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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network3.232.8.0/24
Usable hosts254
Subnet mask255.255.255.0
Addresses256
Network address
3.232.8.0
Broadcast address
3.232.8.255
First usable
3.232.8.1
Last usable
3.232.8.254
Usable hosts
254 (256 less the network and broadcast addresses)
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255 (Cisco ACLs, OSPF)
Prefix length
/24
Type
Public public
Old class
A (default /8)
As numbers
Hex 03E80800 · Integer 65538048 to 65538303
Reverse DNS zone
8.232.3.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000011.11101000.00001000..000000003.232.8.0
Subnet mask11111111.11111111.11111111..00000000255.255.255.0
Network00000011.11101000.00001000..000000003.232.8.0
Broadcast00000011.11101000.00001000..111111113.232.8.255
Split into smaller subnets/32
/25 (2)/26 (4)/27 (8)/28 (16)/29 (32)/30 (64)/31 (128)/32 (256)

3.232.8.0/24 makes 256 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
13.232.8.0/323.232.8.0 to 3.232.8.0—1
23.232.8.1/323.232.8.1 to 3.232.8.1—1
33.232.8.2/323.232.8.2 to 3.232.8.2—1
43.232.8.3/323.232.8.3 to 3.232.8.3—1
53.232.8.4/323.232.8.4 to 3.232.8.4—1
63.232.8.5/323.232.8.5 to 3.232.8.5—1
73.232.8.6/323.232.8.6 to 3.232.8.6—1
83.232.8.7/323.232.8.7 to 3.232.8.7—1
93.232.8.8/323.232.8.8 to 3.232.8.8—1
103.232.8.9/323.232.8.9 to 3.232.8.9—1
113.232.8.10/323.232.8.10 to 3.232.8.10—1
123.232.8.11/323.232.8.11 to 3.232.8.11—1
133.232.8.12/323.232.8.12 to 3.232.8.12—1
143.232.8.13/323.232.8.13 to 3.232.8.13—1
153.232.8.14/323.232.8.14 to 3.232.8.14—1
163.232.8.15/323.232.8.15 to 3.232.8.15—1
173.232.8.16/323.232.8.16 to 3.232.8.16—1
183.232.8.17/323.232.8.17 to 3.232.8.17—1
193.232.8.18/323.232.8.18 to 3.232.8.18—1
203.232.8.19/323.232.8.19 to 3.232.8.19—1
213.232.8.20/323.232.8.20 to 3.232.8.20—1
223.232.8.21/323.232.8.21 to 3.232.8.21—1
233.232.8.22/323.232.8.22 to 3.232.8.22—1
243.232.8.23/323.232.8.23 to 3.232.8.23—1
253.232.8.24/323.232.8.24 to 3.232.8.24—1
263.232.8.25/323.232.8.25 to 3.232.8.25—1
273.232.8.26/323.232.8.26 to 3.232.8.26—1
283.232.8.27/323.232.8.27 to 3.232.8.27—1
293.232.8.28/323.232.8.28 to 3.232.8.28—1
303.232.8.29/323.232.8.29 to 3.232.8.29—1
313.232.8.30/323.232.8.30 to 3.232.8.30—1
323.232.8.31/323.232.8.31 to 3.232.8.31—1
333.232.8.32/323.232.8.32 to 3.232.8.32—1
343.232.8.33/323.232.8.33 to 3.232.8.33—1
353.232.8.34/323.232.8.34 to 3.232.8.34—1
363.232.8.35/323.232.8.35 to 3.232.8.35—1
