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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.

Network80.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
80.0.0.0
Broadcast address
81.255.255.255
First usable
80.0.0.1
Last usable
81.255.255.254
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 50000000 · Integer 1342177280 to 1375731711
Reverse DNS zones
80.in-addr.arpa
81.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
Address01010000.00000000.00000000.0000000080.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01010000.00000000.00000000.0000000080.0.0.0
Broadcast01010001.11111111.11111111.1111111181.255.255.255
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)

80.0.0.0/7 makes 1,024 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.0.0.0/1780.0.0.1 to 80.0.127.25480.0.127.25532,766
280.0.128.0/1780.0.128.1 to 80.0.255.25480.0.255.25532,766
380.1.0.0/1780.1.0.1 to 80.1.127.25480.1.127.25532,766
480.1.128.0/1780.1.128.1 to 80.1.255.25480.1.255.25532,766
580.2.0.0/1780.2.0.1 to 80.2.127.25480.2.127.25532,766
680.2.128.0/1780.2.128.1 to 80.2.255.25480.2.255.25532,766
780.3.0.0/1780.3.0.1 to 80.3.127.25480.3.127.25532,766
880.3.128.0/1780.3.128.1 to 80.3.255.25480.3.255.25532,766
980.4.0.0/1780.4.0.1 to 80.4.127.25480.4.127.25532,766
1080.4.128.0/1780.4.128.1 to 80.4.255.25480.4.255.25532,766
1180.5.0.0/1780.5.0.1 to 80.5.127.25480.5.127.25532,766
1280.5.128.0/1780.5.128.1 to 80.5.255.25480.5.255.25532,766
1380.6.0.0/1780.6.0.1 to 80.6.127.25480.6.127.25532,766
1480.6.128.0/1780.6.128.1 to 80.6.255.25480.6.255.25532,766
1580.7.0.0/1780.7.0.1 to 80.7.127.25480.7.127.25532,766
1680.7.128.0/1780.7.128.1 to 80.7.255.25480.7.255.25532,766
1780.8.0.0/1780.8.0.1 to 80.8.127.25480.8.127.25532,766
1880.8.128.0/1780.8.128.1 to 80.8.255.25480.8.255.25532,766
1980.9.0.0/1780.9.0.1 to 80.9.127.25480.9.127.25532,766
2080.9.128.0/1780.9.128.1 to 80.9.255.25480.9.255.25532,766
2180.10.0.0/1780.10.0.1 to 80.10.127.25480.10.127.25532,766
2280.10.128.0/1780.10.128.1 to 80.10.255.25480.10.255.25532,766
2380.11.0.0/1780.11.0.1 to 80.11.127.25480.11.127.25532,766
2480.11.128.0/1780.11.128.1 to 80.11.255.25480.11.255.25532,766
2580.12.0.0/1780.12.0.1 to 80.12.127.25480.12.127.25532,766
2680.12.128.0/1780.12.128.1 to 80.12.255.25480.12.255.25532,766
2780.13.0.0/1780.13.0.1 to 80.13.127.25480.13.127.25532,766
2880.13.128.0/1780.13.128.1 to 80.13.255.25480.13.255.25532,766
2980.14.0.0/1780.14.0.1 to 80.14.127.25480.14.127.25532,766
3080.14.128.0/1780.14.128.1 to 80.14.255.25480.14.255.25532,766
3180.15.0.0/1780.15.0.1 to 80.15.127.25480.15.127.25532,766
3280.15.128.0/1780.15.128.1 to 80.15.255.25480.15.255.25532,766
3380.16.0.0/1780.16.0.1 to 80.16.127.25480.16.127.25532,766
3480.16.128.0/1780.16.128.1 to 80.16.255.25480.16.255.25532,766
3580.17.0.0/1780.17.0.1 to 80.17.127.25480.17.127.25532,766
