SSL Checker — Verify a Certificate, Chain and Expiry Date
Check any website's SSL certificate in seconds: issuer, validity dates, days remaining, hostname match, chain of trust, protocol and cipher. Free, no sign-up.
What an SSL check actually tells you
An SSL certificate does two jobs: it encrypts traffic between the browser and the server, and it proves the server is really the one it claims to be. A certificate can be installed and still fail at the second job — because it expired, because it was issued for a different hostname, or because an intermediate certificate is missing from the chain the server sends. Browsers treat all three as the same red warning screen, so knowing which one you are looking at saves a lot of guesswork.
The checks this tool runs
- Validity window — the not-before and not-after dates, plus the exact number of days left before renewal is due.
- Hostname match — whether the domain you tested appears in the certificate's common name or subject alternative names. This is the check that catches a certificate installed on the wrong vhost.
- Chain of trust — whether the server sends the intermediate certificates browsers need. A missing intermediate often works in Chrome on desktop and fails on older Android, which makes it easy to miss.
- Issuer and type — which certificate authority signed it, and whether it is domain, organisation or extended validation.
- Protocol and cipher — the TLS version and cipher suite actually negotiated, so you can spot a server still allowing outdated protocols.
- HTTPS behaviour — whether plain HTTP redirects to HTTPS and whether HSTS is set.
Why an expired certificate costs more than it looks
When a certificate lapses, browsers stop showing the site and show an interstitial warning instead. Most visitors leave at that screen. Checkout flows break, APIs that call your domain start failing, and search engines that recrawl during the outage see an unreachable site. The fix is nearly always a five-minute renewal — the damage comes entirely from nobody noticing in time. Checking monthly, or hosting somewhere that renews automatically, removes the failure mode.
Frequently asked questions
What does this SSL checker verify?
It connects to the domain over HTTPS and reports the certificate's issuer, subject, validity dates, days remaining, hostname match, subject alternative names, chain of trust, serial number, signature algorithm, and the TLS protocol and cipher negotiated. It also checks whether HTTP redirects to HTTPS and whether HSTS is enabled.
How do I check if a website has a valid SSL certificate?
Enter the domain above and press Check SSL. If the result shows a valid status with days remaining, a matching hostname and a complete chain, the certificate is working correctly for visitors. Any failure is listed individually so you know exactly what to fix.
What happens if my SSL certificate expires?
Browsers block the page with a full-screen security warning and most visitors leave immediately. Forms, checkouts and any API integration pointing at your domain stop working until a valid certificate is installed. Nothing is permanently damaged, but traffic and orders are lost for as long as the outage lasts.
How often should I check my SSL certificate?
Once a month is enough for most sites, plus an extra check straight after any server migration, control-panel change or DNS move. Certificates issued by Let's Encrypt run on 90-day cycles, so an automation failure can go unnoticed for weeks without a periodic check.
Does an SSL certificate affect SEO?
Yes, in two ways. HTTPS has been a lightweight ranking signal since 2014, and browsers label plain HTTP pages as "Not secure", which raises bounce rate. The indirect effect — visitors leaving at a warning screen — is far larger than the direct ranking effect.
Do I get a free SSL certificate with hosting?
Yes. Every HosterSale hosting plan includes a free SSL certificate that is issued automatically and renews for as long as the site stays with us, with nothing to configure and no renewal fee.