The following table lists the variable length subnets from 1 to 32,
the CIDR [3] representation form (/xx) and the Decmial equivalents.
(M = Million, K=Thousand, A,B,C= traditional class values)
Mask value: # of
Hex CIDR Decimal addresses Classfull
80.00.00.00 /1 128.0.0.0 2048 M 128 A
C0.00.00.00 /2 192.0.0.0 1024 M 64 A
E0.00.00.00 /3 224.0.0.0 512 M 32 A
F0.00.00.00 /4 240.0.0.0 256 M 16 A
F8.00.00.00 /5 248.0.0.0 128 M 8 A
FC.00.00.00 /6 252.0.0.0 64 M 4 A
FE.00.00.00 /7 254.0.0.0 32 M 2 A
FF.00.00.00 /8 255.0.0.0 16 M 1 A
FF.80.00.00 /9 255.128.0.0 8 M 128 B
FF.C0.00.00 /10 255.192.0.0 4 M 64 B
FF.E0.00.00 /11 255.224.0.0 2 M 32 B
FF.F0.00.00 /12 255.240.0.0 1024 K 16 B
FF.F8.00.00 /13 255.248.0.0 512 K 8 B
FF.FC.00.00 /14 255.252.0.0 256 K 4 B
FF.FE.00.00 /15 255.254.0.0 128 K 2 B
FF.FF.00.00 /16 255.255.0.0 64 K 1 B
FF.FF.80.00 /17 255.255.128.0 32 K 128 C
FF.FF.C0.00 /18 255.255.192.0 16 K 64 C
FF.FF.E0.00 /19 255.255.224.0 8 K 32 C
FF.FF.F0.00 /20 255.255.240.0 4 K 16 C
FF.FF.F8.00 /21 255.255.248.0 2 K 8 C
FF.FF.FC.00 /22 255.255.252.0 1 K 4 C
FF.FF.FE.00 /23 255.255.254.0 512 2 C
FF.FF.FF.00 /24 255.255.255.0 256 1 C
FF.FF.FF.80 /25 255.255.255.128 128 1/2 C
FF.FF.FF.C0 /26 255.255.255.192 64 1/4 C
FF.FF.FF.E0 /27 255.255.255.224 32 1/8 C
FF.FF.FF.F0 /28 255.255.255.240 16 1/16 C
FF.FF.FF.F8 /29 255.255.255.248 8 1/32 C
FF.FF.FF.FC /30 255.255.255.252 4 1/64 C
FF.FF.FF.FE /31 255.255.255.254 2 1/128 C
FF.FF.FF.FF /32 255.255.255.255 This is a single host route
See also RFC 1878.
|
Addresses |
Hosts |
Netmask |
Amount of a Class C |
/30 |
4 |
2 |
255.255.255.252 |
1/64 |
/29 |
8 |
6 |
255.255.255.248 |
1/32 |
/28 |
16 |
14 |
255.255.255.240 |
1/16 |
/27 |
32 |
30 |
255.255.255.224 |
1/8 |
/26 |
64 |
62 |
255.255.255.192 |
1/4 |
/25 |
128 |
126 |
255.255.255.128 |
1/2 |
/24 |
256 |
254 |
255.255.255.0 |
1 |
/23 |
512 |
510 |
255.255.254.0 |
2 |
/22 |
1024 |
1022 |
255.255.252.0 |
4 |
/21 |
2048 |
2046 |
255.255.248.0 |
8 |
/20 |
4096 |
4094 |
255.255.240.0 |
16 |
/19 |
8192 |
8190 |
255.255.224.0 |
32 |
/18 |
16384 |
16382 |
255.255.192.0 |
64 |
/17 |
32768 |
32766 |
255.255.128.0 |
128 |
/16 |
65536 |
65534 |
255.255.0.0 |
256 |
Guide to sub-class C blocks
/25 — 2 Subnets — 126 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.126 |
.127 |
.128 |
.129-.254 |
.255 |
|
/30 — 64 Subnets — 2 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.2 |
.3 |
.4 |
.5-.6 |
.7 |
.8 |
.9-.10 |
.11 |
.12 |
.13-.14 |
.15 |
.16 |
.17-.18 |
.19 |
.20 |
.21-.22 |
.23 |
.24 |
.25-.26 |
.27 |
.28 |
.29-.30 |
.31 |
.32 |
.33-.34 |
.35 |
.36 |
.37-.38 |
.39 |
.40 |
.41-.42 |
.43 |
.44 |
.45-.46 |
.47 |
.48 |
.49-.50 |
.51 |
.52 |
.53-.54 |
.55 |
.56 |
.57-.58 |
.59 |
.60 |
.61-.62 |
.63 |
.64 |
.65-.66 |
.67 |
.68 |
.69-.70 |
.71 |
.72 |
.73-.74 |
.75 |
.76 |
.77-.78 |
.79 |
.80 |
.81-.82 |
