IPv4 addressing uses 32 bits to identify hosts and networks. Subnetting allocates address space efficiently by applying variable masks. Classless Inter-Domain Routing, abbreviated CIDR, replaces rigid classes with a slash notation. Mastering these fundamentals lets you predict host capacity and minimise overlap. Accurate calculations underpin reliable routing and security policies.

The IP Subnet Calculator provides real-time network, broadcast, and usable host information for any IPv4 and CIDR pair. Enter an address, pick a mask, and review binary representations alongside decimal values. The interface updates instantly, records no data, and exposes shortcut links for further analysis. Built-in validation prevents malformed inputs and pinpoints subnet class and type.

Apply the results when designing LAN segments, configuring access control lists, or documenting change requests. Copy binary masks into training slides, audit private-range usage, and share quick links with colleagues. Because processing happens entirely in your browser, sensitive network plans remain private. Quick recalculations accelerate troubleshooting during live maintenance windows.

No data is transmitted or stored server-side.

Technical Details:

The list outlines essential capabilities for dependable subnet planning.

• Accepts any IPv4 address with CIDR /1–/32.
• Displays network, broadcast and host boundaries.
• Shows total and usable host counts.
• Provides binary views for address, subnet and mask.
• Determines IP class and private or public type.
• Validates input live and explains errors.
• Offers copy-ready outputs for documentation.
• Processes data offline for privacy.

Calculations-and-Scoring:

The segments below demystify each formula.

Formula Breakdown

Usable Hosts = 2^{(32 − CIDR)} − 2. Netmask = −1 « (32 − CIDR).

Worked Example

A /24 mask yields 254 usable addresses within 192.168.0.0/24.

Interpretation

The host count guides capacity planning and informs IP request approvals.

Recommendations

Allocate small ranges to reduce broadcast traffic; monitor utilisation overtime.

Step-by-Step Guide:

Complete the steps to retrieve your subnet details.

1. Type an IPv4 address in the input field.
2. Choose the desired CIDR from the list.
3. Tip Use arrow keys for quick mask changes.
4. Observe live updates in the results card.
5. Copy any field by selecting the text.
6. Adjust masks until the host count suits your design.

FAQ:

Look up frequent questions here.