Free SSL Certificate Checker
An SSL checker connects to a website over HTTPS and reads its certificate to see whether browsers trust it. This free checker reports who issued the certificate, which names it covers, when it expires and the days left, whether the chain is complete, the TLS version, and the key strength, with a pass or fix verdict on each.
SSL Checker
Technical SEO
About this tool
An expired or mismatched certificate makes browsers show a full-page security warning, and most visitors leave on the spot. Search engines and payment providers expect working HTTPS as well. Many certificates now last only a few months, so an automatic renewal that silently fails is one of the most common reasons a healthy site suddenly looks broken.
The checker resolves the domain, refuses private and local addresses, and opens a TLS connection to port 443 using the site's name, the same way a browser does. If the certificate does not verify, it connects once more without verification so it can still read the certificate and tell you exactly what is wrong: expired, issued for another name, self-signed, or missing an intermediate certificate. Expiry within 14 days is flagged as a warning.
Most fixes are simple once you know the cause: renew or reissue the certificate, include every host name you use (with and without www), and install the full chain file your certificate authority provides rather than the certificate alone. After any change, run the check again, and run the redirect checker to confirm every HTTP address now lands on HTTPS.
Frequently asked questions
How do I check if my SSL certificate is valid?
Enter your domain and submit. The checker opens a TLS connection the way a browser does and reports whether the certificate verifies, which names it covers, who issued it, when it expires and whether the full chain is installed. A page of all passes means browsers will trust it; any fix now row explains what to change.
What does "certificate chain incomplete" mean?
Your server sends its own certificate but not the intermediate certificate that links it to a trusted root. Some browsers fill the gap themselves, others show a warning, and many apps and crawlers simply fail. Install the full chain file from your certificate authority, often called fullchain.pem or ca-bundle, alongside the certificate, then check again.
How early should I renew an SSL certificate?
Automatic renewal usually runs about 30 days before expiry, so this checker warns once fewer than 14 days are left, which often means renewal has failed. If you renew by hand, set a reminder a month ahead. Free certificates such as Let's Encrypt last three months or less, so automation is the only reliable way to keep them current.
Does SSL affect SEO?
HTTPS is a light ranking signal for Google, but the bigger effect is on visitors: a certificate warning stops most people before they see your page, and browsers mark plain HTTP pages as not secure. A valid certificate, a redirect from HTTP to HTTPS and no mixed content are basic requirements for any site that wants to rank.