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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/26
/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 256 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
177.2.64.0/2677.2.64.1 to 77.2.64.6277.2.64.6362
277.2.64.64/2677.2.64.65 to 77.2.64.12677.2.64.12762
377.2.64.128/2677.2.64.129 to 77.2.64.19077.2.64.19162
477.2.64.192/2677.2.64.193 to 77.2.64.25477.2.64.25562
577.2.65.0/2677.2.65.1 to 77.2.65.6277.2.65.6362
677.2.65.64/2677.2.65.65 to 77.2.65.12677.2.65.12762
777.2.65.128/2677.2.65.129 to 77.2.65.19077.2.65.19162
877.2.65.192/2677.2.65.193 to 77.2.65.25477.2.65.25562
977.2.66.0/2677.2.66.1 to 77.2.66.6277.2.66.6362
1077.2.66.64/2677.2.66.65 to 77.2.66.12677.2.66.12762
1177.2.66.128/2677.2.66.129 to 77.2.66.19077.2.66.19162
1277.2.66.192/2677.2.66.193 to 77.2.66.25477.2.66.25562
1377.2.67.0/2677.2.67.1 to 77.2.67.6277.2.67.6362
1477.2.67.64/2677.2.67.65 to 77.2.67.12677.2.67.12762
1577.2.67.128/2677.2.67.129 to 77.2.67.19077.2.67.19162
1677.2.67.192/2677.2.67.193 to 77.2.67.25477.2.67.25562
1777.2.68.0/2677.2.68.1 to 77.2.68.6277.2.68.6362
1877.2.68.64/2677.2.68.65 to 77.2.68.12677.2.68.12762
1977.2.68.128/2677.2.68.129 to 77.2.68.19077.2.68.19162
2077.2.68.192/2677.2.68.193 to 77.2.68.25477.2.68.25562
2177.2.69.0/2677.2.69.1 to 77.2.69.6277.2.69.6362
2277.2.69.64/2677.2.69.65 to 77.2.69.12677.2.69.12762
2377.2.69.128/2677.2.69.129 to 77.2.69.19077.2.69.19162
2477.2.69.192/2677.2.69.193 to 77.2.69.25477.2.69.25562
2577.2.70.0/2677.2.70.1 to 77.2.70.6277.2.70.6362
2677.2.70.64/2677.2.70.65 to 77.2.70.12677.2.70.12762
2777.2.70.128/2677.2.70.129 to 77.2.70.19077.2.70.19162
2877.2.70.192/2677.2.70.193 to 77.2.70.25477.2.70.25562
2977.2.71.0/2677.2.71.1 to 77.2.71.6277.2.71.6362
3077.2.71.64/2677.2.71.65 to 77.2.71.12677.2.71.12762
3177.2.71.128/2677.2.71.129 to 77.2.71.19077.2.71.19162
3277.2.71.192/2677.2.71.193 to 77.2.71.25477.2.71.25562
3377.2.72.0/2677.2.72.1 to 77.2.72.6277.2.72.6362
3477.2.72.64/2677.2.72.65 to 77.2.72.12677.2.72.12762
3577.2.72.128/2677.2.72.129 to 77.2.72.19077.2.72.19162
3677.2.72.192/2677.2.72.193 to 77.2.72.25477.2.72.25562
3777.2.73.0/2677.2.73.1 to 77.2.73.6277.2.73.6362
3877.2.73.64/2677.2.73.65 to 77.2.73.12677.2.73.12762
3977.2.73.128/2677.2.73.129 to 77.2.73.19077.2.73.19162
4077.2.73.192/2677.2.73.193 to 77.2.73.25477.2.73.25562
4177.2.74.0/2677.2.74.1 to 77.2.74.6277.2.74.6362