373.232.8.36/323.232.8.36 to 3.232.8.36—1
383.232.8.37/323.232.8.37 to 3.232.8.37—1
393.232.8.38/323.232.8.38 to 3.232.8.38—1
403.232.8.39/323.232.8.39 to 3.232.8.39—1
413.232.8.40/323.232.8.40 to 3.232.8.40—1
423.232.8.41/323.232.8.41 to 3.232.8.41—1
433.232.8.42/323.232.8.42 to 3.232.8.42—1
443.232.8.43/323.232.8.43 to 3.232.8.43—1
453.232.8.44/323.232.8.44 to 3.232.8.44—1
463.232.8.45/323.232.8.45 to 3.232.8.45—1
473.232.8.46/323.232.8.46 to 3.232.8.46—1
483.232.8.47/323.232.8.47 to 3.232.8.47—1
493.232.8.48/323.232.8.48 to 3.232.8.48—1
503.232.8.49/323.232.8.49 to 3.232.8.49—1
513.232.8.50/323.232.8.50 to 3.232.8.50—1
523.232.8.51/323.232.8.51 to 3.232.8.51—1
533.232.8.52/323.232.8.52 to 3.232.8.52—1
543.232.8.53/323.232.8.53 to 3.232.8.53—1
553.232.8.54/323.232.8.54 to 3.232.8.54—1
563.232.8.55/323.232.8.55 to 3.232.8.55—1
573.232.8.56/323.232.8.56 to 3.232.8.56—1
583.232.8.57/323.232.8.57 to 3.232.8.57—1
593.232.8.58/323.232.8.58 to 3.232.8.58—1
603.232.8.59/323.232.8.59 to 3.232.8.59—1
613.232.8.60/323.232.8.60 to 3.232.8.60—1
623.232.8.61/323.232.8.61 to 3.232.8.61—1
633.232.8.62/323.232.8.62 to 3.232.8.62—1
643.232.8.63/323.232.8.63 to 3.232.8.63—1
653.232.8.64/323.232.8.64 to 3.232.8.64—1
663.232.8.65/323.232.8.65 to 3.232.8.65—1
673.232.8.66/323.232.8.66 to 3.232.8.66—1
683.232.8.67/323.232.8.67 to 3.232.8.67—1
693.232.8.68/323.232.8.68 to 3.232.8.68—1
703.232.8.69/323.232.8.69 to 3.232.8.69—1
713.232.8.70/323.232.8.70 to 3.232.8.70—1
723.232.8.71/323.232.8.71 to 3.232.8.71—1
733.232.8.72/323.232.8.72 to 3.232.8.72—1
743.232.8.73/323.232.8.73 to 3.232.8.73—1
753.232.8.74/323.232.8.74 to 3.232.8.74—1
763.232.8.75/323.232.8.75 to 3.232.8.75—1
773.232.8.76/323.232.8.76 to 3.232.8.76—1
783.232.8.77/323.232.8.77 to 3.232.8.77—1
793.232.8.78/323.232.8.78 to 3.232.8.78—1
803.232.8.79/323.232.8.79 to 3.232.8.79—1
813.232.8.80/323.232.8.80 to 3.232.8.80—1
823.232.8.81/323.232.8.81 to 3.232.8.81—1
833.232.8.82/323.232.8.82 to 3.232.8.82—1
843.232.8.83/323.232.8.83 to 3.232.8.83—1
853.232.8.84/323.232.8.84 to 3.232.8.84—1
863.232.8.85/323.232.8.85 to 3.232.8.85—1
873.232.8.86/323.232.8.86 to 3.232.8.86—1
883.232.8.87/323.232.8.87 to 3.232.8.87—1
893.232.8.88/323.232.8.88 to 3.232.8.88—1
903.232.8.89/323.232.8.89 to 3.232.8.89—1
913.232.8.90/323.232.8.90 to 3.232.8.90—1
923.232.8.91/323.232.8.91 to 3.232.8.91—1
933.232.8.92/323.232.8.92 to 3.232.8.92—1
943.232.8.93/323.232.8.93 to 3.232.8.93—1
953.232.8.94/323.232.8.94 to 3.232.8.94—1
