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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.

Network79.2.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
79.2.64.0
Broadcast address
79.2.127.255
First usable
79.2.64.1
Last usable
79.2.127.254
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 4F024000 · Integer 1325547520 to 1325563903
Reverse DNS zones
64.2.79.in-addr.arpa
65.2.79.in-addr.arpa
66.2.79.in-addr.arpa
67.2.79.in-addr.arpa
68.2.79.in-addr.arpa
69.2.79.in-addr.arpa
70.2.79.in-addr.arpa
71.2.79.in-addr.arpa
72.2.79.in-addr.arpa
73.2.79.in-addr.arpa
74.2.79.in-addr.arpa
75.2.79.in-addr.arpa
76.2.79.in-addr.arpa
77.2.79.in-addr.arpa
78.2.79.in-addr.arpa
79.2.79.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
Address01001111.00000010.01000000.0000000079.2.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01001111.00000010.01000000.0000000079.2.64.0
Broadcast01001111.00000010.01111111.1111111179.2.127.255
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)

79.2.64.0/18 makes 256 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
179.2.64.0/2679.2.64.1 to 79.2.64.6279.2.64.6362
279.2.64.64/2679.2.64.65 to 79.2.64.12679.2.64.12762
379.2.64.128/2679.2.64.129 to 79.2.64.19079.2.64.19162
479.2.64.192/2679.2.64.193 to 79.2.64.25479.2.64.25562
579.2.65.0/2679.2.65.1 to 79.2.65.6279.2.65.6362
679.2.65.64/2679.2.65.65 to 79.2.65.12679.2.65.12762
779.2.65.128/2679.2.65.129 to 79.2.65.19079.2.65.19162
879.2.65.192/2679.2.65.193 to 79.2.65.25479.2.65.25562
979.2.66.0/2679.2.66.1 to 79.2.66.6279.2.66.6362
1079.2.66.64/2679.2.66.65 to 79.2.66.12679.2.66.12762
1179.2.66.128/2679.2.66.129 to 79.2.66.19079.2.66.19162
1279.2.66.192/2679.2.66.193 to 79.2.66.25479.2.66.25562
1379.2.67.0/2679.2.67.1 to 79.2.67.6279.2.67.6362
1479.2.67.64/2679.2.67.65 to 79.2.67.12679.2.67.12762
1579.2.67.128/2679.2.67.129 to 79.2.67.19079.2.67.19162
1679.2.67.192/2679.2.67.193 to 79.2.67.25479.2.67.25562
1779.2.68.0/2679.2.68.1 to 79.2.68.6279.2.68.6362
1879.2.68.64/2679.2.68.65 to 79.2.68.12679.2.68.12762
1979.2.68.128/2679.2.68.129 to 79.2.68.19079.2.68.19162
2079.2.68.192/2679.2.68.193 to 79.2.68.25479.2.68.25562
2179.2.69.0/2679.2.69.1 to 79.2.69.6279.2.69.6362
2279.2.69.64/2679.2.69.65 to 79.2.69.12679.2.69.12762
2379.2.69.128/2679.2.69.129 to 79.2.69.19079.2.69.19162
2479.2.69.192/2679.2.69.193 to 79.2.69.25479.2.69.25562
2579.2.70.0/2679.2.70.1 to 79.2.70.6279.2.70.6362
2679.2.70.64/2679.2.70.65 to 79.2.70.12679.2.70.12762
2779.2.70.128/2679.2.70.129 to 79.2.70.19079.2.70.19162
2879.2.70.192/2679.2.70.193 to 79.2.70.25479.2.70.25562
