SSL Checker
Check whether a site's SSL/TLS certificate is valid, who issued it and when it expires.
Looks up live data What you enter is sent to our server to fetch live results from public sources. Results are cached briefly.
About this tool
Enter a domain to see whether its HTTPS certificate is accepted right now. The tool makes a real HTTPS request from our server, which only succeeds if the certificate chain is trusted, matches the hostname and is within its validity dates. It also reads the HSTS header and, where available, the latest certificate's issuer, validity dates and days remaining from public Certificate Transparency logs. It checks the public HTTPS endpoint on port 443 only.
How to use it
- Enter a domain such as example.com (no https:// needed).
- Press Check SSL certificate.
- Read the result: valid or not, HSTS setting, issuer and days until expiry.
- If it is invalid, use the common problems below to find the cause.
Common problems
- Result says the connection failed or the certificate is not trusted
- The certificate may be expired, issued for a different hostname, missing an intermediate certificate, or the site may not offer HTTPS.
- Certificate details are unavailable
- The Certificate Transparency lookup is best-effort and can time out. The valid/invalid verdict comes from the live connection and is still reliable.
- Only a few days remain
- Renew now. Most certificates renew automatically; check that your renewal job is running.
Frequently asked questions
Does this check subdomains and other ports?
It checks the exact hostname you enter on the standard HTTPS port (443) only.
What does HSTS mean?
HTTP Strict Transport Security tells browsers to always use HTTPS for your site. "not set" means the header was not sent.