Subnet Cheat Sheet

A handy sheet for cheating in IPv4 subnetting

Posted by Kai Pazdzewicz on 12 December 2019

Overview

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

Sub-class C blocks (e.g. /24)

/25 - 2 Subnets - 126 Hosts per Subnet

Network Usable Host IP Range Broadcast
.0 .1 - .126 .127
.128 .129 - .254 .255

/26 - 4 Subnets - 62 Hosts per Subnet

Network Usable Host IP Range Broadcast
.0 .1 - .62 .63
.64 .65 - .126 .127
.128 .129 - .190 .191
.192 .193 - .254 .255

/27 - 8 Subnets - 30 Hosts per Subnet

Network Usable Host 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 per Subnet

Network Usable Host 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 per Subnet

Network Usable Host 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

/30 - 64 Subnets - 2 Hosts per Subnet

Network Usable Host 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