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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.

Network93.2.64.0/21
Usable hosts2,046
Subnet mask255.255.248.0
Addresses2,048
Network address
93.2.64.0
Broadcast address
93.2.71.255
First usable
93.2.64.1
Last usable
93.2.71.254
Usable hosts
2,046 (2,048 less the network and broadcast addresses)
Subnet mask
255.255.248.0
Wildcard mask
0.0.7.255 (Cisco ACLs, OSPF)
Prefix length
/21
Type
Public public
Old class
A (default /8)
As numbers
Hex 5D024000 · Integer 1560428544 to 1560430591
Reverse DNS zones
64.2.93.in-addr.arpa
65.2.93.in-addr.arpa
66.2.93.in-addr.arpa
67.2.93.in-addr.arpa
68.2.93.in-addr.arpa
69.2.93.in-addr.arpa
70.2.93.in-addr.arpa
71.2.93.in-addr.arpa
/21 is not on a 8-bit boundary, so it takes 8 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011101.00000010.01000000.0000000093.2.64.0
Subnet mask11111111.11111111.11111000.00000000255.255.248.0
Network01011101.00000010.01000000.0000000093.2.64.0
Broadcast01011101.00000010.01000111.1111111193.2.71.255
Split into smaller subnets/30
/22 (2)/23 (4)/24 (8)/25 (16)/26 (32)/27 (64)/28 (128)/29 (256)/30 (512)/31 (1,024)/32 (2,048)

93.2.64.0/21 makes 512 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
193.2.64.0/3093.2.64.1 to 93.2.64.293.2.64.32
293.2.64.4/3093.2.64.5 to 93.2.64.693.2.64.72
393.2.64.8/3093.2.64.9 to 93.2.64.1093.2.64.112
493.2.64.12/3093.2.64.13 to 93.2.64.1493.2.64.152
593.2.64.16/3093.2.64.17 to 93.2.64.1893.2.64.192
693.2.64.20/3093.2.64.21 to 93.2.64.2293.2.64.232
793.2.64.24/3093.2.64.25 to 93.2.64.2693.2.64.272
893.2.64.28/3093.2.64.29 to 93.2.64.3093.2.64.312
993.2.64.32/3093.2.64.33 to 93.2.64.3493.2.64.352
1093.2.64.36/3093.2.64.37 to 93.2.64.3893.2.64.392
1193.2.64.40/3093.2.64.41 to 93.2.64.4293.2.64.432
1293.2.64.44/3093.2.64.45 to 93.2.64.4693.2.64.472
1393.2.64.48/3093.2.64.49 to 93.2.64.5093.2.64.512
1493.2.64.52/3093.2.64.53 to 93.2.64.5493.2.64.552
1593.2.64.56/3093.2.64.57 to 93.2.64.5893.2.64.592
1693.2.64.60/3093.2.64.61 to 93.2.64.6293.2.64.632
1793.2.64.64/3093.2.64.65 to 93.2.64.6693.2.64.672
1893.2.64.68/3093.2.64.69 to 93.2.64.7093.2.64.712
1993.2.64.72/3093.2.64.73 to 93.2.64.7493.2.64.752
2093.2.64.76/3093.2.64.77 to 93.2.64.7893.2.64.792
2193.2.64.80/3093.2.64.81 to 93.2.64.8293.2.64.832
2293.2.64.84/3093.2.64.85 to 93.2.64.8693.2.64.872
2393.2.64.88/3093.2.64.89 to 93.2.64.9093.2.64.912
2493.2.64.92/3093.2.64.93 to 93.2.64.9493.2.64.952
2593.2.64.96/3093.2.64.97 to 93.2.64.9893.2.64.992
