Check a website's SSL certificate

Check whether a site's HTTPS certificate is valid, who issued it and how many days it has left.

✓ Free, no sign-up

How it works

We connect to the site's port 443 the way a browser would and inspect the certificate it presents: whether it covers the name, whether the chain reaches a trusted authority and when it expires. Free Let's Encrypt certificates last a few months and renew themselves if automatic renewal is set up correctly.

FAQ

What happens if the certificate expires?

Browsers show a full-page security warning and most visitors leave. Renew in time or automate renewal.

What does "name mismatch" mean?

The certificate was issued for other domains. It usually happens when the www or non-www variant is left out, or when a new domain points to a server holding another domain's certificate.