3680.17.128.0/1780.17.128.1 to 80.17.255.25480.17.255.25532,766
3780.18.0.0/1780.18.0.1 to 80.18.127.25480.18.127.25532,766
3880.18.128.0/1780.18.128.1 to 80.18.255.25480.18.255.25532,766
3980.19.0.0/1780.19.0.1 to 80.19.127.25480.19.127.25532,766
4080.19.128.0/1780.19.128.1 to 80.19.255.25480.19.255.25532,766
4180.20.0.0/1780.20.0.1 to 80.20.127.25480.20.127.25532,766
4280.20.128.0/1780.20.128.1 to 80.20.255.25480.20.255.25532,766
4380.21.0.0/1780.21.0.1 to 80.21.127.25480.21.127.25532,766
4480.21.128.0/1780.21.128.1 to 80.21.255.25480.21.255.25532,766
4580.22.0.0/1780.22.0.1 to 80.22.127.25480.22.127.25532,766
4680.22.128.0/1780.22.128.1 to 80.22.255.25480.22.255.25532,766
4780.23.0.0/1780.23.0.1 to 80.23.127.25480.23.127.25532,766
4880.23.128.0/1780.23.128.1 to 80.23.255.25480.23.255.25532,766
4980.24.0.0/1780.24.0.1 to 80.24.127.25480.24.127.25532,766
5080.24.128.0/1780.24.128.1 to 80.24.255.25480.24.255.25532,766
5180.25.0.0/1780.25.0.1 to 80.25.127.25480.25.127.25532,766
5280.25.128.0/1780.25.128.1 to 80.25.255.25480.25.255.25532,766
5380.26.0.0/1780.26.0.1 to 80.26.127.25480.26.127.25532,766
5480.26.128.0/1780.26.128.1 to 80.26.255.25480.26.255.25532,766
5580.27.0.0/1780.27.0.1 to 80.27.127.25480.27.127.25532,766
5680.27.128.0/1780.27.128.1 to 80.27.255.25480.27.255.25532,766
5780.28.0.0/1780.28.0.1 to 80.28.127.25480.28.127.25532,766
5880.28.128.0/1780.28.128.1 to 80.28.255.25480.28.255.25532,766
5980.29.0.0/1780.29.0.1 to 80.29.127.25480.29.127.25532,766
6080.29.128.0/1780.29.128.1 to 80.29.255.25480.29.255.25532,766
6180.30.0.0/1780.30.0.1 to 80.30.127.25480.30.127.25532,766
6280.30.128.0/1780.30.128.1 to 80.30.255.25480.30.255.25532,766
6380.31.0.0/1780.31.0.1 to 80.31.127.25480.31.127.25532,766
6480.31.128.0/1780.31.128.1 to 80.31.255.25480.31.255.25532,766
6580.32.0.0/1780.32.0.1 to 80.32.127.25480.32.127.25532,766
6680.32.128.0/1780.32.128.1 to 80.32.255.25480.32.255.25532,766
6780.33.0.0/1780.33.0.1 to 80.33.127.25480.33.127.25532,766
6880.33.128.0/1780.33.128.1 to 80.33.255.25480.33.255.25532,766
6980.34.0.0/1780.34.0.1 to 80.34.127.25480.34.127.25532,766
7080.34.128.0/1780.34.128.1 to 80.34.255.25480.34.255.25532,766
7180.35.0.0/1780.35.0.1 to 80.35.127.25480.35.127.25532,766
7280.35.128.0/1780.35.128.1 to 80.35.255.25480.35.255.25532,766
7380.36.0.0/1780.36.0.1 to 80.36.127.25480.36.127.25532,766
7480.36.128.0/1780.36.128.1 to 80.36.255.25480.36.255.25532,766
7580.37.0.0/1780.37.0.1 to 80.37.127.25480.37.127.25532,766
7680.37.128.0/1780.37.128.1 to 80.37.255.25480.37.255.25532,766
7780.38.0.0/1780.38.0.1 to 80.38.127.25480.38.127.25532,766
7880.38.128.0/1780.38.128.1 to 80.38.255.25480.38.255.25532,766
7980.39.0.0/1780.39.0.1 to 80.39.127.25480.39.127.25532,766
8080.39.128.0/1780.39.128.1 to 80.39.255.25480.39.255.25532,766
