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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.

Network80.1.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
80.1.0.0
Broadcast address
80.1.255.255
First usable
80.1.0.1
Last usable
80.1.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 50010000 · Integer 1342242816 to 1342308351
Reverse DNS zone
1.80.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010000.00000001..00000000.0000000080.1.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01010000.00000001..00000000.0000000080.1.0.0
Broadcast01010000.00000001..11111111.1111111180.1.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

80.1.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.1.0.0/2580.1.0.1 to 80.1.0.12680.1.0.127126
280.1.0.128/2580.1.0.129 to 80.1.0.25480.1.0.255126
380.1.1.0/2580.1.1.1 to 80.1.1.12680.1.1.127126
480.1.1.128/2580.1.1.129 to 80.1.1.25480.1.1.255126
580.1.2.0/2580.1.2.1 to 80.1.2.12680.1.2.127126
680.1.2.128/2580.1.2.129 to 80.1.2.25480.1.2.255126
780.1.3.0/2580.1.3.1 to 80.1.3.12680.1.3.127126
880.1.3.128/2580.1.3.129 to 80.1.3.25480.1.3.255126
980.1.4.0/2580.1.4.1 to 80.1.4.12680.1.4.127126
1080.1.4.128/2580.1.4.129 to 80.1.4.25480.1.4.255126
1180.1.5.0/2580.1.5.1 to 80.1.5.12680.1.5.127126
1280.1.5.128/2580.1.5.129 to 80.1.5.25480.1.5.255126
1380.1.6.0/2580.1.6.1 to 80.1.6.12680.1.6.127126
1480.1.6.128/2580.1.6.129 to 80.1.6.25480.1.6.255126
1580.1.7.0/2580.1.7.1 to 80.1.7.12680.1.7.127126
1680.1.7.128/2580.1.7.129 to 80.1.7.25480.1.7.255126
1780.1.8.0/2580.1.8.1 to 80.1.8.12680.1.8.127126
1880.1.8.128/2580.1.8.129 to 80.1.8.25480.1.8.255126
1980.1.9.0/2580.1.9.1 to 80.1.9.12680.1.9.127126
2080.1.9.128/2580.1.9.129 to 80.1.9.25480.1.9.255126
2180.1.10.0/2580.1.10.1 to 80.1.10.12680.1.10.127126
2280.1.10.128/2580.1.10.129 to 80.1.10.25480.1.10.255126
2380.1.11.0/2580.1.11.1 to 80.1.11.12680.1.11.127126
2480.1.11.128/2580.1.11.129 to 80.1.11.25480.1.11.255126
2580.1.12.0/2580.1.12.1 to 80.1.12.12680.1.12.127126
2680.1.12.128/2580.1.12.129 to 80.1.12.25480.1.12.255126
2780.1.13.0/2580.1.13.1 to 80.1.13.12680.1.13.127126
2880.1.13.128/2580.1.13.129 to 80.1.13.25480.1.13.255126
2980.1.14.0/2580.1.14.1 to 80.1.14.12680.1.14.127126
3080.1.14.128/2580.1.14.129 to 80.1.14.25480.1.14.255126
3180.1.15.0/2580.1.15.1 to 80.1.15.12680.1.15.127126
3280.1.15.128/2580.1.15.129 to 80.1.15.25480.1.15.255126
3380.1.16.0/2580.1.16.1 to 80.1.16.12680.1.16.127126
3480.1.16.128/2580.1.16.129 to 80.1.16.25480.1.16.255126
