IP Subnet Calculator

Enter an address and a mask in either CIDR or dotted-decimal form. The calculation updates as you type and persists in the URL hash.

VLSM Calculator

Variable-length subnetting

Enter required host counts, one per line or comma-separated. Subnets are allocated from the current network in descending size order.

Base block: -
Req. Hosts Allocated Subnet Network Broadcast Usable Range Prefix
Subnet Table

Subnet Splitter

Choose a more specific prefix to generate every subnet within the current network boundary.

Current network
-
Generated subnets: 0
# Subnet Network Broadcast Range Hosts