Calculate IP Subnet
Instant Calculations
Get detailed subnet information including IP ranges, masks, and CIDR notation
Network Planning
Plan your network infrastructure and IP allocation efficiently
Binary Insight
View binary representations to understand network addressing at a deeper level
Common Questions
What is a subnet calculator?
A subnet calculator is a tool that helps you determine important network parameters when dividing a large network into smaller, more manageable segments (subnets). It calculates values like network address, broadcast address, number of hosts, and more based on an IP address and subnet mask.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation is a compact method for specifying IP addresses and their routing prefix. It appears as a suffix with a forward slash, like 192.168.1.0/24, where 24 is the number of bits in the routing prefix. This replaces the older method of using subnet masks like 255.255.255.0.
How do I use the subnet calculator?
Simply enter an IPv4 address (like 192.168.1.1) and a CIDR prefix (like 24, representing a /24 network). Then click 'Calculate' to get comprehensive information about your subnet, including network address, broadcast address, usable IP range, and more.
What's the difference between network address and broadcast address?
The network address is the first address in a subnet and identifies the network itself. It can't be assigned to a device. The broadcast address is the last address in a subnet and is used to send data to all devices on that subnet simultaneously. Neither can be assigned to individual devices.
Why do the 'Number of Usable Hosts' calculation exclude two addresses?
In typical subnets, two addresses are reserved and cannot be assigned to devices: the network address (first address) and the broadcast address (last address). That's why we subtract 2 from the total number of addresses to get the number of usable hosts. Special cases exist for /31 and /32 networks.
What is a wildcard mask?
A wildcard mask is essentially the inverse of a subnet mask. While a subnet mask uses 1s to indicate network bits and 0s for host bits, a wildcard mask does the opposite. It's commonly used in access control lists (ACLs) on routers and firewalls to specify which IP addresses should match a rule.