Dedicated IPv4 Network Tool

IPv4 Subnet Calculator

Analyze IPv4 network segments, calculate network IDs, broadcast domains, usable host spans, and verify RFC 1918 private scopes.

IPv4 Address

Dotted decimal IPv4 address

CIDR Mask

Prefix length

Network Class Preset

Jump to class defaults

Network Address

172.16.16.0

Broadcast Address

172.16.31.255

Usable Hosts

4,094

Subnet Mask

255.255.240.0

Usable IP Range:172.16.16.1 – 172.16.31.254

Wildcard Mask:0.0.15.255

Address Scope:Private (RFC 1918)

Bit-Level Binary Representation32-Bit IPv4

Visual breakdown of Network bits (prefix) vs. Host bits with exact CIDR boundary line.

Network Bits (24)

Host Bits (8)

Binary Netmask:11111111.11111111.11111111.00000000

Boundary Cut: Bit 24

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Frequently Asked Questions

Clear answers to common questions about subnetting, CIDR notation, and network design.

What are the historic IPv4 Network Classes (A, B, C)?

Historically under RFC 791, IPv4 networks were divided into three main unicast classes: Class A (1.0.0.0 to 126.255.255.255, default /8 prefix, 16.7M hosts), Class B (128.0.0.0 to 191.255.255.255, default /16 prefix, 65,534 hosts), and Class C (192.0.0.0 to 223.255.255.255, default /24 prefix, 254 hosts). Class D (224-239) is reserved for Multicast, and Class E (240-255) is experimental.

What is subnetting and why do we borrow host bits?

Subnetting is the process of borrowing bits from the host portion of an IP address to create multiple smaller logical networks (subnets). Each borrowed bit doubles the number of available subnets ($2^n$) while halving the number of hosts per subnet.