Subnet Calculator | CIDR, Mask and Host Range
Calculate IPv4 subnet mask, CIDR range, network address, broadcast address, total hosts, and usable host count.
What the Subnet Calculator Calculates
The subnet calculator takes an IPv4 address and CIDR prefix, then returns subnet mask, network address, broadcast address, address range, total hosts, and usable hosts.
CIDR Inputs to Check
Enter a valid IPv4 address with prefix length, such as 192.168.1.10/24. Small prefix changes can greatly change the host range and usable address count.
Where Subnet Calculations Help
Use subnet calculations for router setup, firewall rules, DHCP planning, cloud networks, VPN ranges, lab environments, and documentation.
About This Tool
Subnet Calculator computes the network address, broadcast address, host range, and number of usable hosts for any IPv4 subnet in CIDR notation. It is an essential tool for network planning and IP address management.
When to Use It
Use this when designing a network to determine how many hosts a subnet supports, when configuring firewall rules that require knowing the broadcast address, or when learning subnetting for a networking exam.
How to Use
- Enter the IP address and subnet mask in CIDR notation such as 192.168.1.0/24.
- Click Calculate to compute the subnet details.
- Review the network address, broadcast address, and usable host range.
- Use the split function to divide a subnet into smaller subnets.
Frequently Asked Questions
What does /24 mean in CIDR notation?
/24 means the first 24 bits of the address are the network portion and the remaining 8 bits are for hosts, giving 256 addresses and 254 usable hosts.
What is the difference between the network address and the broadcast address?
The network address is the first address in a subnet and cannot be assigned to a host. The broadcast address is the last address and is used to reach all hosts simultaneously.
How many hosts does a /30 subnet support?
A /30 subnet has 4 addresses: one network address, one broadcast address, and 2 usable host addresses, commonly used for point-to-point links.