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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.

Network74.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
74.0.0.0
Broadcast address
75.255.255.255
First usable
74.0.0.1
Last usable
75.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 4A000000 · Integer 1241513984 to 1275068415
Reverse DNS zones
74.in-addr.arpa
75.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.00000000.00000000.0000000074.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01001010.00000000.00000000.0000000074.0.0.0
Broadcast01001011.11111111.11111111.1111111175.255.255.255
Split into smaller subnets/17
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

74.0.0.0/7 makes 1,024 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.0.0.0/1774.0.0.1 to 74.0.127.25474.0.127.25532,766
274.0.128.0/1774.0.128.1 to 74.0.255.25474.0.255.25532,766
374.1.0.0/1774.1.0.1 to 74.1.127.25474.1.127.25532,766
474.1.128.0/1774.1.128.1 to 74.1.255.25474.1.255.25532,766
574.2.0.0/1774.2.0.1 to 74.2.127.25474.2.127.25532,766
674.2.128.0/1774.2.128.1 to 74.2.255.25474.2.255.25532,766
774.3.0.0/1774.3.0.1 to 74.3.127.25474.3.127.25532,766
874.3.128.0/1774.3.128.1 to 74.3.255.25474.3.255.25532,766
974.4.0.0/1774.4.0.1 to 74.4.127.25474.4.127.25532,766
1074.4.128.0/1774.4.128.1 to 74.4.255.25474.4.255.25532,766
1174.5.0.0/1774.5.0.1 to 74.5.127.25474.5.127.25532,766
1274.5.128.0/1774.5.128.1 to 74.5.255.25474.5.255.25532,766
1374.6.0.0/1774.6.0.1 to 74.6.127.25474.6.127.25532,766
1474.6.128.0/1774.6.128.1 to 74.6.255.25474.6.255.25532,766
1574.7.0.0/1774.7.0.1 to 74.7.127.25474.7.127.25532,766
1674.7.128.0/1774.7.128.1 to 74.7.255.25474.7.255.25532,766
1774.8.0.0/1774.8.0.1 to 74.8.127.25474.8.127.25532,766
1874.8.128.0/1774.8.128.1 to 74.8.255.25474.8.255.25532,766
1974.9.0.0/1774.9.0.1 to 74.9.127.25474.9.127.25532,766
2074.9.128.0/1774.9.128.1 to 74.9.255.25474.9.255.25532,766
2174.10.0.0/1774.10.0.1 to 74.10.127.25474.10.127.25532,766
2274.10.128.0/1774.10.128.1 to 74.10.255.25474.10.255.25532,766
2374.11.0.0/1774.11.0.1 to 74.11.127.25474.11.127.25532,766
2474.11.128.0/1774.11.128.1 to 74.11.255.25474.11.255.25532,766
2574.12.0.0/1774.12.0.1 to 74.12.127.25474.12.127.25532,766
2674.12.128.0/1774.12.128.1 to 74.12.255.25474.12.255.25532,766
2774.13.0.0/1774.13.0.1 to 74.13.127.25474.13.127.25532,766
2874.13.128.0/1774.13.128.1 to 74.13.255.25474.13.255.25532,766
2974.14.0.0/1774.14.0.1 to 74.14.127.25474.14.127.25532,766
3074.14.128.0/1774.14.128.1 to 74.14.255.25474.14.255.25532,766
3174.15.0.0/1774.15.0.1 to 74.15.127.25474.15.127.25532,766
3274.15.128.0/1774.15.128.1 to 74.15.255.25474.15.255.25532,766
3374.16.0.0/1774.16.0.1 to 74.16.127.25474.16.127.25532,766
3474.16.128.0/1774.16.128.1 to 74.16.255.25474.16.255.25532,766
3574.17.0.0/1774.17.0.1 to 74.17.127.25474.17.127.25532,766
