CIDR Subnet Splitter

Split a network into equal subnets

This tool divides a CIDR block into equal smaller subnets of a prefix length you choose and lists every resulting subnet with its network and broadcast addresses. Splitting a /24 into /26 subnets, for example, produces four subnets of sixty-two usable hosts each. The number of subnets created is two raised to the difference between the new and original prefix lengths, and each subnet is a contiguous, correctly aligned block.

The table makes it easy to assign subnets to departments, floors or services, since you can see the exact address boundaries of each one.

Why split networks

Dividing a larger allocation into equal subnets is a core network-design task. It isolates broadcast domains, improves security by separating groups of devices, and keeps address usage organised. Equal splitting is the simplest scheme and is ideal when every subnet needs roughly the same number of hosts; variable-length subnetting suits cases where sizes differ widely.

The results align exactly to subnet boundaries, matching how routers and the subnets function in networking libraries behave. To keep the output manageable the tool caps very large splits and shows the first part of enormous lists. All calculation happens locally in your browser.

Related tools

• Port Scanner — Check which common ports respond on a host and understand what each exposed service means. Scan only systems you are authorised to test.
• DNS Misconfiguration — Analyze DNS records (TXT, SPF) for security gaps.
• TLS Compat Tester — Check client-server compatibility for TLS versions.
• Firewall Rule Risk — Evaluate firewall rules for over-permissive exposure.