IP Calculator
Enter an IPv4 address and CIDR prefix to calculate subnet, network and host information.
What is an IP subnet calculator?
An IP calculator converts an IPv4 address and CIDR prefix into detailed subnet information. It calculates the network address, broadcast address, subnet mask, address count and usable host range for the selected network.
Subnet calculations are useful because IPv4 networks are defined by both an address and a prefix length. Changing the prefix can significantly change the size of the subnet even when the IP address itself remains the same.
How to use the IP Calculator
- Enter the IPv4 address you want to calculate.
- Enter or select the CIDR prefix for the subnet.
- Run the calculation and review the resulting network, mask and host information.
What the subnet calculation means
The CIDR prefix determines how many leading address bits form the network portion. A larger prefix creates a smaller subnet, while a smaller prefix creates a larger address range.
The network and broadcast values define the subnet boundaries for ordinary IPv4 networks. The usable host range identifies addresses normally available for devices. Special cases such as /31 point-to-point networks and /32 single-host networks follow different addressing rules.
Common uses for an IP calculator
- Plan IPv4 subnet sizes for network deployments.
- Verify an address and subnet mask before configuring a host.
- Calculate firewall and routing network ranges.
- Understand how CIDR prefixes affect available addresses.
- Troubleshoot subnetting mistakes and overlapping networks.