3580.1.17.0/2580.1.17.1 to 80.1.17.12680.1.17.127126
3680.1.17.128/2580.1.17.129 to 80.1.17.25480.1.17.255126
3780.1.18.0/2580.1.18.1 to 80.1.18.12680.1.18.127126
3880.1.18.128/2580.1.18.129 to 80.1.18.25480.1.18.255126
3980.1.19.0/2580.1.19.1 to 80.1.19.12680.1.19.127126
4080.1.19.128/2580.1.19.129 to 80.1.19.25480.1.19.255126
4180.1.20.0/2580.1.20.1 to 80.1.20.12680.1.20.127126
4280.1.20.128/2580.1.20.129 to 80.1.20.25480.1.20.255126
4380.1.21.0/2580.1.21.1 to 80.1.21.12680.1.21.127126
4480.1.21.128/2580.1.21.129 to 80.1.21.25480.1.21.255126
4580.1.22.0/2580.1.22.1 to 80.1.22.12680.1.22.127126
4680.1.22.128/2580.1.22.129 to 80.1.22.25480.1.22.255126
4780.1.23.0/2580.1.23.1 to 80.1.23.12680.1.23.127126
4880.1.23.128/2580.1.23.129 to 80.1.23.25480.1.23.255126
4980.1.24.0/2580.1.24.1 to 80.1.24.12680.1.24.127126
5080.1.24.128/2580.1.24.129 to 80.1.24.25480.1.24.255126
5180.1.25.0/2580.1.25.1 to 80.1.25.12680.1.25.127126
5280.1.25.128/2580.1.25.129 to 80.1.25.25480.1.25.255126
5380.1.26.0/2580.1.26.1 to 80.1.26.12680.1.26.127126
5480.1.26.128/2580.1.26.129 to 80.1.26.25480.1.26.255126
5580.1.27.0/2580.1.27.1 to 80.1.27.12680.1.27.127126
5680.1.27.128/2580.1.27.129 to 80.1.27.25480.1.27.255126
5780.1.28.0/2580.1.28.1 to 80.1.28.12680.1.28.127126
5880.1.28.128/2580.1.28.129 to 80.1.28.25480.1.28.255126
5980.1.29.0/2580.1.29.1 to 80.1.29.12680.1.29.127126
6080.1.29.128/2580.1.29.129 to 80.1.29.25480.1.29.255126
6180.1.30.0/2580.1.30.1 to 80.1.30.12680.1.30.127126
6280.1.30.128/2580.1.30.129 to 80.1.30.25480.1.30.255126
6380.1.31.0/2580.1.31.1 to 80.1.31.12680.1.31.127126
6480.1.31.128/2580.1.31.129 to 80.1.31.25480.1.31.255126
6580.1.32.0/2580.1.32.1 to 80.1.32.12680.1.32.127126
6680.1.32.128/2580.1.32.129 to 80.1.32.25480.1.32.255126
6780.1.33.0/2580.1.33.1 to 80.1.33.12680.1.33.127126
6880.1.33.128/2580.1.33.129 to 80.1.33.25480.1.33.255126
6980.1.34.0/2580.1.34.1 to 80.1.34.12680.1.34.127126
7080.1.34.128/2580.1.34.129 to 80.1.34.25480.1.34.255126
7180.1.35.0/2580.1.35.1 to 80.1.35.12680.1.35.127126
7280.1.35.128/2580.1.35.129 to 80.1.35.25480.1.35.255126
7380.1.36.0/2580.1.36.1 to 80.1.36.12680.1.36.127126
7480.1.36.128/2580.1.36.129 to 80.1.36.25480.1.36.255126
7580.1.37.0/2580.1.37.1 to 80.1.37.12680.1.37.127126
7680.1.37.128/2580.1.37.129 to 80.1.37.25480.1.37.255126
7780.1.38.0/2580.1.38.1 to 80.1.38.12680.1.38.127126
7880.1.38.128/2580.1.38.129 to 80.1.38.25480.1.38.255126
7980.1.39.0/2580.1.39.1 to 80.1.39.12680.1.39.127126
8080.1.39.128/2580.1.39.129 to 80.1.39.25480.1.39.255126
