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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.

Network77.2.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
77.2.64.0
Broadcast address
77.2.127.255
First usable
77.2.64.1
Last usable
77.2.127.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 4D024000 · Integer 1291993088 to 1292009471
Reverse DNS zones
64.2.77.in-addr.arpa
65.2.77.in-addr.arpa
66.2.77.in-addr.arpa
67.2.77.in-addr.arpa
68.2.77.in-addr.arpa
69.2.77.in-addr.arpa
70.2.77.in-addr.arpa
71.2.77.in-addr.arpa
72.2.77.in-addr.arpa
73.2.77.in-addr.arpa
74.2.77.in-addr.arpa
75.2.77.in-addr.arpa
76.2.77.in-addr.arpa
77.2.77.in-addr.arpa
78.2.77.in-addr.arpa
79.2.77.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001101.00000010.01000000.0000000077.2.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01001101.00000010.01000000.0000000077.2.64.0
Broadcast01001101.00000010.01111111.1111111177.2.127.255
Split into smaller subnets/28
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

77.2.64.0/18 makes 1,024 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
177.2.64.0/2877.2.64.1 to 77.2.64.1477.2.64.1514
277.2.64.16/2877.2.64.17 to 77.2.64.3077.2.64.3114
377.2.64.32/2877.2.64.33 to 77.2.64.4677.2.64.4714
477.2.64.48/2877.2.64.49 to 77.2.64.6277.2.64.6314
577.2.64.64/2877.2.64.65 to 77.2.64.7877.2.64.7914
677.2.64.80/2877.2.64.81 to 77.2.64.9477.2.64.9514
777.2.64.96/2877.2.64.97 to 77.2.64.11077.2.64.11114
877.2.64.112/2877.2.64.113 to 77.2.64.12677.2.64.12714
977.2.64.128/2877.2.64.129 to 77.2.64.14277.2.64.14314
1077.2.64.144/2877.2.64.145 to 77.2.64.15877.2.64.15914
1177.2.64.160/2877.2.64.161 to 77.2.64.17477.2.64.17514
1277.2.64.176/2877.2.64.177 to 77.2.64.19077.2.64.19114
1377.2.64.192/2877.2.64.193 to 77.2.64.20677.2.64.20714
1477.2.64.208/2877.2.64.209 to 77.2.64.22277.2.64.22314
1577.2.64.224/2877.2.64.225 to 77.2.64.23877.2.64.23914
1677.2.64.240/2877.2.64.241 to 77.2.64.25477.2.64.25514
1777.2.65.0/2877.2.65.1 to 77.2.65.1477.2.65.1514
1877.2.65.16/2877.2.65.17 to 77.2.65.3077.2.65.3114
1977.2.65.32/2877.2.65.33 to 77.2.65.4677.2.65.4714
2077.2.65.48/2877.2.65.49 to 77.2.65.6277.2.65.6314
2177.2.65.64/2877.2.65.65 to 77.2.65.7877.2.65.7914
2277.2.65.80/2877.2.65.81 to 77.2.65.9477.2.65.9514
2377.2.65.96/2877.2.65.97 to 77.2.65.11077.2.65.11114
2477.2.65.112/2877.2.65.113 to 77.2.65.12677.2.65.12714
2577.2.65.128/2877.2.65.129 to 77.2.65.14277.2.65.14314
2677.2.65.144/2877.2.65.145 to 77.2.65.15877.2.65.15914
2777.2.65.160/2877.2.65.161 to 77.2.65.17477.2.65.17514