2693.2.64.100/3093.2.64.101 to 93.2.64.10293.2.64.1032
2793.2.64.104/3093.2.64.105 to 93.2.64.10693.2.64.1072
2893.2.64.108/3093.2.64.109 to 93.2.64.11093.2.64.1112
2993.2.64.112/3093.2.64.113 to 93.2.64.11493.2.64.1152
3093.2.64.116/3093.2.64.117 to 93.2.64.11893.2.64.1192
3193.2.64.120/3093.2.64.121 to 93.2.64.12293.2.64.1232
3293.2.64.124/3093.2.64.125 to 93.2.64.12693.2.64.1272
3393.2.64.128/3093.2.64.129 to 93.2.64.13093.2.64.1312
3493.2.64.132/3093.2.64.133 to 93.2.64.13493.2.64.1352
3593.2.64.136/3093.2.64.137 to 93.2.64.13893.2.64.1392
3693.2.64.140/3093.2.64.141 to 93.2.64.14293.2.64.1432
3793.2.64.144/3093.2.64.145 to 93.2.64.14693.2.64.1472
3893.2.64.148/3093.2.64.149 to 93.2.64.15093.2.64.1512
3993.2.64.152/3093.2.64.153 to 93.2.64.15493.2.64.1552
4093.2.64.156/3093.2.64.157 to 93.2.64.15893.2.64.1592
4193.2.64.160/3093.2.64.161 to 93.2.64.16293.2.64.1632
4293.2.64.164/3093.2.64.165 to 93.2.64.16693.2.64.1672
4393.2.64.168/3093.2.64.169 to 93.2.64.17093.2.64.1712
4493.2.64.172/3093.2.64.173 to 93.2.64.17493.2.64.1752
4593.2.64.176/3093.2.64.177 to 93.2.64.17893.2.64.1792
4693.2.64.180/3093.2.64.181 to 93.2.64.18293.2.64.1832
4793.2.64.184/3093.2.64.185 to 93.2.64.18693.2.64.1872
4893.2.64.188/3093.2.64.189 to 93.2.64.19093.2.64.1912
4993.2.64.192/3093.2.64.193 to 93.2.64.19493.2.64.1952
5093.2.64.196/3093.2.64.197 to 93.2.64.19893.2.64.1992
5193.2.64.200/3093.2.64.201 to 93.2.64.20293.2.64.2032
5293.2.64.204/3093.2.64.205 to 93.2.64.20693.2.64.2072
5393.2.64.208/3093.2.64.209 to 93.2.64.21093.2.64.2112
5493.2.64.212/3093.2.64.213 to 93.2.64.21493.2.64.2152
5593.2.64.216/3093.2.64.217 to 93.2.64.21893.2.64.2192
5693.2.64.220/3093.2.64.221 to 93.2.64.22293.2.64.2232
5793.2.64.224/3093.2.64.225 to 93.2.64.22693.2.64.2272
5893.2.64.228/3093.2.64.229 to 93.2.64.23093.2.64.2312
5993.2.64.232/3093.2.64.233 to 93.2.64.23493.2.64.2352
6093.2.64.236/3093.2.64.237 to 93.2.64.23893.2.64.2392
6193.2.64.240/3093.2.64.241 to 93.2.64.24293.2.64.2432
6293.2.64.244/3093.2.64.245 to 93.2.64.24693.2.64.2472
6393.2.64.248/3093.2.64.249 to 93.2.64.25093.2.64.2512
6493.2.64.252/3093.2.64.253 to 93.2.64.25493.2.64.2552
6593.2.65.0/3093.2.65.1 to 93.2.65.293.2.65.32
6693.2.65.4/3093.2.65.5 to 93.2.65.693.2.65.72
6793.2.65.8/3093.2.65.9 to 93.2.65.1093.2.65.112
6893.2.65.12/3093.2.65.13 to 93.2.65.1493.2.65.152
6993.2.65.16/3093.2.65.17 to 93.2.65.1893.2.65.192
7093.2.65.20/3093.2.65.21 to 93.2.65.2293.2.65.232
7193.2.65.24/3093.2.65.25 to 93.2.65.2693.2.65.272
7293.2.65.28/3093.2.65.29 to 93.2.65.3093.2.65.312
