IPv4 Subnet Calculator
Calculate network subnets
How to Use
1
Enter IP address
Type an IP address like 192.168.1.0.
2
Enter subnet mask
Enter CIDR notation (/24) or dotted mask.
3
View details
See network address, broadcast, host range, and count.
4
Calculate subnets
Optionally divide into smaller subnets.
Frequently Asked Questions
What is a subnet mask?
A 32-bit number that divides IP addresses into network and host portions. Common masks: /24 (255.255.255.0), /16 (255.255.0.0).
What is CIDR notation?
CIDR notation shows the network address and prefix length (e.g., 192.168.1.0/24). The number after / indicates network bits.
How many hosts can a /24 network have?
254 usable hosts. A /24 has 256 addresses, minus network address and broadcast address.