Subnet CIDR Calculator
Network address, broadcast and usable host range from a CIDR block.
Enter your values
ⓘ Live results
Results
- Network address
- 192.168.1.0/24
- Broadcast address
- 192.168.1.255
- Subnet mask
- 255.255.255.0
- First usable host
- 192.168.1.1
- Last usable host
- 192.168.1.254
- Usable hosts
- 254
Quick answer
Number of usable hosts = 2^(32-prefix) - 2 for standard subnets.
hosts = 2^(32-prefix) - 2
How to use the Subnet CIDR Calculator
- 1Enter an IPv4 address inside the subnet.
- 2Enter the CIDR prefix length (e.g. /24 for a common 254-host subnet).
- 3Read the network address, broadcast address, usable host range and total host count.
Worked example
Using the values the calculator loads with:
Inputs
- IP address192.168.1.50
- CIDR prefix24 /bits
Results
- Network address192.168.1.0/24
- Broadcast address192.168.1.255
- Subnet mask255.255.255.0
- First usable host192.168.1.1
- Last usable host192.168.1.254
- Usable hosts254
Frequently asked questions
What does /24 mean?
It means the first 24 bits are the network portion, leaving 8 bits (256 addresses, 254 usable) for hosts.
Why subtract 2 hosts?
The first address is the network address and the last is the broadcast address; both are reserved.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.