3674.17.128.0/1774.17.128.1 to 74.17.255.25474.17.255.25532,766
3774.18.0.0/1774.18.0.1 to 74.18.127.25474.18.127.25532,766
3874.18.128.0/1774.18.128.1 to 74.18.255.25474.18.255.25532,766
3974.19.0.0/1774.19.0.1 to 74.19.127.25474.19.127.25532,766
4074.19.128.0/1774.19.128.1 to 74.19.255.25474.19.255.25532,766
4174.20.0.0/1774.20.0.1 to 74.20.127.25474.20.127.25532,766
4274.20.128.0/1774.20.128.1 to 74.20.255.25474.20.255.25532,766
4374.21.0.0/1774.21.0.1 to 74.21.127.25474.21.127.25532,766
4474.21.128.0/1774.21.128.1 to 74.21.255.25474.21.255.25532,766
4574.22.0.0/1774.22.0.1 to 74.22.127.25474.22.127.25532,766
4674.22.128.0/1774.22.128.1 to 74.22.255.25474.22.255.25532,766
4774.23.0.0/1774.23.0.1 to 74.23.127.25474.23.127.25532,766
4874.23.128.0/1774.23.128.1 to 74.23.255.25474.23.255.25532,766
4974.24.0.0/1774.24.0.1 to 74.24.127.25474.24.127.25532,766
5074.24.128.0/1774.24.128.1 to 74.24.255.25474.24.255.25532,766
5174.25.0.0/1774.25.0.1 to 74.25.127.25474.25.127.25532,766
5274.25.128.0/1774.25.128.1 to 74.25.255.25474.25.255.25532,766
5374.26.0.0/1774.26.0.1 to 74.26.127.25474.26.127.25532,766
5474.26.128.0/1774.26.128.1 to 74.26.255.25474.26.255.25532,766
5574.27.0.0/1774.27.0.1 to 74.27.127.25474.27.127.25532,766
5674.27.128.0/1774.27.128.1 to 74.27.255.25474.27.255.25532,766
5774.28.0.0/1774.28.0.1 to 74.28.127.25474.28.127.25532,766
5874.28.128.0/1774.28.128.1 to 74.28.255.25474.28.255.25532,766
5974.29.0.0/1774.29.0.1 to 74.29.127.25474.29.127.25532,766
6074.29.128.0/1774.29.128.1 to 74.29.255.25474.29.255.25532,766
6174.30.0.0/1774.30.0.1 to 74.30.127.25474.30.127.25532,766
6274.30.128.0/1774.30.128.1 to 74.30.255.25474.30.255.25532,766
6374.31.0.0/1774.31.0.1 to 74.31.127.25474.31.127.25532,766
6474.31.128.0/1774.31.128.1 to 74.31.255.25474.31.255.25532,766
6574.32.0.0/1774.32.0.1 to 74.32.127.25474.32.127.25532,766
6674.32.128.0/1774.32.128.1 to 74.32.255.25474.32.255.25532,766
6774.33.0.0/1774.33.0.1 to 74.33.127.25474.33.127.25532,766
6874.33.128.0/1774.33.128.1 to 74.33.255.25474.33.255.25532,766
6974.34.0.0/1774.34.0.1 to 74.34.127.25474.34.127.25532,766
7074.34.128.0/1774.34.128.1 to 74.34.255.25474.34.255.25532,766
7174.35.0.0/1774.35.0.1 to 74.35.127.25474.35.127.25532,766
7274.35.128.0/1774.35.128.1 to 74.35.255.25474.35.255.25532,766
7374.36.0.0/1774.36.0.1 to 74.36.127.25474.36.127.25532,766
7474.36.128.0/1774.36.128.1 to 74.36.255.25474.36.255.25532,766
7574.37.0.0/1774.37.0.1 to 74.37.127.25474.37.127.25532,766
7674.37.128.0/1774.37.128.1 to 74.37.255.25474.37.255.25532,766
7774.38.0.0/1774.38.0.1 to 74.38.127.25474.38.127.25532,766
7874.38.128.0/1774.38.128.1 to 74.38.255.25474.38.255.25532,766
7974.39.0.0/1774.39.0.1 to 74.39.127.25474.39.127.25532,766
8074.39.128.0/1774.39.128.1 to 74.39.255.25474.39.255.25532,766
