in Your Browser
All modern browsers let you inspect SSL certificates directly:
- Chrome/Edge: Click the padlock icon → "Connection is secure" → "Certificate is valid"
- Firefox: Click the padlock → "Connection secure" → "More information" → "View Certificate"
- Safari: Click the padlock → "Show Certificate"
This shows the certificate's issuer, validity period, and which domains it covers.
Check SSL via Command Line
For automation and detailed analysis, use the OpenSSL command-line tool:
# Check certificate details
openssl s_client -connect example.com:443 -servername example.com /dev/null | openssl x509 -noout -text
# Check expiry date
echo | openssl s_client -connect example.com:443 2>/dev/null | openssl x509 -noout -enddate
# Check certificate chain
openssl s_client -connect example.com:443 -showcerts
# Verify certificate against CA bundle
openssl verify -CAfile /etc/ssl/certs/ca-certificates.crt cert.pemCommon SSL Errors & How to Fix Them
Frequently Asked Questions
See the FAQ section above for answers to common questions about SSL certificates.
Need to verify an SSL certificate?
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Frequently Asked Questions
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