SUBNET ALLOCATION TOOL

Enter a parent CIDR block and the subnets you need. Subnetsplit packs them, checks every allocation for overlap, and shows the result.

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Network Plan

The network block you want to divide (e.g. 10.0.0.0/16, 192.168.1.0/24)
One per line. Use prefix length (/24) or host count (254 hosts or just 254). Bare numbers up to 32 are treated as prefix lengths.

Allocation Plan

CIDR Network Broadcast Mask Usable First Usable Last Usable Address Range
Enter a parent CIDR and subnet requirements, then click Calculate.