SSL Certificate Expiration Checker

Find out exactly when a website's SSL certificate expires. Enter a domain and this tool connects to the live server, reads its certificate, and shows the days remaining, the precise valid-until date, when it was issued, and who issued it. An expired certificate is the most common cause of a sudden "Your connection is not private" outage — catch it before your visitors do.

How to use the SSL Certificate Expiration Checker

Enter the domain you want to check and press Check expiry. The result shows a large days-remaining figure, colour-coded so you can see the urgency at a glance:

• Green — more than 30 days left; you are fine.
• Amber — 15 to 30 days; schedule the renewal now.
• Red — 14 days or fewer, or already expired; act immediately.

Below that you get the exact valid-from and valid-until timestamps, the issuing certificate authority, and confirmation that the certificate actually covers the hostname you entered. To watch a domain over time, bookmark this page with ?host=yourdomain.com on the end — it pre-fills and runs the check automatically each time you open it.

Why SSL certificate expiry matters

Every TLS certificate is issued for a fixed lifetime and then stops being trusted. Public certificates today are capped at about 13 months (398 days), and the industry is moving toward even shorter lifetimes, which makes expiry tracking more important than ever. When a certificate expires:

• Browsers block the site with a full-page interstitial warning that most visitors will not click through. Traffic, sign-ups and sales stop until it is fixed.
• APIs and integrations fail — any client that verifies certificates (mobile apps, server-to-server calls, webhooks, payment processors) will refuse to connect, often with cryptic errors.
• Email and other TLS services break too, not just the website, if they share or depend on the same certificate.

The frustrating part is that an expiry outage is completely predictable and completely preventable — the date is printed right in the certificate. The fix is to either automate renewal (Let's Encrypt with certbot, or your hosting provider's managed certificates) or to monitor the expiry date and renew a few weeks ahead. This tool gives you that date from the live server, which is more reliable than a control-panel field that might show a certificate you have not actually deployed yet.

Note that a certificate can be renewed and reissued well before it expires. Most certificate authorities let you renew up to 90 days early and carry the unused time forward, so renewing ahead of schedule costs you nothing and removes the risk of a last-minute scramble.

Common use cases

• Routine expiry monitoring — check your production domains on a schedule so a certificate never lapses by surprise.
• Confirming a renewal deployed — after renewing, verify the valid-until date jumped forward, proving the new certificate is actually live and not just issued.
• Vendor and dependency checks — make sure an API, CDN or partner host you rely on is not about to expire and take your service down with it.
• Incident response — when something "suddenly broke over HTTPS," the days-remaining figure tells you in seconds whether expiry is the cause.
• Pre-handoff QA — confirm a client's site has plenty of runway before you finish an engagement.

How to never miss an SSL expiry again

• Automate it. Let's Encrypt certificates are free and renew automatically with certbot, acme.sh or your platform's built-in TLS. Automated 90-day certificates effectively eliminate manual expiry tracking.
• Use managed certificates. Cloudflare, most hosts, and cloud load balancers can provision and rotate certificates for you.
• Set calendar reminders for any certificate you still renew by hand — two to four weeks before the valid-until date shown here.
• Renew early. There is no penalty: CAs carry the remaining validity forward, so renewing weeks ahead removes all risk.