SUBNET
CALCULATOR.
Calculate IPv4 and IPv6 networks, test whether an address belongs to a CIDR, and plan IPv4 subnets by host requirements.
IPv4 or IPv6 network
Does this IP belong to the CIDR?
Split an IPv4 network by hosts
Enter the IPv4 network above and the required host counts, separated by commas. Example: 50, 20, 10, 2. Allocation runs from largest to smallest.
Frequently asked questions
What is CIDR notation?
The address/prefix form, such as 192.168.10.0/24. The prefix says how many bits identify the network; the rest identify hosts.
How many hosts fit in a /24?
A /24 has 256 IPv4 addresses, 254 usable by hosts, because the first is the network address and the last is the broadcast.
What is VLSM?
Splitting a network into subnets of different sizes based on how many hosts each needs, without wasting addresses. The tool plans the split for IPv4.
Does the tool handle IPv6?
Yes. It shows the network, range and size of IPv6 prefixes and checks whether an address belongs to a block.
Are the calculations sent to a server?
No. Everything is calculated in your browser.