IP & CIDR

IP & CIDR is a free web & network tool that runs entirely in your browser — subnet math, ranges & masks. No upload, no account, no limits.

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How to use IP & CIDR

Open the IP & CIDR tool.
Paste or type your URL, header or IP address into the input field.
The output updates as you type — adjust the options if you need a different format.
Copy the result, or share the URL to hand the exact input to someone else.

About IP & CIDR

Do IPv4 subnet math from an address with CIDR notation. Enter something like 192.168.1.130/26 and get the network and broadcast addresses, netmask, wildcard mask, usable host range and the total and usable host counts.

What people use it for

Find the network, broadcast and host range for a subnet.
Convert a CIDR prefix into a netmask and host count.
Plan or verify IP address allocations.

Frequently asked questions

What does it calculate?

Network, netmask, wildcard, broadcast, first/last usable host, and total and usable address counts for an IPv4 CIDR.

IPv6?

This tool covers IPv4/CIDR subnetting.

Is it private?

Every calculation happens on this page, in your own browser. Your input is never sent to a server, never logged and never used for training — which also means the tool keeps working when you are offline.