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Subnet calculator

Find the network and broadcast address, usable host range and masks of any IPv4 or IPv6 network, then split it into smaller subnets. Everything runs in your browser.

For example 192.168.10.0/26, 10.0.0.5 255.255.255.0 or 2001:db8::/48.

EXAMPLES

Binary view

Network bits are bold; the bar marks where the host part begins.

Split into subnets

Nothing you enter leaves your browser. In IPv4 the first address of a network names the network and the last is its broadcast address, so a network has two fewer usable hosts than addresses. The exceptions are a /31, which RFC 3021 lets a point-to-point link use for both ends, and a /32, a single host. IPv6 has no broadcast address, and a LAN should be a /64 so devices can configure themselves (SLAAC). Address classes A to E are shown for reference only; networks have been classless (CIDR) since 1993.