SSL Certificate Checker
Free SSL certificate checker. Check any website's SSL/TLS certificate expiration date, issuer, and validity, read from a live TLS handshake. No account needed.
3 free checks per day. No signup needed.
What this SSL checker looks at
This tool opens a real TLS connection to the site, the same handshake a browser performs, and reads the certificate the server presents: its issuer and its exact expiration date. An SSL certificate isn't a one-time setup, most are valid for 90 days to a year and need renewing before they lapse, and an expired one triggers a full browser security warning regardless of how well the rest of the site works.
How to check an SSL certificate
- 1Enter the domain (for example, example.com) and run the check.
- 2We open a real TLS handshake to the server and read the certificate it presents.
- 3You get the issuer, the exact expiration date, and the days remaining, so you can renew before it lapses.
The certificate chain of trust
Every browser ships with a store of trusted root certificate authorities. Your site's certificate (the leaf) is signed by an intermediate CA, which chains up to one of those roots. If any link in that chain is missing, misconfigured, or expired, the browser shows a security warning even when the leaf certificate itself is fine.
SSL certificate expiration and renewal
Certificates are issued for a fixed window, 90 days for Let's Encrypt and up to a year for many paid certificates, and must be renewed before they lapse. The moment a certificate expires, browsers block the site with a full-page warning that functions like an outage. Checking the live expiration date is how you catch a failed auto-renewal before your visitors do.
Frequently asked
What happens when an SSL certificate expires?
Every browser shows a hard security warning and blocks or interrupts the connection, even if the site is otherwise fine. Most visitors leave rather than click through, so an expired certificate functions like an outage for traffic and conversions.
Who issues an SSL certificate and how do I know it's trusted?
A certificate authority (CA), like Let's Encrypt, DigiCert, or Sectigo, issues and digitally signs it. A browser trusts it if that CA is in its built-in trusted root store and the chain back to that root is intact and unexpired.
Why does this tool say it can't check my site?
Sites proxied through Cloudflare (orange-clouded) can't be checked this way, since Cloudflare's network blocks the direct raw TLS connection this tool uses, on any destination it fronts. That's a limitation of this checking method, not a certificate problem with the site.
How do I check an SSL certificate's expiration date?
Enter the domain above and run the check. This SSL certificate checker opens a live TLS connection, reads the certificate the server presents, and shows the exact expiration date, the issuer, and how many days are left.
How often do SSL certificates need renewing?
It depends on the certificate. Let's Encrypt certificates last 90 days and are usually auto-renewed; many paid certificates last a year. Renewal can silently fail, so confirm the live expiry date rather than assuming it renewed.
What is the difference between SSL and TLS?
TLS is the modern protocol that replaced the older SSL; in everyday use the terms are interchangeable, and an SSL certificate is really a TLS certificate. This checker performs a real TLS handshake to read it.
Related tools: Domain Expiry Checker ·Whois Lookup ·DNS Lookup
Read more: what ongoing SSL monitoring covers
An expired SSL certificate is an outage.
A one-off check is a snapshot. Expiroo watches your SSL certificate, uptime, and domain expiration continuously, and alerts you by email, Telegram, WhatsApp, or webhook well before anything lapses.
Start monitoring for freeNo charge during your 7-day trial.