SSL Certificate Checker
Check SSL certificate details for any domain.
How to use SSL Certificate Checker
Enter Your Domain Name
Click the text input field labeled 'Enter Domain' at the top of the checker. Type your domain (e.g., example.com or https://example.com) without spaces. You can include or exclude the protocol—the tool handles both formats automatically.
Click the Check Certificate Button
Press the blue 'Check Certificate' button located directly below the input field. The tool will immediately begin scanning the SSL certificate for that domain. A loading spinner will appear while the connection is being verified.
Review Certificate Details
View the results table showing Certificate Status (Valid/Expired/Self-Signed), Issuer name, Subject, Issue Date, Expiry Date, and Certificate Version. Green checkmarks indicate secure certificates; red warnings indicate potential security issues.
Export or Share Results
Click the 'Download Report' button to save certificate details as a PDF, or use the 'Copy to Clipboard' button next to each field to copy specific information for documentation or sharing with your team.
Related Tools
SSL checker online: verify any domain's certificate instantly
SSL checker online: verify any domain's certificate instantly
An SSL checker lets you look up the SSL/TLS certificate for any domain and see its validity status, expiry date, issuer, and full certificate chain in seconds. Use the free ToolHQ SSL checker to verify any domain's certificate right now.
An SSL checker is a network tool that connects to a domain, retrieves its SSL/TLS certificate, and presents the key details in a human-readable format: whether the certificate is valid, when it expires, who issued it, and whether the chain is properly configured.
An expired SSL certificate breaks HTTPS for every visitor to a site, triggers browser security warnings, and causes search engines to flag the site as potentially unsafe. A misconfigured certificate chain produces trust errors even when the certificate itself is valid. Running an SSL check before problems are reported takes under ten seconds and can prevent the kind of outage that damages both user trust and search rankings.
Key takeaways
- Shows certificate validity status, expiry date, days remaining, and issuer in one view
- Displays the full certificate chain so misconfigurations are visible before they cause errors
- Only the domain you enter is queried, no personal data is stored
- Works on any publicly accessible domain or subdomain
- Free, instant, no account required
What SSL/TLS certificates are and what the checker looks for
SSL/TLS (Secure Sockets Layer/Transport Layer Security) is the cryptographic protocol that secures HTTPS connections. When you visit a site with https://, your browser and the server negotiate an encrypted connection using a certificate. The certificate serves two functions: it enables encryption and it verifies that the server you are connecting to is actually the one it claims to be.
The TLS 1.3 specification (RFC 8446) is the current standard for secure web communications. Most modern browsers require TLS 1.2 or higher and will display security warnings for older protocol versions.
An SSL certificate contains several fields the checker reads:
- Common Name or Subject Alternative Names (SANs): the domain or domains the certificate covers
- Issuer: the Certificate Authority (CA) that issued and vouches for the certificate
- Valid from / Valid to: the date range during which the certificate is trusted
- Certificate chain: the sequence of certificates from the site's certificate up to a trusted root CA
- TLS version: the protocol version the server supports
A certificate fails trust checks when: the domain does not match, the certificate has expired, the issuer is not a recognized CA, or the chain is incomplete (an intermediate certificate is missing). The SSL checker detects all of these issues.
When to use an SSL checker
Before launching a new site or domain. Confirm the certificate was installed correctly, covers the right domain (including the www subdomain if needed), and the chain is complete before going live.
After renewing a certificate. Renewal is a common failure point. Check that the new certificate was installed correctly and the old one is no longer being served.
Troubleshooting HTTPS errors. When visitors report security warnings or your monitoring alerts fire, the SSL checker gives you an immediate view of what is wrong without needing server access.
Monitoring expiry dates. Most certificate-related outages happen because nobody noticed the expiry approaching. A periodic manual check (or better, an automated monitor) prevents the surprise expiry.
Auditing third-party domains. Agencies, developers, and security teams use SSL checkers to audit client sites, partner integrations, and API endpoints for certificate health.
Mini-story: Rena, a 36-year-old web developer at a digital agency in Melbourne, was doing a pre-launch check on a client's new e-commerce site. She ran the domain through the ToolHQ SSL checker and immediately saw that while the certificate itself was valid and not expired, the intermediate certificate was missing from the chain. The certificate had been installed without the full chain file. Most major desktop browsers cached the intermediate certificate and showed no error, but some mobile browsers and API clients would have shown trust warnings. She fixed the server configuration before launch, and the client never knew the issue existed.
Check your SSL certificate now
How to use the SSL checker: step by step
Enter the domain. Type or paste the domain name you want to check. Include the full domain (e.g.,
example.comorshop.example.com). You do not need to includehttps://.Run the check. The tool queries the domain on port 443 (the standard HTTPS port), retrieves the certificate, and parses the details.