4277.2.74.64/2677.2.74.65 to 77.2.74.12677.2.74.12762
4377.2.74.128/2677.2.74.129 to 77.2.74.19077.2.74.19162
4477.2.74.192/2677.2.74.193 to 77.2.74.25477.2.74.25562
4577.2.75.0/2677.2.75.1 to 77.2.75.6277.2.75.6362
4677.2.75.64/2677.2.75.65 to 77.2.75.12677.2.75.12762
4777.2.75.128/2677.2.75.129 to 77.2.75.19077.2.75.19162
4877.2.75.192/2677.2.75.193 to 77.2.75.25477.2.75.25562
4977.2.76.0/2677.2.76.1 to 77.2.76.6277.2.76.6362
5077.2.76.64/2677.2.76.65 to 77.2.76.12677.2.76.12762
5177.2.76.128/2677.2.76.129 to 77.2.76.19077.2.76.19162
5277.2.76.192/2677.2.76.193 to 77.2.76.25477.2.76.25562
5377.2.77.0/2677.2.77.1 to 77.2.77.6277.2.77.6362
5477.2.77.64/2677.2.77.65 to 77.2.77.12677.2.77.12762
5577.2.77.128/2677.2.77.129 to 77.2.77.19077.2.77.19162
5677.2.77.192/2677.2.77.193 to 77.2.77.25477.2.77.25562
5777.2.78.0/2677.2.78.1 to 77.2.78.6277.2.78.6362
5877.2.78.64/2677.2.78.65 to 77.2.78.12677.2.78.12762
5977.2.78.128/2677.2.78.129 to 77.2.78.19077.2.78.19162
6077.2.78.192/2677.2.78.193 to 77.2.78.25477.2.78.25562
6177.2.79.0/2677.2.79.1 to 77.2.79.6277.2.79.6362
6277.2.79.64/2677.2.79.65 to 77.2.79.12677.2.79.12762
6377.2.79.128/2677.2.79.129 to 77.2.79.19077.2.79.19162
6477.2.79.192/2677.2.79.193 to 77.2.79.25477.2.79.25562
6577.2.80.0/2677.2.80.1 to 77.2.80.6277.2.80.6362
6677.2.80.64/2677.2.80.65 to 77.2.80.12677.2.80.12762
6777.2.80.128/2677.2.80.129 to 77.2.80.19077.2.80.19162
6877.2.80.192/2677.2.80.193 to 77.2.80.25477.2.80.25562
6977.2.81.0/2677.2.81.1 to 77.2.81.6277.2.81.6362
7077.2.81.64/2677.2.81.65 to 77.2.81.12677.2.81.12762
7177.2.81.128/2677.2.81.129 to 77.2.81.19077.2.81.19162
7277.2.81.192/2677.2.81.193 to 77.2.81.25477.2.81.25562
7377.2.82.0/2677.2.82.1 to 77.2.82.6277.2.82.6362
7477.2.82.64/2677.2.82.65 to 77.2.82.12677.2.82.12762
7577.2.82.128/2677.2.82.129 to 77.2.82.19077.2.82.19162
7677.2.82.192/2677.2.82.193 to 77.2.82.25477.2.82.25562
7777.2.83.0/2677.2.83.1 to 77.2.83.6277.2.83.6362
7877.2.83.64/2677.2.83.65 to 77.2.83.12677.2.83.12762
7977.2.83.128/2677.2.83.129 to 77.2.83.19077.2.83.19162
8077.2.83.192/2677.2.83.193 to 77.2.83.25477.2.83.25562
8177.2.84.0/2677.2.84.1 to 77.2.84.6277.2.84.6362
8277.2.84.64/2677.2.84.65 to 77.2.84.12677.2.84.12762
8377.2.84.128/2677.2.84.129 to 77.2.84.19077.2.84.19162
8477.2.84.192/2677.2.84.193 to 77.2.84.25477.2.84.25562
8577.2.85.0/2677.2.85.1 to 77.2.85.6277.2.85.6362
8677.2.85.64/2677.2.85.65 to 77.2.85.12677.2.85.12762
8777.2.85.128/2677.2.85.129 to 77.2.85.19077.2.85.19162
