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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.

Network20.64.4.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
20.64.4.0
Broadcast address
20.64.7.255
First usable
20.64.4.1
Last usable
20.64.7.254
Usable hosts
1,022 (1,024 less the network and broadcast addresses)
Subnet mask
255.255.252.0
Wildcard mask
0.0.3.255 (Cisco ACLs, OSPF)
Prefix length
/22
Type
Public public
Old class
A (default /8)
As numbers
Hex 14400400 · Integer 339739648 to 339740671
Reverse DNS zones
4.64.20.in-addr.arpa
5.64.20.in-addr.arpa
6.64.20.in-addr.arpa
7.64.20.in-addr.arpa
/22 is not on a 8-bit boundary, so it takes 4 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010100.01000000.00000100.0000000020.64.4.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00010100.01000000.00000100.0000000020.64.4.0
Broadcast00010100.01000000.00000111.1111111120.64.7.255
Split into smaller subnets/30
/23 (2)/24 (4)/25 (8)/26 (16)/27 (32)/28 (64)/29 (128)/30 (256)/31 (512)/32 (1,024)

20.64.4.0/22 makes 256 subnets of /30.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
120.64.4.0/3020.64.4.1 to 20.64.4.220.64.4.32
220.64.4.4/3020.64.4.5 to 20.64.4.620.64.4.72
320.64.4.8/3020.64.4.9 to 20.64.4.1020.64.4.112
420.64.4.12/3020.64.4.13 to 20.64.4.1420.64.4.152
520.64.4.16/3020.64.4.17 to 20.64.4.1820.64.4.192
620.64.4.20/3020.64.4.21 to 20.64.4.2220.64.4.232
720.64.4.24/3020.64.4.25 to 20.64.4.2620.64.4.272
820.64.4.28/3020.64.4.29 to 20.64.4.3020.64.4.312
920.64.4.32/3020.64.4.33 to 20.64.4.3420.64.4.352
1020.64.4.36/3020.64.4.37 to 20.64.4.3820.64.4.392
1120.64.4.40/3020.64.4.41 to 20.64.4.4220.64.4.432
1220.64.4.44/3020.64.4.45 to 20.64.4.4620.64.4.472
1320.64.4.48/3020.64.4.49 to 20.64.4.5020.64.4.512
1420.64.4.52/3020.64.4.53 to 20.64.4.5420.64.4.552
1520.64.4.56/3020.64.4.57 to 20.64.4.5820.64.4.592
1620.64.4.60/3020.64.4.61 to 20.64.4.6220.64.4.632
1720.64.4.64/3020.64.4.65 to 20.64.4.6620.64.4.672
1820.64.4.68/3020.64.4.69 to 20.64.4.7020.64.4.712
1920.64.4.72/3020.64.4.73 to 20.64.4.7420.64.4.752
2020.64.4.76/3020.64.4.77 to 20.64.4.7820.64.4.792
2120.64.4.80/3020.64.4.81 to 20.64.4.8220.64.4.832
2220.64.4.84/3020.64.4.85 to 20.64.4.8620.64.4.872
2320.64.4.88/3020.64.4.89 to 20.64.4.9020.64.4.912
2420.64.4.92/3020.64.4.93 to 20.64.4.9420.64.4.952
2520.64.4.96/3020.64.4.97 to 20.64.4.9820.64.4.992
2620.64.4.100/3020.64.4.101 to 20.64.4.10220.64.4.1032
2720.64.4.104/3020.64.4.105 to 20.64.4.10620.64.4.1072
