CIDR Calculator Online

Calculate IPv4 subnet details from CIDR notation. Use it for testing, debugging, prototyping, demos, and day-to-day developer workflows without installing anything.

What is this tool?

CIDR Calculator Online provides a focused browser utility for technical work. Calculate IPv4 subnet details from CIDR notation. Free online developer tool for fast browser-based work. Use it with reduced data, documentation and controlled checks.

How to use

Use a small safe input for the fields shown in the interface.
Review options such as format, quantity, encoding mode or output style when they are available.
Use the result in fixtures, docs, debugging notes or interface validation.

CIDR notation

Input IP192.168.1.0 /24

Network address192.168.1.0

Broadcast address192.168.1.255

First usable host192.168.1.1

Last usable host192.168.1.254

Usable hosts254

Total addresses256

Subnet mask255.255.255.0

Wildcard mask0.0.0.255

Practical example

A small input and output example is usually enough to confirm the workflow before using it in QA or documentation:

Input:
one
two
three

Output:
one, two, three

API

When you need to automate this workflow outside the interface, check the 4DevTool API documentation.

View API Docs

When to use

🧪

Testing and QA

Validate inputs, outputs, and UI rules in controlled scenarios.

💻

Development

Use fast browser output while debugging, prototyping, and integrating systems.

📋

Documentation

Create reproducible examples for tickets, specs, and technical reviews.

⚡

Local workflows

Most operations run in the browser with no sign-up and no installation.

Privacy

This tool is designed for developer productivity and testing workflows. Avoid entering sensitive information, credentials or real production data. Use outputs only in QA, demos and development.

Frequently asked questions

What is CIDR Calculator Online used for?

CIDR Calculator Online is used to speed up testing, debugging, prototypes, documentation, and common development tasks directly in the browser.

Does 4DevTool store the data?

The tools are designed for browser-based use whenever possible. Avoid pasting sensitive information or real production data.

Can I use this in QA automation?

Yes. Use the output in automated tests, fixtures, mocks, demos, and development environments.

Limitations / when not to use

Use this tool for development, QA, documentation, and demos. Do not paste production secrets, private credentials, customer data, or information that should stay inside your controlled environment.