CHECK ANY DOMAIN'S SSL CERTIFICATE DETAILS AND EXPIRY
SSL Certificate Checker
Look up a domain's live SSL/TLS certificate — issuer, validity dates, days until expiry, and subject alternative names.
Frequently asked questions
An expired certificate causes browsers to show visitors a hard security warning and blocks HTTPS access entirely — checking days-until-expiry regularly lets you renew before it becomes a live outage.
Additional hostnames a single certificate is valid for beyond the primary domain — e.g. a cert for "example.com" often also covers "www.example.com" via its SAN list.
It connects directly to the domain over HTTPS and reads the actual certificate being served right now — the same thing a visitor's browser sees.