What this checker looks at
The same checks a browser runs before showing the padlock icon.
Expiry
How many days are left before the certificate expires, so you can renew it before visitors see a warning.
Trust & hostname match
Whether the certificate is issued by a trusted authority and covers the exact domain being checked.
Issuer & protocol
Who issued the certificate, and which TLS protocol and cipher the server negotiated.
SSL checker — common questions
Need the certificate fixed, not just diagnosed? Our engineers can install or renew it for you.
Enter your domain above. The checker connects over TLS and reports the certificate's expiry date, issuer, and whether it matches your domain and is trusted by browsers.
This usually means the certificate has expired, was issued for a different hostname, is self-signed, or was issued by a certificate authority browsers don't recognize. This checker tells you which of these applies.
Most certificate authorities issue certificates for 90 days (Let's Encrypt) to 1 year. Renew before expiry — many hosting setups auto-renew, but it's worth checking periodically. See our SSL installation service if you'd rather have it managed for you.
A SAN lists every hostname a certificate is valid for, including the main domain and any subdomains like www. A certificate only works for hostnames listed in its SANs.
Yes, completely free with no signup. There's a small rate limit per visitor to keep the service fast for everyone.
Need your SSL certificate installed or renewed?
Our engineers can install, renew or fix SSL certificates directly — 24/7, no long-term contract required.