SSL Certificate Checker
Check a TLS certificate: issuer, validity dates, days until expiry, covered host names, protocol, cipher and the full chain. Free online SSL checker.
This check runs from our server, not from your browser, and is rate limited. Nothing you enter is stored. Private and internal addresses are refused on purpose.
What this tool is for
An expired certificate takes a site down completely: browsers refuse to load it, and there is no partial failure to warn you first. This shows the dates, who issued it, which names it covers, the negotiated protocol and cipher, and the chain above it. This is one of the few tools here that needs a server, because the question is about the internet rather than about your data. The request is made from our server, rate limited, and nothing you enter is stored.
How to use it
- Enter a domain name, and a port if it is not 443.
- Check the days remaining and whether the certificate actually covers the name you entered.
- Look at the chain if a browser complains despite a valid end certificate.
Frequently asked questions
The certificate is valid but the browser still complains.
Usually an incomplete chain: the server sends the leaf but not the intermediate. Browsers on desktop often paper over it from cache, mobile clients do not, which is why it looks intermittent.
When should I renew?
Automatic renewal should run at about a third of the lifetime remaining, which for a 90 day certificate means 30 days out. If you are renewing by hand, treat 14 days as an emergency.
What does the wildcard cover?
A wildcard like *.example.com covers one level: shop.example.com yes, a.b.example.com no, and the bare example.com only if it is listed separately.