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Tools SSL Checker

SSL Checker: Check your SSL certificate

We open an encrypted connection to the website and read its certificate. You see how long it is still valid and whether visitors get a security warning.

Why the expiry date matters

When an SSL certificate expires, all major browsers show a full-page warning. Most visitors leave immediately, online shops lose orders and contact forms stay empty. This happens more often than you might think, especially when automatic renewal stops working after a server move.

Certificates are getting shorter lifetimes

Browser makers and certificate authorities have agreed to shorten the maximum lifetime of SSL certificates step by step: to 200 days since March 2026, to 100 days from March 2027 and to only 47 days from March 2029. If you have been renewing certificates by hand once a year, now is the time to switch to automatic renewal, for example with Let’s Encrypt.

How to read the result

  • Trusted means browsers accept the certificate without a warning.
  • Days remaining below 14 is a warning sign if you are not sure automatic renewal is working.
  • Covered domains shows which addresses the certificate is valid for. If, for example, the www version is missing, visitors see a warning there.
  • Incomplete chain means an intermediate certificate is missing on the server. Some browsers compensate, but many phones and programs do not.

In detail: SSL certificate expired? How to fix it.

Frequently asked questions: SSL Checker

How do I check when my SSL certificate expires?

Enter your domain into the SSL checker. You immediately see the expiry date, the days remaining, the issuer and which domains the certificate covers.

What happens when an SSL certificate expires?

Browsers show a full-page security warning, and most visitors leave. The data on the server is not at risk, but forms and online shops effectively stop working for visitors.

How long is an SSL certificate valid?

Since March 2026 for at most 200 days, from March 2027 at most 100 days, and from March 2029 only 47 days. Let’s Encrypt certificates are valid for 90 days and are normally renewed automatically.

What does “incomplete certificate chain” mean?

An intermediate certificate is missing on the server. Some browsers compensate for it, but many phones and programs do not. The fix is to install the full chain (fullchain) on the server.

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