8174.40.0.0/1774.40.0.1 to 74.40.127.25474.40.127.25532,766
8274.40.128.0/1774.40.128.1 to 74.40.255.25474.40.255.25532,766
8374.41.0.0/1774.41.0.1 to 74.41.127.25474.41.127.25532,766
8474.41.128.0/1774.41.128.1 to 74.41.255.25474.41.255.25532,766
8574.42.0.0/1774.42.0.1 to 74.42.127.25474.42.127.25532,766
8674.42.128.0/1774.42.128.1 to 74.42.255.25474.42.255.25532,766
8774.43.0.0/1774.43.0.1 to 74.43.127.25474.43.127.25532,766
8874.43.128.0/1774.43.128.1 to 74.43.255.25474.43.255.25532,766
8974.44.0.0/1774.44.0.1 to 74.44.127.25474.44.127.25532,766
9074.44.128.0/1774.44.128.1 to 74.44.255.25474.44.255.25532,766
9174.45.0.0/1774.45.0.1 to 74.45.127.25474.45.127.25532,766
9274.45.128.0/1774.45.128.1 to 74.45.255.25474.45.255.25532,766
9374.46.0.0/1774.46.0.1 to 74.46.127.25474.46.127.25532,766
9474.46.128.0/1774.46.128.1 to 74.46.255.25474.46.255.25532,766
9574.47.0.0/1774.47.0.1 to 74.47.127.25474.47.127.25532,766
9674.47.128.0/1774.47.128.1 to 74.47.255.25474.47.255.25532,766
9774.48.0.0/1774.48.0.1 to 74.48.127.25474.48.127.25532,766
9874.48.128.0/1774.48.128.1 to 74.48.255.25474.48.255.25532,766
9974.49.0.0/1774.49.0.1 to 74.49.127.25474.49.127.25532,766
10074.49.128.0/1774.49.128.1 to 74.49.255.25474.49.255.25532,766
10174.50.0.0/1774.50.0.1 to 74.50.127.25474.50.127.25532,766
10274.50.128.0/1774.50.128.1 to 74.50.255.25474.50.255.25532,766
10374.51.0.0/1774.51.0.1 to 74.51.127.25474.51.127.25532,766
10474.51.128.0/1774.51.128.1 to 74.51.255.25474.51.255.25532,766
10574.52.0.0/1774.52.0.1 to 74.52.127.25474.52.127.25532,766
10674.52.128.0/1774.52.128.1 to 74.52.255.25474.52.255.25532,766
10774.53.0.0/1774.53.0.1 to 74.53.127.25474.53.127.25532,766
10874.53.128.0/1774.53.128.1 to 74.53.255.25474.53.255.25532,766
10974.54.0.0/1774.54.0.1 to 74.54.127.25474.54.127.25532,766
11074.54.128.0/1774.54.128.1 to 74.54.255.25474.54.255.25532,766
11174.55.0.0/1774.55.0.1 to 74.55.127.25474.55.127.25532,766
11274.55.128.0/1774.55.128.1 to 74.55.255.25474.55.255.25532,766
11374.56.0.0/1774.56.0.1 to 74.56.127.25474.56.127.25532,766
11474.56.128.0/1774.56.128.1 to 74.56.255.25474.56.255.25532,766
11574.57.0.0/1774.57.0.1 to 74.57.127.25474.57.127.25532,766
11674.57.128.0/1774.57.128.1 to 74.57.255.25474.57.255.25532,766
11774.58.0.0/1774.58.0.1 to 74.58.127.25474.58.127.25532,766
11874.58.128.0/1774.58.128.1 to 74.58.255.25474.58.255.25532,766
11974.59.0.0/1774.59.0.1 to 74.59.127.25474.59.127.25532,766
12074.59.128.0/1774.59.128.1 to 74.59.255.25474.59.255.25532,766
12174.60.0.0/1774.60.0.1 to 74.60.127.25474.60.127.25532,766
12274.60.128.0/1774.60.128.1 to 74.60.255.25474.60.255.25532,766
12374.61.0.0/1774.61.0.1 to 74.61.127.25474.61.127.25532,766
12474.61.128.0/1774.61.128.1 to 74.61.255.25474.61.255.25532,766
12574.62.0.0/1774.62.0.1 to 74.62.127.25474.62.127.25532,766
