Skip to main content
DevToolkit
30+ Free Online Tools

IPv4 Subnet & CIDR Calculator

Network & Web Tools100% Client-Side

Calculate IPv4 subnets, network address, broadcast address, usable host ranges, and wildcard masks from CIDR notation.

Quick Presets:
CIDR: 192.168.1.100/24
Class CPrivate (RFC 1918)
Network Address
192.168.1.0
Broadcast Address
192.168.1.255
Subnet Mask
255.255.255.0
Usable Host Range
192.168.1.1 — 192.168.1.254
Usable Hosts Count
254 hosts
Wildcard Mask
0.0.0.255
Binary Subnet Mask
11111111.11111111.11111111.00000000
SponsorNon-intrusive

What is IPv4 Subnet & CIDR Calculator?

A high-precision IPv4 Subnet and CIDR calculator that computes network addresses, broadcast addresses, usable host ranges, netmasks, and RFC 1918 private/public classifications.

How to Use Online

  1. 1
    Enter IPv4 AddressInput an IP address (e.g. 192.168.1.1, 10.0.0.1) into the IP address field.
  2. 2
    Select Subnet Mask / CIDRChoose prefix notation (/24, /16, /28) or standard subnet mask (255.255.255.0).
  3. 3
    Inspect Network BoundariesReview Network Address, Broadcast Address, Subnet Class, and Wildcard Mask.
  4. 4
    Verify Usable Host RangeView total usable hosts and exact first and last usable host IP addresses.

Key Features

  • Calculates Network, Broadcast, First Usable, and Last Usable IP addresses
  • Displays Total Hosts and Usable Hosts count for any prefix /0 to /32
  • Provides Subnet Mask, Wildcard Mask, and Binary Mask notation
  • Identifies IP Classes (A, B, C, D, E) and RFC 1918 Private vs Public types

Common Use Cases

  • Planning AWS VPC / Cloudflare / Azure subnet network topology
  • Configuring router and switch IP interfaces
  • Troubleshooting network routing and overlapping IP ranges

Frequently Asked Questions

CIDR (Classless Inter-Domain Routing) notation specifies an IP address followed by a slash and the number of bits in the network prefix (e.g., 192.168.1.0/24).