7393.2.65.32/3093.2.65.33 to 93.2.65.3493.2.65.352
7493.2.65.36/3093.2.65.37 to 93.2.65.3893.2.65.392
7593.2.65.40/3093.2.65.41 to 93.2.65.4293.2.65.432
7693.2.65.44/3093.2.65.45 to 93.2.65.4693.2.65.472
7793.2.65.48/3093.2.65.49 to 93.2.65.5093.2.65.512
7893.2.65.52/3093.2.65.53 to 93.2.65.5493.2.65.552
7993.2.65.56/3093.2.65.57 to 93.2.65.5893.2.65.592
8093.2.65.60/3093.2.65.61 to 93.2.65.6293.2.65.632
8193.2.65.64/3093.2.65.65 to 93.2.65.6693.2.65.672
8293.2.65.68/3093.2.65.69 to 93.2.65.7093.2.65.712
8393.2.65.72/3093.2.65.73 to 93.2.65.7493.2.65.752
8493.2.65.76/3093.2.65.77 to 93.2.65.7893.2.65.792
8593.2.65.80/3093.2.65.81 to 93.2.65.8293.2.65.832
8693.2.65.84/3093.2.65.85 to 93.2.65.8693.2.65.872
8793.2.65.88/3093.2.65.89 to 93.2.65.9093.2.65.912
8893.2.65.92/3093.2.65.93 to 93.2.65.9493.2.65.952
8993.2.65.96/3093.2.65.97 to 93.2.65.9893.2.65.992
9093.2.65.100/3093.2.65.101 to 93.2.65.10293.2.65.1032
9193.2.65.104/3093.2.65.105 to 93.2.65.10693.2.65.1072
9293.2.65.108/3093.2.65.109 to 93.2.65.11093.2.65.1112
9393.2.65.112/3093.2.65.113 to 93.2.65.11493.2.65.1152
9493.2.65.116/3093.2.65.117 to 93.2.65.11893.2.65.1192
9593.2.65.120/3093.2.65.121 to 93.2.65.12293.2.65.1232
9693.2.65.124/3093.2.65.125 to 93.2.65.12693.2.65.1272
9793.2.65.128/3093.2.65.129 to 93.2.65.13093.2.65.1312
9893.2.65.132/3093.2.65.133 to 93.2.65.13493.2.65.1352
9993.2.65.136/3093.2.65.137 to 93.2.65.13893.2.65.1392
10093.2.65.140/3093.2.65.141 to 93.2.65.14293.2.65.1432
10193.2.65.144/3093.2.65.145 to 93.2.65.14693.2.65.1472
10293.2.65.148/3093.2.65.149 to 93.2.65.15093.2.65.1512
10393.2.65.152/3093.2.65.153 to 93.2.65.15493.2.65.1552
10493.2.65.156/3093.2.65.157 to 93.2.65.15893.2.65.1592
10593.2.65.160/3093.2.65.161 to 93.2.65.16293.2.65.1632
10693.2.65.164/3093.2.65.165 to 93.2.65.16693.2.65.1672
10793.2.65.168/3093.2.65.169 to 93.2.65.17093.2.65.1712
10893.2.65.172/3093.2.65.173 to 93.2.65.17493.2.65.1752
10993.2.65.176/3093.2.65.177 to 93.2.65.17893.2.65.1792
11093.2.65.180/3093.2.65.181 to 93.2.65.18293.2.65.1832
11193.2.65.184/3093.2.65.185 to 93.2.65.18693.2.65.1872
11293.2.65.188/3093.2.65.189 to 93.2.65.19093.2.65.1912
11393.2.65.192/3093.2.65.193 to 93.2.65.19493.2.65.1952
11493.2.65.196/3093.2.65.197 to 93.2.65.19893.2.65.1992
11593.2.65.200/3093.2.65.201 to 93.2.65.20293.2.65.2032
11693.2.65.204/3093.2.65.205 to 93.2.65.20693.2.65.2072
11793.2.65.208/3093.2.65.209 to 93.2.65.21093.2.65.2112
11893.2.65.212/3093.2.65.213 to 93.2.65.21493.2.65.2152
