The default network port number used for HTTPS is 443. When a URL begins with https:// and does not specify another port, browsers normally connect to port 443.
HTTPS stands for Hypertext Transfer Protocol Secure. It uses HTTP for web communication while protecting the connection with TLS encryption, which helps provide confidentiality, authentication, and integrity between a client and server. Port 443 is the standard service port associated with HTTPS, just as port 80 is conventionally associated with unencrypted HTTP.
The port number is a default, not a technical requirement. A website or application can run HTTPS on another port, such as 8443, but that port must normally be written explicitly in the URL—for example, https://example.com:8443. Servers can also host different services on port 443, although doing so may require additional configuration.
Another modern detail is that HTTPS is not limited to TCP. HTTP/3 carries HTTPS traffic over QUIC, which uses UDP, while earlier HTTP versions commonly use TCP. The familiar number 443 still identifies the standard HTTPS endpoint, but the underlying transport can vary.