2979.2.71.0/2679.2.71.1 to 79.2.71.6279.2.71.6362
3079.2.71.64/2679.2.71.65 to 79.2.71.12679.2.71.12762
3179.2.71.128/2679.2.71.129 to 79.2.71.19079.2.71.19162
3279.2.71.192/2679.2.71.193 to 79.2.71.25479.2.71.25562
3379.2.72.0/2679.2.72.1 to 79.2.72.6279.2.72.6362
3479.2.72.64/2679.2.72.65 to 79.2.72.12679.2.72.12762
3579.2.72.128/2679.2.72.129 to 79.2.72.19079.2.72.19162
3679.2.72.192/2679.2.72.193 to 79.2.72.25479.2.72.25562
3779.2.73.0/2679.2.73.1 to 79.2.73.6279.2.73.6362
3879.2.73.64/2679.2.73.65 to 79.2.73.12679.2.73.12762
3979.2.73.128/2679.2.73.129 to 79.2.73.19079.2.73.19162
4079.2.73.192/2679.2.73.193 to 79.2.73.25479.2.73.25562
4179.2.74.0/2679.2.74.1 to 79.2.74.6279.2.74.6362
4279.2.74.64/2679.2.74.65 to 79.2.74.12679.2.74.12762
4379.2.74.128/2679.2.74.129 to 79.2.74.19079.2.74.19162
4479.2.74.192/2679.2.74.193 to 79.2.74.25479.2.74.25562
4579.2.75.0/2679.2.75.1 to 79.2.75.6279.2.75.6362
4679.2.75.64/2679.2.75.65 to 79.2.75.12679.2.75.12762
4779.2.75.128/2679.2.75.129 to 79.2.75.19079.2.75.19162
4879.2.75.192/2679.2.75.193 to 79.2.75.25479.2.75.25562
4979.2.76.0/2679.2.76.1 to 79.2.76.6279.2.76.6362
5079.2.76.64/2679.2.76.65 to 79.2.76.12679.2.76.12762
5179.2.76.128/2679.2.76.129 to 79.2.76.19079.2.76.19162
5279.2.76.192/2679.2.76.193 to 79.2.76.25479.2.76.25562
5379.2.77.0/2679.2.77.1 to 79.2.77.6279.2.77.6362
5479.2.77.64/2679.2.77.65 to 79.2.77.12679.2.77.12762
5579.2.77.128/2679.2.77.129 to 79.2.77.19079.2.77.19162
5679.2.77.192/2679.2.77.193 to 79.2.77.25479.2.77.25562
5779.2.78.0/2679.2.78.1 to 79.2.78.6279.2.78.6362
5879.2.78.64/2679.2.78.65 to 79.2.78.12679.2.78.12762
5979.2.78.128/2679.2.78.129 to 79.2.78.19079.2.78.19162
6079.2.78.192/2679.2.78.193 to 79.2.78.25479.2.78.25562
6179.2.79.0/2679.2.79.1 to 79.2.79.6279.2.79.6362
6279.2.79.64/2679.2.79.65 to 79.2.79.12679.2.79.12762
6379.2.79.128/2679.2.79.129 to 79.2.79.19079.2.79.19162
6479.2.79.192/2679.2.79.193 to 79.2.79.25479.2.79.25562
6579.2.80.0/2679.2.80.1 to 79.2.80.6279.2.80.6362
6679.2.80.64/2679.2.80.65 to 79.2.80.12679.2.80.12762
6779.2.80.128/2679.2.80.129 to 79.2.80.19079.2.80.19162
6879.2.80.192/2679.2.80.193 to 79.2.80.25479.2.80.25562
6979.2.81.0/2679.2.81.1 to 79.2.81.6279.2.81.6362
7079.2.81.64/2679.2.81.65 to 79.2.81.12679.2.81.12762
7179.2.81.128/2679.2.81.129 to 79.2.81.19079.2.81.19162
7279.2.81.192/2679.2.81.193 to 79.2.81.25479.2.81.25562
7379.2.82.0/2679.2.82.1 to 79.2.82.6279.2.82.6362
7479.2.82.64/2679.2.82.65 to 79.2.82.12679.2.82.12762
7579.2.82.128/2679.2.82.129 to 79.2.82.19079.2.82.19162
7679.2.82.192/2679.2.82.193 to 79.2.82.25479.2.82.25562
