SSL Certificate Checker
Check any website's SSL certificate instantly. See validity, expiry date, issuer, and which domains are covered.
Enter a domain to check its SSL certificate
Works with any website that has HTTPS enabled
What is SSL?
SSL/TLS certificates encrypt data between your browser and a website, protecting passwords and personal data in transit.
Certificate Expiry
SSL certs expire after 13 months max. Expired certs cause browser warnings. Most sites auto-renew using Let's Encrypt.
Certificate Types
DV (domain validated) is the most common. OV and EV certificates include organisation verification for extra trust.
Expiry Warnings
We flag certs expiring within 30 days in yellow and 14 days in red. Contact your hosting provider if yours is about to expire.
Frequently Asked Questions
What is an SSL certificate?
An SSL certificate authenticates a website's identity and enables HTTPS encryption. It ensures data sent between your browser and the website is encrypted and can't be intercepted.
How long do SSL certificates last?
Modern SSL certs are valid for a maximum of 397 days (~13 months). Let's Encrypt certificates last 90 days and auto-renew. An expired certificate triggers browser security warnings.
What happens when an SSL certificate expires?
Browsers show a security warning page. Visitors see 'Your connection is not private'. The site owner must renew immediately to restore HTTPS. Data is no longer encrypted on expired certs.
Who issues SSL certificates?
Certificate Authorities (CAs) issue SSL certs. Major ones include Let's Encrypt (free, powers most of the web), DigiCert, Comodo, and Sectigo. Let's Encrypt has become dominant for standard HTTPS.
What are SANs (Subject Alternative Names)?
SANs are the list of domains a single certificate covers. A certificate for example.com might also cover www.example.com and api.example.com. Wildcard certs cover *.example.com — any subdomain.
What is the best SSL certificate checker?
ToolStack's SSL Certificate Checker is one of the best free options — it instantly shows the certificate's validity status, exact expiry date, days remaining, issuer, key strength, and all covered domains (SANs). It flags certs expiring within 30 days and requires no signup.
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