8180.1.40.0/2580.1.40.1 to 80.1.40.12680.1.40.127126
8280.1.40.128/2580.1.40.129 to 80.1.40.25480.1.40.255126
8380.1.41.0/2580.1.41.1 to 80.1.41.12680.1.41.127126
8480.1.41.128/2580.1.41.129 to 80.1.41.25480.1.41.255126
8580.1.42.0/2580.1.42.1 to 80.1.42.12680.1.42.127126
8680.1.42.128/2580.1.42.129 to 80.1.42.25480.1.42.255126
8780.1.43.0/2580.1.43.1 to 80.1.43.12680.1.43.127126
8880.1.43.128/2580.1.43.129 to 80.1.43.25480.1.43.255126
8980.1.44.0/2580.1.44.1 to 80.1.44.12680.1.44.127126
9080.1.44.128/2580.1.44.129 to 80.1.44.25480.1.44.255126
9180.1.45.0/2580.1.45.1 to 80.1.45.12680.1.45.127126
9280.1.45.128/2580.1.45.129 to 80.1.45.25480.1.45.255126
9380.1.46.0/2580.1.46.1 to 80.1.46.12680.1.46.127126
9480.1.46.128/2580.1.46.129 to 80.1.46.25480.1.46.255126
9580.1.47.0/2580.1.47.1 to 80.1.47.12680.1.47.127126
9680.1.47.128/2580.1.47.129 to 80.1.47.25480.1.47.255126
9780.1.48.0/2580.1.48.1 to 80.1.48.12680.1.48.127126
9880.1.48.128/2580.1.48.129 to 80.1.48.25480.1.48.255126
9980.1.49.0/2580.1.49.1 to 80.1.49.12680.1.49.127126
10080.1.49.128/2580.1.49.129 to 80.1.49.25480.1.49.255126
10180.1.50.0/2580.1.50.1 to 80.1.50.12680.1.50.127126
10280.1.50.128/2580.1.50.129 to 80.1.50.25480.1.50.255126
10380.1.51.0/2580.1.51.1 to 80.1.51.12680.1.51.127126
10480.1.51.128/2580.1.51.129 to 80.1.51.25480.1.51.255126
10580.1.52.0/2580.1.52.1 to 80.1.52.12680.1.52.127126
10680.1.52.128/2580.1.52.129 to 80.1.52.25480.1.52.255126
10780.1.53.0/2580.1.53.1 to 80.1.53.12680.1.53.127126
10880.1.53.128/2580.1.53.129 to 80.1.53.25480.1.53.255126
10980.1.54.0/2580.1.54.1 to 80.1.54.12680.1.54.127126
11080.1.54.128/2580.1.54.129 to 80.1.54.25480.1.54.255126
11180.1.55.0/2580.1.55.1 to 80.1.55.12680.1.55.127126
11280.1.55.128/2580.1.55.129 to 80.1.55.25480.1.55.255126
11380.1.56.0/2580.1.56.1 to 80.1.56.12680.1.56.127126
11480.1.56.128/2580.1.56.129 to 80.1.56.25480.1.56.255126
11580.1.57.0/2580.1.57.1 to 80.1.57.12680.1.57.127126
11680.1.57.128/2580.1.57.129 to 80.1.57.25480.1.57.255126
11780.1.58.0/2580.1.58.1 to 80.1.58.12680.1.58.127126
11880.1.58.128/2580.1.58.129 to 80.1.58.25480.1.58.255126
11980.1.59.0/2580.1.59.1 to 80.1.59.12680.1.59.127126
12080.1.59.128/2580.1.59.129 to 80.1.59.25480.1.59.255126
12180.1.60.0/2580.1.60.1 to 80.1.60.12680.1.60.127126
12280.1.60.128/2580.1.60.129 to 80.1.60.25480.1.60.255126
12380.1.61.0/2580.1.61.1 to 80.1.61.12680.1.61.127126
12480.1.61.128/2580.1.61.129 to 80.1.61.25480.1.61.255126
12580.1.62.0/2580.1.62.1 to 80.1.62.12680.1.62.127126
12680.1.62.128/2580.1.62.129 to 80.1.62.25480.1.62.255126