2877.2.65.176/2877.2.65.177 to 77.2.65.19077.2.65.19114
2977.2.65.192/2877.2.65.193 to 77.2.65.20677.2.65.20714
3077.2.65.208/2877.2.65.209 to 77.2.65.22277.2.65.22314
3177.2.65.224/2877.2.65.225 to 77.2.65.23877.2.65.23914
3277.2.65.240/2877.2.65.241 to 77.2.65.25477.2.65.25514
3377.2.66.0/2877.2.66.1 to 77.2.66.1477.2.66.1514
3477.2.66.16/2877.2.66.17 to 77.2.66.3077.2.66.3114
3577.2.66.32/2877.2.66.33 to 77.2.66.4677.2.66.4714
3677.2.66.48/2877.2.66.49 to 77.2.66.6277.2.66.6314
3777.2.66.64/2877.2.66.65 to 77.2.66.7877.2.66.7914
3877.2.66.80/2877.2.66.81 to 77.2.66.9477.2.66.9514
3977.2.66.96/2877.2.66.97 to 77.2.66.11077.2.66.11114
4077.2.66.112/2877.2.66.113 to 77.2.66.12677.2.66.12714
4177.2.66.128/2877.2.66.129 to 77.2.66.14277.2.66.14314
4277.2.66.144/2877.2.66.145 to 77.2.66.15877.2.66.15914
4377.2.66.160/2877.2.66.161 to 77.2.66.17477.2.66.17514
4477.2.66.176/2877.2.66.177 to 77.2.66.19077.2.66.19114
4577.2.66.192/2877.2.66.193 to 77.2.66.20677.2.66.20714
4677.2.66.208/2877.2.66.209 to 77.2.66.22277.2.66.22314
4777.2.66.224/2877.2.66.225 to 77.2.66.23877.2.66.23914
4877.2.66.240/2877.2.66.241 to 77.2.66.25477.2.66.25514
4977.2.67.0/2877.2.67.1 to 77.2.67.1477.2.67.1514
5077.2.67.16/2877.2.67.17 to 77.2.67.3077.2.67.3114
5177.2.67.32/2877.2.67.33 to 77.2.67.4677.2.67.4714
5277.2.67.48/2877.2.67.49 to 77.2.67.6277.2.67.6314
5377.2.67.64/2877.2.67.65 to 77.2.67.7877.2.67.7914
5477.2.67.80/2877.2.67.81 to 77.2.67.9477.2.67.9514
5577.2.67.96/2877.2.67.97 to 77.2.67.11077.2.67.11114
5677.2.67.112/2877.2.67.113 to 77.2.67.12677.2.67.12714
5777.2.67.128/2877.2.67.129 to 77.2.67.14277.2.67.14314
5877.2.67.144/2877.2.67.145 to 77.2.67.15877.2.67.15914
5977.2.67.160/2877.2.67.161 to 77.2.67.17477.2.67.17514
6077.2.67.176/2877.2.67.177 to 77.2.67.19077.2.67.19114
6177.2.67.192/2877.2.67.193 to 77.2.67.20677.2.67.20714
6277.2.67.208/2877.2.67.209 to 77.2.67.22277.2.67.22314
6377.2.67.224/2877.2.67.225 to 77.2.67.23877.2.67.23914
6477.2.67.240/2877.2.67.241 to 77.2.67.25477.2.67.25514
6577.2.68.0/2877.2.68.1 to 77.2.68.1477.2.68.1514
6677.2.68.16/2877.2.68.17 to 77.2.68.3077.2.68.3114
6777.2.68.32/2877.2.68.33 to 77.2.68.4677.2.68.4714
6877.2.68.48/2877.2.68.49 to 77.2.68.6277.2.68.6314
6977.2.68.64/2877.2.68.65 to 77.2.68.7877.2.68.7914
7077.2.68.80/2877.2.68.81 to 77.2.68.9477.2.68.9514
7177.2.68.96/2877.2.68.97 to 77.2.68.11077.2.68.11114
7277.2.68.112/2877.2.68.113 to 77.2.68.12677.2.68.12714
7377.2.68.128/2877.2.68.129 to 77.2.68.14277.2.68.14314