12674.62.128.0/1774.62.128.1 to 74.62.255.25474.62.255.25532,766
12774.63.0.0/1774.63.0.1 to 74.63.127.25474.63.127.25532,766
12874.63.128.0/1774.63.128.1 to 74.63.255.25474.63.255.25532,766
12974.64.0.0/1774.64.0.1 to 74.64.127.25474.64.127.25532,766
13074.64.128.0/1774.64.128.1 to 74.64.255.25474.64.255.25532,766
13174.65.0.0/1774.65.0.1 to 74.65.127.25474.65.127.25532,766
13274.65.128.0/1774.65.128.1 to 74.65.255.25474.65.255.25532,766
13374.66.0.0/1774.66.0.1 to 74.66.127.25474.66.127.25532,766
13474.66.128.0/1774.66.128.1 to 74.66.255.25474.66.255.25532,766
13574.67.0.0/1774.67.0.1 to 74.67.127.25474.67.127.25532,766
13674.67.128.0/1774.67.128.1 to 74.67.255.25474.67.255.25532,766
13774.68.0.0/1774.68.0.1 to 74.68.127.25474.68.127.25532,766
13874.68.128.0/1774.68.128.1 to 74.68.255.25474.68.255.25532,766
13974.69.0.0/1774.69.0.1 to 74.69.127.25474.69.127.25532,766
14074.69.128.0/1774.69.128.1 to 74.69.255.25474.69.255.25532,766
14174.70.0.0/1774.70.0.1 to 74.70.127.25474.70.127.25532,766
14274.70.128.0/1774.70.128.1 to 74.70.255.25474.70.255.25532,766
14374.71.0.0/1774.71.0.1 to 74.71.127.25474.71.127.25532,766
14474.71.128.0/1774.71.128.1 to 74.71.255.25474.71.255.25532,766
14574.72.0.0/1774.72.0.1 to 74.72.127.25474.72.127.25532,766
14674.72.128.0/1774.72.128.1 to 74.72.255.25474.72.255.25532,766
14774.73.0.0/1774.73.0.1 to 74.73.127.25474.73.127.25532,766
14874.73.128.0/1774.73.128.1 to 74.73.255.25474.73.255.25532,766
14974.74.0.0/1774.74.0.1 to 74.74.127.25474.74.127.25532,766
15074.74.128.0/1774.74.128.1 to 74.74.255.25474.74.255.25532,766
15174.75.0.0/1774.75.0.1 to 74.75.127.25474.75.127.25532,766
15274.75.128.0/1774.75.128.1 to 74.75.255.25474.75.255.25532,766
15374.76.0.0/1774.76.0.1 to 74.76.127.25474.76.127.25532,766
15474.76.128.0/1774.76.128.1 to 74.76.255.25474.76.255.25532,766
15574.77.0.0/1774.77.0.1 to 74.77.127.25474.77.127.25532,766
15674.77.128.0/1774.77.128.1 to 74.77.255.25474.77.255.25532,766
15774.78.0.0/1774.78.0.1 to 74.78.127.25474.78.127.25532,766
15874.78.128.0/1774.78.128.1 to 74.78.255.25474.78.255.25532,766
15974.79.0.0/1774.79.0.1 to 74.79.127.25474.79.127.25532,766
16074.79.128.0/1774.79.128.1 to 74.79.255.25474.79.255.25532,766
16174.80.0.0/1774.80.0.1 to 74.80.127.25474.80.127.25532,766
16274.80.128.0/1774.80.128.1 to 74.80.255.25474.80.255.25532,766
16374.81.0.0/1774.81.0.1 to 74.81.127.25474.81.127.25532,766
16474.81.128.0/1774.81.128.1 to 74.81.255.25474.81.255.25532,766
16574.82.0.0/1774.82.0.1 to 74.82.127.25474.82.127.25532,766
16674.82.128.0/1774.82.128.1 to 74.82.255.25474.82.255.25532,766
16774.83.0.0/1774.83.0.1 to 74.83.127.25474.83.127.25532,766
16874.83.128.0/1774.83.128.1 to 74.83.255.25474.83.255.25532,766
16974.84.0.0/1774.84.0.1 to 74.84.127.25474.84.127.25532,766
17074.84.128.0/1774.84.128.1 to 74.84.255.25474.84.255.25532,766