963.232.8.95/323.232.8.95 to 3.232.8.95—1
973.232.8.96/323.232.8.96 to 3.232.8.96—1
983.232.8.97/323.232.8.97 to 3.232.8.97—1
993.232.8.98/323.232.8.98 to 3.232.8.98—1
1003.232.8.99/323.232.8.99 to 3.232.8.99—1
1013.232.8.100/323.232.8.100 to 3.232.8.100—1
1023.232.8.101/323.232.8.101 to 3.232.8.101—1
1033.232.8.102/323.232.8.102 to 3.232.8.102—1
1043.232.8.103/323.232.8.103 to 3.232.8.103—1
1053.232.8.104/323.232.8.104 to 3.232.8.104—1
1063.232.8.105/323.232.8.105 to 3.232.8.105—1
1073.232.8.106/323.232.8.106 to 3.232.8.106—1
1083.232.8.107/323.232.8.107 to 3.232.8.107—1
1093.232.8.108/323.232.8.108 to 3.232.8.108—1
1103.232.8.109/323.232.8.109 to 3.232.8.109—1
1113.232.8.110/323.232.8.110 to 3.232.8.110—1
1123.232.8.111/323.232.8.111 to 3.232.8.111—1
1133.232.8.112/323.232.8.112 to 3.232.8.112—1
1143.232.8.113/323.232.8.113 to 3.232.8.113—1
1153.232.8.114/323.232.8.114 to 3.232.8.114—1
1163.232.8.115/323.232.8.115 to 3.232.8.115—1
1173.232.8.116/323.232.8.116 to 3.232.8.116—1
1183.232.8.117/323.232.8.117 to 3.232.8.117—1
1193.232.8.118/323.232.8.118 to 3.232.8.118—1
1203.232.8.119/323.232.8.119 to 3.232.8.119—1
1213.232.8.120/323.232.8.120 to 3.232.8.120—1
1223.232.8.121/323.232.8.121 to 3.232.8.121—1
1233.232.8.122/323.232.8.122 to 3.232.8.122—1
1243.232.8.123/323.232.8.123 to 3.232.8.123—1
1253.232.8.124/323.232.8.124 to 3.232.8.124—1
1263.232.8.125/323.232.8.125 to 3.232.8.125—1
1273.232.8.126/323.232.8.126 to 3.232.8.126—1
1283.232.8.127/323.232.8.127 to 3.232.8.127—1
1293.232.8.128/323.232.8.128 to 3.232.8.128—1
1303.232.8.129/323.232.8.129 to 3.232.8.129—1
1313.232.8.130/323.232.8.130 to 3.232.8.130—1
1323.232.8.131/323.232.8.131 to 3.232.8.131—1
1333.232.8.132/323.232.8.132 to 3.232.8.132—1
1343.232.8.133/323.232.8.133 to 3.232.8.133—1
1353.232.8.134/323.232.8.134 to 3.232.8.134—1
1363.232.8.135/323.232.8.135 to 3.232.8.135—1
1373.232.8.136/323.232.8.136 to 3.232.8.136—1
1383.232.8.137/323.232.8.137 to 3.232.8.137—1
1393.232.8.138/323.232.8.138 to 3.232.8.138—1
1403.232.8.139/323.232.8.139 to 3.232.8.139—1
1413.232.8.140/323.232.8.140 to 3.232.8.140—1
1423.232.8.141/323.232.8.141 to 3.232.8.141—1
1433.232.8.142/323.232.8.142 to 3.232.8.142—1
1443.232.8.143/323.232.8.143 to 3.232.8.143—1
1453.232.8.144/323.232.8.144 to 3.232.8.144—1
1463.232.8.145/323.232.8.145 to 3.232.8.145—1
1473.232.8.146/323.232.8.146 to 3.232.8.146—1
1483.232.8.147/323.232.8.147 to 3.232.8.147—1
1493.232.8.148/323.232.8.148 to 3.232.8.148—1
