Check a popular website
host = google.comport = 443
Result: Subject: CN=google.com, Issuer: CN=GTS CA 1C3 (Google Trust Services), Valid: 2026-05-19 to 2026-08-11, Status: Valid
SSL Certificate Checker
Verify the SSL/TLS certificate of any website. Enter a domain name to check certificate issuer, subject, validity dates, serial number, signature algorithm, and Subject Alternative Names (SANs). Useful for security audits and certificate monitoring.
Enter your values and press Calculate — the result appears here.
Worked examples
Check with custom port
host = example.comport = 8443
Result: Retrieves the SSL certificate on port 8443 instead of the default 443.
Frequently asked questions
How does this work?
The tool connects to the specified host and port over SSL/TLS, retrieves the certificate, and parses its details using OpenSSL.
Can I check internal/non-public servers?
Only if the server is reachable from our hosting environment. Internal servers behind firewalls may not be accessible.
What does "days until expiry" mean?
The number of days from today until the certificate expires. Negative values mean the certificate has already expired.
Is this a security scan?
No. This only reads the publicly available SSL certificate. It does not perform vulnerability scanning or penetration testing.
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