How to Check a Website's SSL Certificate
An expired or misconfigured SSL certificate kills HTTPS, triggers browser security warnings, and destroys user trust instantly. This guide shows how to check any site's SSL certificate — expiry date, issuer, and validity — free in your browser.
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Free SSL Checker
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Step-by-Step Guide
- 1
Enter the domain name
Type or paste the domain (e.g., example.com). Do not include https:// — just the domain name.
- 2
Click Check SSL
The tool queries the domain's SSL certificate and returns the certificate details within seconds.
- 3
Check the expiry date
The most important field: when the certificate expires. Certificates typically expire every 90 days (Let's Encrypt) or 1–2 years (paid certificates). Set a renewal reminder 30 days before expiry.
- 4
Verify the issuer and certificate chain
The issuer should be a recognized Certificate Authority (Let's Encrypt, DigiCert, Sectigo, etc.). If the issuer is unknown or the chain is incomplete, browsers will show a warning.
- 5
Check the Subject Alternative Names (SANs)
SANs list which domains the certificate covers. Verify your domain (and www subdomain) is included — a certificate missing a subdomain will cause errors for that subdomain.
Who This Is For
Website owners
Checking their own SSL certificate before it expires and causes browser warnings that drive away visitors.
Developers
Verifying SSL configuration is correct after deploying a new certificate or migrating to HTTPS.
SEO professionals
Checking SSL status as part of a site audit — HTTPS is a Google ranking factor and mixed content warnings affect user experience.
Frequently Asked Questions
How do I know if a website's SSL certificate is expired?
Use the free SSL checker: enter the domain and the tool will show the certificate's expiry date and current validity status. An expired certificate causes browsers to show a 'Your connection is not private' or 'NET::ERR_CERT_DATE_INVALID' error.
What is the difference between HTTP and HTTPS?
HTTP sends data in plain text — readable by anyone on the network. HTTPS encrypts traffic using TLS (the protocol underlying SSL). HTTPS is required for any page that handles passwords, payment information, or personal data, and is a Google ranking signal.
How often do SSL certificates expire?
Let's Encrypt certificates expire every 90 days (auto-renewed by most hosting providers). Commercial certificates typically last 1 year (398 days maximum as of 2020 browser policy). Always check your certificate's expiry and set a renewal reminder 30 days before.