7779.2.83.0/2679.2.83.1 to 79.2.83.6279.2.83.6362
7879.2.83.64/2679.2.83.65 to 79.2.83.12679.2.83.12762
7979.2.83.128/2679.2.83.129 to 79.2.83.19079.2.83.19162
8079.2.83.192/2679.2.83.193 to 79.2.83.25479.2.83.25562
8179.2.84.0/2679.2.84.1 to 79.2.84.6279.2.84.6362
8279.2.84.64/2679.2.84.65 to 79.2.84.12679.2.84.12762
8379.2.84.128/2679.2.84.129 to 79.2.84.19079.2.84.19162
8479.2.84.192/2679.2.84.193 to 79.2.84.25479.2.84.25562
8579.2.85.0/2679.2.85.1 to 79.2.85.6279.2.85.6362
8679.2.85.64/2679.2.85.65 to 79.2.85.12679.2.85.12762
8779.2.85.128/2679.2.85.129 to 79.2.85.19079.2.85.19162
8879.2.85.192/2679.2.85.193 to 79.2.85.25479.2.85.25562
8979.2.86.0/2679.2.86.1 to 79.2.86.6279.2.86.6362
9079.2.86.64/2679.2.86.65 to 79.2.86.12679.2.86.12762
9179.2.86.128/2679.2.86.129 to 79.2.86.19079.2.86.19162
9279.2.86.192/2679.2.86.193 to 79.2.86.25479.2.86.25562
9379.2.87.0/2679.2.87.1 to 79.2.87.6279.2.87.6362
9479.2.87.64/2679.2.87.65 to 79.2.87.12679.2.87.12762
9579.2.87.128/2679.2.87.129 to 79.2.87.19079.2.87.19162
9679.2.87.192/2679.2.87.193 to 79.2.87.25479.2.87.25562
9779.2.88.0/2679.2.88.1 to 79.2.88.6279.2.88.6362
9879.2.88.64/2679.2.88.65 to 79.2.88.12679.2.88.12762
9979.2.88.128/2679.2.88.129 to 79.2.88.19079.2.88.19162
10079.2.88.192/2679.2.88.193 to 79.2.88.25479.2.88.25562
10179.2.89.0/2679.2.89.1 to 79.2.89.6279.2.89.6362
10279.2.89.64/2679.2.89.65 to 79.2.89.12679.2.89.12762
10379.2.89.128/2679.2.89.129 to 79.2.89.19079.2.89.19162
10479.2.89.192/2679.2.89.193 to 79.2.89.25479.2.89.25562
10579.2.90.0/2679.2.90.1 to 79.2.90.6279.2.90.6362
10679.2.90.64/2679.2.90.65 to 79.2.90.12679.2.90.12762
10779.2.90.128/2679.2.90.129 to 79.2.90.19079.2.90.19162
10879.2.90.192/2679.2.90.193 to 79.2.90.25479.2.90.25562
10979.2.91.0/2679.2.91.1 to 79.2.91.6279.2.91.6362
11079.2.91.64/2679.2.91.65 to 79.2.91.12679.2.91.12762
11179.2.91.128/2679.2.91.129 to 79.2.91.19079.2.91.19162
11279.2.91.192/2679.2.91.193 to 79.2.91.25479.2.91.25562
11379.2.92.0/2679.2.92.1 to 79.2.92.6279.2.92.6362
11479.2.92.64/2679.2.92.65 to 79.2.92.12679.2.92.12762
11579.2.92.128/2679.2.92.129 to 79.2.92.19079.2.92.19162
11679.2.92.192/2679.2.92.193 to 79.2.92.25479.2.92.25562
11779.2.93.0/2679.2.93.1 to 79.2.93.6279.2.93.6362
11879.2.93.64/2679.2.93.65 to 79.2.93.12679.2.93.12762
11979.2.93.128/2679.2.93.129 to 79.2.93.19079.2.93.19162
12079.2.93.192/2679.2.93.193 to 79.2.93.25479.2.93.25562
12179.2.94.0/2679.2.94.1 to 79.2.94.6279.2.94.6362
12279.2.94.64/2679.2.94.65 to 79.2.94.12679.2.94.12762
12379.2.94.128/2679.2.94.129 to 79.2.94.19079.2.94.19162
12479.2.94.192/2679.2.94.193 to 79.2.94.25479.2.94.25562