7477.2.68.144/2877.2.68.145 to 77.2.68.15877.2.68.15914
7577.2.68.160/2877.2.68.161 to 77.2.68.17477.2.68.17514
7677.2.68.176/2877.2.68.177 to 77.2.68.19077.2.68.19114
7777.2.68.192/2877.2.68.193 to 77.2.68.20677.2.68.20714
7877.2.68.208/2877.2.68.209 to 77.2.68.22277.2.68.22314
7977.2.68.224/2877.2.68.225 to 77.2.68.23877.2.68.23914
8077.2.68.240/2877.2.68.241 to 77.2.68.25477.2.68.25514
8177.2.69.0/2877.2.69.1 to 77.2.69.1477.2.69.1514
8277.2.69.16/2877.2.69.17 to 77.2.69.3077.2.69.3114
8377.2.69.32/2877.2.69.33 to 77.2.69.4677.2.69.4714
8477.2.69.48/2877.2.69.49 to 77.2.69.6277.2.69.6314
8577.2.69.64/2877.2.69.65 to 77.2.69.7877.2.69.7914
8677.2.69.80/2877.2.69.81 to 77.2.69.9477.2.69.9514
8777.2.69.96/2877.2.69.97 to 77.2.69.11077.2.69.11114
8877.2.69.112/2877.2.69.113 to 77.2.69.12677.2.69.12714
8977.2.69.128/2877.2.69.129 to 77.2.69.14277.2.69.14314
9077.2.69.144/2877.2.69.145 to 77.2.69.15877.2.69.15914
9177.2.69.160/2877.2.69.161 to 77.2.69.17477.2.69.17514
9277.2.69.176/2877.2.69.177 to 77.2.69.19077.2.69.19114
9377.2.69.192/2877.2.69.193 to 77.2.69.20677.2.69.20714
9477.2.69.208/2877.2.69.209 to 77.2.69.22277.2.69.22314
9577.2.69.224/2877.2.69.225 to 77.2.69.23877.2.69.23914
9677.2.69.240/2877.2.69.241 to 77.2.69.25477.2.69.25514
9777.2.70.0/2877.2.70.1 to 77.2.70.1477.2.70.1514
9877.2.70.16/2877.2.70.17 to 77.2.70.3077.2.70.3114
9977.2.70.32/2877.2.70.33 to 77.2.70.4677.2.70.4714
10077.2.70.48/2877.2.70.49 to 77.2.70.6277.2.70.6314
10177.2.70.64/2877.2.70.65 to 77.2.70.7877.2.70.7914
10277.2.70.80/2877.2.70.81 to 77.2.70.9477.2.70.9514
10377.2.70.96/2877.2.70.97 to 77.2.70.11077.2.70.11114
10477.2.70.112/2877.2.70.113 to 77.2.70.12677.2.70.12714
10577.2.70.128/2877.2.70.129 to 77.2.70.14277.2.70.14314
10677.2.70.144/2877.2.70.145 to 77.2.70.15877.2.70.15914
10777.2.70.160/2877.2.70.161 to 77.2.70.17477.2.70.17514
10877.2.70.176/2877.2.70.177 to 77.2.70.19077.2.70.19114
10977.2.70.192/2877.2.70.193 to 77.2.70.20677.2.70.20714
11077.2.70.208/2877.2.70.209 to 77.2.70.22277.2.70.22314
11177.2.70.224/2877.2.70.225 to 77.2.70.23877.2.70.23914
11277.2.70.240/2877.2.70.241 to 77.2.70.25477.2.70.25514
11377.2.71.0/2877.2.71.1 to 77.2.71.1477.2.71.1514
11477.2.71.16/2877.2.71.17 to 77.2.71.3077.2.71.3114
11577.2.71.32/2877.2.71.33 to 77.2.71.4677.2.71.4714
11677.2.71.48/2877.2.71.49 to 77.2.71.6277.2.71.6314
11777.2.71.64/2877.2.71.65 to 77.2.71.7877.2.71.7914
11877.2.71.80/2877.2.71.81 to 77.2.71.9477.2.71.9514
11977.2.71.96/2877.2.71.97 to 77.2.71.11077.2.71.11114
12077.2.71.112/2877.2.71.113 to 77.2.71.12677.2.71.12714