8877.2.85.192/2677.2.85.193 to 77.2.85.25477.2.85.25562
8977.2.86.0/2677.2.86.1 to 77.2.86.6277.2.86.6362
9077.2.86.64/2677.2.86.65 to 77.2.86.12677.2.86.12762
9177.2.86.128/2677.2.86.129 to 77.2.86.19077.2.86.19162
9277.2.86.192/2677.2.86.193 to 77.2.86.25477.2.86.25562
9377.2.87.0/2677.2.87.1 to 77.2.87.6277.2.87.6362
9477.2.87.64/2677.2.87.65 to 77.2.87.12677.2.87.12762
9577.2.87.128/2677.2.87.129 to 77.2.87.19077.2.87.19162
9677.2.87.192/2677.2.87.193 to 77.2.87.25477.2.87.25562
9777.2.88.0/2677.2.88.1 to 77.2.88.6277.2.88.6362
9877.2.88.64/2677.2.88.65 to 77.2.88.12677.2.88.12762
9977.2.88.128/2677.2.88.129 to 77.2.88.19077.2.88.19162
10077.2.88.192/2677.2.88.193 to 77.2.88.25477.2.88.25562
10177.2.89.0/2677.2.89.1 to 77.2.89.6277.2.89.6362
10277.2.89.64/2677.2.89.65 to 77.2.89.12677.2.89.12762
10377.2.89.128/2677.2.89.129 to 77.2.89.19077.2.89.19162
10477.2.89.192/2677.2.89.193 to 77.2.89.25477.2.89.25562
10577.2.90.0/2677.2.90.1 to 77.2.90.6277.2.90.6362
10677.2.90.64/2677.2.90.65 to 77.2.90.12677.2.90.12762
10777.2.90.128/2677.2.90.129 to 77.2.90.19077.2.90.19162
10877.2.90.192/2677.2.90.193 to 77.2.90.25477.2.90.25562
10977.2.91.0/2677.2.91.1 to 77.2.91.6277.2.91.6362
11077.2.91.64/2677.2.91.65 to 77.2.91.12677.2.91.12762
11177.2.91.128/2677.2.91.129 to 77.2.91.19077.2.91.19162
11277.2.91.192/2677.2.91.193 to 77.2.91.25477.2.91.25562
11377.2.92.0/2677.2.92.1 to 77.2.92.6277.2.92.6362
11477.2.92.64/2677.2.92.65 to 77.2.92.12677.2.92.12762
11577.2.92.128/2677.2.92.129 to 77.2.92.19077.2.92.19162
11677.2.92.192/2677.2.92.193 to 77.2.92.25477.2.92.25562
11777.2.93.0/2677.2.93.1 to 77.2.93.6277.2.93.6362
11877.2.93.64/2677.2.93.65 to 77.2.93.12677.2.93.12762
11977.2.93.128/2677.2.93.129 to 77.2.93.19077.2.93.19162
12077.2.93.192/2677.2.93.193 to 77.2.93.25477.2.93.25562
12177.2.94.0/2677.2.94.1 to 77.2.94.6277.2.94.6362
12277.2.94.64/2677.2.94.65 to 77.2.94.12677.2.94.12762
12377.2.94.128/2677.2.94.129 to 77.2.94.19077.2.94.19162
12477.2.94.192/2677.2.94.193 to 77.2.94.25477.2.94.25562
12577.2.95.0/2677.2.95.1 to 77.2.95.6277.2.95.6362
12677.2.95.64/2677.2.95.65 to 77.2.95.12677.2.95.12762
12777.2.95.128/2677.2.95.129 to 77.2.95.19077.2.95.19162
12877.2.95.192/2677.2.95.193 to 77.2.95.25477.2.95.25562
12977.2.96.0/2677.2.96.1 to 77.2.96.6277.2.96.6362
13077.2.96.64/2677.2.96.65 to 77.2.96.12677.2.96.12762
13177.2.96.128/2677.2.96.129 to 77.2.96.19077.2.96.19162
13277.2.96.192/2677.2.96.193 to 77.2.96.25477.2.96.25562