2820.64.4.108/3020.64.4.109 to 20.64.4.11020.64.4.1112
2920.64.4.112/3020.64.4.113 to 20.64.4.11420.64.4.1152
3020.64.4.116/3020.64.4.117 to 20.64.4.11820.64.4.1192
3120.64.4.120/3020.64.4.121 to 20.64.4.12220.64.4.1232
3220.64.4.124/3020.64.4.125 to 20.64.4.12620.64.4.1272
3320.64.4.128/3020.64.4.129 to 20.64.4.13020.64.4.1312
3420.64.4.132/3020.64.4.133 to 20.64.4.13420.64.4.1352
3520.64.4.136/3020.64.4.137 to 20.64.4.13820.64.4.1392
3620.64.4.140/3020.64.4.141 to 20.64.4.14220.64.4.1432
3720.64.4.144/3020.64.4.145 to 20.64.4.14620.64.4.1472
3820.64.4.148/3020.64.4.149 to 20.64.4.15020.64.4.1512
3920.64.4.152/3020.64.4.153 to 20.64.4.15420.64.4.1552
4020.64.4.156/3020.64.4.157 to 20.64.4.15820.64.4.1592
4120.64.4.160/3020.64.4.161 to 20.64.4.16220.64.4.1632
4220.64.4.164/3020.64.4.165 to 20.64.4.16620.64.4.1672
4320.64.4.168/3020.64.4.169 to 20.64.4.17020.64.4.1712
4420.64.4.172/3020.64.4.173 to 20.64.4.17420.64.4.1752
4520.64.4.176/3020.64.4.177 to 20.64.4.17820.64.4.1792
4620.64.4.180/3020.64.4.181 to 20.64.4.18220.64.4.1832
4720.64.4.184/3020.64.4.185 to 20.64.4.18620.64.4.1872
4820.64.4.188/3020.64.4.189 to 20.64.4.19020.64.4.1912
4920.64.4.192/3020.64.4.193 to 20.64.4.19420.64.4.1952
5020.64.4.196/3020.64.4.197 to 20.64.4.19820.64.4.1992
5120.64.4.200/3020.64.4.201 to 20.64.4.20220.64.4.2032
5220.64.4.204/3020.64.4.205 to 20.64.4.20620.64.4.2072
5320.64.4.208/3020.64.4.209 to 20.64.4.21020.64.4.2112
5420.64.4.212/3020.64.4.213 to 20.64.4.21420.64.4.2152
5520.64.4.216/3020.64.4.217 to 20.64.4.21820.64.4.2192
5620.64.4.220/3020.64.4.221 to 20.64.4.22220.64.4.2232
5720.64.4.224/3020.64.4.225 to 20.64.4.22620.64.4.2272
5820.64.4.228/3020.64.4.229 to 20.64.4.23020.64.4.2312
5920.64.4.232/3020.64.4.233 to 20.64.4.23420.64.4.2352
6020.64.4.236/3020.64.4.237 to 20.64.4.23820.64.4.2392
6120.64.4.240/3020.64.4.241 to 20.64.4.24220.64.4.2432
6220.64.4.244/3020.64.4.245 to 20.64.4.24620.64.4.2472
6320.64.4.248/3020.64.4.249 to 20.64.4.25020.64.4.2512
6420.64.4.252/3020.64.4.253 to 20.64.4.25420.64.4.2552
6520.64.5.0/3020.64.5.1 to 20.64.5.220.64.5.32
6620.64.5.4/3020.64.5.5 to 20.64.5.620.64.5.72
6720.64.5.8/3020.64.5.9 to 20.64.5.1020.64.5.112
6820.64.5.12/3020.64.5.13 to 20.64.5.1420.64.5.152
6920.64.5.16/3020.64.5.17 to 20.64.5.1820.64.5.192
7020.64.5.20/3020.64.5.21 to 20.64.5.2220.64.5.232
7120.64.5.24/3020.64.5.25 to 20.64.5.2620.64.5.272
7220.64.5.28/3020.64.5.29 to 20.64.5.3020.64.5.312
7320.64.5.32/3020.64.5.33 to 20.64.5.3420.64.5.352
