Free SSL Certificate Checker
Check a site's SSL certificate and expiry.
What is the SSL Certificate Checker?
An SSL certificate is what turns the padlock on and lets browsers trust your site — and it quietly expires on a schedule most people forget. When it lapses, every visitor hits a full-page security warning, forms stop being safe to submit, and search rankings can slip, all at once.
This SSL certificate checker connects to your domain over TLS and reads its certificate, so you can confirm it's valid, trusted and not about to expire.
Last updated: Aug 13, 2026
What does this tool do?
You enter a domain and the tool performs a live TLS handshake and reads the certificate the server presents.
It reports whether the certificate is trusted, when it was issued and expires, how many days remain, which hostnames it covers, the issuer and the negotiated TLS version.
Key features
Trust check
Confirms the certificate is valid and trusted.
Expiry countdown
Days remaining, with warnings before it lapses.
Hostname coverage
Checks the certificate actually covers the domain.
Issuer & dates
Who issued it and its validity window.
TLS version
Flags outdated protocols.
Example
Common use cases
- Site owners — Make sure the padlock stays on.
- Developers — Verify a certificate after deploying it.
- DevOps — Catch certificates before they expire.
- Agencies — Monitor client certificate health.
- Security teams — Confirm modern TLS and valid trust chains.
- E-commerce owners — Keep checkout secure and trusted.
- Migrators — Check the certificate after a server move.
- Anyone with HTTPS — Know exactly when to renew.
Benefits
- It warns you before a certificate expires, not after.
- It confirms the certificate actually covers your hostname.
- It verifies the certificate is trusted by browsers.
- It flags outdated TLS versions worth upgrading.
Tips
- Renew certificates well before expiry — aim for 30+ days of buffer.
- Automate renewal (e.g. Let's Encrypt with certbot) to avoid lapses.
- Make sure the certificate covers both www and non-www if you use both.
- Use a wildcard or SAN certificate to cover multiple subdomains.
- Serve only TLS 1.2 and 1.3; disable older protocols.
- Redirect all http traffic to https.
- Add HSTS so browsers force https on return visits.
- Re-check after any certificate or server change.
Common mistakes to avoid
Letting a certificate expire
Fix: Automate renewal and monitor the expiry date.
Certificate doesn't cover www
Fix: Include every hostname you serve (www and non-www) in the certificate.
Serving outdated TLS
Fix: Disable TLS 1.0/1.1 and serve only 1.2 and 1.3.
No HTTP→HTTPS redirect
Fix: Redirect all http traffic to https and add HSTS.
How it works
- 1
Enter a domain
For example, example.com.
- 2
Check
It connects over TLS and reads the certificate.
- 3
Review
See trust, expiry, coverage and TLS version.
Frequently asked questions
Whether the certificate is trusted and valid, when it expires, whether it covers the hostname, the issuer, and the negotiated TLS version.
No. It performs a live TLS handshake to read the public certificate and returns the result without storing anything.
Whether the certificate is trusted and valid, when it expires, whether it covers the hostname, the issuer, and the negotiated TLS version.
Yes — HTTPS is a Google ranking signal, and an expired or invalid certificate drives visitors away with security warnings.
The tool still reads it and tells you why it isn't trusted — for example a self-signed certificate or an incomplete chain.
Keep at least 30 days of buffer, and automate renewal so it never lapses.
Any public domain serving HTTPS on a standard port. Internal or private hosts aren't reachable.
No. The certificate is read over a live handshake and nothing is saved.
Conclusion
An SSL certificate checker takes the guesswork out of certificate health — trust, coverage and, above all, expiry. Pair it with the HTTP header checker and redirect checker to keep your HTTPS setup solid end to end.