IP Subnet Calculator & Slicer
Enter an IPv4 network in CIDR form. See how many smaller subnets fit inside it, list them, or slice it up by hand.
Network details
Click any row to list every subnet of that size.
| Prefix | Subnets | Subnet mask | Addresses each | Usable hosts each | Block size |
|---|
| # | Subnet | First usable | Last usable | Broadcast | Usable |
|---|
Divide any block in half, again and again, to build a mixed plan (e.g. one /17, two /18s, four /20s…). Join puts two halves back together.
| Subnet | Mask | Range | Usable | Actions |
|---|