Check a website's SSL certificate
Check whether a site's HTTPS certificate is valid, who issued it and how many days it has left.
✓ Free, no sign-up
How it works
We connect to the site's port 443 the way a browser would and inspect the certificate it presents: whether it covers the name, whether the chain reaches a trusted authority and when it expires. Free Let's Encrypt certificates last a few months and renew themselves if automatic renewal is set up correctly.
How to use it, step by step
- Enter the website's domain.
- We connect to port 443 just like a browser would.
- You'll see the issuer, validity dates, days left, TLS version and whether the name matches.
- If something fails, renew or reinstall the certificate on your host.
What it's useful for
- Check when your site's certificate expires.
- Troubleshoot a «not secure» warning.
- Confirm a new domain already has HTTPS.
FAQ
What happens if the certificate expires?
Browsers show a full-page security warning and most visitors leave. Renew in time or automate renewal.
What does "name mismatch" mean?
The certificate was issued for other domains. It usually happens when the www or non-www variant is left out, or when a new domain points to a server holding another domain's certificate.
What happens if my SSL certificate expires?
Browsers show a full-page warning and most visitors leave. It hurts trust and sales too.
Is a free certificate just as secure?
Yes. Free certificates like Let's Encrypt encrypt exactly like paid ones; the difference is company validation and support.
What does «name mismatch» mean?
The certificate was issued for another domain. It usually happens when the domain or its www version wasn't included.
Which TLS version should I use?
TLS 1.2 at minimum, ideally TLS 1.3. Versions 1.0 and 1.1 are obsolete.
How often do I need to renew?
Free ones last about 90 days and usually auto-renew. Paid ones last up to a year. Monitor it so it doesn't catch you off guard.