berikut rumus untuk menghitung ip address dan subnetnya,
| Class | Leading bits | Start | End | Default Subnet Mask in dotted decimal | CIDR notation |
|---|---|---|---|---|---|
| A | 0 | 0.0.0.0 | 127.255.255.255 | 255.0.0.0 | /8 |
| B | 10 | 128.0.0.0 | 191.255.255.255 | 255.255.0.0 | /16 |
| C | 110 | 192.0.0.0 | 223.255.255.255 | 255.255.255.0 | /24 |
| D | 1110 | 224.0.0.0 | 239.255.255.255 | not defined | not defined |
| E | 1111 | 240.0.0.0 | 255.255.255.254 | not defined | not defined |
untuk network 127.0.0.0 / 8 adalah suatu jaringan Class A, itu ditujukan untuk loopback dan tidak dapat ditugaskan ke jaringan.
| CIDR | host bits | Netmask | Addresses in subnet | Classful name | Typical usage |
|---|---|---|---|---|---|
| /8 | 24 | 255.0.0.0 | 16777216 = 224 | Class A (see this list) | Largest block allocation made by IANA |
| /9 | 23 | 255.128.0.0 | 8388608 = 223 | ||
| /10 | 22 | 255.192.0.0 | 4194304 = 222 | ||
| /11 | 21 | 255.224.0.0 | 2097152 = 221 | ||
| /12 | 20 | 255.240.0.0 | 1048576 = 220 | ||
| /13 | 19 | 255.248.0.0 | 524288 = 219 | ||
| /14 | 18 | 255.252.0.0 | 262144 = 218 | ||
| /15 | 17 | 255.254.0.0 | 131072 = 217 | ||
| /16 | 16 | 255.255.0.0 | 65536 = 216 | Class B | |
| /17 | 15 | 255.255.128.0 | 32768 = 215 | ISP / large business | |
| /18 | 14 | 255.255.192.0 | 16384 = 214 | ISP / large business | |
| /19 | 13 | 255.255.224.0 | 8192 = 213 | ISP / large business | |
| /20 | 12 | 255.255.240.0 | 4096 = 212 | Small ISP / large business | |
| /21 | 11 | 255.255.248.0 | 2048 = 211 | Small ISP / large business | |
| /22 | 10 | 255.255.252.0 | 1024 = 210 | ||
| /23 | 9 | 255.255.254.0 | 512 = 29 | ||
| /24 | 8 | 255.255.255.0 | 256 = 28 | Class C | Large LAN |
| /25 | 7 | 255.255.255.128 | 128 = 27 | Large LAN | |
| /26 | 6 | 255.255.255.192 | 64 = 26 | Small LAN | |
| /27 | 5 | 255.255.255.224 | 32 = 25 | Small LAN | |
| /28 | 4 | 255.255.255.240 | 16 = 24 | Small LAN | |
| /29 | 3 | 255.255.255.248 | 8 = 23 | Smallest multi-host network | |
| /30 | 2 | 255.255.255.252 | 4 = 22 | “Glue network” (point to point links) | |
| /31 | 1 | 255.255.255.254 | 2 = 21 | Rarely used, point to point links (RFC 3021) | |
| /32 | 0 | 255.255.255.255 | 1 = 20 | Host route |