IPv4 quarters
8.8.8.0/24 into /26
Produces four child networks, each containing 64 IPv4 addresses.
Split /24 into /26
Network tool
Subnet splitter
Split an IPv4 or IPv6 CIDR network into smaller child networks. Output is limited to the first 256 child networks.
Reference
Output fields
- Parent network
- The original CIDR block being split into smaller child networks.
- Child prefix
- The longer prefix length used for each smaller subnet.
- Child networks
- The ordered subnet list, starting from the first address in the parent block.
- Output cap
- Large splits are limited to the first 256 child networks to keep the page fast.
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Overview
What this tool does
Subnet splitter divides one CIDR network into smaller child networks with a longer prefix length.
Use it when you need to allocate a larger network into smaller ranges for teams, environments, routers, firewall rules, or documentation. Output is capped at 256 child networks so very large splits stay fast.
Examples
Example splits
IPv6 child prefixes
2001:db8::/32 into /36
Shows the first child networks for a larger IPv6 documentation prefix.
Split IPv6 example
Results
How to read results
The parent prefix is the original network size. The child prefix must be larger, which creates smaller networks. The child network list is ordered from the first address in the parent block upward.
Boundaries
Limits
Very large splits are capped at 256 displayed child networks to keep the page responsive. If the result is capped, use a narrower parent network or a less-specific child prefix for a smaller output.
IP and CIDR libraries
Build the same kind of checks into your code using these documented libraries.
Python: ipaddress
Standard-library IPv4 and IPv6 parsing, networks and membership checks.
Go: net/netip
Standard-library address and prefix types with Contains and Overlaps methods.
JavaScript: ipaddr.js
A third-party library for IPv4/IPv6 parsing and CIDR matching.
Next steps
Related guides and tools
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