A healthy certificate
example.com
Issued to example.com, trusted, TLS 1.3, with the exact date it expires and how many days remain.
SSL Certificate Checker
Check a website's TLS certificate: issuer, expiry date, days remaining and whether browsers trust it.
Certificate
The result will appear here.
We fetch the target from our server on your behalf — the address you enter isn't stored.
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About this tool
An expired or misconfigured TLS certificate usually surfaces as a scary browser warning at the worst possible moment. Checking it ahead of time means opening a real TLS handshake and reading the certificate the server presents — including an invalid one, which is exactly the case worth catching early.
How to use it
- Enter a domain (a port other than 443 can be included, e.g. example.com:8443).
- Press Check to open a TLS connection and read the certificate it presents.
- Subject, issuer, alternative names, validity dates and days remaining are all shown, along with whether the certificate would actually be trusted by browsers.
Examples
Common problems
- The result says the certificate is not trusted, but the site loads fine in my browser.
- Most often the certificate is valid but for a different name than the one you checked (a wildcard on a subdomain, say) — the alternative names list shows exactly which hostnames the certificate actually covers.