12579.2.95.0/2679.2.95.1 to 79.2.95.6279.2.95.6362
12679.2.95.64/2679.2.95.65 to 79.2.95.12679.2.95.12762
12779.2.95.128/2679.2.95.129 to 79.2.95.19079.2.95.19162
12879.2.95.192/2679.2.95.193 to 79.2.95.25479.2.95.25562
12979.2.96.0/2679.2.96.1 to 79.2.96.6279.2.96.6362
13079.2.96.64/2679.2.96.65 to 79.2.96.12679.2.96.12762
13179.2.96.128/2679.2.96.129 to 79.2.96.19079.2.96.19162
13279.2.96.192/2679.2.96.193 to 79.2.96.25479.2.96.25562
13379.2.97.0/2679.2.97.1 to 79.2.97.6279.2.97.6362
13479.2.97.64/2679.2.97.65 to 79.2.97.12679.2.97.12762
13579.2.97.128/2679.2.97.129 to 79.2.97.19079.2.97.19162
13679.2.97.192/2679.2.97.193 to 79.2.97.25479.2.97.25562
13779.2.98.0/2679.2.98.1 to 79.2.98.6279.2.98.6362
13879.2.98.64/2679.2.98.65 to 79.2.98.12679.2.98.12762
13979.2.98.128/2679.2.98.129 to 79.2.98.19079.2.98.19162
14079.2.98.192/2679.2.98.193 to 79.2.98.25479.2.98.25562
14179.2.99.0/2679.2.99.1 to 79.2.99.6279.2.99.6362
14279.2.99.64/2679.2.99.65 to 79.2.99.12679.2.99.12762
14379.2.99.128/2679.2.99.129 to 79.2.99.19079.2.99.19162
14479.2.99.192/2679.2.99.193 to 79.2.99.25479.2.99.25562
14579.2.100.0/2679.2.100.1 to 79.2.100.6279.2.100.6362
14679.2.100.64/2679.2.100.65 to 79.2.100.12679.2.100.12762
14779.2.100.128/2679.2.100.129 to 79.2.100.19079.2.100.19162
14879.2.100.192/2679.2.100.193 to 79.2.100.25479.2.100.25562
14979.2.101.0/2679.2.101.1 to 79.2.101.6279.2.101.6362
15079.2.101.64/2679.2.101.65 to 79.2.101.12679.2.101.12762
15179.2.101.128/2679.2.101.129 to 79.2.101.19079.2.101.19162
15279.2.101.192/2679.2.101.193 to 79.2.101.25479.2.101.25562
15379.2.102.0/2679.2.102.1 to 79.2.102.6279.2.102.6362
15479.2.102.64/2679.2.102.65 to 79.2.102.12679.2.102.12762
15579.2.102.128/2679.2.102.129 to 79.2.102.19079.2.102.19162
15679.2.102.192/2679.2.102.193 to 79.2.102.25479.2.102.25562
15779.2.103.0/2679.2.103.1 to 79.2.103.6279.2.103.6362
15879.2.103.64/2679.2.103.65 to 79.2.103.12679.2.103.12762
15979.2.103.128/2679.2.103.129 to 79.2.103.19079.2.103.19162
16079.2.103.192/2679.2.103.193 to 79.2.103.25479.2.103.25562
16179.2.104.0/2679.2.104.1 to 79.2.104.6279.2.104.6362
16279.2.104.64/2679.2.104.65 to 79.2.104.12679.2.104.12762
16379.2.104.128/2679.2.104.129 to 79.2.104.19079.2.104.19162
16479.2.104.192/2679.2.104.193 to 79.2.104.25479.2.104.25562
16579.2.105.0/2679.2.105.1 to 79.2.105.6279.2.105.6362
16679.2.105.64/2679.2.105.65 to 79.2.105.12679.2.105.12762
16779.2.105.128/2679.2.105.129 to 79.2.105.19079.2.105.19162
16879.2.105.192/2679.2.105.193 to 79.2.105.25479.2.105.25562
16979.2.106.0/2679.2.106.1 to 79.2.106.6279.2.106.6362