17174.85.0.0/1774.85.0.1 to 74.85.127.25474.85.127.25532,766
17274.85.128.0/1774.85.128.1 to 74.85.255.25474.85.255.25532,766
17374.86.0.0/1774.86.0.1 to 74.86.127.25474.86.127.25532,766
17474.86.128.0/1774.86.128.1 to 74.86.255.25474.86.255.25532,766
17574.87.0.0/1774.87.0.1 to 74.87.127.25474.87.127.25532,766
17674.87.128.0/1774.87.128.1 to 74.87.255.25474.87.255.25532,766
17774.88.0.0/1774.88.0.1 to 74.88.127.25474.88.127.25532,766
17874.88.128.0/1774.88.128.1 to 74.88.255.25474.88.255.25532,766
17974.89.0.0/1774.89.0.1 to 74.89.127.25474.89.127.25532,766
18074.89.128.0/1774.89.128.1 to 74.89.255.25474.89.255.25532,766
18174.90.0.0/1774.90.0.1 to 74.90.127.25474.90.127.25532,766
18274.90.128.0/1774.90.128.1 to 74.90.255.25474.90.255.25532,766
18374.91.0.0/1774.91.0.1 to 74.91.127.25474.91.127.25532,766
18474.91.128.0/1774.91.128.1 to 74.91.255.25474.91.255.25532,766
18574.92.0.0/1774.92.0.1 to 74.92.127.25474.92.127.25532,766
18674.92.128.0/1774.92.128.1 to 74.92.255.25474.92.255.25532,766
18774.93.0.0/1774.93.0.1 to 74.93.127.25474.93.127.25532,766
18874.93.128.0/1774.93.128.1 to 74.93.255.25474.93.255.25532,766
18974.94.0.0/1774.94.0.1 to 74.94.127.25474.94.127.25532,766
19074.94.128.0/1774.94.128.1 to 74.94.255.25474.94.255.25532,766
19174.95.0.0/1774.95.0.1 to 74.95.127.25474.95.127.25532,766
19274.95.128.0/1774.95.128.1 to 74.95.255.25474.95.255.25532,766
19374.96.0.0/1774.96.0.1 to 74.96.127.25474.96.127.25532,766
19474.96.128.0/1774.96.128.1 to 74.96.255.25474.96.255.25532,766
19574.97.0.0/1774.97.0.1 to 74.97.127.25474.97.127.25532,766
19674.97.128.0/1774.97.128.1 to 74.97.255.25474.97.255.25532,766
19774.98.0.0/1774.98.0.1 to 74.98.127.25474.98.127.25532,766
19874.98.128.0/1774.98.128.1 to 74.98.255.25474.98.255.25532,766
19974.99.0.0/1774.99.0.1 to 74.99.127.25474.99.127.25532,766
20074.99.128.0/1774.99.128.1 to 74.99.255.25474.99.255.25532,766
20174.100.0.0/1774.100.0.1 to 74.100.127.25474.100.127.25532,766
20274.100.128.0/1774.100.128.1 to 74.100.255.25474.100.255.25532,766
20374.101.0.0/1774.101.0.1 to 74.101.127.25474.101.127.25532,766
20474.101.128.0/1774.101.128.1 to 74.101.255.25474.101.255.25532,766
20574.102.0.0/1774.102.0.1 to 74.102.127.25474.102.127.25532,766
20674.102.128.0/1774.102.128.1 to 74.102.255.25474.102.255.25532,766
20774.103.0.0/1774.103.0.1 to 74.103.127.25474.103.127.25532,766
20874.103.128.0/1774.103.128.1 to 74.103.255.25474.103.255.25532,766
20974.104.0.0/1774.104.0.1 to 74.104.127.25474.104.127.25532,766
21074.104.128.0/1774.104.128.1 to 74.104.255.25474.104.255.25532,766
21174.105.0.0/1774.105.0.1 to 74.105.127.25474.105.127.25532,766
21274.105.128.0/1774.105.128.1 to 74.105.255.25474.105.255.25532,766
21374.106.0.0/1774.106.0.1 to 74.106.127.25474.106.127.25532,766
21474.106.128.0/1774.106.128.1 to 74.106.255.25474.106.255.25532,766
21574.107.0.0/1774.107.0.1 to 74.107.127.25474.107.127.25532,766