12780.1.63.0/2580.1.63.1 to 80.1.63.12680.1.63.127126
12880.1.63.128/2580.1.63.129 to 80.1.63.25480.1.63.255126
12980.1.64.0/2580.1.64.1 to 80.1.64.12680.1.64.127126
13080.1.64.128/2580.1.64.129 to 80.1.64.25480.1.64.255126
13180.1.65.0/2580.1.65.1 to 80.1.65.12680.1.65.127126
13280.1.65.128/2580.1.65.129 to 80.1.65.25480.1.65.255126
13380.1.66.0/2580.1.66.1 to 80.1.66.12680.1.66.127126
13480.1.66.128/2580.1.66.129 to 80.1.66.25480.1.66.255126
13580.1.67.0/2580.1.67.1 to 80.1.67.12680.1.67.127126
13680.1.67.128/2580.1.67.129 to 80.1.67.25480.1.67.255126
13780.1.68.0/2580.1.68.1 to 80.1.68.12680.1.68.127126
13880.1.68.128/2580.1.68.129 to 80.1.68.25480.1.68.255126
13980.1.69.0/2580.1.69.1 to 80.1.69.12680.1.69.127126
14080.1.69.128/2580.1.69.129 to 80.1.69.25480.1.69.255126
14180.1.70.0/2580.1.70.1 to 80.1.70.12680.1.70.127126
14280.1.70.128/2580.1.70.129 to 80.1.70.25480.1.70.255126
14380.1.71.0/2580.1.71.1 to 80.1.71.12680.1.71.127126
14480.1.71.128/2580.1.71.129 to 80.1.71.25480.1.71.255126
14580.1.72.0/2580.1.72.1 to 80.1.72.12680.1.72.127126
14680.1.72.128/2580.1.72.129 to 80.1.72.25480.1.72.255126
14780.1.73.0/2580.1.73.1 to 80.1.73.12680.1.73.127126
14880.1.73.128/2580.1.73.129 to 80.1.73.25480.1.73.255126
14980.1.74.0/2580.1.74.1 to 80.1.74.12680.1.74.127126
15080.1.74.128/2580.1.74.129 to 80.1.74.25480.1.74.255126
15180.1.75.0/2580.1.75.1 to 80.1.75.12680.1.75.127126
15280.1.75.128/2580.1.75.129 to 80.1.75.25480.1.75.255126
15380.1.76.0/2580.1.76.1 to 80.1.76.12680.1.76.127126
15480.1.76.128/2580.1.76.129 to 80.1.76.25480.1.76.255126
15580.1.77.0/2580.1.77.1 to 80.1.77.12680.1.77.127126
15680.1.77.128/2580.1.77.129 to 80.1.77.25480.1.77.255126
15780.1.78.0/2580.1.78.1 to 80.1.78.12680.1.78.127126
15880.1.78.128/2580.1.78.129 to 80.1.78.25480.1.78.255126
15980.1.79.0/2580.1.79.1 to 80.1.79.12680.1.79.127126
16080.1.79.128/2580.1.79.129 to 80.1.79.25480.1.79.255126
16180.1.80.0/2580.1.80.1 to 80.1.80.12680.1.80.127126
16280.1.80.128/2580.1.80.129 to 80.1.80.25480.1.80.255126
16380.1.81.0/2580.1.81.1 to 80.1.81.12680.1.81.127126
16480.1.81.128/2580.1.81.129 to 80.1.81.25480.1.81.255126
16580.1.82.0/2580.1.82.1 to 80.1.82.12680.1.82.127126
16680.1.82.128/2580.1.82.129 to 80.1.82.25480.1.82.255126
16780.1.83.0/2580.1.83.1 to 80.1.83.12680.1.83.127126
16880.1.83.128/2580.1.83.129 to 80.1.83.25480.1.83.255126
16980.1.84.0/2580.1.84.1 to 80.1.84.12680.1.84.127126
17080.1.84.128/2580.1.84.129 to 80.1.84.25480.1.84.255126
17180.1.85.0/2580.1.85.1 to 80.1.85.12680.1.85.127126
