Free SSL Certificate Checker
Check your SSL/TLS certificate: expiry date, issuer, domain match, www coverage, HTTP to HTTPS redirect, HSTS and mixed content – with clear steps to fix every security warning.
What is an SSL Certificate Checker?
An SSL certificate checker connects to your website over HTTPS and reads its certificate: who issued it, which domains it covers and when it expires. It also checks that visitors are redirected from http:// to https:// and that the padlock is not broken by insecure files.
An expired or mismatched certificate shows visitors a full-page “Your connection is not private” warning – most people leave immediately and Google stops sending traffic. HTTPS is also a confirmed Google ranking signal.
What the SSL Certificate Checker checks
Every problem comes with plain-English steps to fix it, and every result is added to your downloadable Technical SEO report.
Days left, with warnings at 30 and 14 days.
Checks the certificate covers your domain.
Tests the other version of your domain too.
Certificate authority and signature algorithm.
Confirms http:// sends visitors to https:// with a 301.
Checks the HSTS header and insecure files on the homepage.
How to use the SSL Certificate Checker
Click Load Example above to see a real result first.
Enter your domain
Just the domain, e.g. yourwebsite.com – no need for https://.
Click “Check SSL”
We open a secure connection and read the certificate.
Read the “Fix first” tab
Expiry, mismatch and redirect problems come first.
Review certificate details
See issuer, validity dates and every domain covered.
Common problems and how to fix them
| Problem | Why it matters | How to fix it |
|---|---|---|
| Expired certificate | Browsers block the site. | Renew it and enable auto-renewal. |
| Domain mismatch | “Not private” warning. | Reissue for the right domains (with and without www). |
| No HTTP → HTTPS redirect | Insecure duplicate of the site. | Add a 301 redirect to HTTPS. |
| Mixed content | Padlock disappears. | Load every file over https://. |
| No HSTS | Visitors can be downgraded. | Add Strict-Transport-Security. |
Frequently asked questions
Is a free SSL certificate good enough?
Yes. Free Let’s Encrypt certificates give the same encryption as paid ones. Paid certificates mainly add warranties or organisation validation.
How often do certificates expire?
Free certificates last 90 days and renew automatically. Paid certificates are limited to about one year and the maximum is getting shorter.
Does SSL help SEO?
HTTPS is a light ranking signal, and Chrome marks HTTP pages as “Not secure”, which hurts trust and conversions.
Why does my site show “Not secure” with a valid certificate?
Usually because of mixed content – images, scripts or styles loaded over http://. Use our Mixed Content Checker to find them.
Do I need a certificate for www and non-www?
Yes. Both versions should be covered so the redirect to your main version happens without a warning.
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Built and maintained by the AM Digital Marketing Agency SEO team. Last updated: .
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