IP Calculator
Calculate IPv4 subnets from CIDR, split networks and plan VLSM.
Subnet math is quick to get wrong when you do it by hand at the end of a long day. Enter an IPv4 address with a CIDR prefix or a subnet mask and the IP Calculator shows the network, broadcast, masks, host range and binary form, then helps you split the network or size subnets for a set of host counts. It is pure calculation in the app, so nothing you type leaves your machine.
CIDR or mask input
Type 192.168.1.100/24 or an address followed by a subnet mask such as 255.255.255.0. Results update as you type.
Full network details
See the network address, broadcast address, subnet mask, wildcard mask, host range, total and usable hosts, address class and whether the address is private.
Binary representation
View the address, mask, network and broadcast in dotted binary, which helps when checking where the network boundary falls.
Subnet planning
Split a network into 2 to 256 equal subnets and get each subnet's CIDR, network, broadcast, host range and usable hosts.
VLSM calculator
Enter host requirements such as 100,50,25,10 and get subnets allocated from largest to smallest inside your parent network.
Copy and quick picks
Copy any value or the whole result as JSON, and load common ranges such as the private blocks, localhost, link-local and multicast in one click.
Does the IP Calculator support IPv6?
No. It works with IPv4 addresses only, in CIDR notation or with a dotted subnet mask.
How are usable hosts calculated?
Usable hosts are the total addresses in the block minus two, one for the network address and one for the broadcast address. Keep this in mind for very small blocks such as /31 and /32.
Convert hex, decimal, octal and binary with a clickable bit grid.
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Open →No card, no account. Every tool included, bought once.