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SSL certificate checker

Paste a website address to see whether its HTTPS certificate is valid and how many days are left before it expires. Free, no signup.

Free, no signup. We check from Poland, New York and Singapore.

What we check

  • Whether the site answers over HTTP(S) from three locations: Poland, New York and Singapore, with the status code and response time.
  • Whether the certificate is valid for the domain and not expired.
  • How many days are left until the certificate expires.
  • When the domain registration expires, so you see both deadlines in one place.

How to read the result

Days left. More than 30 days is comfortable. Under 30 days on a certificate that should renew automatically is a warning sign that renewal has stopped. Under 7 days needs action now.

Invalid or expired. Visitors see a full-page browser warning and many will leave. Renew or reissue the certificate and check that the full chain is installed.

Different results per location. If one location fails and the others answer, the cause is usually routing, a firewall or a CDN edge rather than the certificate itself.

Frequently asked questions

How do I check when an SSL certificate expires?

Paste the website address into the checker. It connects to the site over HTTPS, reads the certificate it presents and shows how many days are left before it expires.

How many days before expiry should I renew a certificate?

Renew at least two weeks before the date, and more if renewal needs approval or manual steps. Certificates from Let's Encrypt are valid for 90 days and are usually renewed automatically after about 60 days, so a certificate with fewer than 30 days left often means automatic renewal has stopped working.

Why does the checker say the certificate is invalid?

Common reasons are an expired certificate, a certificate issued for a different domain name, a missing intermediate certificate or a certificate from an authority browsers do not trust. Browsers will show a security warning to visitors in each of these cases.

Does the checker work for any website?

It works for public websites that answer on the standard HTTPS port. Addresses on private networks and local hosts are refused. To watch a site that is not public, monitor it from your own server with an agent.

How do I get a warning before a certificate expires?

A one-time check only tells you the state today. Add the site to Zuzia and it checks the certificate regularly and emails you before it expires, so an expiry does not surprise you.

Related: All tools · Domain expiry checker · SSL certificate expiration monitoring · Pricing

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