Internet Protocol version 4, often abbreviated IPv4, assigns unique 32-bit addresses to hosts. A subnet divides an address block into smaller networks. CIDR, short for Classless Inter-Domain Routing, expresses the subnet mask with a slash and number. Understanding these concepts prevents address waste and guides reliable network segmentation. Network engineers rely on precise calculations for security and scalability.

Use the IPv4 Subnet Split Calculator to divide an existing network into equal-sized child subnets quickly. The tool computes network, broadcast, and usable address ranges for every segment. It highlights totals, detects invalid entries, and helps you predict addressing capacity before implementation. Accurate previews reduce configuration errors and accelerate change approvals.

Apply the results when allocating VLANs, configuring firewall rules, or documenting hand-over diagrams. Managers gain clear figures for audits, while technicians copy formatted ranges directly into routers. Because everything runs locally, sensitive address plans stay private. Integrate the calculator into training sessions to illustrate how varying CIDR lengths influence available hosts.

No data is transmitted or stored server-side.

Technical Details:

The list outlines core capabilities you leverage within seconds.

• Supports IPv4 addresses from /1 to /32.
• Accepts custom base and target CIDR values.
• Generates network, broadcast and usable address fields.
• Enumerates all child subnets with pagination.
• Displays cumulative usable hosts and subnet count.
• Validates input and highlights format issues instantly.
• Works offline with zero external requests.
• Exports tables via standard copy shortcuts.

Calculations-and-Scoring:

The subsections clarify every computation step.

Formula Breakdown

Child Subnets = 2^{(CIDR_new − CIDR_base)}. Usable Hosts = 2^{(32 − CIDR)} − 2.

Worked Example

A /24 network split to /26 yields four subnets, each offering 62 usable addresses.

Interpretation

The calculation shows growth while preserving broadcast and network reservation rules.

Recommendations

Document subnet plans and avoid allocating all addresses; retain room for future growth.

Step-by-Step Guide:

Follow these steps for accurate results.

1. Enter the base IPv4 address.
2. Select the current CIDR mask.
3. Choose the target CIDR mask.
4. Tip Review highlighted errors before continuing.
5. Scroll to inspect the summary card.
6. Copy results or export the subnet table.

FAQ:

Find quick answers below.