21674.107.128.0/1774.107.128.1 to 74.107.255.25474.107.255.25532,766
21774.108.0.0/1774.108.0.1 to 74.108.127.25474.108.127.25532,766
21874.108.128.0/1774.108.128.1 to 74.108.255.25474.108.255.25532,766
21974.109.0.0/1774.109.0.1 to 74.109.127.25474.109.127.25532,766
22074.109.128.0/1774.109.128.1 to 74.109.255.25474.109.255.25532,766
22174.110.0.0/1774.110.0.1 to 74.110.127.25474.110.127.25532,766
22274.110.128.0/1774.110.128.1 to 74.110.255.25474.110.255.25532,766
22374.111.0.0/1774.111.0.1 to 74.111.127.25474.111.127.25532,766
22474.111.128.0/1774.111.128.1 to 74.111.255.25474.111.255.25532,766
22574.112.0.0/1774.112.0.1 to 74.112.127.25474.112.127.25532,766
22674.112.128.0/1774.112.128.1 to 74.112.255.25474.112.255.25532,766
22774.113.0.0/1774.113.0.1 to 74.113.127.25474.113.127.25532,766
22874.113.128.0/1774.113.128.1 to 74.113.255.25474.113.255.25532,766
22974.114.0.0/1774.114.0.1 to 74.114.127.25474.114.127.25532,766
23074.114.128.0/1774.114.128.1 to 74.114.255.25474.114.255.25532,766
23174.115.0.0/1774.115.0.1 to 74.115.127.25474.115.127.25532,766
23274.115.128.0/1774.115.128.1 to 74.115.255.25474.115.255.25532,766
23374.116.0.0/1774.116.0.1 to 74.116.127.25474.116.127.25532,766
23474.116.128.0/1774.116.128.1 to 74.116.255.25474.116.255.25532,766
23574.117.0.0/1774.117.0.1 to 74.117.127.25474.117.127.25532,766
23674.117.128.0/1774.117.128.1 to 74.117.255.25474.117.255.25532,766
23774.118.0.0/1774.118.0.1 to 74.118.127.25474.118.127.25532,766
23874.118.128.0/1774.118.128.1 to 74.118.255.25474.118.255.25532,766
23974.119.0.0/1774.119.0.1 to 74.119.127.25474.119.127.25532,766
24074.119.128.0/1774.119.128.1 to 74.119.255.25474.119.255.25532,766
24174.120.0.0/1774.120.0.1 to 74.120.127.25474.120.127.25532,766
24274.120.128.0/1774.120.128.1 to 74.120.255.25474.120.255.25532,766
24374.121.0.0/1774.121.0.1 to 74.121.127.25474.121.127.25532,766
24474.121.128.0/1774.121.128.1 to 74.121.255.25474.121.255.25532,766
24574.122.0.0/1774.122.0.1 to 74.122.127.25474.122.127.25532,766
24674.122.128.0/1774.122.128.1 to 74.122.255.25474.122.255.25532,766
24774.123.0.0/1774.123.0.1 to 74.123.127.25474.123.127.25532,766
24874.123.128.0/1774.123.128.1 to 74.123.255.25474.123.255.25532,766
24974.124.0.0/1774.124.0.1 to 74.124.127.25474.124.127.25532,766
25074.124.128.0/1774.124.128.1 to 74.124.255.25474.124.255.25532,766
25174.125.0.0/1774.125.0.1 to 74.125.127.25474.125.127.25532,766
25274.125.128.0/1774.125.128.1 to 74.125.255.25474.125.255.25532,766
25374.126.0.0/1774.126.0.1 to 74.126.127.25474.126.127.25532,766
25474.126.128.0/1774.126.128.1 to 74.126.255.25474.126.255.25532,766
25574.127.0.0/1774.127.0.1 to 74.127.127.25474.127.127.25532,766
25674.127.128.0/1774.127.128.1 to 74.127.255.25474.127.255.25532,766

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.