1503.232.8.149/323.232.8.149 to 3.232.8.149—1
1513.232.8.150/323.232.8.150 to 3.232.8.150—1
1523.232.8.151/323.232.8.151 to 3.232.8.151—1
1533.232.8.152/323.232.8.152 to 3.232.8.152—1
1543.232.8.153/323.232.8.153 to 3.232.8.153—1
1553.232.8.154/323.232.8.154 to 3.232.8.154—1
1563.232.8.155/323.232.8.155 to 3.232.8.155—1
1573.232.8.156/323.232.8.156 to 3.232.8.156—1
1583.232.8.157/323.232.8.157 to 3.232.8.157—1
1593.232.8.158/323.232.8.158 to 3.232.8.158—1
1603.232.8.159/323.232.8.159 to 3.232.8.159—1
1613.232.8.160/323.232.8.160 to 3.232.8.160—1
1623.232.8.161/323.232.8.161 to 3.232.8.161—1
1633.232.8.162/323.232.8.162 to 3.232.8.162—1
1643.232.8.163/323.232.8.163 to 3.232.8.163—1
1653.232.8.164/323.232.8.164 to 3.232.8.164—1
1663.232.8.165/323.232.8.165 to 3.232.8.165—1
1673.232.8.166/323.232.8.166 to 3.232.8.166—1
1683.232.8.167/323.232.8.167 to 3.232.8.167—1
1693.232.8.168/323.232.8.168 to 3.232.8.168—1
1703.232.8.169/323.232.8.169 to 3.232.8.169—1
1713.232.8.170/323.232.8.170 to 3.232.8.170—1
1723.232.8.171/323.232.8.171 to 3.232.8.171—1
1733.232.8.172/323.232.8.172 to 3.232.8.172—1
1743.232.8.173/323.232.8.173 to 3.232.8.173—1
1753.232.8.174/323.232.8.174 to 3.232.8.174—1
1763.232.8.175/323.232.8.175 to 3.232.8.175—1
1773.232.8.176/323.232.8.176 to 3.232.8.176—1
1783.232.8.177/323.232.8.177 to 3.232.8.177—1
1793.232.8.178/323.232.8.178 to 3.232.8.178—1
1803.232.8.179/323.232.8.179 to 3.232.8.179—1
1813.232.8.180/323.232.8.180 to 3.232.8.180—1
1823.232.8.181/323.232.8.181 to 3.232.8.181—1
1833.232.8.182/323.232.8.182 to 3.232.8.182—1
1843.232.8.183/323.232.8.183 to 3.232.8.183—1
1853.232.8.184/323.232.8.184 to 3.232.8.184—1
1863.232.8.185/323.232.8.185 to 3.232.8.185—1
1873.232.8.186/323.232.8.186 to 3.232.8.186—1
1883.232.8.187/323.232.8.187 to 3.232.8.187—1
1893.232.8.188/323.232.8.188 to 3.232.8.188—1
1903.232.8.189/323.232.8.189 to 3.232.8.189—1
1913.232.8.190/323.232.8.190 to 3.232.8.190—1
1923.232.8.191/323.232.8.191 to 3.232.8.191—1
1933.232.8.192/323.232.8.192 to 3.232.8.192—1
1943.232.8.193/323.232.8.193 to 3.232.8.193—1
1953.232.8.194/323.232.8.194 to 3.232.8.194—1
1963.232.8.195/323.232.8.195 to 3.232.8.195—1
1973.232.8.196/323.232.8.196 to 3.232.8.196—1
1983.232.8.197/323.232.8.197 to 3.232.8.197—1
1993.232.8.198/323.232.8.198 to 3.232.8.198—1
2003.232.8.199/323.232.8.199 to 3.232.8.199—1
2013.232.8.200/323.232.8.200 to 3.232.8.200—1
2023.232.8.201/323.232.8.201 to 3.232.8.201—1
2033.232.8.202/323.232.8.202 to 3.232.8.202—1