11993.2.65.216/3093.2.65.217 to 93.2.65.21893.2.65.2192
12093.2.65.220/3093.2.65.221 to 93.2.65.22293.2.65.2232
12193.2.65.224/3093.2.65.225 to 93.2.65.22693.2.65.2272
12293.2.65.228/3093.2.65.229 to 93.2.65.23093.2.65.2312
12393.2.65.232/3093.2.65.233 to 93.2.65.23493.2.65.2352
12493.2.65.236/3093.2.65.237 to 93.2.65.23893.2.65.2392
12593.2.65.240/3093.2.65.241 to 93.2.65.24293.2.65.2432
12693.2.65.244/3093.2.65.245 to 93.2.65.24693.2.65.2472
12793.2.65.248/3093.2.65.249 to 93.2.65.25093.2.65.2512
12893.2.65.252/3093.2.65.253 to 93.2.65.25493.2.65.2552
12993.2.66.0/3093.2.66.1 to 93.2.66.293.2.66.32
13093.2.66.4/3093.2.66.5 to 93.2.66.693.2.66.72
13193.2.66.8/3093.2.66.9 to 93.2.66.1093.2.66.112
13293.2.66.12/3093.2.66.13 to 93.2.66.1493.2.66.152
13393.2.66.16/3093.2.66.17 to 93.2.66.1893.2.66.192
13493.2.66.20/3093.2.66.21 to 93.2.66.2293.2.66.232
13593.2.66.24/3093.2.66.25 to 93.2.66.2693.2.66.272
13693.2.66.28/3093.2.66.29 to 93.2.66.3093.2.66.312
13793.2.66.32/3093.2.66.33 to 93.2.66.3493.2.66.352
13893.2.66.36/3093.2.66.37 to 93.2.66.3893.2.66.392
13993.2.66.40/3093.2.66.41 to 93.2.66.4293.2.66.432
14093.2.66.44/3093.2.66.45 to 93.2.66.4693.2.66.472
14193.2.66.48/3093.2.66.49 to 93.2.66.5093.2.66.512
14293.2.66.52/3093.2.66.53 to 93.2.66.5493.2.66.552
14393.2.66.56/3093.2.66.57 to 93.2.66.5893.2.66.592
14493.2.66.60/3093.2.66.61 to 93.2.66.6293.2.66.632
14593.2.66.64/3093.2.66.65 to 93.2.66.6693.2.66.672
14693.2.66.68/3093.2.66.69 to 93.2.66.7093.2.66.712
14793.2.66.72/3093.2.66.73 to 93.2.66.7493.2.66.752
14893.2.66.76/3093.2.66.77 to 93.2.66.7893.2.66.792
14993.2.66.80/3093.2.66.81 to 93.2.66.8293.2.66.832
15093.2.66.84/3093.2.66.85 to 93.2.66.8693.2.66.872
15193.2.66.88/3093.2.66.89 to 93.2.66.9093.2.66.912
15293.2.66.92/3093.2.66.93 to 93.2.66.9493.2.66.952
15393.2.66.96/3093.2.66.97 to 93.2.66.9893.2.66.992
15493.2.66.100/3093.2.66.101 to 93.2.66.10293.2.66.1032
15593.2.66.104/3093.2.66.105 to 93.2.66.10693.2.66.1072
15693.2.66.108/3093.2.66.109 to 93.2.66.11093.2.66.1112
15793.2.66.112/3093.2.66.113 to 93.2.66.11493.2.66.1152
15893.2.66.116/3093.2.66.117 to 93.2.66.11893.2.66.1192
15993.2.66.120/3093.2.66.121 to 93.2.66.12293.2.66.1232
16093.2.66.124/3093.2.66.125 to 93.2.66.12693.2.66.1272
16193.2.66.128/3093.2.66.129 to 93.2.66.13093.2.66.1312
16293.2.66.132/3093.2.66.133 to 93.2.66.13493.2.66.1352
16393.2.66.136/3093.2.66.137 to 93.2.66.13893.2.66.1392
16493.2.66.140/3093.2.66.141 to 93.2.66.14293.2.66.1432
16593.2.66.144/3093.2.66.145 to 93.2.66.14693.2.66.1472
