How do I check when an SSL certificate expires?
Enter a domain into an SSL expiry checker and it reads the certificate served over HTTPS, returning the expiry date, days remaining, issuer and validity status. SiteGuard Monitor's checker does this instantly and runs a full risk scan covering uptime, DNS, email security and headers — so you see the certificate alongside everything else on one page.
An expired SSL certificate breaks HTTPS, throws scary browser warnings and can take a client site offline for hours before anyone notices. This free SSL expiry checker shows exactly when a certificate expires so you can renew before it bites.
The problem with letting SSL certificates lapse
Certificates expire on a fixed date, but renewal reminders get lost and auto-renewal silently fails more often than you'd think. The first sign is usually an angry client or a flood of browser security warnings — by then trust is already damaged and you're firefighting.
- Expired certs trigger full-page browser warnings that scare off visitors
- Auto-renewal can fail quietly when DNS or webroot validation breaks
- You rarely find out until traffic drops or a client calls
What this SSL checker shows you
- Exact expiry date and days remaining
- Certificate issuer and the full chain
- Whether the certificate is currently valid for the hostname
- Any mismatch or near-expiry warning flagged clearly
It also runs a full free website scan
The SSL check is one part of a complete passive scan. Alongside the certificate you'll see HTTP/HTTPS uptime, DNS records, email security (SPF and DMARC) and security headers, all rolled into a single explainable 0-100 risk score so you know where the real risk sits.
Stop tracking renewals in a spreadsheet
Add a domain to SiteGuard Monitor and it watches the certificate continuously, alerting you by email and Discord well before expiry. For agencies and MSPs that means no more surprise outages across a portfolio of client sites.
- Continuous SSL monitoring with early-warning alerts
- One dashboard for every client domain
- Expiry data feeds branded monthly client reports
Passive and read-only
SiteGuard only inspects the certificate a server presents publicly over HTTPS. There is no aggressive scanning, no probing and no intrusive testing — just the same read-only check a browser performs, run on a schedule.