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Netmask Calculator
// paste an ip and a mask — or just the /prefix. the switch stays out of it
automationhub — ~/tools/netmask
Netmask & Subnet Calculator
Paste an IPv4 address and a subnet mask — or just the /prefix, the mask fills itself in. Network, broadcast, usable hosts and the inverse mask update live. Drop a second ip in to check if it fits the same subnet.
output — live result
192.168.10.20/24
host #20 of 254 in this subnet
- network
- 192.168.10.0
- broadcast
- 192.168.10.255
- first usable
- 192.168.10.1
- last usable
- 192.168.10.254
- usable hosts
- 254
- inverse mask
- 0.0.0.255
32-bit view — network | host
peer check — other device
// add an ip above to check if it fits this subnet
// subnetting: where "it's only 254 hosts" became a lifestyle
// common prefixes — the ones you'll actually use
| prefix | mask | usable hosts | typical |
|---|---|---|---|
| /24 | 255.255.255.0 | 254 | office line |
| /25 | 255.255.255.128 | 126 | half of a /24 |
| /26 | 255.255.255.192 | 62 | small line |
| /27 | 255.255.255.224 | 30 | even smaller |
| /28 | 255.255.255.240 | 14 | camera closet |
| /29 | 255.255.255.248 | 6 | panel |
| /30 | 255.255.255.252 | 2 | point-to-point |