7420.64.5.36/3020.64.5.37 to 20.64.5.3820.64.5.392
7520.64.5.40/3020.64.5.41 to 20.64.5.4220.64.5.432
7620.64.5.44/3020.64.5.45 to 20.64.5.4620.64.5.472
7720.64.5.48/3020.64.5.49 to 20.64.5.5020.64.5.512
7820.64.5.52/3020.64.5.53 to 20.64.5.5420.64.5.552
7920.64.5.56/3020.64.5.57 to 20.64.5.5820.64.5.592
8020.64.5.60/3020.64.5.61 to 20.64.5.6220.64.5.632
8120.64.5.64/3020.64.5.65 to 20.64.5.6620.64.5.672
8220.64.5.68/3020.64.5.69 to 20.64.5.7020.64.5.712
8320.64.5.72/3020.64.5.73 to 20.64.5.7420.64.5.752
8420.64.5.76/3020.64.5.77 to 20.64.5.7820.64.5.792
8520.64.5.80/3020.64.5.81 to 20.64.5.8220.64.5.832
8620.64.5.84/3020.64.5.85 to 20.64.5.8620.64.5.872
8720.64.5.88/3020.64.5.89 to 20.64.5.9020.64.5.912
8820.64.5.92/3020.64.5.93 to 20.64.5.9420.64.5.952
8920.64.5.96/3020.64.5.97 to 20.64.5.9820.64.5.992
9020.64.5.100/3020.64.5.101 to 20.64.5.10220.64.5.1032
9120.64.5.104/3020.64.5.105 to 20.64.5.10620.64.5.1072
9220.64.5.108/3020.64.5.109 to 20.64.5.11020.64.5.1112
9320.64.5.112/3020.64.5.113 to 20.64.5.11420.64.5.1152
9420.64.5.116/3020.64.5.117 to 20.64.5.11820.64.5.1192
9520.64.5.120/3020.64.5.121 to 20.64.5.12220.64.5.1232
9620.64.5.124/3020.64.5.125 to 20.64.5.12620.64.5.1272
9720.64.5.128/3020.64.5.129 to 20.64.5.13020.64.5.1312
9820.64.5.132/3020.64.5.133 to 20.64.5.13420.64.5.1352
9920.64.5.136/3020.64.5.137 to 20.64.5.13820.64.5.1392
10020.64.5.140/3020.64.5.141 to 20.64.5.14220.64.5.1432
10120.64.5.144/3020.64.5.145 to 20.64.5.14620.64.5.1472
10220.64.5.148/3020.64.5.149 to 20.64.5.15020.64.5.1512
10320.64.5.152/3020.64.5.153 to 20.64.5.15420.64.5.1552
10420.64.5.156/3020.64.5.157 to 20.64.5.15820.64.5.1592
10520.64.5.160/3020.64.5.161 to 20.64.5.16220.64.5.1632
10620.64.5.164/3020.64.5.165 to 20.64.5.16620.64.5.1672
10720.64.5.168/3020.64.5.169 to 20.64.5.17020.64.5.1712
10820.64.5.172/3020.64.5.173 to 20.64.5.17420.64.5.1752
10920.64.5.176/3020.64.5.177 to 20.64.5.17820.64.5.1792
11020.64.5.180/3020.64.5.181 to 20.64.5.18220.64.5.1832
11120.64.5.184/3020.64.5.185 to 20.64.5.18620.64.5.1872
11220.64.5.188/3020.64.5.189 to 20.64.5.19020.64.5.1912
11320.64.5.192/3020.64.5.193 to 20.64.5.19420.64.5.1952
11420.64.5.196/3020.64.5.197 to 20.64.5.19820.64.5.1992
11520.64.5.200/3020.64.5.201 to 20.64.5.20220.64.5.2032
11620.64.5.204/3020.64.5.205 to 20.64.5.20620.64.5.2072
11720.64.5.208/3020.64.5.209 to 20.64.5.21020.64.5.2112
11820.64.5.212/3020.64.5.213 to 20.64.5.21420.64.5.2152
11920.64.5.216/3020.64.5.217 to 20.64.5.21820.64.5.2192
