SSL checker: wikipedia.org
Check whether a site's SSL certificate is valid and trusted, when it expires, which domains it covers, and whether HTTPS is set up properly.
Try: wikipedia.org · github.com · sitehostingfinder.com
VALID The SSL certificate for wikipedia.org is valid
Checked Thu, 12 Nov 2026 14:40:16 UTC on 208.80.154.224.
- Issued to
- *.wikipedia.org
- Issuer
- Let's Encrypt (YE2)
- Valid
- Oct 4 18:34:51 2026 GMT → Jan 2 18:34:50 2027 GMT 51 days left
- Trusted
- yes
- Covers
- *.m.mediawiki.org, *.m.wikibooks.org, *.m.wikidata.org, *.m.wikimedia.org, *.m.wikinews.org, *.m.wikipedia.org, *.m.wikiquote.org, *.m.wikisource.org, *.m.wikiversity.org, *.m.wikivoyage.org, *.m.wiktionary.org, *.mediawiki.org and 29 more
- Key
- EC prime256v1 256-bit
- Protocol
- TLSv1.3 · TLS_AES_128_GCM_SHA256 · h2
- HTTP → HTTPS
- redirects
- HSTS
- on max-age 106384710 · includeSubDomains · preload
Certificate chain
- *.wikipedia.org issued by YE2 · until Jan 2 18:34:50 2027 GMT
- YE2 issued by Root YE · until Sep 2 23:59:59 2028 GMT
- Root YE issued by ISRG Root X2 · until Sep 2 23:59:59 2032 GMT
- ISRG Root X2 issued by ISRG Root X1 · until Sep 2 23:59:59 2032 GMT
- ISRG Root X1 issued by ISRG Root X1 · until Jun 4 11:04:38 2035 GMT
What we check
- Trust: is the certificate signed by an authority browsers trust, with a complete chain?
- Name: does it cover this exact domain (including www)?
- Expiry: how many days are left?
- Protocol: TLS 1.2 or 1.3 (older versions are blocked by browsers).
- HTTPS setup: does http:// redirect to https://, and is HSTS on?
The most common SSL problems and fixes
| Problem | Fix |
|---|---|
| Expired | Renew it. Free Let's Encrypt certificates renew automatically on most hosts; if yours didn't, check that the domain still points to the host. |
| Name mismatch | The certificate was issued for another name (often missing www). Reissue it to cover both. |
| Incomplete chain | Install the intermediate certificate on the server; hosts with automatic SSL do this for you. |
| No HTTPS redirect | Turn on "Force HTTPS" in your host's panel or add a redirect rule. |
Do you need a paid certificate?
For most sites, no: free certificates use the same encryption. See free vs paid SSL.
FAQ
How do I check if an SSL certificate is valid?
Enter the domain above. We connect over HTTPS, check that the certificate is trusted, covers the domain and hasn't expired, and show the full chain.
How do I check when my SSL certificate expires?
The result shows the expiry date and the number of days left. Free Let's Encrypt certificates last 90 days and renew automatically about 30 days before expiry.
Why does my browser say "Not secure" when I have SSL?
Usually the certificate doesn't cover the exact name (www vs no www), has expired, or the page loads some images or scripts over http://. This check covers the first two.
What is HSTS?
A header that tells browsers to only ever use HTTPS for the site. It prevents downgrade attacks. Only turn on preload once every subdomain supports HTTPS.
CHANGING HOSTS?
DNS is where most migrations go wrong. Follow the hosting switch checklist, lower your TTL a day before, and use the propagation checker after the switch. Comparing new hosts? See real renewal prices.