SSL Checker
Check the validity, expiry date, and chain of a domain's SSL/TLS certificate.
Certificate Status
- days remaining
Subject (CN)
Issuer
Valid From
Valid Until
Signature Algorithm
Serial Number
Subject Alternative Name (SAN)
About SSL Checker
SSL Checker connects to a domain on port 443 and reads the certificate it presents: who it was issued to (subject and SAN), who issued it (issuer/CA), when it becomes valid and when it expires, and whether the chain to a trusted root is complete. This check catches common problems such as expired certificates, domains missing from the SAN, or missing intermediate certificates - the usual causes of security warnings in your visitors' browsers.
How to use
- 1 Enter the target you want to check (a domain, IP address, or URL) in the field provided.
- 2 Click the run button - the request is processed on Computing ID servers and the results are shown in the panel.
- 3 Read the results; copy the parts you need, or change the input and run it again to compare.
Frequently asked questions
My certificate is valid but the browser still shows a warning. Why?
Often because the intermediate certificate is not installed on the server, so the chain to the root CA is incomplete. This tool flags chains that are not complete.
How long before expiry should I renew?
Ideally 2-4 weeks before the expiry date. Let's Encrypt certificates are renewed automatically about 30 days before they expire.
Free tools from Computing ID
SSL Checker is one of dozens of network, security, and developer utilities provided free of charge by Computing ID (PT Intprism Computing Technology). Every tool can be used without creating an account or logging in. For tools that run entirely in the browser, your data is never sent to our servers; for tools that need to call a server (such as a DNS lookup or SSL check), only the target you enter is processed, and it is not stored. If you need infrastructure to run your own services, Computing ID also offers Linux and Windows VPS, cPanel hosting, email hosting, S3 Object Storage, WireGuard VPN, and domain registration, with data centers in Indonesia and Singapore and 24/7 technical support.
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