Free tool
SSL Checker.
Check a domain's SSL certificate in seconds. See the issuer, the expiry date, how many days remain, the protocol, and whether the certificate is valid and trusted.
What it does
The most avoidable outage there is.
An SSL certificate is what puts the padlock on your website and encrypts the connection to it. Every certificate has an expiry date, and when it passes, browsers stop trusting the site and show a security warning to everyone who visits. It is one of the few outages that is completely predictable, and one of the most common, because the date sits in a certificate nobody is looking at.
This tool connects to your domain over HTTPS and reads the certificate the server actually presents, so you see the real expiry date and trust status rather than what you assume is in place. If it is expired, untrusted or close to renewal, the result says so plainly, with the number of days you have left.
Common questions
SSL, answered.
Want your certificates and HTTPS handled properly rather than just checked? We can help.
Talk to us →What is an SSL certificate?
An SSL, or more correctly TLS, certificate is what lets a website serve traffic over HTTPS with the padlock in the address bar. It encrypts the connection between a visitor and your site, and it proves the site is really yours. Certificates are issued for a fixed period and have to be renewed before they expire, or visitors start seeing security warnings.
What does this SSL checker tell me?
It connects to the domain over HTTPS and reads the certificate the server presents: who it was issued to, which authority issued it, when it is valid from and to, how many days remain before it expires, the negotiated protocol version, and whether the certificate chain validates. If the certificate is expired, untrusted or close to expiry, the checker says so clearly.
Why does an expired certificate matter?
When a certificate expires, browsers stop trusting the site and show a full-page security warning before anyone can reach it. For a business that means visitors turning away, forms not submitting, and in some cases email or integrations breaking. Expiry is entirely predictable, so it is one of the more avoidable outages, but it still happens because nobody was watching the date.
How often should I renew my SSL certificate?
Most certificates last from three months to a year, and many are now issued for shorter periods. The safest approach is automated renewal, so the certificate reissues itself well before expiry without anyone remembering to act. If yours is renewed manually, put a reminder in place for at least two weeks before the date this checker shows.
Is this SSL checker free?
Yes, the checker is free and needs no signup. If you would like your certificates, HTTPS configuration or wider web security handled properly rather than just checked, IronSights can help as part of an infrastructure or security engagement.