12177.2.71.128/2877.2.71.129 to 77.2.71.14277.2.71.14314
12277.2.71.144/2877.2.71.145 to 77.2.71.15877.2.71.15914
12377.2.71.160/2877.2.71.161 to 77.2.71.17477.2.71.17514
12477.2.71.176/2877.2.71.177 to 77.2.71.19077.2.71.19114
12577.2.71.192/2877.2.71.193 to 77.2.71.20677.2.71.20714
12677.2.71.208/2877.2.71.209 to 77.2.71.22277.2.71.22314
12777.2.71.224/2877.2.71.225 to 77.2.71.23877.2.71.23914
12877.2.71.240/2877.2.71.241 to 77.2.71.25477.2.71.25514
12977.2.72.0/2877.2.72.1 to 77.2.72.1477.2.72.1514
13077.2.72.16/2877.2.72.17 to 77.2.72.3077.2.72.3114
13177.2.72.32/2877.2.72.33 to 77.2.72.4677.2.72.4714
13277.2.72.48/2877.2.72.49 to 77.2.72.6277.2.72.6314
13377.2.72.64/2877.2.72.65 to 77.2.72.7877.2.72.7914
13477.2.72.80/2877.2.72.81 to 77.2.72.9477.2.72.9514
13577.2.72.96/2877.2.72.97 to 77.2.72.11077.2.72.11114
13677.2.72.112/2877.2.72.113 to 77.2.72.12677.2.72.12714
13777.2.72.128/2877.2.72.129 to 77.2.72.14277.2.72.14314
13877.2.72.144/2877.2.72.145 to 77.2.72.15877.2.72.15914
13977.2.72.160/2877.2.72.161 to 77.2.72.17477.2.72.17514
14077.2.72.176/2877.2.72.177 to 77.2.72.19077.2.72.19114
14177.2.72.192/2877.2.72.193 to 77.2.72.20677.2.72.20714
14277.2.72.208/2877.2.72.209 to 77.2.72.22277.2.72.22314
14377.2.72.224/2877.2.72.225 to 77.2.72.23877.2.72.23914
14477.2.72.240/2877.2.72.241 to 77.2.72.25477.2.72.25514
14577.2.73.0/2877.2.73.1 to 77.2.73.1477.2.73.1514
14677.2.73.16/2877.2.73.17 to 77.2.73.3077.2.73.3114
14777.2.73.32/2877.2.73.33 to 77.2.73.4677.2.73.4714
14877.2.73.48/2877.2.73.49 to 77.2.73.6277.2.73.6314
14977.2.73.64/2877.2.73.65 to 77.2.73.7877.2.73.7914
15077.2.73.80/2877.2.73.81 to 77.2.73.9477.2.73.9514
15177.2.73.96/2877.2.73.97 to 77.2.73.11077.2.73.11114
15277.2.73.112/2877.2.73.113 to 77.2.73.12677.2.73.12714
15377.2.73.128/2877.2.73.129 to 77.2.73.14277.2.73.14314
15477.2.73.144/2877.2.73.145 to 77.2.73.15877.2.73.15914
15577.2.73.160/2877.2.73.161 to 77.2.73.17477.2.73.17514
15677.2.73.176/2877.2.73.177 to 77.2.73.19077.2.73.19114
15777.2.73.192/2877.2.73.193 to 77.2.73.20677.2.73.20714
15877.2.73.208/2877.2.73.209 to 77.2.73.22277.2.73.22314
15977.2.73.224/2877.2.73.225 to 77.2.73.23877.2.73.23914
16077.2.73.240/2877.2.73.241 to 77.2.73.25477.2.73.25514
16177.2.74.0/2877.2.74.1 to 77.2.74.1477.2.74.1514
16277.2.74.16/2877.2.74.17 to 77.2.74.3077.2.74.3114
16377.2.74.32/2877.2.74.33 to 77.2.74.4677.2.74.4714
16477.2.74.48/2877.2.74.49 to 77.2.74.6277.2.74.6314
16577.2.74.64/2877.2.74.65 to 77.2.74.7877.2.74.7914
16677.2.74.80/2877.2.74.81 to 77.2.74.9477.2.74.9514
