What does an SSL checker do?

An SSL checker retrieves a website's SSL/TLS certificate and displays key details: whether it is valid, who issued it, when it was issued, and when it expires. This lets you quickly verify a site's HTTPS configuration without installing any software.

Does an expired SSL certificate affect SEO?

Yes. An expired certificate causes browsers to show a security warning, which prevents most visitors from accessing the site. Google also treats HTTPS as a ranking signal, so a broken certificate can cause ranking drops and indexing issues.

What is the difference between SSL and TLS?

SSL (Secure Sockets Layer) is the older protocol, now deprecated. TLS (Transport Layer Security) is the current standard, with TLS 1.2 and 1.3 being widely used. Most people still say 'SSL' colloquially, but all modern certificates use TLS.

How often should I check my SSL certificate?

Check at least 30 days before the expiry date to leave time for renewal. Set up automated monitoring alerts so you are notified if a certificate is about to expire or becomes invalid unexpectedly.

SSL Certificate Checker

Enter any domain name to instantly verify its SSL/TLS certificate — check validity, issuer, expiry date, and signature algorithm. Ensure your site's HTTPS is correctly configured before it affects your visitors or rankings.

SSL Checker

Why SSL Certificates Matter for SEO and Security

An SSL/TLS certificate does two things: it encrypts data in transit between the user's browser and your server, and it authenticates that your domain is who it claims to be. Google has used HTTPS as a ranking signal since 2014, and browsers like Chrome now actively warn users when a site lacks a valid certificate. The result: an invalid or expired SSL certificate can cause both security vulnerabilities and significant ranking drops.

What This Tool Checks

Validity — whether the certificate is currently valid and trusted
Issuer — the Certificate Authority (CA) that issued it (e.g., Let's Encrypt, DigiCert, Sectigo)
Issued and expiry dates — when the certificate was activated and when it will expire
Signature algorithm — the cryptographic algorithm used (e.g., SHA-256 with RSA)
Organization — the entity named in the certificate, if present (OV or EV certificates)

SSL Certificate Types Explained

DV (Domain Validation)

Verifies only that the applicant controls the domain. Issued quickly, often free (Let's Encrypt). Suitable for blogs and personal sites.

OV (Organization Validation)

Verifies the domain and the legal organization behind it. Includes organization name in the certificate. Suitable for business websites.

EV (Extended Validation)

The highest level. Involves thorough vetting of the organization. Previously showed a green bar in browsers; now shows in certificate details. Used by banks and e-commerce.

Common SSL Issues and How to Fix Them

Expired certificate — Renew immediately. Most CAs and hosting panels offer auto-renewal.
Certificate not trusted — The CA may not be in browsers' trusted root store. Use a well-known CA.
Mixed content warnings — Your HTTPS page loads HTTP resources (images, scripts). Update all resource URLs to HTTPS.
Wrong domain — The certificate was issued for a different domain (e.g., www vs. non-www). Get a certificate that covers all variants, or use a wildcard cert.
Incomplete certificate chain — Intermediate certificates are missing from the server config. Install the full chain file provided by your CA.

Related Tools

WHOIS Lookup

Domain registration info

DNS Lookup

Query DNS records

Redirect Checker

Trace URL redirect chains

HTTP Headers Checker

Inspect server response headers

Frequently Asked Questions

Yes. An expired certificate triggers browser security warnings that block most visitors. Google also treats HTTPS as a ranking signal, and certificate errors can cause crawling and indexing problems.

SSL is the older, now-deprecated protocol. TLS is the current standard (TLS 1.2 and 1.3). People still say "SSL certificate" colloquially, but all modern certificates use the TLS protocol.

Check at least 30 days before the expiry date. For production sites, set up automated monitoring to alert you when a certificate is approaching expiration or becomes invalid.