Free SSL Certificate Checker Online | Check SSL | ConvixPro

Check an SSL Certificate Online

The ConvixPro SSL certificate checker lets you check the SSL certificate of any public website in a few seconds. Enter a domain, and the tool shows whether a certificate was found, when it became valid, when it expires and how many days are left.

An expired or badly configured certificate can trigger browser warnings and scare visitors away. A quick check now and then helps you catch the problem before your visitors do. You don't need an account to use it.

What This SSL Certificate Checker Shows

Depending on the details returned for the domain you enter, the result can include:

• Whether an SSL certificate was detected
• The current certificate status
• The date the certificate became valid
• The expiration date
• How many days remain before it expires
• Any connection or certificate error found during the check

How to Check an SSL Certificate Online

1. Enter your domain. Type a hostname such as example.com, or a full address such as https://example.com.
2. Clean up the input. Remove spaces, extra paths and any unrelated text.
3. Click "Check SSL Certificate". The tool looks up the certificate the host is currently serving.
4. Read the status. See whether the certificate was found and is within its validity period.
5. Note the expiry date. Pay attention to the days remaining if the result shows it.
6. Fix and re-check if needed. If the lookup fails, confirm the hostname, make sure the site is publicly reachable and try again.

How to Read Your SSL Certificate Result

A padlock in the browser doesn't tell you the whole story. Here is what each result usually means.

Valid certificate

A valid result means the certificate returned during the check is currently within its stated validity period. This confirms the certificate dates shown by the checker, but it does not by itself confirm every part of the website's HTTPS or TLS configuration.

What to do: If you are investigating a browser warning, continue checking the exact hostname and server configuration.

Expiring soon

If only a few days are left, plan the renewal now. Don't assume auto-renewal will work. It can fail because of DNS changes, a missing validation file, expired credentials or a hosting move. After renewing, run the check again to confirm the new certificate is really the one being served.

Need help checking certificate expiration? Read our guide to Checking SSL certificate expiration and fixing common SSL errors.

Expired certificate

The certificate has passed its expiry date. Visitors may see a security warning, and some apps or services may refuse to connect. Renew or replace the certificate, install it on the correct server, then check again.

Certificate not found or connection failed

This can happen when:

• The hostname is misspelled
• The domain doesn't resolve. Use our DNS Lookup tool to inspect the domain's DNS records and confirm that the hostname resolves correctly.
• Port 443 is closed or HTTPS isn't set up
• A firewall blocks the request
• The server doesn't return a certificate
• The request times out

Open the site in your browser over HTTPS first, then retry with the exact hostname.

Example: Checking a Subdomain

Say you enter store.example.com and get this result:

The certificate works right now, but it needs attention soon. Your next steps would be:

1. Check whether automatic renewal is turned on.
2. Make sure renewal covers store.example.com.
3. Renew or replace the certificate before it expires.
4. Run the check again after installing it.
5. Open the site in a browser to confirm the warnings are gone.

A Valid Date Isn't the Whole Story

A certificate can be inside its validity period and still cause a browser warning. Common reasons:

• The certificate doesn't cover the hostname you entered
• An intermediate certificate is missing
• The certificate is self-signed
• The server is sending the wrong certificate
• A redirect sends visitors to a hostname the certificate doesn't cover
• Different servers behind the same domain return different certificates

If this tool doesn't report hostname matching or chain validation, confirm those points in your browser, with your hosting provider or with your server admin tools.

SSL and TLS: What's the Difference?

People still commonly say “SSL certificate,” but modern HTTPS connections use TLS. SSL is the older term that remains widely used when referring to website certificates.

This ConvixPro checker focuses on the certificate information supported by the tool. It does not test TLS versions or cipher suites.

When Should You Check Your SSL Certificate?

• When you launch a new website
• After moving a domain to a new host
• After installing or renewing a certificate
• When visitors report a browser security warning
• During a technical or SEO audit of a client site, you can check the certificate first and then use our SEO Analyzer to review other website issues
• Before a big marketing campaign
• After a DNS or CDN change
• Regularly on your store, login and checkout pages

If you manage several sites, keep a separate renewal calendar. A one-time check can't replace ongoing expiry reminders.

Common Problems and Fixes

The domain is rejected

Use a plain hostname like example.com. You can also enter https://example.com. Remove quotes, spaces and any extra text. Never paste HTML, certificate files, private keys or login details into the field.

The root domain works but the www version fails

example.com and www.example.com are two different hostnames. A certificate may cover one, both, or a wildcard. Check each hostname your visitors use.

The checker still shows the old expiry date

The renewed certificate may not be installed everywhere. This often happens with a CDN, multiple web servers, a reverse proxy, a load balancer or separate IPv4 and IPv6 endpoints. Check every endpoint and give any provider caching a little time to update.

The website opens but the check fails

Some servers block automated requests, limit certain regions or reject connections temporarily. Retry the check, and confirm the result in your browser.

The result is blank

Make sure JavaScript is enabled and refresh the page. Then try another public domain. If other domains work, the problem is probably with the target server. If nothing works, the lookup service may be temporarily unavailable.

Privacy and Limitations

We only need a public domain name to run the check. Please don't enter passwords, private keys, certificate signing requests or any other confidential information. The result is a quick certificate check, not a full security audit. It doesn't cover things like cipher suites, revocation status, mixed content or every server behind a domain.