Free tool, no signup
SSL certificate checker
Enter a hostname and we’ll connect over TLS right now and read the certificate it presents: expiry date, total lifetime, issuer, and how many days remain, plus where it stands against the shrinking lifetime limits. No account required.
How this check works
We open a TLS connection to the hostname you enter on port 443 (or the port you specify) and read the certificate the server presents: its expiry date, issue date, and issuer. We do not send an HTTP request or read any page content, only the certificate itself.
If a certificate is expired, self-signed, or issued for a different hostname, we still show its expiry and issuer, but mark it as not currently trusted and say why. That matters: a certificate can be technically readable and still not something a browser would accept without warning your visitors.
We also show the certificate’s total lifetime and the first upcoming CA/Browser Forum limit it would break: 200 days from March 15, 2026, 100 days from March 15, 2027, and 47 days from March 15, 2029. Whether it “looks ACME-issued” is a guess from the issuer and the lifetime, since a certificate does not record how it was ordered. The 47-day certificate guide explains what changes.
Don’t wait for a browser warning to find out
This tool answers one question at one moment. RealUptime’s certificate expiry monitoring checks your certificates on a daily schedule and alerts you at 30, 14, 7, and 1 day before expiry, so you renew on your own timeline instead of finding out from a customer’s browser warning.
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