Installing an SSL Certificate on Windows Server (IIS)

Steps on Windows Server (IIS)

1. Create a CSR: IIS Manager → server → Server Certificates → Create Certificate Request; Common Name = your domain, key length at least 2048 bits.
2. Get the certificate from your CA after domain validation.
3. Install intermediates into Intermediate Certification Authorities.
4. Complete Certificate Request with the .cer file.
5. Add an https binding on port 443 (enable SNI for multiple sites).
6. Redirect HTTP to HTTPS and test the certificate.

Free SSL and automatic renewal

Let’s Encrypt certificates can be installed and renewed automatically on IIS with tools such as win-acme. Under a CA/Browser Forum decision, maximum public TLS certificate validity is 200 days from 15 March 2026, 100 days from 15 March 2027 and 47 days from 15 March 2029 – so automate renewal.

Installing a certificate on a Windows PC / Edge

Double-click the .cer/.crt/.pfx file → Install Certificate → choose Current User or Local Machine → select the right store (Trusted Root or Intermediate). Edge and Chrome use the Windows certificate store; in Edge see Settings → Privacy, search and services → Security → Manage certificates.

Frequently asked questions

How do I install SSL on Windows Server?

Create a CSR in IIS Manager, install the issued certificate with Complete Certificate Request, add intermediates and bind it to the site on port 443.

How long are SSL certificates valid?

Maximum 200 days from 15 March 2026, 100 days from 2027 and 47 days from 2029.

Can I use free SSL on IIS?

Yes, Let’s Encrypt with win-acme, including automatic renewal.