Network Tools
Calculate network details from CIDR notation including mask, range, broadcast, and usable hosts.
Use this CIDR Calculator to analyze an IPv4 CIDR block and return important subnet details such as subnet mask, network address, broadcast address, first usable IP, last usable IP, and usable host count. It is useful for subnet planning, firewall rules, routing, network labs, and day-to-day infrastructure work.
Use this CIDR Calculator to analyze an IPv4 CIDR block and return important subnet details such as subnet mask, network address, broadcast address, first usable IP, last usable IP, and usable host count. It is useful for subnet planning, firewall rules, routing, network labs, and day-to-day infrastructure work.
Use cidr calculator when you need a fast browser-based result without extra setup. It works well for quick checks, one-off tasks, and routine formatting or calculation work.
Read step-by-step usage guidance, best practices, and common mistakes.
See common questions and answers about input, output, and tool usage.
Review practical input and output examples before running the tool.
Find similar and supporting tools for adjacent actions and follow-up tasks.
Input
192.168.1.0/24
Output
CIDR: 192.168.1.0/24 Subnet mask: 255.255.255.0 Network address: 192.168.1.0 Broadcast address: 192.168.1.255 First usable IP: 192.168.1.1 Last usable IP: 192.168.1.254 Total addresses: 256 Usable hosts: 254
A common LAN subnet used in offices, homes, and labs.
Input
10.0.0.4/30
Output
CIDR: 10.0.0.4/30 Subnet mask: 255.255.255.252 Network address: 10.0.0.4 Broadcast address: 10.0.0.7 First usable IP: 10.0.0.5 Last usable IP: 10.0.0.6 Total addresses: 4 Usable hosts: 2
Useful for point-to-point style network examples and small subnets.
Fix: Use full CIDR notation such as 192.168.1.0/24 instead of only an IP address.
Fix: For IPv4 CIDR, the prefix must be between /0 and /32.
Fix: Remember that many IPv4 subnets reserve the first and last address for network and broadcast.
A CIDR calculator converts CIDR notation into subnet details such as mask, network range, broadcast address, and usable hosts.
CIDR notation combines an IP address with a prefix length, such as 192.168.1.0/24.
CIDR Calculator starts from CIDR notation, while IP Range Calculator may focus more generally on subnet boundaries and host ranges.
This version is focused on IPv4 CIDR calculation.
In many IPv4 subnets, the first address is the network address and the last is the broadcast address, so they are not counted as normal usable hosts.