12020.64.5.220/3020.64.5.221 to 20.64.5.22220.64.5.2232
12120.64.5.224/3020.64.5.225 to 20.64.5.22620.64.5.2272
12220.64.5.228/3020.64.5.229 to 20.64.5.23020.64.5.2312
12320.64.5.232/3020.64.5.233 to 20.64.5.23420.64.5.2352
12420.64.5.236/3020.64.5.237 to 20.64.5.23820.64.5.2392
12520.64.5.240/3020.64.5.241 to 20.64.5.24220.64.5.2432
12620.64.5.244/3020.64.5.245 to 20.64.5.24620.64.5.2472
12720.64.5.248/3020.64.5.249 to 20.64.5.25020.64.5.2512
12820.64.5.252/3020.64.5.253 to 20.64.5.25420.64.5.2552
12920.64.6.0/3020.64.6.1 to 20.64.6.220.64.6.32
13020.64.6.4/3020.64.6.5 to 20.64.6.620.64.6.72
13120.64.6.8/3020.64.6.9 to 20.64.6.1020.64.6.112
13220.64.6.12/3020.64.6.13 to 20.64.6.1420.64.6.152
13320.64.6.16/3020.64.6.17 to 20.64.6.1820.64.6.192
13420.64.6.20/3020.64.6.21 to 20.64.6.2220.64.6.232
13520.64.6.24/3020.64.6.25 to 20.64.6.2620.64.6.272
13620.64.6.28/3020.64.6.29 to 20.64.6.3020.64.6.312
13720.64.6.32/3020.64.6.33 to 20.64.6.3420.64.6.352
13820.64.6.36/3020.64.6.37 to 20.64.6.3820.64.6.392
13920.64.6.40/3020.64.6.41 to 20.64.6.4220.64.6.432
14020.64.6.44/3020.64.6.45 to 20.64.6.4620.64.6.472
14120.64.6.48/3020.64.6.49 to 20.64.6.5020.64.6.512
14220.64.6.52/3020.64.6.53 to 20.64.6.5420.64.6.552
14320.64.6.56/3020.64.6.57 to 20.64.6.5820.64.6.592
14420.64.6.60/3020.64.6.61 to 20.64.6.6220.64.6.632
14520.64.6.64/3020.64.6.65 to 20.64.6.6620.64.6.672
14620.64.6.68/3020.64.6.69 to 20.64.6.7020.64.6.712
14720.64.6.72/3020.64.6.73 to 20.64.6.7420.64.6.752
14820.64.6.76/3020.64.6.77 to 20.64.6.7820.64.6.792
14920.64.6.80/3020.64.6.81 to 20.64.6.8220.64.6.832
15020.64.6.84/3020.64.6.85 to 20.64.6.8620.64.6.872
15120.64.6.88/3020.64.6.89 to 20.64.6.9020.64.6.912
15220.64.6.92/3020.64.6.93 to 20.64.6.9420.64.6.952
15320.64.6.96/3020.64.6.97 to 20.64.6.9820.64.6.992
15420.64.6.100/3020.64.6.101 to 20.64.6.10220.64.6.1032
15520.64.6.104/3020.64.6.105 to 20.64.6.10620.64.6.1072
15620.64.6.108/3020.64.6.109 to 20.64.6.11020.64.6.1112
15720.64.6.112/3020.64.6.113 to 20.64.6.11420.64.6.1152
15820.64.6.116/3020.64.6.117 to 20.64.6.11820.64.6.1192
15920.64.6.120/3020.64.6.121 to 20.64.6.12220.64.6.1232
16020.64.6.124/3020.64.6.125 to 20.64.6.12620.64.6.1272
16120.64.6.128/3020.64.6.129 to 20.64.6.13020.64.6.1312
16220.64.6.132/3020.64.6.133 to 20.64.6.13420.64.6.1352
16320.64.6.136/3020.64.6.137 to 20.64.6.13820.64.6.1392
16420.64.6.140/3020.64.6.141 to 20.64.6.14220.64.6.1432
16520.64.6.144/3020.64.6.145 to 20.64.6.14620.64.6.1472
16620.64.6.148/3020.64.6.149 to 20.64.6.15020.64.6.1512
