CIDR Calculator
Description
CIDR Calculator computes subnet masks, network ranges, and host counts from CIDR notation, essential for network administration and planning.
Use Cases
Network planning: Calculate IP ranges for subnets
System administration: Determine host capacity
Cloud computing: Allocate VPC address spaces
Security: Define firewall rules by subnet
Education: Learn about IP addressing and subnetting
Instructions
Enter a CIDR notation (e.g., 192.168.1.0/24)
View the calculated network information
See the subnet mask and wildcard mask
Check the available host range
Review the broadcast address and network class
Notes
- CIDR notation uses / prefix length (0-32 for IPv4)
- Private IP ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
- The network and broadcast addresses are not usable for hosts
- IPv6 CIDR uses / prefix length (0-128)
FAQ
What is the difference between /24 and /25?
/24 gives 256 addresses (254 usable hosts), while /25 gives 128 addresses (126 usable hosts).
Can I use this for IPv6?
The calculator supports both IPv4 and IPv6 CIDR calculations.