13377.2.97.0/2677.2.97.1 to 77.2.97.6277.2.97.6362
13477.2.97.64/2677.2.97.65 to 77.2.97.12677.2.97.12762
13577.2.97.128/2677.2.97.129 to 77.2.97.19077.2.97.19162
13677.2.97.192/2677.2.97.193 to 77.2.97.25477.2.97.25562
13777.2.98.0/2677.2.98.1 to 77.2.98.6277.2.98.6362
13877.2.98.64/2677.2.98.65 to 77.2.98.12677.2.98.12762
13977.2.98.128/2677.2.98.129 to 77.2.98.19077.2.98.19162
14077.2.98.192/2677.2.98.193 to 77.2.98.25477.2.98.25562
14177.2.99.0/2677.2.99.1 to 77.2.99.6277.2.99.6362
14277.2.99.64/2677.2.99.65 to 77.2.99.12677.2.99.12762
14377.2.99.128/2677.2.99.129 to 77.2.99.19077.2.99.19162
14477.2.99.192/2677.2.99.193 to 77.2.99.25477.2.99.25562
14577.2.100.0/2677.2.100.1 to 77.2.100.6277.2.100.6362
14677.2.100.64/2677.2.100.65 to 77.2.100.12677.2.100.12762
14777.2.100.128/2677.2.100.129 to 77.2.100.19077.2.100.19162
14877.2.100.192/2677.2.100.193 to 77.2.100.25477.2.100.25562
14977.2.101.0/2677.2.101.1 to 77.2.101.6277.2.101.6362
15077.2.101.64/2677.2.101.65 to 77.2.101.12677.2.101.12762
15177.2.101.128/2677.2.101.129 to 77.2.101.19077.2.101.19162
15277.2.101.192/2677.2.101.193 to 77.2.101.25477.2.101.25562
15377.2.102.0/2677.2.102.1 to 77.2.102.6277.2.102.6362
15477.2.102.64/2677.2.102.65 to 77.2.102.12677.2.102.12762
15577.2.102.128/2677.2.102.129 to 77.2.102.19077.2.102.19162
15677.2.102.192/2677.2.102.193 to 77.2.102.25477.2.102.25562
15777.2.103.0/2677.2.103.1 to 77.2.103.6277.2.103.6362
15877.2.103.64/2677.2.103.65 to 77.2.103.12677.2.103.12762
15977.2.103.128/2677.2.103.129 to 77.2.103.19077.2.103.19162
16077.2.103.192/2677.2.103.193 to 77.2.103.25477.2.103.25562
16177.2.104.0/2677.2.104.1 to 77.2.104.6277.2.104.6362
16277.2.104.64/2677.2.104.65 to 77.2.104.12677.2.104.12762
16377.2.104.128/2677.2.104.129 to 77.2.104.19077.2.104.19162
16477.2.104.192/2677.2.104.193 to 77.2.104.25477.2.104.25562
16577.2.105.0/2677.2.105.1 to 77.2.105.6277.2.105.6362
16677.2.105.64/2677.2.105.65 to 77.2.105.12677.2.105.12762
16777.2.105.128/2677.2.105.129 to 77.2.105.19077.2.105.19162
16877.2.105.192/2677.2.105.193 to 77.2.105.25477.2.105.25562
16977.2.106.0/2677.2.106.1 to 77.2.106.6277.2.106.6362
17077.2.106.64/2677.2.106.65 to 77.2.106.12677.2.106.12762
17177.2.106.128/2677.2.106.129 to 77.2.106.19077.2.106.19162
17277.2.106.192/2677.2.106.193 to 77.2.106.25477.2.106.25562
17377.2.107.0/2677.2.107.1 to 77.2.107.6277.2.107.6362
17477.2.107.64/2677.2.107.65 to 77.2.107.12677.2.107.12762
