SSL Certificate Checker
Check SSL certificate validity and security details
Enter a domain name to check its certificate.
Result
Certificate details appear here.
About Our Free SSL Certificate Checker
Our SSL certificate checker lets you instantly verify the security status of any website’s SSL/TLS certificate. Simply enter a domain name and the tool retrieves the certificate details, expiration date, issuer information, and protocol version, giving you a complete SSL health check in seconds.
An SSL certificate (Secure Sockets Layer) authenticates a website’s identity and enables encrypted HTTPS connections. When a browser connects to an SSL-secured site, the certificate provides encryption (data stays private), authentication (the site is legitimate), and data integrity (content has not been tampered with). Monitoring these certificates is critical for website owners, developers, and security professionals.
For a site owner watching one blog or an agency renewing certificates across client domains, this free online SSL checker helps you catch expired certificates, protocol misconfigurations, and name-mismatch errors before they affect your visitors or SEO rankings. The tool supports any publicly accessible domain and provides color-coded status indicators for quick assessment.
Key Features
- Instant certificate validation with color-coded expiry status (valid, warning, critical, expired)
- Displays issuer, subject, protocol version, and validity dates
- SHA-256 fingerprint and serial number for advanced verification
- Subject Alternative Names (SAN) list showing all covered domains
- Days-until-expiry countdown for proactive renewal planning
- Quick-test buttons for popular domains like Google, GitHub, Amazon & Microsoft
- Automatic domain normalization (strips http://, www., and paths)
- Full dark mode support with responsive design for all devices
- Checks any publicly accessible domain, not only your own
How to Use the SSL Checker
- Enter a domain: Type or paste any domain name (e.g., example.com) into the input field. HTTP prefixes and paths are stripped automatically.
- Click Check SSL: Press the button or hit Enter to initiate the certificate lookup.
- Review the status card: A color-coded banner shows whether the certificate is valid, expiring soon, or already expired.
- Inspect details: Check issuer, validity dates, protocol version, fingerprint, and SAN entries in the detailed breakdown below.
- Take action: If the certificate is expiring or invalid, renew it through your hosting provider or Certificate Authority before it disrupts your site.
Use Cases
- Website owners: Monitor your own SSL certificates to avoid unexpected expirations and browser security warnings.
- DevOps & sysadmins: Quickly verify certificate deployments after server migrations, load balancer updates, or CDN changes.
- SEO professionals: Confirm HTTPS is properly configured since Google uses it as a ranking signal.
- Security auditors: Check protocol versions and certificate details during security assessments.
- Digital marketers: Verify that landing pages and partner sites have valid SSL before running ad campaigns.
- Developers: Debug SSL handshake issues by inspecting certificate details, SAN entries, and fingerprints.
- E-commerce managers: Ensure customer data is protected with a valid, non-expired certificate on checkout pages.
Frequently Asked Questions
What is the difference between SSL and TLS?
SSL is the predecessor to TLS. All modern “SSL certificates” actually use TLS (Transport Layer Security). TLS 1.2 and TLS 1.3 are the current standards, while older SSL 2.0/3.0 and TLS 1.0/1.1 are deprecated.
What happens when an SSL certificate expires?
Browsers will display a full-page security warning, blocking visitors from reaching your site. This destroys user trust, drops traffic, and can hurt SEO rankings.
How often should I check my SSL certificate?
At minimum, check monthly. Many certificates are valid for 90 days (Let’s Encrypt) or one year. Setting up automated renewal with tools like Certbot is the safest approach.
Can I check internal or private domains?
The tool can only check publicly accessible domains. For internal servers behind a firewall, use command-line tools like openssl s_client.
Tips & Best Practices
- Automate renewal: Use Certbot or your hosting provider’s auto-renewal feature to avoid accidental expiration.
- Use TLS 1.3: Upgrade to the latest protocol version for faster handshakes and stronger encryption.
- Install the full chain: Always include intermediate certificates to prevent trust errors on older browsers and mobile devices.
- Monitor SAN coverage: Verify that all your subdomains (www, api, mail) are listed in the Subject Alternative Names.
- Set calendar reminders: Even with auto-renewal, set a reminder 30 days before expiry as a safety net.
- Redirect HTTP to HTTPS: Ensure all traffic is forced through HTTPS with a proper 301 redirect to maximize security and SEO benefit.