17280.1.85.128/2580.1.85.129 to 80.1.85.25480.1.85.255126
17380.1.86.0/2580.1.86.1 to 80.1.86.12680.1.86.127126
17480.1.86.128/2580.1.86.129 to 80.1.86.25480.1.86.255126
17580.1.87.0/2580.1.87.1 to 80.1.87.12680.1.87.127126
17680.1.87.128/2580.1.87.129 to 80.1.87.25480.1.87.255126
17780.1.88.0/2580.1.88.1 to 80.1.88.12680.1.88.127126
17880.1.88.128/2580.1.88.129 to 80.1.88.25480.1.88.255126
17980.1.89.0/2580.1.89.1 to 80.1.89.12680.1.89.127126
18080.1.89.128/2580.1.89.129 to 80.1.89.25480.1.89.255126
18180.1.90.0/2580.1.90.1 to 80.1.90.12680.1.90.127126
18280.1.90.128/2580.1.90.129 to 80.1.90.25480.1.90.255126
18380.1.91.0/2580.1.91.1 to 80.1.91.12680.1.91.127126
18480.1.91.128/2580.1.91.129 to 80.1.91.25480.1.91.255126
18580.1.92.0/2580.1.92.1 to 80.1.92.12680.1.92.127126
18680.1.92.128/2580.1.92.129 to 80.1.92.25480.1.92.255126
18780.1.93.0/2580.1.93.1 to 80.1.93.12680.1.93.127126
18880.1.93.128/2580.1.93.129 to 80.1.93.25480.1.93.255126
18980.1.94.0/2580.1.94.1 to 80.1.94.12680.1.94.127126
19080.1.94.128/2580.1.94.129 to 80.1.94.25480.1.94.255126
19180.1.95.0/2580.1.95.1 to 80.1.95.12680.1.95.127126
19280.1.95.128/2580.1.95.129 to 80.1.95.25480.1.95.255126
19380.1.96.0/2580.1.96.1 to 80.1.96.12680.1.96.127126
19480.1.96.128/2580.1.96.129 to 80.1.96.25480.1.96.255126
19580.1.97.0/2580.1.97.1 to 80.1.97.12680.1.97.127126
19680.1.97.128/2580.1.97.129 to 80.1.97.25480.1.97.255126
19780.1.98.0/2580.1.98.1 to 80.1.98.12680.1.98.127126
19880.1.98.128/2580.1.98.129 to 80.1.98.25480.1.98.255126
19980.1.99.0/2580.1.99.1 to 80.1.99.12680.1.99.127126
20080.1.99.128/2580.1.99.129 to 80.1.99.25480.1.99.255126
20180.1.100.0/2580.1.100.1 to 80.1.100.12680.1.100.127126
20280.1.100.128/2580.1.100.129 to 80.1.100.25480.1.100.255126
20380.1.101.0/2580.1.101.1 to 80.1.101.12680.1.101.127126
20480.1.101.128/2580.1.101.129 to 80.1.101.25480.1.101.255126
20580.1.102.0/2580.1.102.1 to 80.1.102.12680.1.102.127126
20680.1.102.128/2580.1.102.129 to 80.1.102.25480.1.102.255126
20780.1.103.0/2580.1.103.1 to 80.1.103.12680.1.103.127126
20880.1.103.128/2580.1.103.129 to 80.1.103.25480.1.103.255126
20980.1.104.0/2580.1.104.1 to 80.1.104.12680.1.104.127126
21080.1.104.128/2580.1.104.129 to 80.1.104.25480.1.104.255126
21180.1.105.0/2580.1.105.1 to 80.1.105.12680.1.105.127126
21280.1.105.128/2580.1.105.129 to 80.1.105.25480.1.105.255126
21380.1.106.0/2580.1.106.1 to 80.1.106.12680.1.106.127126
21480.1.106.128/2580.1.106.129 to 80.1.106.25480.1.106.255126
21580.1.107.0/2580.1.107.1 to 80.1.107.12680.1.107.127126