17577.2.107.128/2677.2.107.129 to 77.2.107.19077.2.107.19162
17677.2.107.192/2677.2.107.193 to 77.2.107.25477.2.107.25562
17777.2.108.0/2677.2.108.1 to 77.2.108.6277.2.108.6362
17877.2.108.64/2677.2.108.65 to 77.2.108.12677.2.108.12762
17977.2.108.128/2677.2.108.129 to 77.2.108.19077.2.108.19162
18077.2.108.192/2677.2.108.193 to 77.2.108.25477.2.108.25562
18177.2.109.0/2677.2.109.1 to 77.2.109.6277.2.109.6362
18277.2.109.64/2677.2.109.65 to 77.2.109.12677.2.109.12762
18377.2.109.128/2677.2.109.129 to 77.2.109.19077.2.109.19162
18477.2.109.192/2677.2.109.193 to 77.2.109.25477.2.109.25562
18577.2.110.0/2677.2.110.1 to 77.2.110.6277.2.110.6362
18677.2.110.64/2677.2.110.65 to 77.2.110.12677.2.110.12762
18777.2.110.128/2677.2.110.129 to 77.2.110.19077.2.110.19162
18877.2.110.192/2677.2.110.193 to 77.2.110.25477.2.110.25562
18977.2.111.0/2677.2.111.1 to 77.2.111.6277.2.111.6362
19077.2.111.64/2677.2.111.65 to 77.2.111.12677.2.111.12762
19177.2.111.128/2677.2.111.129 to 77.2.111.19077.2.111.19162
19277.2.111.192/2677.2.111.193 to 77.2.111.25477.2.111.25562
19377.2.112.0/2677.2.112.1 to 77.2.112.6277.2.112.6362
19477.2.112.64/2677.2.112.65 to 77.2.112.12677.2.112.12762
19577.2.112.128/2677.2.112.129 to 77.2.112.19077.2.112.19162
19677.2.112.192/2677.2.112.193 to 77.2.112.25477.2.112.25562
19777.2.113.0/2677.2.113.1 to 77.2.113.6277.2.113.6362
19877.2.113.64/2677.2.113.65 to 77.2.113.12677.2.113.12762
19977.2.113.128/2677.2.113.129 to 77.2.113.19077.2.113.19162
20077.2.113.192/2677.2.113.193 to 77.2.113.25477.2.113.25562
20177.2.114.0/2677.2.114.1 to 77.2.114.6277.2.114.6362
20277.2.114.64/2677.2.114.65 to 77.2.114.12677.2.114.12762
20377.2.114.128/2677.2.114.129 to 77.2.114.19077.2.114.19162
20477.2.114.192/2677.2.114.193 to 77.2.114.25477.2.114.25562
20577.2.115.0/2677.2.115.1 to 77.2.115.6277.2.115.6362
20677.2.115.64/2677.2.115.65 to 77.2.115.12677.2.115.12762
20777.2.115.128/2677.2.115.129 to 77.2.115.19077.2.115.19162
20877.2.115.192/2677.2.115.193 to 77.2.115.25477.2.115.25562
20977.2.116.0/2677.2.116.1 to 77.2.116.6277.2.116.6362
21077.2.116.64/2677.2.116.65 to 77.2.116.12677.2.116.12762
21177.2.116.128/2677.2.116.129 to 77.2.116.19077.2.116.19162
21277.2.116.192/2677.2.116.193 to 77.2.116.25477.2.116.25562
21377.2.117.0/2677.2.117.1 to 77.2.117.6277.2.117.6362
21477.2.117.64/2677.2.117.65 to 77.2.117.12677.2.117.12762
21577.2.117.128/2677.2.117.129 to 77.2.117.19077.2.117.19162
