Subnet Calculator

Enter IP/CIDR, get network address, broadcast, host range, and masks

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Built by WOWHOW Team · 14+ yrs engineering

Subnet Calculator is a free, browser-based tool that lets you enter ip/cidr, get network address, broadcast, host range, and masks — with zero signup, zero installation. Your data never leaves your browser. Part of 138+ free developer and business tools at wowhow.cloud, built and maintained by a team with 14+ years of hands-on development experience.

TOOLSubnet Calculator

IPv4 Address

CIDR Prefix /24

/24

Subnet Details

Network Address192.168.1.0

Broadcast Address192.168.1.255

First Usable Host192.168.1.1

Last Usable Host192.168.1.254

Subnet Mask255.255.255.0

Wildcard Mask0.0.0.255

CIDR Notation192.168.1.0/24

Total Hosts256

Usable Hosts254

Network ClassClass C

About Subnet Calculator

Subnet calculations are a daily task for network engineers, cloud architects, and DevOps engineers configuring VPCs, security groups, and firewall rules. Getting the network address, broadcast address, or host range wrong in a cloud security group can expose infrastructure or block valid traffic. This tool computes all subnet properties from a single IP/CIDR input with no room for arithmetic errors.

How It Works

The input IP is parsed into a 32-bit unsigned integer by splitting on dots and bit-shifting each octet into position. The subnet mask is derived from the CIDR prefix by setting the top N bits to 1 and the remaining bits to 0 using a left-shift and fill operation.

Network address = IP & mask (bitwise AND). Broadcast address = IP | ~mask (bitwise OR with the inverted mask). First usable host = network + 1. Last usable host = broadcast − 1. Total hosts = 2^(32−prefix). Usable hosts = total − 2. Binary representation converts each of the four octets to an 8-character zero-padded binary string separated by dots.

Who Is This For

A cloud engineer configuring an AWS VPC CIDR block verifies that 10.0.0.0/20 provides enough host addresses for 4,000 EC2 instances before committing to the design.

A network engineer writing Cisco ACL rules calculates the wildcard mask for a /26 subnet to correctly scope the permit statement.

A DevOps engineer double-checks that two proposed subnets (10.0.1.0/24 and 10.0.2.0/24) do not overlap before peering two VPCs.

How to Use

Enter an IPv4 address in dotted-decimal notation (e.g. 192.168.1.50)

Select or type the CIDR prefix length (e.g. /24)

View network address, broadcast, host range, and masks instantly

Toggle binary view to see the full 32-bit binary representation

Frequently Asked Questions

CIDR (Classless Inter-Domain Routing) uses a /prefix-length suffix to define subnet size. /24 means the first 24 bits are the network prefix, leaving 8 host bits — allowing 254 usable hosts.

254 usable hosts. The formula is 2^(32−prefix) − 2, subtracting the network address and broadcast address. A /24 gives 2^8 − 2 = 254.

The bitwise inverse of the subnet mask. Used in Cisco ACLs and OSPF configurations. For a /24 subnet mask of 255.255.255.0, the wildcard mask is 0.0.0.255.

This calculator covers IPv4 only. IPv6 subnetting uses 128-bit addresses and a different host-count scale — a dedicated IPv6 tool handles those calculations accurately.