Free · no signup
SSL Certificate Checker
Check any certificate’s expiry, chain, protocol, cipher and fingerprint — with an A+–F grade.
Why your SSL/TLS certificate needs watching
An SSL certificate proves your site is who it says it is and encrypts everything between it and your
visitors. But certificates expire — and an expired one turns your site into a full-screen browser
warning that scares customers away. Beyond expiry, the details matter:
Expiry countdown
The #1 cause of preventable outages. Renew at least two weeks out.
Chain validity
A missing intermediate makes some clients reject an otherwise valid cert.
Protocol & cipher
Modern TLS 1.2/1.3 with strong ciphers; anything older is a liability.
Fingerprint
A stable SHA-256 fingerprint lets you spot an unexpected certificate swap.
Frequently asked questions
It opens a live TLS connection to your domain and reports the certificate’s expiry date and days remaining, the issuer, whether the chain validates, the negotiated protocol (e.g. TLS 1.3) and cipher, the key size and the SHA-256 fingerprint — plus an overall A+–F grade.
Renew well before expiry — at least 14–30 days. An expired certificate makes browsers block your site. CompleteStatus can watch the expiry countdown continuously and alert you weeks ahead so you never get caught out.
Yes. Enter the domain and pick a standard TLS port (443 for HTTPS, or 465/587 for mail submission, 993/995 for IMAPS/POP3S, 8443 for alt-HTTPS). The tool connects to that port and grades whatever certificate it serves.
Don’t check it once — watch it 24/7
Certificates expire on a fixed date — and always at the worst possible time. CompleteStatus runs this exact check around the clock and alerts you the moment something changes — before your users (or attackers) notice.
Monitor this free
Try the other free tools
Uptime is table stakes. We watch the rest — security headers, email authentication, certs and DNS, with the fix attached.
Start free
Product
Resources
Account
© 2026 CompleteStatus. All rights reserved.
CompleteStatus — operated in the United States
·
support@completestatus.com