Subnet Mask Cheat Sheet

If you are a network admin like us, this is a little sheet that you will continually need access to. We hope you find it as helpful as we do.

  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

/26 -- 4 Subnets -- 62 Hosts / Subnet

Network # IP Range Broadcast
.0 .1 - .62 .63
.64 .65 - .126 .127
.128 .128 - .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
.128 .129 - .158 .159
.160 .161 - .190 .191
.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-.14 .15
.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/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
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