Free SSL Certificate Checker

The SSL Certificate Checker is a free online tool that verifies SSL/TLS certificates, showing issuer, expiration date, and encryption details for any domain.

Yes, it is completely free with no registration required.

Expired or misconfigured SSL certificates can cause browser warnings that drive visitors away. The SSL Certificate Checker helps you catch issues before users do.

Absolutely. The SSL Certificate Checker processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the SSL Certificate Checker is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the SSL Certificate Checker in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The SSL Certificate Checker works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are protocols that encrypt the connection between a browser and a server, but TLS is the modern successor to SSL. SSL versions 2.0 and 3.0 are obsolete and insecure, broken by attacks like POODLE, so no current site should support them. TLS replaced SSL in 1999, and today TLS 1.2 and TLS 1.3 are the recommended versions, while TLS 1.0 and 1.1 are deprecated and can fail PCI DSS compliance. People still say "SSL certificate" out of habit, but the certificate itself is the same X.509 file used by TLS to prove a server's identity. This checker lists each protocol version a configuration supports and marks which are secure, so you can see the practical SSL-versus-TLS distinction laid out clearly.

An SSL/TLS certificate is valid only between its not-before and not-after dates, and maximum lifetimes have been shrinking for years. The CA/Browser Forum capped public certificates at 398 days, and free authorities like Let's Encrypt issue 90-day certificates by design to encourage automation. The industry is moving even shorter, with plans to reduce maximum validity toward 47 days over the coming years. Because expiry is the single most common cause of HTTPS failures, manual renewal is risky for short-lived certificates, so automated tools like ACME clients are strongly recommended. A good rule is to renew well inside the final 30-day window rather than waiting until the last day. This checker shows the validity dates and days remaining for a report and flags any certificate that falls inside that 30-day renewal window.

A certificate chain is the path of trust from your site's leaf certificate, through one or more intermediate certificates, up to a root certificate that browsers already trust. Browsers only ship root certificates, so your server must send the intermediates to bridge the gap between your leaf and that trusted root. The chain breaks most often when a server is configured to send only the leaf certificate and omits the intermediates, or sends them in the wrong order. The frustrating result is a certificate that validates in one browser, which may cache the intermediate, while failing in another browser or on mobile that does not. Fixing it usually means installing the full chain bundle your certificate authority provides. This checker lays out each link in the chain, from leaf to intermediate to root, so you can see how a complete path should look.

An SSL grade from A+ down to F summarizes overall configuration quality, not just whether a certificate is valid, mirroring how Qualys SSL Labs scores a server. An A+ reflects a strong setup: a valid certificate and chain, modern protocols like TLS 1.2 and 1.3, strong cipher suites, and HSTS enabled with preload. A B typically means the certificate is fine but hardening is missing, such as absent HSTS or support for an outdated protocol. An F signals a serious problem: an expired or revoked certificate, a broken chain, or exposure to a critical vulnerability like Heartbleed or DROWN. The grade weighs the weakest link heavily, so one weak protocol or cipher can cap an otherwise strong score. This checker assigns an illustrative letter grade and lists the reasons behind it, so you can see exactly which factors raise or lower the result.

HSTS, or HTTP Strict Transport Security, is a response header that tells browsers to only ever connect to your site over HTTPS, even if a user types http:// or clicks an old insecure link. It works alongside your SSL certificate rather than replacing it: the certificate proves identity and encrypts traffic, while HSTS removes the brief insecure first request that an attacker could hijack. The header includes a max-age telling browsers how long to remember the rule, and an optional preload flag that bakes your domain into browsers' built-in HSTS lists for protection from the very first visit. Enabling HSTS with preload is often what separates an A from an A+ grade. This checker reports whether HSTS is present, its max-age value, and whether preload is set, so you can see how that hardening factors into the overall security picture.