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ToolIP Subnet Calculator

What is IP Subnet Calculator?

IP Subnet Calculator is a free online tool designed to calculate the network address, usable host IP range, broadcast address, and the subnet and wildcard masks. It can also help to estimate the subnet size by reporting the total number of addresses and the number of usable hosts.

What network formats are supported?

This tool can parse network ranges specified by two IP addresses separated by a dash (e.g. - and subnets in CIDR notation (e.g. and convert them back and forth.

Does it support IPv6 addresses?

Yes. And it was an interesting coding challenge, considering how big the numbers can be for IPv6 subnets, so they don't fit into 64-bit integers. (You can check out the IPv6 network operated by Hurricane Electric as an example.)

What is a subnet?

A subnet or subnetwork is a logical subdivision of an IP network. Each subnet contains a number of IP addresses based on its class or subnet mask. The IP addresses associated with the subnet would be considered the IP range for the subnet.

What is CIDR?

CIDR stands for Classless Inter-Domain Routing and is a system of addressing that is used to create unique identifiers for networks. CIDR notation is a shorthand representation of a range of IP addresses. It consists of an IP address followed by a slash and the bit-length of the subnet mask, for example,

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