21680.1.107.128/2580.1.107.129 to 80.1.107.25480.1.107.255126
21780.1.108.0/2580.1.108.1 to 80.1.108.12680.1.108.127126
21880.1.108.128/2580.1.108.129 to 80.1.108.25480.1.108.255126
21980.1.109.0/2580.1.109.1 to 80.1.109.12680.1.109.127126
22080.1.109.128/2580.1.109.129 to 80.1.109.25480.1.109.255126
22180.1.110.0/2580.1.110.1 to 80.1.110.12680.1.110.127126
22280.1.110.128/2580.1.110.129 to 80.1.110.25480.1.110.255126
22380.1.111.0/2580.1.111.1 to 80.1.111.12680.1.111.127126
22480.1.111.128/2580.1.111.129 to 80.1.111.25480.1.111.255126
22580.1.112.0/2580.1.112.1 to 80.1.112.12680.1.112.127126
22680.1.112.128/2580.1.112.129 to 80.1.112.25480.1.112.255126
22780.1.113.0/2580.1.113.1 to 80.1.113.12680.1.113.127126
22880.1.113.128/2580.1.113.129 to 80.1.113.25480.1.113.255126
22980.1.114.0/2580.1.114.1 to 80.1.114.12680.1.114.127126
23080.1.114.128/2580.1.114.129 to 80.1.114.25480.1.114.255126
23180.1.115.0/2580.1.115.1 to 80.1.115.12680.1.115.127126
23280.1.115.128/2580.1.115.129 to 80.1.115.25480.1.115.255126
23380.1.116.0/2580.1.116.1 to 80.1.116.12680.1.116.127126
23480.1.116.128/2580.1.116.129 to 80.1.116.25480.1.116.255126
23580.1.117.0/2580.1.117.1 to 80.1.117.12680.1.117.127126
23680.1.117.128/2580.1.117.129 to 80.1.117.25480.1.117.255126
23780.1.118.0/2580.1.118.1 to 80.1.118.12680.1.118.127126
23880.1.118.128/2580.1.118.129 to 80.1.118.25480.1.118.255126
23980.1.119.0/2580.1.119.1 to 80.1.119.12680.1.119.127126
24080.1.119.128/2580.1.119.129 to 80.1.119.25480.1.119.255126
24180.1.120.0/2580.1.120.1 to 80.1.120.12680.1.120.127126
24280.1.120.128/2580.1.120.129 to 80.1.120.25480.1.120.255126
24380.1.121.0/2580.1.121.1 to 80.1.121.12680.1.121.127126
24480.1.121.128/2580.1.121.129 to 80.1.121.25480.1.121.255126
24580.1.122.0/2580.1.122.1 to 80.1.122.12680.1.122.127126
24680.1.122.128/2580.1.122.129 to 80.1.122.25480.1.122.255126
24780.1.123.0/2580.1.123.1 to 80.1.123.12680.1.123.127126
24880.1.123.128/2580.1.123.129 to 80.1.123.25480.1.123.255126
24980.1.124.0/2580.1.124.1 to 80.1.124.12680.1.124.127126
25080.1.124.128/2580.1.124.129 to 80.1.124.25480.1.124.255126
25180.1.125.0/2580.1.125.1 to 80.1.125.12680.1.125.127126
25280.1.125.128/2580.1.125.129 to 80.1.125.25480.1.125.255126
25380.1.126.0/2580.1.126.1 to 80.1.126.12680.1.126.127126
25480.1.126.128/2580.1.126.129 to 80.1.126.25480.1.126.255126
25580.1.127.0/2580.1.127.1 to 80.1.127.12680.1.127.127126
25680.1.127.128/2580.1.127.129 to 80.1.127.25480.1.127.255126

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.