16720.64.6.152/3020.64.6.153 to 20.64.6.15420.64.6.1552
16820.64.6.156/3020.64.6.157 to 20.64.6.15820.64.6.1592
16920.64.6.160/3020.64.6.161 to 20.64.6.16220.64.6.1632
17020.64.6.164/3020.64.6.165 to 20.64.6.16620.64.6.1672
17120.64.6.168/3020.64.6.169 to 20.64.6.17020.64.6.1712
17220.64.6.172/3020.64.6.173 to 20.64.6.17420.64.6.1752
17320.64.6.176/3020.64.6.177 to 20.64.6.17820.64.6.1792
17420.64.6.180/3020.64.6.181 to 20.64.6.18220.64.6.1832
17520.64.6.184/3020.64.6.185 to 20.64.6.18620.64.6.1872
17620.64.6.188/3020.64.6.189 to 20.64.6.19020.64.6.1912
17720.64.6.192/3020.64.6.193 to 20.64.6.19420.64.6.1952
17820.64.6.196/3020.64.6.197 to 20.64.6.19820.64.6.1992
17920.64.6.200/3020.64.6.201 to 20.64.6.20220.64.6.2032
18020.64.6.204/3020.64.6.205 to 20.64.6.20620.64.6.2072
18120.64.6.208/3020.64.6.209 to 20.64.6.21020.64.6.2112
18220.64.6.212/3020.64.6.213 to 20.64.6.21420.64.6.2152
18320.64.6.216/3020.64.6.217 to 20.64.6.21820.64.6.2192
18420.64.6.220/3020.64.6.221 to 20.64.6.22220.64.6.2232
18520.64.6.224/3020.64.6.225 to 20.64.6.22620.64.6.2272
18620.64.6.228/3020.64.6.229 to 20.64.6.23020.64.6.2312
18720.64.6.232/3020.64.6.233 to 20.64.6.23420.64.6.2352
18820.64.6.236/3020.64.6.237 to 20.64.6.23820.64.6.2392
18920.64.6.240/3020.64.6.241 to 20.64.6.24220.64.6.2432
19020.64.6.244/3020.64.6.245 to 20.64.6.24620.64.6.2472
19120.64.6.248/3020.64.6.249 to 20.64.6.25020.64.6.2512
19220.64.6.252/3020.64.6.253 to 20.64.6.25420.64.6.2552
19320.64.7.0/3020.64.7.1 to 20.64.7.220.64.7.32
19420.64.7.4/3020.64.7.5 to 20.64.7.620.64.7.72
19520.64.7.8/3020.64.7.9 to 20.64.7.1020.64.7.112
19620.64.7.12/3020.64.7.13 to 20.64.7.1420.64.7.152
19720.64.7.16/3020.64.7.17 to 20.64.7.1820.64.7.192
19820.64.7.20/3020.64.7.21 to 20.64.7.2220.64.7.232
19920.64.7.24/3020.64.7.25 to 20.64.7.2620.64.7.272
20020.64.7.28/3020.64.7.29 to 20.64.7.3020.64.7.312
20120.64.7.32/3020.64.7.33 to 20.64.7.3420.64.7.352
20220.64.7.36/3020.64.7.37 to 20.64.7.3820.64.7.392
20320.64.7.40/3020.64.7.41 to 20.64.7.4220.64.7.432
20420.64.7.44/3020.64.7.45 to 20.64.7.4620.64.7.472
20520.64.7.48/3020.64.7.49 to 20.64.7.5020.64.7.512
20620.64.7.52/3020.64.7.53 to 20.64.7.5420.64.7.552
20720.64.7.56/3020.64.7.57 to 20.64.7.5820.64.7.592
20820.64.7.60/3020.64.7.61 to 20.64.7.6220.64.7.632
20920.64.7.64/3020.64.7.65 to 20.64.7.6620.64.7.672
21020.64.7.68/3020.64.7.69 to 20.64.7.7020.64.7.712
21120.64.7.72/3020.64.7.73 to 20.64.7.7420.64.7.752
21220.64.7.76/3020.64.7.77 to 20.64.7.7820.64.7.792
