IPv4 Network & Broadcast Calculator
Enter an IPv4 address and subnet (CIDR prefix or dotted mask) to instantly compute network details.
What this network broadcast calculator does
A network broadcast calculator helps you convert a single IP address and subnet into practical networking values: network address, broadcast address, host range, usable host count, wildcard mask, and prefix length. Whether you are setting up a small office router, planning VLANs, or documenting IP space for cloud infrastructure, this saves time and reduces mistakes.
Instead of calculating in binary by hand every time, you can input one host IP and subnet and immediately see how that subnet behaves. This is especially useful when you're troubleshooting overlap, designing ACLs, or validating DHCP scope boundaries.
How subnet calculations work
1) Network address
The network address is computed by applying a bitwise AND between the host IP and the subnet mask. Every host in the same subnet shares this network portion.
- IP: 192.168.1.130
- Mask: 255.255.255.0 (/24)
- Network result: 192.168.1.0
2) Broadcast address
The broadcast address is the highest address in the subnet. It is used to send traffic to all hosts in that broadcast domain. It can be derived by keeping the network bits and setting all host bits to 1.
3) Usable host range
For traditional subnets (/30 and larger host spaces), usable hosts are between network+1 and broadcast-1. Special cases:
- /31 is often used for point-to-point links (2 usable endpoints).
- /32 identifies a single host route.
Common CIDR blocks at a glance
- /24 → 256 total addresses, 254 usable hosts
- /25 → 128 total addresses, 126 usable hosts
- /26 → 64 total addresses, 62 usable hosts
- /27 → 32 total addresses, 30 usable hosts
- /28 → 16 total addresses, 14 usable hosts
- /29 → 8 total addresses, 6 usable hosts
- /30 → 4 total addresses, 2 usable hosts
Why this matters in real environments
In production networks, subnetting errors are one of the most common causes of silent connectivity problems. A host may look “up,” but if the subnet mask is wrong, traffic can be routed incorrectly or never leave a segment.
- Prevent overlapping networks across offices or cloud VPCs
- Validate firewall and ACL source/destination networks
- Plan DHCP ranges safely within usable host boundaries
- Document precise broadcast domains for incident response
Frequent mistakes this tool helps you avoid
Using non-contiguous subnet masks
Valid subnet masks must have contiguous 1s followed by contiguous 0s in binary. Values like 255.0.255.0 are invalid and can break assumptions in routers and operating systems.
Confusing host IP with network ID
A host should not be assigned the network or broadcast address in standard subnetting. The calculator clearly separates these values.
Assuming all subnet sizes have “minus two” usable hosts
The classic formula works for many ranges, but /31 and /32 are special. Modern point-to-point links often use /31, while /32 is a single-address route.
Final takeaway
If you work with IPv4, a network broadcast calculator is a practical daily utility. It speeds up subnet checks, improves configuration accuracy, and gives you instant visibility into address boundaries. Use it before changes go live, and your network planning will be cleaner and more predictable.