8180.40.0.0/1780.40.0.1 to 80.40.127.25480.40.127.25532,766
8280.40.128.0/1780.40.128.1 to 80.40.255.25480.40.255.25532,766
8380.41.0.0/1780.41.0.1 to 80.41.127.25480.41.127.25532,766
8480.41.128.0/1780.41.128.1 to 80.41.255.25480.41.255.25532,766
8580.42.0.0/1780.42.0.1 to 80.42.127.25480.42.127.25532,766
8680.42.128.0/1780.42.128.1 to 80.42.255.25480.42.255.25532,766
8780.43.0.0/1780.43.0.1 to 80.43.127.25480.43.127.25532,766
8880.43.128.0/1780.43.128.1 to 80.43.255.25480.43.255.25532,766
8980.44.0.0/1780.44.0.1 to 80.44.127.25480.44.127.25532,766
9080.44.128.0/1780.44.128.1 to 80.44.255.25480.44.255.25532,766
9180.45.0.0/1780.45.0.1 to 80.45.127.25480.45.127.25532,766
9280.45.128.0/1780.45.128.1 to 80.45.255.25480.45.255.25532,766
9380.46.0.0/1780.46.0.1 to 80.46.127.25480.46.127.25532,766
9480.46.128.0/1780.46.128.1 to 80.46.255.25480.46.255.25532,766
9580.47.0.0/1780.47.0.1 to 80.47.127.25480.47.127.25532,766
9680.47.128.0/1780.47.128.1 to 80.47.255.25480.47.255.25532,766
9780.48.0.0/1780.48.0.1 to 80.48.127.25480.48.127.25532,766
9880.48.128.0/1780.48.128.1 to 80.48.255.25480.48.255.25532,766
9980.49.0.0/1780.49.0.1 to 80.49.127.25480.49.127.25532,766
10080.49.128.0/1780.49.128.1 to 80.49.255.25480.49.255.25532,766
10180.50.0.0/1780.50.0.1 to 80.50.127.25480.50.127.25532,766
10280.50.128.0/1780.50.128.1 to 80.50.255.25480.50.255.25532,766
10380.51.0.0/1780.51.0.1 to 80.51.127.25480.51.127.25532,766
10480.51.128.0/1780.51.128.1 to 80.51.255.25480.51.255.25532,766
10580.52.0.0/1780.52.0.1 to 80.52.127.25480.52.127.25532,766
10680.52.128.0/1780.52.128.1 to 80.52.255.25480.52.255.25532,766
10780.53.0.0/1780.53.0.1 to 80.53.127.25480.53.127.25532,766
10880.53.128.0/1780.53.128.1 to 80.53.255.25480.53.255.25532,766
10980.54.0.0/1780.54.0.1 to 80.54.127.25480.54.127.25532,766
11080.54.128.0/1780.54.128.1 to 80.54.255.25480.54.255.25532,766
11180.55.0.0/1780.55.0.1 to 80.55.127.25480.55.127.25532,766
11280.55.128.0/1780.55.128.1 to 80.55.255.25480.55.255.25532,766
11380.56.0.0/1780.56.0.1 to 80.56.127.25480.56.127.25532,766
11480.56.128.0/1780.56.128.1 to 80.56.255.25480.56.255.25532,766
11580.57.0.0/1780.57.0.1 to 80.57.127.25480.57.127.25532,766
11680.57.128.0/1780.57.128.1 to 80.57.255.25480.57.255.25532,766
11780.58.0.0/1780.58.0.1 to 80.58.127.25480.58.127.25532,766
11880.58.128.0/1780.58.128.1 to 80.58.255.25480.58.255.25532,766
11980.59.0.0/1780.59.0.1 to 80.59.127.25480.59.127.25532,766
12080.59.128.0/1780.59.128.1 to 80.59.255.25480.59.255.25532,766
12180.60.0.0/1780.60.0.1 to 80.60.127.25480.60.127.25532,766
12280.60.128.0/1780.60.128.1 to 80.60.255.25480.60.255.25532,766
12380.61.0.0/1780.61.0.1 to 80.61.127.25480.61.127.25532,766
12480.61.128.0/1780.61.128.1 to 80.61.255.25480.61.255.25532,766
12580.62.0.0/1780.62.0.1 to 80.62.127.25480.62.127.25532,766
12680.62.128.0/1780.62.128.1 to 80.62.255.25480.62.255.25532,766
