🧮 Subnet Calculator
Calculate network address, broadcast, host range, subnet mask and wildcard from any IPv4 address and CIDR prefix.
🔐 All calculations run locally in your browser. Nothing is sent to 0Appz or any third party.
📊 Subnet details
How to use this tool
Overview
Subnet Calculator - Free IPv4 CIDR & Network Calculator is a complete IPv4 subnetting tool for developers and network engineers. Enter any address like 192.168.1.10 with a CIDR prefix such as /24 and instantly get the network address, broadcast address, first and last usable host, usable host count, total addresses, subnet mask, wildcard mask, CIDR notation, IP class and scope (private, public, loopback, link-local, multicast). Special prefixes are handled correctly: /31 uses the RFC 3021 two-host rule and /32 returns a single address. Everything is calculated locally in your browser with pure JavaScript — no data is sent anywhere and the tool even works offline.Frequently asked questions
How do I use the subnet calculator? +
Enter an IPv4 address such as 192.168.1.10, choose a CIDR prefix like /24, and the Subnet Calculator - Free IPv4 CIDR & Network Calculator shows the network address, broadcast, host range, mask and wildcard instantly.
How many usable hosts does a subnet have? +
For prefixes /0 to /30 the usable hosts are 2^(32-prefix) minus 2 (network and broadcast). Special cases: /31 has 2 usable addresses (RFC 3021) and /32 has 1.
What is a wildcard mask used for? +
Wildcard masks are the inverse of a subnet mask and are used in Cisco ACLs and routing configurations to match address ranges.
Does this tool work offline? +
Yes. All calculations run in JavaScript in your browser — no data is sent anywhere and the tool works without a network connection.