Subnet Mask Cheat Sheet

Subnet Mask Cheat Sheet

See also RFC 1878.

Hosts Netmask Amount of a Class C

/30 4 255.255.255.252 1/64

/29 8 255.255.255.248 1/32

/28 16 255.255.255.240 1/16

/27 32 255.255.255.224 1/8

/26 64 255.255.255.192 1/4

/25 128 255.255.255.128 1/2

/24 256 255.255.255.0 1

/23 512 255.255.254.0 2

/22 1024 255.255.252.0 4

/21 2048 255.255.248.0 8

/20 4096 255.255.240.0 16

/19 8192 255.255.224.0 32

/18 16384 255.255.192.0 64

/17 32768 255.255.128.0 128

/16 65536 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