IP / CIDR Calculator
Calculate subnets, host ranges, and masks for IPv4 CIDR notation.
Quick Presets
Network Address
192.168.1.0
Broadcast Address
192.168.1.255
Subnet Mask
255.255.255.0
Wildcard Mask
0.0.0.255
First Usable Host
192.168.1.1
Last Usable Host
192.168.1.254
Total Addresses
256
Usable Hosts
254
CIDR Notation
192.168.1.0/24
IP Class
Class C
Address Type
Private (RFC 1918)
Host Range
192.168.1.1 – 192.168.1.254
Binary Breakdown
IP Address
11000000101010000000000100000000
192.168.1.0Subnet Mask
11111111111111111111111100000000
255.255.255.0Network
11000000101010000000000100000000
192.168.1.0CIDR /24
NNNNNNNNNNNNNNNNNNNNNNNNHHHHHHHH N=network H=host
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How to Calculate IPv4 Subnets and CIDR Ranges
This IP / CIDR calculator takes an IPv4 address and prefix length and shows the network, broadcast, host range, mask, and a binary breakdown. Useful for VPC planning, firewall rules, and reading AWS security groups.
All math is client-side. It does not look up WHOIS or DNS — for name resolution use the DNS lookup tool. IPv6 is out of scope for this calculator.
Tips
/24is 256 addresses (254 usable hosts)./32is a single host.- The first and last addresses in a subnet are network and broadcast on classic Ethernet — cloud VPCs sometimes treat them differently.
- Paste CIDR like
10.0.0.0/16rather than a dotted mask if you already have prefix length.