17079.2.106.64/2679.2.106.65 to 79.2.106.12679.2.106.12762
17179.2.106.128/2679.2.106.129 to 79.2.106.19079.2.106.19162
17279.2.106.192/2679.2.106.193 to 79.2.106.25479.2.106.25562
17379.2.107.0/2679.2.107.1 to 79.2.107.6279.2.107.6362
17479.2.107.64/2679.2.107.65 to 79.2.107.12679.2.107.12762
17579.2.107.128/2679.2.107.129 to 79.2.107.19079.2.107.19162
17679.2.107.192/2679.2.107.193 to 79.2.107.25479.2.107.25562
17779.2.108.0/2679.2.108.1 to 79.2.108.6279.2.108.6362
17879.2.108.64/2679.2.108.65 to 79.2.108.12679.2.108.12762
17979.2.108.128/2679.2.108.129 to 79.2.108.19079.2.108.19162
18079.2.108.192/2679.2.108.193 to 79.2.108.25479.2.108.25562
18179.2.109.0/2679.2.109.1 to 79.2.109.6279.2.109.6362
18279.2.109.64/2679.2.109.65 to 79.2.109.12679.2.109.12762
18379.2.109.128/2679.2.109.129 to 79.2.109.19079.2.109.19162
18479.2.109.192/2679.2.109.193 to 79.2.109.25479.2.109.25562
18579.2.110.0/2679.2.110.1 to 79.2.110.6279.2.110.6362
18679.2.110.64/2679.2.110.65 to 79.2.110.12679.2.110.12762
18779.2.110.128/2679.2.110.129 to 79.2.110.19079.2.110.19162
18879.2.110.192/2679.2.110.193 to 79.2.110.25479.2.110.25562
18979.2.111.0/2679.2.111.1 to 79.2.111.6279.2.111.6362
19079.2.111.64/2679.2.111.65 to 79.2.111.12679.2.111.12762
19179.2.111.128/2679.2.111.129 to 79.2.111.19079.2.111.19162
19279.2.111.192/2679.2.111.193 to 79.2.111.25479.2.111.25562
19379.2.112.0/2679.2.112.1 to 79.2.112.6279.2.112.6362
19479.2.112.64/2679.2.112.65 to 79.2.112.12679.2.112.12762
19579.2.112.128/2679.2.112.129 to 79.2.112.19079.2.112.19162
19679.2.112.192/2679.2.112.193 to 79.2.112.25479.2.112.25562
19779.2.113.0/2679.2.113.1 to 79.2.113.6279.2.113.6362
19879.2.113.64/2679.2.113.65 to 79.2.113.12679.2.113.12762
19979.2.113.128/2679.2.113.129 to 79.2.113.19079.2.113.19162
20079.2.113.192/2679.2.113.193 to 79.2.113.25479.2.113.25562
20179.2.114.0/2679.2.114.1 to 79.2.114.6279.2.114.6362
20279.2.114.64/2679.2.114.65 to 79.2.114.12679.2.114.12762
20379.2.114.128/2679.2.114.129 to 79.2.114.19079.2.114.19162
20479.2.114.192/2679.2.114.193 to 79.2.114.25479.2.114.25562
20579.2.115.0/2679.2.115.1 to 79.2.115.6279.2.115.6362
20679.2.115.64/2679.2.115.65 to 79.2.115.12679.2.115.12762
20779.2.115.128/2679.2.115.129 to 79.2.115.19079.2.115.19162
20879.2.115.192/2679.2.115.193 to 79.2.115.25479.2.115.25562
20979.2.116.0/2679.2.116.1 to 79.2.116.6279.2.116.6362
21079.2.116.64/2679.2.116.65 to 79.2.116.12679.2.116.12762
21179.2.116.128/2679.2.116.129 to 79.2.116.19079.2.116.19162
21279.2.116.192/2679.2.116.193 to 79.2.116.25479.2.116.25562
21379.2.117.0/2679.2.117.1 to 79.2.117.6279.2.117.6362
