IPv4 Subnet Calculator
Calculate network address, subnet mask, broadcast, host range, and usable hosts from IP + prefix. Use this online tool instantly.
About This Tool
This free online IPv4 Subnet Calculator helps you quickly derive accurate subnet details from an IPv4 address and CIDR prefix. It calculates network and broadcast addresses, subnet mask, wildcard mask, first and last host, and usable host count. This saves time during infrastructure design, cloud security setup, and routing validation.
Use it for LAN planning, VPN segmentation, firewall rule preparation, and interview practice. All calculations run directly in your browser, and no input data is sent or stored on our servers. You can copy formatted output for tickets, architecture docs, and deployment runbooks.