21677.2.117.192/2677.2.117.193 to 77.2.117.25477.2.117.25562
21777.2.118.0/2677.2.118.1 to 77.2.118.6277.2.118.6362
21877.2.118.64/2677.2.118.65 to 77.2.118.12677.2.118.12762
21977.2.118.128/2677.2.118.129 to 77.2.118.19077.2.118.19162
22077.2.118.192/2677.2.118.193 to 77.2.118.25477.2.118.25562
22177.2.119.0/2677.2.119.1 to 77.2.119.6277.2.119.6362
22277.2.119.64/2677.2.119.65 to 77.2.119.12677.2.119.12762
22377.2.119.128/2677.2.119.129 to 77.2.119.19077.2.119.19162
22477.2.119.192/2677.2.119.193 to 77.2.119.25477.2.119.25562
22577.2.120.0/2677.2.120.1 to 77.2.120.6277.2.120.6362
22677.2.120.64/2677.2.120.65 to 77.2.120.12677.2.120.12762
22777.2.120.128/2677.2.120.129 to 77.2.120.19077.2.120.19162
22877.2.120.192/2677.2.120.193 to 77.2.120.25477.2.120.25562
22977.2.121.0/2677.2.121.1 to 77.2.121.6277.2.121.6362
23077.2.121.64/2677.2.121.65 to 77.2.121.12677.2.121.12762
23177.2.121.128/2677.2.121.129 to 77.2.121.19077.2.121.19162
23277.2.121.192/2677.2.121.193 to 77.2.121.25477.2.121.25562
23377.2.122.0/2677.2.122.1 to 77.2.122.6277.2.122.6362
23477.2.122.64/2677.2.122.65 to 77.2.122.12677.2.122.12762
23577.2.122.128/2677.2.122.129 to 77.2.122.19077.2.122.19162
23677.2.122.192/2677.2.122.193 to 77.2.122.25477.2.122.25562
23777.2.123.0/2677.2.123.1 to 77.2.123.6277.2.123.6362
23877.2.123.64/2677.2.123.65 to 77.2.123.12677.2.123.12762
23977.2.123.128/2677.2.123.129 to 77.2.123.19077.2.123.19162
24077.2.123.192/2677.2.123.193 to 77.2.123.25477.2.123.25562
24177.2.124.0/2677.2.124.1 to 77.2.124.6277.2.124.6362
24277.2.124.64/2677.2.124.65 to 77.2.124.12677.2.124.12762
24377.2.124.128/2677.2.124.129 to 77.2.124.19077.2.124.19162
24477.2.124.192/2677.2.124.193 to 77.2.124.25477.2.124.25562
24577.2.125.0/2677.2.125.1 to 77.2.125.6277.2.125.6362
24677.2.125.64/2677.2.125.65 to 77.2.125.12677.2.125.12762
24777.2.125.128/2677.2.125.129 to 77.2.125.19077.2.125.19162
24877.2.125.192/2677.2.125.193 to 77.2.125.25477.2.125.25562
24977.2.126.0/2677.2.126.1 to 77.2.126.6277.2.126.6362
25077.2.126.64/2677.2.126.65 to 77.2.126.12677.2.126.12762
25177.2.126.128/2677.2.126.129 to 77.2.126.19077.2.126.19162
25277.2.126.192/2677.2.126.193 to 77.2.126.25477.2.126.25562
25377.2.127.0/2677.2.127.1 to 77.2.127.6277.2.127.6362
25477.2.127.64/2677.2.127.65 to 77.2.127.12677.2.127.12762
25577.2.127.128/2677.2.127.129 to 77.2.127.19077.2.127.19162
25677.2.127.192/2677.2.127.193 to 77.2.127.25477.2.127.25562

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.