CIDR & Subnet Calculator
Network, broadcast, host range, mask and binary view for any IPv4 CIDR.
Enter an IPv4 CIDR (10.0.0.0/16) to see the network address, broadcast, first/last usable host, netmask, wildcard mask and host count.
Split into smaller subnets
Runs entirely in your browser — nothing you enter is sent to a server.
Need this for real, on your stack?
These free tools are a taste of how we think. We’re a senior software team across Romania & Pakistan that ships deep technical work — platforms, infra, data and the gnarly bits in between.
Talk to our engineers →Splitter
The splitter divides your block into equal-size subnets at a new prefix length — handy for AZ-by-AZ VPC layout.
Reserved space
RFC 1918 (10/8, 172.16/12, 192.168/16) and the loopback/multicast ranges are flagged when you wander into them.
Built by WeWorkWorldwide — a senior software team in Romania & Pakistan that ships deep technical work. Need this turned into something production-grade for your stack? Talk to our engineers →