Subnet calculator & designer
Break down any IPv4 CIDR, then split it into subnets. Instant · in your browser
The gateway isn't fixed by the subnet — it's whichever address your router uses. By convention it's the first usable host (e.g. .1); some networks use the last usable instead.
Split into subnets
Divide this network into equal-size subnets by choosing a longer prefix.
Frequently asked questions
What's the gateway IP?
The subnet itself doesn't define a gateway — it's whichever address your router uses. By convention it's the first usable host (e.g. .1), though some networks use the last.
What does the subnet splitter do?
It divides a network into equal smaller subnets at a prefix you choose, listing each subnet's usable range and broadcast address.
Does it handle /31 and /32?
Yes. It correctly handles point-to-point (/31) and single-host (/32) cases.