How to use the SSL certificate checker
- Enter a hostname such as example.com or www.example.com — no protocol needed.
- Press Check. The tool connects to the server and reads its live certificate.
- Read the subject (the domain the certificate covers), the issuer (who signed it), and the valid-from and valid-to dates.
- Check the days-until-expiry figure. A warning appears when fewer than 30 days remain, so you can renew in time.
Why SSL certificates matter
An SSL/TLS certificate encrypts the connection between a visitor's browser and your server, so passwords, card numbers and private messages cannot be read in transit. It is also what puts the padlock in the address bar. Browsers flag sites without a valid certificate as "Not secure", which drives visitors away and, for site owners, hurts conversions and search ranking.
Search engines treat HTTPS as a lightweight ranking signal, and some browser features — geolocation, camera access, service workers — are only available over a secure connection. Keeping a valid, current certificate is no longer optional; it is part of running any trustworthy site.
Understanding certificate expiry
Certificates do not last forever. Many providers now issue certificates for just 90 days, while traditional certificate authorities typically issue one-year certificates. When a certificate lapses, browsers show a full-page warning that blocks visitors until the owner renews and reinstalls it.
The single most common cause of an unexpected outage is a forgotten renewal. Checking the days-left figure regularly — especially for certificates with short lifetimes — is the cheapest insurance against that. If this tool shows fewer than 30 days remaining, treat it as a prompt to renew now.
What each field means
| Field | What it tells you |
|---|---|
| Host | The hostname the certificate was fetched from. |
| Subject | The domain (or set of domains) the certificate is valid for. |
| Issuer | The certificate authority that signed and verified the certificate. |
| Valid from | The date the certificate became active. |
| Valid to | The date the certificate expires. |
| Days left | How many days remain before expiry, with a warning under 30 days. |