IP Subnet Calculator
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255.255.255.255 (/32)
255.255.255.254 (/31)
255.255.255.252 (/30)
255.255.255.248 (/29)
255.255.255.240 (/28)
255.255.255.224 (/27)
255.255.255.192 (/26)
255.255.255.128 (/25)
255.255.255.0 (/24)
255.255.254.0 (/23)
255.255.252.0 (/22)
255.255.248.0 (/21)
255.255.240.0 (/20)
255.255.224.0 (/19)
255.255.192.0 (/18)
255.255.128.0 (/17)
255.255.0.0 (/16)
255.254.0.0 (/15)
255.252.0.0 (/14)
255.248.0.0 (/13)
255.240.0.0 (/12)
255.224.0.0 (/11)
255.192.0.0 (/10)
255.128.0.0 (/9)
255.0.0.0 (/8)
Network Information
Network Address:
Usable Host Range:
Broadcast Address:
Total Number of Hosts:
Usable Number of Hosts:
Subnet Mask:
Wildcard Mask:
CIDR Notation:
Understanding IP Subnetting
Subnetting is the process of dividing a single physical network into multiple logical sub-networks (subnets). This technique is essential for efficient IP address management, reducing network congestion, and enhancing security. By breaking down a large network, IT professionals can group devices logically based on department, floor, or function.
How to Calculate Subnet Details
Calculating a subnet involves bitwise operations on the IP address and the subnet mask. The subnet mask determines which part of the IP address represents the network ID and which part represents the host ID.
- Network Address: This is the first address in the subnet. It is found by performing a bitwise AND operation between the IP address and the subnet mask.
- Broadcast Address: This is the last address in the subnet. It is used to send data to all hosts on that network.
- Usable Hosts: In most subnets, the first address (Network) and last address (Broadcast) cannot be assigned to devices, so the number of usable hosts is 2(32 – prefix) – 2.
Example Calculation:
If you have an IP of 192.168.1.10 with a /24 mask:
– Subnet Mask: 255.255.255.0
– Network Address: 192.168.1.0
– Broadcast Address: 192.168.1.255
– Usable Hosts: 192.168.1.1 to 192.168.1.254 (254 hosts total)
If you have an IP of 192.168.1.10 with a /24 mask:
– Subnet Mask: 255.255.255.0
– Network Address: 192.168.1.0
– Broadcast Address: 192.168.1.255
– Usable Hosts: 192.168.1.1 to 192.168.1.254 (254 hosts total)
Why Use a Subnet Calculator?
Manual subnetting requires converting decimal numbers to binary, performing bitwise math, and converting back to decimal. While critical for CCNA or Network+ exams, using a calculator in real-world scenarios prevents configuration errors that could lead to network downtime or IP address conflicts. It provides immediate visibility into CIDR notation, wildcard masks, and usable host ranges for complex networks like /27 or /22.