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littlekit.app

CIDR splitter

Split an IPv4 network into equal subnets and inspect each address range.

Subnet plan4 equal subnets
Parent network192.168.1.0/24
Addresses per subnet64
26 network bits6 host bits
192.168.1.0/26192.168.1.0 → 192.168.1.6364 addresses · /26

Select a subnet to inspect its boundaries. The saved file contains the entire plan.

A longer prefix creates smaller subnets. Limit: 1,024 subnets.
Processed on your device

How it works & useful details

How it works & limits

Split one IPv4 CIDR into equal-sized subnets. The new prefix must be at least as long as the original. Host bits in the input are cleared; the normalized parent is shown. The output covers the parent exactly.

At most 1,024 subnets can be created. /31 and /32 blocks are supported. Counts shown here include all addresses in each block; use the subnet calculator for conventional host counts. Saved text contains every resulting CIDR, one per line.

Your working space

Explore the live view, then save copyable text and a downloadable file. Everything is calculated locally. Inputs are not stored; refreshing clears them.

These tools inspect address notation and ranges. They do not contact addresses, check availability or establish connectivity.

About this tool

CIDR splitter divides an IPv4 network into equal subnets at the new prefix length you choose, listing each resulting range and its address counts. It is the standard step when allocating blocks to departments or environments.

The split is exact: every address of the parent network appears in exactly one child subnet. Calculation is local and no network is contacted.

How to use it

  1. Enter the parent network in CIDR notation.
  2. Choose the prefix length of the subnets you want.
  3. Run the split and review each resulting range.
  4. Copy the subnet list into your allocation plan.

Worked example

Splitting 192.168.1.0/24 into /26 subnets gives four blocks of 64 addresses:

192.168.1.0/26     192.168.1.0   – 192.168.1.63
192.168.1.64/26    192.168.1.64  – 192.168.1.127
192.168.1.128/26   192.168.1.128 – 192.168.1.191
192.168.1.192/26   192.168.1.192 – 192.168.1.255

Each extra prefix bit doubles the number of subnets and halves their size. Going from /24 to /26 adds two bits, so there are 2² = 4 subnets.

Planning a network layout

Splitting is the first step of most network plans: one subnet per VLAN, office floor, cloud availability zone, or environment. Leave room to grow. It is easier to hand out two of four /26 blocks and keep two in reserve than to renumber later.

The counts shown include every address in each block. In a conventional LAN, each subnet loses two addresses to the network and broadcast addresses, so a /26 has 62 usable hosts. Cloud providers often reserve more. AWS reserves five addresses per subnet, for example. Check the subnet calculator or your provider's documentation for usable counts.

Frequently asked questions

What prefix length should I choose?

Each added bit doubles the number of subnets and halves their size. Pick the smallest block that still holds the hosts you need, remembering the network and broadcast addresses.

Can I split an IPv6 network?

This tool targets IPv4; IPv6 subnetting works on the same bit logic but needs a 128-bit view.

What is the limit?

At most 1,024 subnets per split, and the new prefix must be at least as long as the original. Splitting a /16 into /26 blocks (1,024 subnets) is the largest split of that kind.

Can I split into subnets of different sizes?

This tool creates equal-sized subnets. For a mixed layout, split once, then split one of the resulting blocks again. For example, split a /24 into /25s, then split the second /25 into /27s.