SSL Certificate Checker
Check SSL certificate expiry and learn how HTTPS certificates work.
Manual SSL Expiry Calculator
SSL/TLS Certificate Types
Verifies domain ownership only. Issued in minutes. Free from Let's Encrypt.
Verifies organization identity. Takes 1-3 days. Shows company name in certificate details.
Most rigorous verification. Takes 1-2 weeks. Previously showed green bar in browsers.
What Are SSL/TLS Certificates?
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that encrypt communication between your browser and a website. An SSL certificate proves a website's identity and enables HTTPS. When you see a padlock in your browser's address bar, it means the connection is encrypted with TLS. The certificate contains the domain name, issuing authority, validity dates, and a public key used for encryption.
Why SSL Expiry Matters
SSL certificates expire (typically every 90 days for Let's Encrypt, or annually for paid certificates). When a certificate expires, browsers display scary warning pages that drive visitors away. Google Chrome shows "Your connection is not private," which most users won't bypass. An expired SSL can also affect your SEO rankings, email deliverability (if using the same domain), and customer trust. Set reminders to renew at least 30 days before expiry.
Let's Encrypt — Free SSL
Let's Encrypt is a free, automated, and open Certificate Authority that has issued over 3 billion certificates since 2016. It provides DV certificates valid for 90 days, with automated renewal via tools like Certbot. Most web hosts now offer one-click Let's Encrypt integration. The 90-day validity period encourages automation and limits the impact of key compromise. There is no security difference between free and paid DV certificates.
HTTPS as a Ranking Signal
Google confirmed HTTPS as a ranking signal in 2014. While it's a lightweight signal compared to content quality and backlinks, HTTPS is now effectively required for modern websites. Beyond SEO, HTTPS is required for many browser features (geolocation, service workers, HTTP/2), and Chrome marks HTTP sites as "Not Secure." In 2025, there's no reason not to use HTTPS — free certificates from Let's Encrypt make cost a non-issue.
Mixed Content Warnings
Mixed content occurs when an HTTPS page loads resources (images, scripts, stylesheets) over HTTP. This breaks the security chain and triggers browser warnings. "Mixed active content" (scripts, iframes) is blocked entirely by modern browsers. "Mixed passive content" (images) shows a warning. To fix mixed content, update all resource URLs to use HTTPS or protocol-relative URLs (//example.com/image.jpg). Use Content-Security-Policy headers to catch mixed content in development.