ToolsSubnet Calculator

    Subnet Calculator

    Calculate network addresses, host ranges, and subnet details from CIDR notation

    Calculate Subnet

    Enter an IP address with CIDR prefix or subnet mask

    10.0.0.0/8
    172.16.0.0/12
    192.168.1.0/24
    192.168.1.128/25
    10.10.0.0/22

    Common Subnets Reference

    CIDRNetmaskHostsUse Case
    /32255.255.255.2551Single host
    /31255.255.255.2542Point-to-point link
    /30255.255.255.2522Point-to-point link
    /29255.255.255.2486Small segment
    /28255.255.255.24014Small LAN
    /27255.255.255.22430Small LAN
    /26255.255.255.19262Medium LAN
    /25255.255.255.128126Medium LAN
    /24255.255.255.0254Class C / Standard LAN
    /23255.255.254.0510Large LAN
    /22255.255.252.01,022Large LAN
    /21255.255.248.02,046Campus network
    /20255.255.240.04,094Campus network
    /16255.255.0.065,534Class B network
    /8255.0.0.016,777,214Class A network

    Enter an IP address with CIDR prefix and click Calculate

    Example: 192.168.1.0/24

    About Subnet Calculation

    A subnet calculator helps network administrators and security professionals determine the network address, broadcast address, host range, and other details for a given IP address and subnet mask.

    CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length (e.g., 192.168.1.0/24) to define a network. The prefix length indicates how many bits are used for the network portion of the address.

    Why is this useful for security?

    • Defining firewall rules and ACLs with precise network ranges
    • Segmenting networks to limit lateral movement during incidents
    • Validating that VPN tunnels and routes cover the correct subnets
    • Planning IP address allocation for new infrastructure
    • Analyzing network scan results and mapping attack surfaces