16693.2.66.148/3093.2.66.149 to 93.2.66.15093.2.66.1512
16793.2.66.152/3093.2.66.153 to 93.2.66.15493.2.66.1552
16893.2.66.156/3093.2.66.157 to 93.2.66.15893.2.66.1592
16993.2.66.160/3093.2.66.161 to 93.2.66.16293.2.66.1632
17093.2.66.164/3093.2.66.165 to 93.2.66.16693.2.66.1672
17193.2.66.168/3093.2.66.169 to 93.2.66.17093.2.66.1712
17293.2.66.172/3093.2.66.173 to 93.2.66.17493.2.66.1752
17393.2.66.176/3093.2.66.177 to 93.2.66.17893.2.66.1792
17493.2.66.180/3093.2.66.181 to 93.2.66.18293.2.66.1832
17593.2.66.184/3093.2.66.185 to 93.2.66.18693.2.66.1872
17693.2.66.188/3093.2.66.189 to 93.2.66.19093.2.66.1912
17793.2.66.192/3093.2.66.193 to 93.2.66.19493.2.66.1952
17893.2.66.196/3093.2.66.197 to 93.2.66.19893.2.66.1992
17993.2.66.200/3093.2.66.201 to 93.2.66.20293.2.66.2032
18093.2.66.204/3093.2.66.205 to 93.2.66.20693.2.66.2072
18193.2.66.208/3093.2.66.209 to 93.2.66.21093.2.66.2112
18293.2.66.212/3093.2.66.213 to 93.2.66.21493.2.66.2152
18393.2.66.216/3093.2.66.217 to 93.2.66.21893.2.66.2192
18493.2.66.220/3093.2.66.221 to 93.2.66.22293.2.66.2232
18593.2.66.224/3093.2.66.225 to 93.2.66.22693.2.66.2272
18693.2.66.228/3093.2.66.229 to 93.2.66.23093.2.66.2312
18793.2.66.232/3093.2.66.233 to 93.2.66.23493.2.66.2352
18893.2.66.236/3093.2.66.237 to 93.2.66.23893.2.66.2392
18993.2.66.240/3093.2.66.241 to 93.2.66.24293.2.66.2432
19093.2.66.244/3093.2.66.245 to 93.2.66.24693.2.66.2472
19193.2.66.248/3093.2.66.249 to 93.2.66.25093.2.66.2512
19293.2.66.252/3093.2.66.253 to 93.2.66.25493.2.66.2552
19393.2.67.0/3093.2.67.1 to 93.2.67.293.2.67.32
19493.2.67.4/3093.2.67.5 to 93.2.67.693.2.67.72
19593.2.67.8/3093.2.67.9 to 93.2.67.1093.2.67.112
19693.2.67.12/3093.2.67.13 to 93.2.67.1493.2.67.152
19793.2.67.16/3093.2.67.17 to 93.2.67.1893.2.67.192
19893.2.67.20/3093.2.67.21 to 93.2.67.2293.2.67.232
19993.2.67.24/3093.2.67.25 to 93.2.67.2693.2.67.272
20093.2.67.28/3093.2.67.29 to 93.2.67.3093.2.67.312
20193.2.67.32/3093.2.67.33 to 93.2.67.3493.2.67.352
20293.2.67.36/3093.2.67.37 to 93.2.67.3893.2.67.392
20393.2.67.40/3093.2.67.41 to 93.2.67.4293.2.67.432
20493.2.67.44/3093.2.67.45 to 93.2.67.4693.2.67.472
20593.2.67.48/3093.2.67.49 to 93.2.67.5093.2.67.512
20693.2.67.52/3093.2.67.53 to 93.2.67.5493.2.67.552
20793.2.67.56/3093.2.67.57 to 93.2.67.5893.2.67.592
20893.2.67.60/3093.2.67.61 to 93.2.67.6293.2.67.632
20993.2.67.64/3093.2.67.65 to 93.2.67.6693.2.67.672
21093.2.67.68/3093.2.67.69 to 93.2.67.7093.2.67.712
21193.2.67.72/3093.2.67.73 to 93.2.67.7493.2.67.752
21293.2.67.76/3093.2.67.77 to 93.2.67.7893.2.67.792
