SSL Expiry Checker

What it does

The SSL Expiry Checker inspects the TLS/SSL certificate a website presents over HTTPS and tells you whether it's valid, who issued it, when it expires, and how many days remain. An expired or invalid certificate shows visitors a scary browser warning and can take a site offline in practice — this catches it before that happens.

Use it to confirm a renewal worked, to see how long is left before you need to renew, or to diagnose a "your connection is not private" warning.

How to use it

1. Enter the domain (e.g. example.com) and press Check.
2. Read the status and the days remaining.
3. Review the certificate details — issuer, valid-from/valid-to dates, and the domains it covers.

What the results mean

Result	What it means
Valid	The certificate is trusted, matches the domain, and has more than 30 days left.
Warning	The certificate is valid but expiring soon (within 30 days). Plan the renewal now — the tool flags ≤30, ≤14, ≤7 and ≤3 days.
Invalid	The certificate can't be trusted as-is — it's expired, not yet valid, doesn't match the domain, is self-signed, or its chain is broken. Visitors will see a warning.

Errors & warnings explained

Message	What it means
Expired	The certificate's end date has passed. Renew it — browsers now block the site.
Not yet valid	The certificate's start date is in the future, often a server clock or installation issue.
Hostname mismatch	The certificate is for a different domain than the one you checked — e.g. installed on the wrong host.
Self-signed	The certificate wasn't issued by a trusted authority, so browsers won't trust it.
Chain invalid	An intermediate certificate is missing or broken, so the chain to a trusted root can't be built.
No SSL certificate found	The domain didn't present a certificate — it may not support HTTPS at all.
Connection timed out	The connection timed out before the certificate could be read.
Connection refused	The connection was refused — HTTPS may not be enabled on this domain.
TLS handshake failed	The secure handshake failed, so the certificate couldn't be read. Often a protocol or cipher mismatch.
We couldn't find that domain	DNS lookup failed — check the spelling, or the site's DNS may be down.

Good to know

• Free, no login, no stored URLs.
• Rate limited to roughly 8 checks per minute per network.
• It reads the certificate as presented over HTTPS on the standard port — one point-in-time check.
• For automatic "your certificate expires in N days" alerts, monitor the site with an account and set your own warning threshold.

Related guides

• Uptime Checker
• Homepage Health Checker
• WordPress Site Check