CIDR Calculator
1. Enter CIDR Block
Load Sample
2. Calculated Details
IP Address–
Network Range–
Usable Host Range–
Broadcast Address–
Total Hosts–
Usable Hosts–
Subnet Mask–
Wildcard Mask–
How to Use the CIDR Calculator
- Input an IP address with a CIDR notation (e.g., 192.168.1.0/24).
- Click calculate.
- Review the generated IP ranges, masks, and host counts.
Formulas and Technical Logic
Classless Inter-Domain Routing (CIDR) replaces class-based IP routing. The suffix (e.g., /24) dictates the number of fixed network bits. The remaining bits (32 – suffix) dictate the number of host bits. Total IP addresses equal 2^(32 – suffix). Available host addresses equal 2^(32 – suffix) – 2.
Key Features
- Validates CIDR notation input.
- Calculates first and last usable IP addresses.
- Determines wildcard masks.
- Supports both IPv4 and IPv6 syntax parsing.
Reference Table: Wildcard Masks
| CIDR | Subnet Mask | Wildcard Mask |
|---|---|---|
| /22 | 255.255.252.0 | 0.0.3.255 |
| /23 | 255.255.254.0 | 0.0.1.255 |
| /24 | 255.255.255.0 | 0.0.0.255 |
| /25 | 255.255.255.128 | 0.0.0.127 |
| /26 | 255.255.255.192 | 0.0.0.63 |
| /27 | 255.255.255.224 | 0.0.0.31 |
| /28 | 255.255.255.240 | 0.0.0.15 |
Frequently Asked Questions
What is CIDR?
CIDR is a method for allocating IP addresses and routing IP packets efficiently without rigid classes.
What is a wildcard mask?
A wildcard mask is the inverse of a subnet mask. It is commonly used in access control lists (ACLs) and routing protocols.