Free Online SSL Certificate Checker
Check a website SSL certificate, issuer, validity dates, and days until expiry.
This check reads the certificate presented to the server. It does not replace a full security audit, but it is a fast way to catch upcoming expiry dates and mismatched hostnames.
What this certificate check shows
About the SSL Certificate Checker
SSL and TLS certificates encrypt traffic between a browser and a website and prove that the server owns the domain. An expired, misconfigured, or mismatched certificate triggers browser warnings and can stop visitors from reaching your site. This checker reads the live certificate and reports its issuer, validity window, and remaining days.
What to look for
- Expiry: renew well before the remaining days reach zero.
- Issuer: public sites should use a trusted certificate authority.
- Common name and SANs: every hostname you serve must be covered.
- Signature algorithm: modern certificates use SHA-256 or ECDSA.
How to use this tool
- Enter the domain you want to test.
- Click Check certificate.
- Review the status, expiry countdown, and covered names.
Frequently asked questions
Why did the check fail?
The host may be offline, may not listen on port 443, may block automated connections, or may not present a certificate at all.
Does this validate the full chain?
The tool reads the leaf certificate presented by the server. Full chain validation, revocation checks, and protocol support require a dedicated TLS scanner.
How often should I check my certificate?
Check after every deployment and set a calendar reminder about two weeks before expiry. Automated renewal monitoring is strongly recommended for production sites.