IP ADDRESS PLANNING TOOL
Calculate IPv4 and IPv6 prefixes, visualize network and host bits, and build a VLSM allocation plan for multiple departments or services.
Choose IPv4, IPv6 or VLSM mode. Results update automatically.
| # | Subnet name | Required hosts | Reserved |
|---|
Network range, capacity, binary view and allocation details.
| # | Name | Hosts | Reserve | CIDR | First host | Last host | Broadcast | Usable |
|---|
METHODOLOGY
The prefix length creates a contiguous subnet mask. Network and broadcast addresses are derived with bitwise AND and wildcard operations.
A /31 is treated as a two-address point-to-point subnet, while a /32 represents one host route.
Requirements are sorted from largest to smallest and aligned to the next valid network boundary before allocation.
IPv6 results use 128-bit integer arithmetic and show the network, last address, host bits and subnet count from the parent prefix.
FAQ
A /24 has 256 total addresses and normally 254 usable host addresses.
RFC 3021 permits both addresses on a point-to-point link, eliminating network and broadcast reservations.
It is the bitwise inverse of the subnet mask and is commonly used in ACLs and routing configuration.
Each row has an editable reserve field. Use it for gateways, redundancy addresses, infrastructure or growth.
Yes. The calculator uses BigInt arithmetic and displays the full decimal address count.
No. Consider failure domains, broadcast traffic, security zones, routing summarization and operational boundaries.
PROJECT RECORDS
ENGINEERING WORKFLOW
Plan addressing, VLAN capacity, packet size, uplinks, optics, access policy and DNS behavior as one LAN design sequence.