# IPv4 Range Expander

Expand an IP range into the CIDR blocks that cover it.

## URL

https://ilham.dev/tools/ipv4-range-expander/

## What It Does

Given a start and end address, list the CIDR blocks that cover the range exactly, so you can turn an arbitrary range into something a firewall or a route table will accept.

## Features

- Runs in the browser
- No login required

## Input

text input.

## Output

text output.

## Privacy

Processing happens locally in the browser.

No input data is uploaded to ilham.dev.

- Requires login: false
- Requires API key: false
- Stores user data: false


## Examples

- Why does it return several blocks instead of one?




## Questions

### Why does it return several blocks instead of one?

CIDR blocks are always powers of two, so an arbitrary range almost never lands on one. The tool finds the smallest set of blocks that covers it without going over.