21320.64.7.80/3020.64.7.81 to 20.64.7.8220.64.7.832
21420.64.7.84/3020.64.7.85 to 20.64.7.8620.64.7.872
21520.64.7.88/3020.64.7.89 to 20.64.7.9020.64.7.912
21620.64.7.92/3020.64.7.93 to 20.64.7.9420.64.7.952
21720.64.7.96/3020.64.7.97 to 20.64.7.9820.64.7.992
21820.64.7.100/3020.64.7.101 to 20.64.7.10220.64.7.1032
21920.64.7.104/3020.64.7.105 to 20.64.7.10620.64.7.1072
22020.64.7.108/3020.64.7.109 to 20.64.7.11020.64.7.1112
22120.64.7.112/3020.64.7.113 to 20.64.7.11420.64.7.1152
22220.64.7.116/3020.64.7.117 to 20.64.7.11820.64.7.1192
22320.64.7.120/3020.64.7.121 to 20.64.7.12220.64.7.1232
22420.64.7.124/3020.64.7.125 to 20.64.7.12620.64.7.1272
22520.64.7.128/3020.64.7.129 to 20.64.7.13020.64.7.1312
22620.64.7.132/3020.64.7.133 to 20.64.7.13420.64.7.1352
22720.64.7.136/3020.64.7.137 to 20.64.7.13820.64.7.1392
22820.64.7.140/3020.64.7.141 to 20.64.7.14220.64.7.1432
22920.64.7.144/3020.64.7.145 to 20.64.7.14620.64.7.1472
23020.64.7.148/3020.64.7.149 to 20.64.7.15020.64.7.1512
23120.64.7.152/3020.64.7.153 to 20.64.7.15420.64.7.1552
23220.64.7.156/3020.64.7.157 to 20.64.7.15820.64.7.1592
23320.64.7.160/3020.64.7.161 to 20.64.7.16220.64.7.1632
23420.64.7.164/3020.64.7.165 to 20.64.7.16620.64.7.1672
23520.64.7.168/3020.64.7.169 to 20.64.7.17020.64.7.1712
23620.64.7.172/3020.64.7.173 to 20.64.7.17420.64.7.1752
23720.64.7.176/3020.64.7.177 to 20.64.7.17820.64.7.1792
23820.64.7.180/3020.64.7.181 to 20.64.7.18220.64.7.1832
23920.64.7.184/3020.64.7.185 to 20.64.7.18620.64.7.1872
24020.64.7.188/3020.64.7.189 to 20.64.7.19020.64.7.1912
24120.64.7.192/3020.64.7.193 to 20.64.7.19420.64.7.1952
24220.64.7.196/3020.64.7.197 to 20.64.7.19820.64.7.1992
24320.64.7.200/3020.64.7.201 to 20.64.7.20220.64.7.2032
24420.64.7.204/3020.64.7.205 to 20.64.7.20620.64.7.2072
24520.64.7.208/3020.64.7.209 to 20.64.7.21020.64.7.2112
24620.64.7.212/3020.64.7.213 to 20.64.7.21420.64.7.2152
24720.64.7.216/3020.64.7.217 to 20.64.7.21820.64.7.2192
24820.64.7.220/3020.64.7.221 to 20.64.7.22220.64.7.2232
24920.64.7.224/3020.64.7.225 to 20.64.7.22620.64.7.2272
25020.64.7.228/3020.64.7.229 to 20.64.7.23020.64.7.2312
25120.64.7.232/3020.64.7.233 to 20.64.7.23420.64.7.2352
25220.64.7.236/3020.64.7.237 to 20.64.7.23820.64.7.2392
25320.64.7.240/3020.64.7.241 to 20.64.7.24220.64.7.2432
25420.64.7.244/3020.64.7.245 to 20.64.7.24620.64.7.2472
25520.64.7.248/3020.64.7.249 to 20.64.7.25020.64.7.2512
25620.64.7.252/3020.64.7.253 to 20.64.7.25420.64.7.2552

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.