.83 |
.84 |
.85-.86 |
.87 |
.88 |
.89-.90 |
.91 |
.92 |
.93-.94 |
.95 |
.96 |
.97-.98 |
.99 |
.100 |
.101-.102 |
.103 |
.104 |
.105-.106 |
.107 |
.108 |
.109-.110 |
.111 |
.112 |
.113-.114 |
.115 |
.116 |
.117-.118 |
.119 |
.120 |
.121-.122 |
.123 |
.124 |
.125-.126 |
.127 |
.128 |
.129-.130 |
.131 |
.132 |
.133-.134 |
.135 |
.136 |
.137-.138 |
.139 |
.140 |
.141-.142 |
.143 |
.144 |
.145-.146 |
.147 |
.148 |
.149-.150 |
.151 |
.152 |
.153-.154 |
.155 |
.156 |
.157-.158 |
.159 |
.160 |
.161-.162 |
.163 |
.164 |
.165-.166 |
.167 |
.168 |
.169-.170 |
.171 |
.172 |
.173-.174 |
.175 |
.176 |
.177-.178 |
.179 |
.180 |
.181-.182 |
.183 |
.184 |
.185-.186 |
.187 |
.188 |
.189-.190 |
.191 |
.192 |
.193-.194 |
.195 |
.196 |
.197-.198 |
.199 |
.200 |
.201-.202 |
.203 |
.204 |
.205-.206 |
.207 |
.208 |
.209-.210 |
.211 |
.212 |
.213-.214 |
.215 |
.216 |
.217-.218 |
.219 |
.220 |
.221-.222 |
.223 |
.224 |
.225-.226 |
.227 |
.228 |
.229-.230 |
.231 |
.232 |
.233-.234 |
.235 |
.236 |
.237-.238 |
.239 |
.240 |
.241-.242 |
.243 |
.244 |
.245-.246 |
.247 |
.248 |
.249-.250 |
.251 |
.252 |
.253-.254 |
.255 |
|
/26 — 4 Subnets — 62 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.62 |
.63 |
.64 |
.65-.126 |
.127 |
.128 |
.129-.190 |
.191 |
.192 |
.193-.254 |
.255 |
|
/27 — 8 Subnets — 30 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.30 |
.31 |
.32 |
.33-.62 |
.63 |
.64 |
.65-.94 |
.95 |
.96 |
.97-.126 |
.127 |
.128 |
.129-.158 |
.159 |
.160 |
.161-.190 |
.191 |
.192 |
.193-.222 |
.223 |
.224 |
.225-.254 |
.255 |
|
/28 — 16 Subnets — 14 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.14 |
.15 |
.16 |
.17-.30 |
.31 |
.32 |
.33-.46 |
.47 |
.48 |
.49-.62 |
.63 |
.64 |
.65-.78 |
.79 |
.80 |
.81-.94 |
.95 |
.96 |
.97-.110 |
.111 |
.112 |
.113-.126 |
.127 |
.128 |
.129-.142 |
.143 |
.144 |
.145-.158 |
.159 |
.160 |
.161-.174 |
.175 |
.176 |
.177-.190 |
.191 |
.192 |
.193-.206 |
.207 |
.208 |
.209-.222 |
.223 |
.224 |
.225-.238 |
.239 |
.240 |
.241-.254 |
.255 |
|
/29 — 32 Subnets — 6 Hosts/Subnet
Network # |
IP Range |
Broadcast |
.0 |
.1-.6 |
.7 |
.8 |
.9-.14 |
.15 |
.16 |
.17-.22 |
.23 |
.24 |
.25-.30 |
.31 |
.32 |
.33-.38 |
.39 |
.40 |
.41-.46 |
.47 |
.48 |
.49-.54 |
.55 |
.56 |
.57-.62 |
.63 |
.64 |
.65-.70 |
.71 |
.72 |
.73-.78 |
.79 |
.80 |
.81-.86 |
.87 |
.88 |
.89-.94 |
.95 |
.96 |
.97-.102 |
.103 |
.104 |
.105-.110 |
.111 |
.112 |
.113-.118 |
.119 |
.120 |
.121-.126 |
.127 |
.128 |
.129-.134 |
.135 |
.136 |
.137-.142 |
.143 |
.144 |
.145-.150 |
.151 |
.152 |
.153-.158 |
.159 |
.160 |
.161-.166 |
.167 |
.168 |
.169-.174 |
.175 |
.176 |
.177-.182 |
.183 |
.184 |
.185-.190 |
.191 |
.192 |
.193-.198 |
.199 |
.200 |
.201-.206 |
.207 |
.208 |
.209-.214 |
.215 |
.216 |
.217-.222 |
.223 |
.224 |
.225-.230 |
.231 |
.232 |
.233-.238 |
.239 |
.240 |
.241-.246 |
.247 |
.248 |
.249-.254 |
.255 |
|