12780.63.0.0/1780.63.0.1 to 80.63.127.25480.63.127.25532,766
12880.63.128.0/1780.63.128.1 to 80.63.255.25480.63.255.25532,766
12980.64.0.0/1780.64.0.1 to 80.64.127.25480.64.127.25532,766
13080.64.128.0/1780.64.128.1 to 80.64.255.25480.64.255.25532,766
13180.65.0.0/1780.65.0.1 to 80.65.127.25480.65.127.25532,766
13280.65.128.0/1780.65.128.1 to 80.65.255.25480.65.255.25532,766
13380.66.0.0/1780.66.0.1 to 80.66.127.25480.66.127.25532,766
13480.66.128.0/1780.66.128.1 to 80.66.255.25480.66.255.25532,766
13580.67.0.0/1780.67.0.1 to 80.67.127.25480.67.127.25532,766
13680.67.128.0/1780.67.128.1 to 80.67.255.25480.67.255.25532,766
13780.68.0.0/1780.68.0.1 to 80.68.127.25480.68.127.25532,766
13880.68.128.0/1780.68.128.1 to 80.68.255.25480.68.255.25532,766
13980.69.0.0/1780.69.0.1 to 80.69.127.25480.69.127.25532,766
14080.69.128.0/1780.69.128.1 to 80.69.255.25480.69.255.25532,766
14180.70.0.0/1780.70.0.1 to 80.70.127.25480.70.127.25532,766
14280.70.128.0/1780.70.128.1 to 80.70.255.25480.70.255.25532,766
14380.71.0.0/1780.71.0.1 to 80.71.127.25480.71.127.25532,766
14480.71.128.0/1780.71.128.1 to 80.71.255.25480.71.255.25532,766
14580.72.0.0/1780.72.0.1 to 80.72.127.25480.72.127.25532,766
14680.72.128.0/1780.72.128.1 to 80.72.255.25480.72.255.25532,766
14780.73.0.0/1780.73.0.1 to 80.73.127.25480.73.127.25532,766
14880.73.128.0/1780.73.128.1 to 80.73.255.25480.73.255.25532,766
14980.74.0.0/1780.74.0.1 to 80.74.127.25480.74.127.25532,766
15080.74.128.0/1780.74.128.1 to 80.74.255.25480.74.255.25532,766
15180.75.0.0/1780.75.0.1 to 80.75.127.25480.75.127.25532,766
15280.75.128.0/1780.75.128.1 to 80.75.255.25480.75.255.25532,766
15380.76.0.0/1780.76.0.1 to 80.76.127.25480.76.127.25532,766
15480.76.128.0/1780.76.128.1 to 80.76.255.25480.76.255.25532,766
15580.77.0.0/1780.77.0.1 to 80.77.127.25480.77.127.25532,766
15680.77.128.0/1780.77.128.1 to 80.77.255.25480.77.255.25532,766
15780.78.0.0/1780.78.0.1 to 80.78.127.25480.78.127.25532,766
15880.78.128.0/1780.78.128.1 to 80.78.255.25480.78.255.25532,766
15980.79.0.0/1780.79.0.1 to 80.79.127.25480.79.127.25532,766
16080.79.128.0/1780.79.128.1 to 80.79.255.25480.79.255.25532,766
16180.80.0.0/1780.80.0.1 to 80.80.127.25480.80.127.25532,766
16280.80.128.0/1780.80.128.1 to 80.80.255.25480.80.255.25532,766
16380.81.0.0/1780.81.0.1 to 80.81.127.25480.81.127.25532,766
16480.81.128.0/1780.81.128.1 to 80.81.255.25480.81.255.25532,766
16580.82.0.0/1780.82.0.1 to 80.82.127.25480.82.127.25532,766
16680.82.128.0/1780.82.128.1 to 80.82.255.25480.82.255.25532,766
16780.83.0.0/1780.83.0.1 to 80.83.127.25480.83.127.25532,766
16880.83.128.0/1780.83.128.1 to 80.83.255.25480.83.255.25532,766
16980.84.0.0/1780.84.0.1 to 80.84.127.25480.84.127.25532,766
17080.84.128.0/1780.84.128.1 to 80.84.255.25480.84.255.25532,766