21479.2.117.64/2679.2.117.65 to 79.2.117.12679.2.117.12762
21579.2.117.128/2679.2.117.129 to 79.2.117.19079.2.117.19162
21679.2.117.192/2679.2.117.193 to 79.2.117.25479.2.117.25562
21779.2.118.0/2679.2.118.1 to 79.2.118.6279.2.118.6362
21879.2.118.64/2679.2.118.65 to 79.2.118.12679.2.118.12762
21979.2.118.128/2679.2.118.129 to 79.2.118.19079.2.118.19162
22079.2.118.192/2679.2.118.193 to 79.2.118.25479.2.118.25562
22179.2.119.0/2679.2.119.1 to 79.2.119.6279.2.119.6362
22279.2.119.64/2679.2.119.65 to 79.2.119.12679.2.119.12762
22379.2.119.128/2679.2.119.129 to 79.2.119.19079.2.119.19162
22479.2.119.192/2679.2.119.193 to 79.2.119.25479.2.119.25562
22579.2.120.0/2679.2.120.1 to 79.2.120.6279.2.120.6362
22679.2.120.64/2679.2.120.65 to 79.2.120.12679.2.120.12762
22779.2.120.128/2679.2.120.129 to 79.2.120.19079.2.120.19162
22879.2.120.192/2679.2.120.193 to 79.2.120.25479.2.120.25562
22979.2.121.0/2679.2.121.1 to 79.2.121.6279.2.121.6362
23079.2.121.64/2679.2.121.65 to 79.2.121.12679.2.121.12762
23179.2.121.128/2679.2.121.129 to 79.2.121.19079.2.121.19162
23279.2.121.192/2679.2.121.193 to 79.2.121.25479.2.121.25562
23379.2.122.0/2679.2.122.1 to 79.2.122.6279.2.122.6362
23479.2.122.64/2679.2.122.65 to 79.2.122.12679.2.122.12762
23579.2.122.128/2679.2.122.129 to 79.2.122.19079.2.122.19162
23679.2.122.192/2679.2.122.193 to 79.2.122.25479.2.122.25562
23779.2.123.0/2679.2.123.1 to 79.2.123.6279.2.123.6362
23879.2.123.64/2679.2.123.65 to 79.2.123.12679.2.123.12762
23979.2.123.128/2679.2.123.129 to 79.2.123.19079.2.123.19162
24079.2.123.192/2679.2.123.193 to 79.2.123.25479.2.123.25562
24179.2.124.0/2679.2.124.1 to 79.2.124.6279.2.124.6362
24279.2.124.64/2679.2.124.65 to 79.2.124.12679.2.124.12762
24379.2.124.128/2679.2.124.129 to 79.2.124.19079.2.124.19162
24479.2.124.192/2679.2.124.193 to 79.2.124.25479.2.124.25562
24579.2.125.0/2679.2.125.1 to 79.2.125.6279.2.125.6362
24679.2.125.64/2679.2.125.65 to 79.2.125.12679.2.125.12762
24779.2.125.128/2679.2.125.129 to 79.2.125.19079.2.125.19162
24879.2.125.192/2679.2.125.193 to 79.2.125.25479.2.125.25562
24979.2.126.0/2679.2.126.1 to 79.2.126.6279.2.126.6362
25079.2.126.64/2679.2.126.65 to 79.2.126.12679.2.126.12762
25179.2.126.128/2679.2.126.129 to 79.2.126.19079.2.126.19162
25279.2.126.192/2679.2.126.193 to 79.2.126.25479.2.126.25562
25379.2.127.0/2679.2.127.1 to 79.2.127.6279.2.127.6362
25479.2.127.64/2679.2.127.65 to 79.2.127.12679.2.127.12762
25579.2.127.128/2679.2.127.129 to 79.2.127.19079.2.127.19162
25679.2.127.192/2679.2.127.193 to 79.2.127.25479.2.127.25562

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.