Subnet Calculator
What a CIDR block contains, including the two cases most calculators get wrong.
192.168.1.0/24
| Family | IPv4 |
|---|---|
| Network address | 192.168.1.0 |
| Netmask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
| Last address | 192.168.1.255 |
| Broadcast | 192.168.1.255 |
| First host | 192.168.1.1 |
| Last host | 192.168.1.254 |
| Addresses in the block | 256 |
| Usable by a host | 254 |
Worked out here, not fetched. Nothing is sent anywhere, nothing is stored, and the answer for a given block is the same today as it will be in ten years.
What it cannot tell you: whether this range is actually routed, who holds it, or whether anything is answering on it. It solves the maths of the notation you typed.