17180.85.0.0/1780.85.0.1 to 80.85.127.25480.85.127.25532,766
17280.85.128.0/1780.85.128.1 to 80.85.255.25480.85.255.25532,766
17380.86.0.0/1780.86.0.1 to 80.86.127.25480.86.127.25532,766
17480.86.128.0/1780.86.128.1 to 80.86.255.25480.86.255.25532,766
17580.87.0.0/1780.87.0.1 to 80.87.127.25480.87.127.25532,766
17680.87.128.0/1780.87.128.1 to 80.87.255.25480.87.255.25532,766
17780.88.0.0/1780.88.0.1 to 80.88.127.25480.88.127.25532,766
17880.88.128.0/1780.88.128.1 to 80.88.255.25480.88.255.25532,766
17980.89.0.0/1780.89.0.1 to 80.89.127.25480.89.127.25532,766
18080.89.128.0/1780.89.128.1 to 80.89.255.25480.89.255.25532,766
18180.90.0.0/1780.90.0.1 to 80.90.127.25480.90.127.25532,766
18280.90.128.0/1780.90.128.1 to 80.90.255.25480.90.255.25532,766
18380.91.0.0/1780.91.0.1 to 80.91.127.25480.91.127.25532,766
18480.91.128.0/1780.91.128.1 to 80.91.255.25480.91.255.25532,766
18580.92.0.0/1780.92.0.1 to 80.92.127.25480.92.127.25532,766
18680.92.128.0/1780.92.128.1 to 80.92.255.25480.92.255.25532,766
18780.93.0.0/1780.93.0.1 to 80.93.127.25480.93.127.25532,766
18880.93.128.0/1780.93.128.1 to 80.93.255.25480.93.255.25532,766
18980.94.0.0/1780.94.0.1 to 80.94.127.25480.94.127.25532,766
19080.94.128.0/1780.94.128.1 to 80.94.255.25480.94.255.25532,766
19180.95.0.0/1780.95.0.1 to 80.95.127.25480.95.127.25532,766
19280.95.128.0/1780.95.128.1 to 80.95.255.25480.95.255.25532,766
19380.96.0.0/1780.96.0.1 to 80.96.127.25480.96.127.25532,766
19480.96.128.0/1780.96.128.1 to 80.96.255.25480.96.255.25532,766
19580.97.0.0/1780.97.0.1 to 80.97.127.25480.97.127.25532,766
19680.97.128.0/1780.97.128.1 to 80.97.255.25480.97.255.25532,766
19780.98.0.0/1780.98.0.1 to 80.98.127.25480.98.127.25532,766
19880.98.128.0/1780.98.128.1 to 80.98.255.25480.98.255.25532,766
19980.99.0.0/1780.99.0.1 to 80.99.127.25480.99.127.25532,766
20080.99.128.0/1780.99.128.1 to 80.99.255.25480.99.255.25532,766
20180.100.0.0/1780.100.0.1 to 80.100.127.25480.100.127.25532,766
20280.100.128.0/1780.100.128.1 to 80.100.255.25480.100.255.25532,766
20380.101.0.0/1780.101.0.1 to 80.101.127.25480.101.127.25532,766
20480.101.128.0/1780.101.128.1 to 80.101.255.25480.101.255.25532,766
20580.102.0.0/1780.102.0.1 to 80.102.127.25480.102.127.25532,766
20680.102.128.0/1780.102.128.1 to 80.102.255.25480.102.255.25532,766
20780.103.0.0/1780.103.0.1 to 80.103.127.25480.103.127.25532,766
20880.103.128.0/1780.103.128.1 to 80.103.255.25480.103.255.25532,766
20980.104.0.0/1780.104.0.1 to 80.104.127.25480.104.127.25532,766
21080.104.128.0/1780.104.128.1 to 80.104.255.25480.104.255.25532,766
21180.105.0.0/1780.105.0.1 to 80.105.127.25480.105.127.25532,766
21280.105.128.0/1780.105.128.1 to 80.105.255.25480.105.255.25532,766
21380.106.0.0/1780.106.0.1 to 80.106.127.25480.106.127.25532,766
21480.106.128.0/1780.106.128.1 to 80.106.255.25480.106.255.25532,766
21580.107.0.0/1780.107.0.1 to 80.107.127.25480.107.127.25532,766