2043.232.8.203/323.232.8.203 to 3.232.8.203—1
2053.232.8.204/323.232.8.204 to 3.232.8.204—1
2063.232.8.205/323.232.8.205 to 3.232.8.205—1
2073.232.8.206/323.232.8.206 to 3.232.8.206—1
2083.232.8.207/323.232.8.207 to 3.232.8.207—1
2093.232.8.208/323.232.8.208 to 3.232.8.208—1
2103.232.8.209/323.232.8.209 to 3.232.8.209—1
2113.232.8.210/323.232.8.210 to 3.232.8.210—1
2123.232.8.211/323.232.8.211 to 3.232.8.211—1
2133.232.8.212/323.232.8.212 to 3.232.8.212—1
2143.232.8.213/323.232.8.213 to 3.232.8.213—1
2153.232.8.214/323.232.8.214 to 3.232.8.214—1
2163.232.8.215/323.232.8.215 to 3.232.8.215—1
2173.232.8.216/323.232.8.216 to 3.232.8.216—1
2183.232.8.217/323.232.8.217 to 3.232.8.217—1
2193.232.8.218/323.232.8.218 to 3.232.8.218—1
2203.232.8.219/323.232.8.219 to 3.232.8.219—1
2213.232.8.220/323.232.8.220 to 3.232.8.220—1
2223.232.8.221/323.232.8.221 to 3.232.8.221—1
2233.232.8.222/323.232.8.222 to 3.232.8.222—1
2243.232.8.223/323.232.8.223 to 3.232.8.223—1
2253.232.8.224/323.232.8.224 to 3.232.8.224—1
2263.232.8.225/323.232.8.225 to 3.232.8.225—1
2273.232.8.226/323.232.8.226 to 3.232.8.226—1
2283.232.8.227/323.232.8.227 to 3.232.8.227—1
2293.232.8.228/323.232.8.228 to 3.232.8.228—1
2303.232.8.229/323.232.8.229 to 3.232.8.229—1
2313.232.8.230/323.232.8.230 to 3.232.8.230—1
2323.232.8.231/323.232.8.231 to 3.232.8.231—1
2333.232.8.232/323.232.8.232 to 3.232.8.232—1
2343.232.8.233/323.232.8.233 to 3.232.8.233—1
2353.232.8.234/323.232.8.234 to 3.232.8.234—1
2363.232.8.235/323.232.8.235 to 3.232.8.235—1
2373.232.8.236/323.232.8.236 to 3.232.8.236—1
2383.232.8.237/323.232.8.237 to 3.232.8.237—1
2393.232.8.238/323.232.8.238 to 3.232.8.238—1
2403.232.8.239/323.232.8.239 to 3.232.8.239—1
2413.232.8.240/323.232.8.240 to 3.232.8.240—1
2423.232.8.241/323.232.8.241 to 3.232.8.241—1
2433.232.8.242/323.232.8.242 to 3.232.8.242—1
2443.232.8.243/323.232.8.243 to 3.232.8.243—1
2453.232.8.244/323.232.8.244 to 3.232.8.244—1
2463.232.8.245/323.232.8.245 to 3.232.8.245—1
2473.232.8.246/323.232.8.246 to 3.232.8.246—1
2483.232.8.247/323.232.8.247 to 3.232.8.247—1
2493.232.8.248/323.232.8.248 to 3.232.8.248—1
2503.232.8.249/323.232.8.249 to 3.232.8.249—1
2513.232.8.250/323.232.8.250 to 3.232.8.250—1
2523.232.8.251/323.232.8.251 to 3.232.8.251—1
2533.232.8.252/323.232.8.252 to 3.232.8.252—1
2543.232.8.253/323.232.8.253 to 3.232.8.253—1
2553.232.8.254/323.232.8.254 to 3.232.8.254—1
2563.232.8.255/323.232.8.255 to 3.232.8.255—1

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.