CIDR / Prefix Length Calculator
Calculate subnet masks, network ranges, and usable hosts from CIDR notation
CIDR (Classless Inter-Domain Routing) notation is a compact representation of an IP address and its associated network mask.
The prefix length indicates the number of bits used for the network portion of the address (e.g., /24 = 255.255.255.0).
Input Parameters
CIDR / Prefix Length
/0
/8
/16
/24
/32
IP Address (Optional)
Add an IP to calculate network address and range
/8 (Class A)
/16 (Class B)
/24 (Class C)
/30 (Point-to-point)
Conversion Results
Subnet Mask
255.255.255.0
Binary Mask
11111111.11111111.11111111.00000000
Usable Hosts
254
Total Addresses
256
Network/Host Bit Visualization
Network Bits: 24
Host Bits: 8
Network Information
Network Address
192.168.1.0
First Usable Host
192.168.1.1
Last Usable Host
192.168.1.254
Broadcast Address
192.168.1.255
/32 (Single Host)
1 address
1 address
/30 (Point-to-Point)
2 usable hosts
2 usable hosts
/29 (Small Network)
6 usable hosts
6 usable hosts
/24 (Class C)
254 usable hosts
254 usable hosts
/16 (Class B)
65,534 usable hosts
65,534 usable hosts
CIDR Reference Table
| CIDR | Subnet Mask | Host Bits | Usable Hosts | Total Addresses |
|---|