21680.107.128.0/1780.107.128.1 to 80.107.255.25480.107.255.25532,766
21780.108.0.0/1780.108.0.1 to 80.108.127.25480.108.127.25532,766
21880.108.128.0/1780.108.128.1 to 80.108.255.25480.108.255.25532,766
21980.109.0.0/1780.109.0.1 to 80.109.127.25480.109.127.25532,766
22080.109.128.0/1780.109.128.1 to 80.109.255.25480.109.255.25532,766
22180.110.0.0/1780.110.0.1 to 80.110.127.25480.110.127.25532,766
22280.110.128.0/1780.110.128.1 to 80.110.255.25480.110.255.25532,766
22380.111.0.0/1780.111.0.1 to 80.111.127.25480.111.127.25532,766
22480.111.128.0/1780.111.128.1 to 80.111.255.25480.111.255.25532,766
22580.112.0.0/1780.112.0.1 to 80.112.127.25480.112.127.25532,766
22680.112.128.0/1780.112.128.1 to 80.112.255.25480.112.255.25532,766
22780.113.0.0/1780.113.0.1 to 80.113.127.25480.113.127.25532,766
22880.113.128.0/1780.113.128.1 to 80.113.255.25480.113.255.25532,766
22980.114.0.0/1780.114.0.1 to 80.114.127.25480.114.127.25532,766
23080.114.128.0/1780.114.128.1 to 80.114.255.25480.114.255.25532,766
23180.115.0.0/1780.115.0.1 to 80.115.127.25480.115.127.25532,766
23280.115.128.0/1780.115.128.1 to 80.115.255.25480.115.255.25532,766
23380.116.0.0/1780.116.0.1 to 80.116.127.25480.116.127.25532,766
23480.116.128.0/1780.116.128.1 to 80.116.255.25480.116.255.25532,766
23580.117.0.0/1780.117.0.1 to 80.117.127.25480.117.127.25532,766
23680.117.128.0/1780.117.128.1 to 80.117.255.25480.117.255.25532,766
23780.118.0.0/1780.118.0.1 to 80.118.127.25480.118.127.25532,766
23880.118.128.0/1780.118.128.1 to 80.118.255.25480.118.255.25532,766
23980.119.0.0/1780.119.0.1 to 80.119.127.25480.119.127.25532,766
24080.119.128.0/1780.119.128.1 to 80.119.255.25480.119.255.25532,766
24180.120.0.0/1780.120.0.1 to 80.120.127.25480.120.127.25532,766
24280.120.128.0/1780.120.128.1 to 80.120.255.25480.120.255.25532,766
24380.121.0.0/1780.121.0.1 to 80.121.127.25480.121.127.25532,766
24480.121.128.0/1780.121.128.1 to 80.121.255.25480.121.255.25532,766
24580.122.0.0/1780.122.0.1 to 80.122.127.25480.122.127.25532,766
24680.122.128.0/1780.122.128.1 to 80.122.255.25480.122.255.25532,766
24780.123.0.0/1780.123.0.1 to 80.123.127.25480.123.127.25532,766
24880.123.128.0/1780.123.128.1 to 80.123.255.25480.123.255.25532,766
24980.124.0.0/1780.124.0.1 to 80.124.127.25480.124.127.25532,766
25080.124.128.0/1780.124.128.1 to 80.124.255.25480.124.255.25532,766
25180.125.0.0/1780.125.0.1 to 80.125.127.25480.125.127.25532,766
25280.125.128.0/1780.125.128.1 to 80.125.255.25480.125.255.25532,766
25380.126.0.0/1780.126.0.1 to 80.126.127.25480.126.127.25532,766
25480.126.128.0/1780.126.128.1 to 80.126.255.25480.126.255.25532,766
25580.127.0.0/1780.127.0.1 to 80.127.127.25480.127.127.25532,766
25680.127.128.0/1780.127.128.1 to 80.127.255.25480.127.255.25532,766

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.