This SSL checker reads the certificate your site sends on port 443 and shows the expiry date, the days left, who issued it, the names it covers and whether browsers trust the chain. Type a domain and press Check: our server opens one secure connection, reads the certificate and closes it, with no signup.
How to use the SSL checker
- 1Type the domain, such as example.com. A full URL works too; we only use the domain part.
- 2Press Check, or hit Enter.
- 3Read Status first. Valid means the name matches, the dates are current and the chain is trusted.
- 4Then read Expires and Days left, and check that Covers lists every address you use, with and without www.
When to use it
- A visitor says your site shows a Not secure warning, and you want to know why.
- You got a renewal email and want to see if the new certificate is live.
- You moved hosts or added a CDN and want to be sure it serves your own certificate.
- Your site loads fine on your laptop but a phone or an app says the connection isn't private.
Worked examples
A healthy certificate
We checked our own domain.
- Domain to check
- searchblueprint.io
- Status
- Valid
- Expires
- 2026-12-11
- Days left
- 72 days
- Issued by
- Let's Encrypt
- Covers
- *.searchblueprint.io, searchblueprint.io
- Trusted chain
- Yes
Let's Encrypt certificates last 90 days and this one started on 12 September, 18 days before we checked, with a wildcard that covers www as well, so there's nothing to do.
A chain with a missing link
We checked a public test site that serves its certificate without the intermediate.
- Domain to check
- incomplete-chain.badssl.com
- Status
- Not trusted
- Days left
- 27 days
- Issued by
- Let's Encrypt
- Trusted chain
- The server doesn't send the intermediate certificate. Some browsers fill the gap, many phones and tools don't. Install the full chain your certificate authority gave you.
The certificate itself is fine and in date. The server just doesn't send the certificate that links it to a trusted authority. A desktop browser can paper over that, which is why it looks fine on your laptop. The fix is on the server: install the full chain file your provider gave you.
Why expiry dates matter more each year
Certificates are getting shorter. Let's Encrypt issues them for 90 days today and says it will cut that to 45 days by 2028. The CA/Browser Forum, which sets the rules for every public certificate, voted to bring the longest allowed from 398 days down to 47 in steps between March 2026 and March 2029. More renewals mean more chances for one to fail quietly, so it pays to check the date rather than trust the auto-renewal.
HTTPS also counts for search. Google called it a very lightweight ranking signal when it started using it in 2014, and lists HTTPS in its page experience guidance. The warning page is the bigger cost: it stands between every visitor and your site until they choose to click past it.
What each status means
| Status | What it means | What to do |
|---|---|---|
| Valid | Right name, in date, trusted chain | Nothing |
| Expiring soon | Fewer than 14 days left | Check your renewal ran |
| Expired | Past its end date | Renew and install it now |
| Wrong name | Issued for a different domain | Reissue it with every name you use |
| Not trusted | Self-signed, or a missing intermediate | Install the full chain from your provider |
The checker reads port 443 only. It doesn't test revocation, cipher suites or older protocol versions.
Made by SearchBlueprint
This SSL checker is free with no signup. SearchBlueprint, who make it, sell SEO planning: a plan that shows the searches your customers type and which page on your site should answer each one.
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