CIDR Splitter
Split a network into equal subnets of a longer prefix, e.g. 10.0.0.0/16 into /24s. Up to 4,096 subnets per run.
About the CIDR Splitter
The CIDR Splitter divides a network into equal subnets of a longer prefix, for example 10.0.0.0/16 into sixteen or 256 smaller blocks, and lists each subnet with its usable host range. It is handy for planning VPC and subnet layouts, and works with IPv4 and IPv6.
How to use the CIDR Splitter
- Enter the network in CIDR notation, such as 10.0.0.0/16.
- Enter the new, longer prefix (for example 24).
- Click Split and copy or download the subnet list.
Frequently asked questions
How many subnets can it produce?
Up to 4,096 per run. Choose a shorter new prefix if you hit the limit.
What are the rules for the new prefix?
It must be longer than the current prefix and at most /32 for IPv4 or /128 for IPv6. If the input has host bits set, the tool uses the containing network and tells you.
Are my data stored when I use the CIDR Splitter?
The text you submit is processed in memory to produce the result and is not saved. Like any web server, Code Converter logs basic visit data (page, IP address and browser) but never the content you paste.
Is the CIDR Splitter free, and can I call it from a script?
It is free and needs no account or signup. The same tool is available as a REST endpoint at POST /api/cidr-splitter; see the API documentation for the fields and examples.