Free Security & tech tool
SSL Certificate Checker
See who issued a site’s certificate, when it expires and which domains it covers, and check that HTTPS is set up right.
- Free
- No sign-up
- Results in seconds
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What it checks
Expiry date
Days left before the certificate runs out. Under 30 is a warning, under a week fails.
Domains covered
Every name on the certificate, and whether it covers your host by name or wildcard.
Issuer
The certificate authority that signed it, like Let’s Encrypt or Google Trust Services.
Renewal history
Recent certificates for the host, so you can see how often it renews.
HTTPS connection
Whether a secure connection opens and the certificate is trusted.
Redirect and HSTS
Whether http:// sends visitors to HTTPS, and whether browsers are told to stay there.
Questions
Where does the certificate data come from?
From Certificate Transparency logs, the public record of every certificate a trusted authority issues. We can’t read the live handshake, so we show the newest valid certificate for your host. That’s almost always the one your server sends.
How many days before expiry should I renew?
At least 30. Let’s Encrypt and most hosts renew automatically at about that point. If you see under 30 days and renewal is automatic, check that it ran.
Why does my certificate only last 90 days?
Short lifetimes limit the damage if a key leaks, and automatic renewal makes them painless. New certificates can last at most 200 days, and that limit drops to 47 days by 2029.
What is HSTS?
A header that tells browsers to use HTTPS for your site for a set time, even if someone types http://. With includeSubDomains and preload, you can ask browsers to build it in.