Review the validity status. The checker shows whether the certificate is currently valid (green) or has a problem such as expiration, mismatch, or chain issue (red or orange).
Check the expiry date. Note how many days remain before expiry. Less than 30 days remaining should trigger a renewal. Many organizations set automated alerts at 60 days and again at 30 days.
Review the certificate chain. Confirm the chain shows the site certificate, one or more intermediate certificates, and a trusted root CA. A broken chain (missing intermediate) is a common misconfiguration.
SSL certificate best practices
Renew before 30 days remaining. Most CAs allow renewal with 30-60 days left, which extends the validity period from the current expiry date rather than from today. Renewing at 60 days gives you a buffer for DNS propagation and installation issues.
Set automated expiry reminders. Most certificate management tools, cPanel, Let's Encrypt, and cloud providers, can send email alerts before expiry. If you manage certificates manually, set calendar reminders at 60, 30, and 7 days before expiry.
Cover both the root domain and www subdomain. A certificate for example.com does not automatically cover www.example.com. Use a multi-domain (SAN) certificate or a wildcard certificate to cover both. The SSL checker verifies which domains the certificate covers.
Check subdomains separately. A wildcard certificate (*.example.com) covers all first-level subdomains but not second-level ones (api.shop.example.com). Run the SSL checker on each subdomain that handles sensitive traffic.
Verify after DNS changes. When a domain changes servers, hosting providers, or CDNs, the certificate configuration can break. Always run an SSL check after DNS migrations.
Mini-story: Luis, a 28-year-old freelance developer in Buenos Aires, was doing a routine check on his client portfolio. He ran five client domains through the SSL checker on a single afternoon. Two came back clean. One showed 12 days until expiry, which neither he nor the client had tracked. One showed an expired certificate that had been silently serving HTTPS warnings to visitors for over a week. And one showed a certificate that covered example.com but not www.example.com, causing mixed content warnings on the www version. Four of five domains needed attention. None of the clients had noticed.
After confirming SSL is healthy, check the broader technical picture of your site with the redirect checker to trace any 301/302 chains on your URLs and the broken link checker to find any 404s that need fixing.
Frequently asked questions
What does SSL stand for?
SSL stands for Secure Sockets Layer. SSL was the predecessor to TLS (Transport Layer Security), the protocol in widespread use today. The terms are often used interchangeably in everyday usage even though modern HTTPS connections use TLS, not SSL.
How do I know if my SSL certificate is valid?
The SSL checker shows you the certificate's current status, expiry date, and whether the certificate chain is complete. Your browser also shows a padlock icon in the address bar for valid HTTPS connections.
What is a certificate chain?
A certificate chain is the sequence of certificates from the site's own certificate up to a trusted root certificate authority. Browsers trust the site because they recognize the root CA. If an intermediate certificate is missing from the chain, some clients cannot complete the trust verification.
How often should I check my SSL certificate?
At minimum, check when you install or renew a certificate. For sites where HTTPS issues have business impact, monthly manual checks and automated expiry monitoring provide adequate coverage.
What is the difference between DV, OV, and EV certificates?
SSL certificates come in three validation levels that differ in how thoroughly the issuing Certificate Authority verifies the requester's identity. DV (Domain Validation) certificates only verify that the requester controls the domain. They are issued quickly (often automatically) and are what Let's Encrypt provides for free. They are fully trusted by all browsers and encrypt the connection just as effectively as more expensive certificates. OV (Organization Validation) certificates also verify the legal existence of the organization behind the domain, and the certificate contains the organization's name. EV (Extended Validation) certificates require the most rigorous identity verification and historically displayed the company name in the browser address bar (most browsers have removed this UI element). For the purpose of encrypting HTTPS traffic, a DV certificate from Let's Encrypt is cryptographically equivalent to a paid OV or EV certificate. The difference is in identity assurance, not encryption strength. For most websites including e-commerce and SaaS products, a DV certificate is sufficient.
Is the SSL checker free?
Yes. ToolHQ's SSL checker is free to use for any publicly accessible domain. Only the domain you enter is queried, and no personal data is collected or stored.
The short version
An SSL checker retrieves a domain's certificate and reports whether it is valid, when it expires, who issued it, and whether the chain is complete. ToolHQ's free tool connects directly to the domain, requires no account, and presents everything you need to assess certificate health in one view.
Run it before a launch, after a renewal, and whenever HTTPS errors are reported.
Check your SSL certificate now
Pair the SSL checker with the redirect checker and broken link checker for a complete site health sweep. Browse all network tools on ToolHQ.