16777.2.74.96/2877.2.74.97 to 77.2.74.11077.2.74.11114
16877.2.74.112/2877.2.74.113 to 77.2.74.12677.2.74.12714
16977.2.74.128/2877.2.74.129 to 77.2.74.14277.2.74.14314
17077.2.74.144/2877.2.74.145 to 77.2.74.15877.2.74.15914
17177.2.74.160/2877.2.74.161 to 77.2.74.17477.2.74.17514
17277.2.74.176/2877.2.74.177 to 77.2.74.19077.2.74.19114
17377.2.74.192/2877.2.74.193 to 77.2.74.20677.2.74.20714
17477.2.74.208/2877.2.74.209 to 77.2.74.22277.2.74.22314
17577.2.74.224/2877.2.74.225 to 77.2.74.23877.2.74.23914
17677.2.74.240/2877.2.74.241 to 77.2.74.25477.2.74.25514
17777.2.75.0/2877.2.75.1 to 77.2.75.1477.2.75.1514
17877.2.75.16/2877.2.75.17 to 77.2.75.3077.2.75.3114
17977.2.75.32/2877.2.75.33 to 77.2.75.4677.2.75.4714
18077.2.75.48/2877.2.75.49 to 77.2.75.6277.2.75.6314
18177.2.75.64/2877.2.75.65 to 77.2.75.7877.2.75.7914
18277.2.75.80/2877.2.75.81 to 77.2.75.9477.2.75.9514
18377.2.75.96/2877.2.75.97 to 77.2.75.11077.2.75.11114
18477.2.75.112/2877.2.75.113 to 77.2.75.12677.2.75.12714
18577.2.75.128/2877.2.75.129 to 77.2.75.14277.2.75.14314
18677.2.75.144/2877.2.75.145 to 77.2.75.15877.2.75.15914
18777.2.75.160/2877.2.75.161 to 77.2.75.17477.2.75.17514
18877.2.75.176/2877.2.75.177 to 77.2.75.19077.2.75.19114
18977.2.75.192/2877.2.75.193 to 77.2.75.20677.2.75.20714
19077.2.75.208/2877.2.75.209 to 77.2.75.22277.2.75.22314
19177.2.75.224/2877.2.75.225 to 77.2.75.23877.2.75.23914
19277.2.75.240/2877.2.75.241 to 77.2.75.25477.2.75.25514
19377.2.76.0/2877.2.76.1 to 77.2.76.1477.2.76.1514
19477.2.76.16/2877.2.76.17 to 77.2.76.3077.2.76.3114
19577.2.76.32/2877.2.76.33 to 77.2.76.4677.2.76.4714
19677.2.76.48/2877.2.76.49 to 77.2.76.6277.2.76.6314
19777.2.76.64/2877.2.76.65 to 77.2.76.7877.2.76.7914
19877.2.76.80/2877.2.76.81 to 77.2.76.9477.2.76.9514
19977.2.76.96/2877.2.76.97 to 77.2.76.11077.2.76.11114
20077.2.76.112/2877.2.76.113 to 77.2.76.12677.2.76.12714
20177.2.76.128/2877.2.76.129 to 77.2.76.14277.2.76.14314
20277.2.76.144/2877.2.76.145 to 77.2.76.15877.2.76.15914
20377.2.76.160/2877.2.76.161 to 77.2.76.17477.2.76.17514
20477.2.76.176/2877.2.76.177 to 77.2.76.19077.2.76.19114
20577.2.76.192/2877.2.76.193 to 77.2.76.20677.2.76.20714
20677.2.76.208/2877.2.76.209 to 77.2.76.22277.2.76.22314
20777.2.76.224/2877.2.76.225 to 77.2.76.23877.2.76.23914
20877.2.76.240/2877.2.76.241 to 77.2.76.25477.2.76.25514
20977.2.77.0/2877.2.77.1 to 77.2.77.1477.2.77.1514
21077.2.77.16/2877.2.77.17 to 77.2.77.3077.2.77.3114
21177.2.77.32/2877.2.77.33 to 77.2.77.4677.2.77.4714