21393.2.67.80/3093.2.67.81 to 93.2.67.8293.2.67.832
21493.2.67.84/3093.2.67.85 to 93.2.67.8693.2.67.872
21593.2.67.88/3093.2.67.89 to 93.2.67.9093.2.67.912
21693.2.67.92/3093.2.67.93 to 93.2.67.9493.2.67.952
21793.2.67.96/3093.2.67.97 to 93.2.67.9893.2.67.992
21893.2.67.100/3093.2.67.101 to 93.2.67.10293.2.67.1032
21993.2.67.104/3093.2.67.105 to 93.2.67.10693.2.67.1072
22093.2.67.108/3093.2.67.109 to 93.2.67.11093.2.67.1112
22193.2.67.112/3093.2.67.113 to 93.2.67.11493.2.67.1152
22293.2.67.116/3093.2.67.117 to 93.2.67.11893.2.67.1192
22393.2.67.120/3093.2.67.121 to 93.2.67.12293.2.67.1232
22493.2.67.124/3093.2.67.125 to 93.2.67.12693.2.67.1272
22593.2.67.128/3093.2.67.129 to 93.2.67.13093.2.67.1312
22693.2.67.132/3093.2.67.133 to 93.2.67.13493.2.67.1352
22793.2.67.136/3093.2.67.137 to 93.2.67.13893.2.67.1392
22893.2.67.140/3093.2.67.141 to 93.2.67.14293.2.67.1432
22993.2.67.144/3093.2.67.145 to 93.2.67.14693.2.67.1472
23093.2.67.148/3093.2.67.149 to 93.2.67.15093.2.67.1512
23193.2.67.152/3093.2.67.153 to 93.2.67.15493.2.67.1552
23293.2.67.156/3093.2.67.157 to 93.2.67.15893.2.67.1592
23393.2.67.160/3093.2.67.161 to 93.2.67.16293.2.67.1632
23493.2.67.164/3093.2.67.165 to 93.2.67.16693.2.67.1672
23593.2.67.168/3093.2.67.169 to 93.2.67.17093.2.67.1712
23693.2.67.172/3093.2.67.173 to 93.2.67.17493.2.67.1752
23793.2.67.176/3093.2.67.177 to 93.2.67.17893.2.67.1792
23893.2.67.180/3093.2.67.181 to 93.2.67.18293.2.67.1832
23993.2.67.184/3093.2.67.185 to 93.2.67.18693.2.67.1872
24093.2.67.188/3093.2.67.189 to 93.2.67.19093.2.67.1912
24193.2.67.192/3093.2.67.193 to 93.2.67.19493.2.67.1952
24293.2.67.196/3093.2.67.197 to 93.2.67.19893.2.67.1992
24393.2.67.200/3093.2.67.201 to 93.2.67.20293.2.67.2032
24493.2.67.204/3093.2.67.205 to 93.2.67.20693.2.67.2072
24593.2.67.208/3093.2.67.209 to 93.2.67.21093.2.67.2112
24693.2.67.212/3093.2.67.213 to 93.2.67.21493.2.67.2152
24793.2.67.216/3093.2.67.217 to 93.2.67.21893.2.67.2192
24893.2.67.220/3093.2.67.221 to 93.2.67.22293.2.67.2232
24993.2.67.224/3093.2.67.225 to 93.2.67.22693.2.67.2272
25093.2.67.228/3093.2.67.229 to 93.2.67.23093.2.67.2312
25193.2.67.232/3093.2.67.233 to 93.2.67.23493.2.67.2352
25293.2.67.236/3093.2.67.237 to 93.2.67.23893.2.67.2392
25393.2.67.240/3093.2.67.241 to 93.2.67.24293.2.67.2432
25493.2.67.244/3093.2.67.245 to 93.2.67.24693.2.67.2472
25593.2.67.248/3093.2.67.249 to 93.2.67.25093.2.67.2512
25693.2.67.252/3093.2.67.253 to 93.2.67.25493.2.67.2552

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.