# CIDR Calculator

Canonical: https://dev.eneawork.it/cidr
Language: en
Updated: 2026-11-02
Author: Enea Zani (https://eneawork.it)

Network, broadcast, host range and netmask for an IPv4 CIDR.

## What it does

A CIDR block is an IP address plus a prefix length. This calculator derives the network and broadcast addresses, the usable host range, netmask and wildcard mask. It supports IPv4 prefixes from /0 to /32, including the special /31 and /32 cases.

## How to use

1. Enter an IPv4 address with a prefix, such as 192.168.1.10/24.
2. Read the network and host range.
3. Copy any value you need.

## FAQ

### How are usable hosts calculated?

For /0 to /30 it is 2^(32-prefix) − 2. For /31 both addresses are shown as usable; /32 has one address.

### Does it support IPv6?

Not yet. This calculator is intentionally IPv4-only so the output stays unambiguous.

### What is the wildcard mask?

The bitwise inverse of the netmask. It is used by ACLs and some routing configuration.

## Related tools

- [Chmod Calculator](https://dev.eneawork.it/chmod)
- [URL Parser](https://dev.eneawork.it/url-parser)
- [HTTP Status Codes](https://dev.eneawork.it/http-status)

## Machine-readable

- Tool catalogue: https://dev.eneawork.it/tools.json
- Full AI context: https://dev.eneawork.it/llms-full.txt
- Privacy: https://dev.eneawork.it/privacy
- This page in HTML: https://dev.eneawork.it/cidr
- Italian version: https://dev.eneawork.it/it/cidr