21277.2.77.48/2877.2.77.49 to 77.2.77.6277.2.77.6314
21377.2.77.64/2877.2.77.65 to 77.2.77.7877.2.77.7914
21477.2.77.80/2877.2.77.81 to 77.2.77.9477.2.77.9514
21577.2.77.96/2877.2.77.97 to 77.2.77.11077.2.77.11114
21677.2.77.112/2877.2.77.113 to 77.2.77.12677.2.77.12714
21777.2.77.128/2877.2.77.129 to 77.2.77.14277.2.77.14314
21877.2.77.144/2877.2.77.145 to 77.2.77.15877.2.77.15914
21977.2.77.160/2877.2.77.161 to 77.2.77.17477.2.77.17514
22077.2.77.176/2877.2.77.177 to 77.2.77.19077.2.77.19114
22177.2.77.192/2877.2.77.193 to 77.2.77.20677.2.77.20714
22277.2.77.208/2877.2.77.209 to 77.2.77.22277.2.77.22314
22377.2.77.224/2877.2.77.225 to 77.2.77.23877.2.77.23914
22477.2.77.240/2877.2.77.241 to 77.2.77.25477.2.77.25514
22577.2.78.0/2877.2.78.1 to 77.2.78.1477.2.78.1514
22677.2.78.16/2877.2.78.17 to 77.2.78.3077.2.78.3114
22777.2.78.32/2877.2.78.33 to 77.2.78.4677.2.78.4714
22877.2.78.48/2877.2.78.49 to 77.2.78.6277.2.78.6314
22977.2.78.64/2877.2.78.65 to 77.2.78.7877.2.78.7914
23077.2.78.80/2877.2.78.81 to 77.2.78.9477.2.78.9514
23177.2.78.96/2877.2.78.97 to 77.2.78.11077.2.78.11114
23277.2.78.112/2877.2.78.113 to 77.2.78.12677.2.78.12714
23377.2.78.128/2877.2.78.129 to 77.2.78.14277.2.78.14314
23477.2.78.144/2877.2.78.145 to 77.2.78.15877.2.78.15914
23577.2.78.160/2877.2.78.161 to 77.2.78.17477.2.78.17514
23677.2.78.176/2877.2.78.177 to 77.2.78.19077.2.78.19114
23777.2.78.192/2877.2.78.193 to 77.2.78.20677.2.78.20714
23877.2.78.208/2877.2.78.209 to 77.2.78.22277.2.78.22314
23977.2.78.224/2877.2.78.225 to 77.2.78.23877.2.78.23914
24077.2.78.240/2877.2.78.241 to 77.2.78.25477.2.78.25514
24177.2.79.0/2877.2.79.1 to 77.2.79.1477.2.79.1514
24277.2.79.16/2877.2.79.17 to 77.2.79.3077.2.79.3114
24377.2.79.32/2877.2.79.33 to 77.2.79.4677.2.79.4714
24477.2.79.48/2877.2.79.49 to 77.2.79.6277.2.79.6314
24577.2.79.64/2877.2.79.65 to 77.2.79.7877.2.79.7914
24677.2.79.80/2877.2.79.81 to 77.2.79.9477.2.79.9514
24777.2.79.96/2877.2.79.97 to 77.2.79.11077.2.79.11114
24877.2.79.112/2877.2.79.113 to 77.2.79.12677.2.79.12714
24977.2.79.128/2877.2.79.129 to 77.2.79.14277.2.79.14314
25077.2.79.144/2877.2.79.145 to 77.2.79.15877.2.79.15914
25177.2.79.160/2877.2.79.161 to 77.2.79.17477.2.79.17514
25277.2.79.176/2877.2.79.177 to 77.2.79.19077.2.79.19114
25377.2.79.192/2877.2.79.193 to 77.2.79.20677.2.79.20714
25477.2.79.208/2877.2.79.209 to 77.2.79.22277.2.79.22314
25577.2.79.224/2877.2.79.225 to 77.2.79.23877.2.79.23914
25677.2.79.240/2877.2.79.241 to 77.2.79.25477.2.79.25514

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.