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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.

Network20.84.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
20.84.0.0
Broadcast address
20.84.255.255
First usable
20.84.0.1
Last usable
20.84.255.254
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 14540000 · Integer 341049344 to 341114879
Reverse DNS zone
84.20.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010100.01010100..00000000.0000000020.84.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00010100.01010100..00000000.0000000020.84.0.0
Broadcast00010100.01010100..11111111.1111111120.84.255.255
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)

20.84.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
120.84.0.0/2520.84.0.1 to 20.84.0.12620.84.0.127126
220.84.0.128/2520.84.0.129 to 20.84.0.25420.84.0.255126
320.84.1.0/2520.84.1.1 to 20.84.1.12620.84.1.127126
420.84.1.128/2520.84.1.129 to 20.84.1.25420.84.1.255126
520.84.2.0/2520.84.2.1 to 20.84.2.12620.84.2.127126
620.84.2.128/2520.84.2.129 to 20.84.2.25420.84.2.255126
720.84.3.0/2520.84.3.1 to 20.84.3.12620.84.3.127126
820.84.3.128/2520.84.3.129 to 20.84.3.25420.84.3.255126
920.84.4.0/2520.84.4.1 to 20.84.4.12620.84.4.127126
1020.84.4.128/2520.84.4.129 to 20.84.4.25420.84.4.255126
1120.84.5.0/2520.84.5.1 to 20.84.5.12620.84.5.127126
1220.84.5.128/2520.84.5.129 to 20.84.5.25420.84.5.255126
1320.84.6.0/2520.84.6.1 to 20.84.6.12620.84.6.127126
1420.84.6.128/2520.84.6.129 to 20.84.6.25420.84.6.255126
1520.84.7.0/2520.84.7.1 to 20.84.7.12620.84.7.127126
1620.84.7.128/2520.84.7.129 to 20.84.7.25420.84.7.255126
1720.84.8.0/2520.84.8.1 to 20.84.8.12620.84.8.127126
1820.84.8.128/2520.84.8.129 to 20.84.8.25420.84.8.255126
1920.84.9.0/2520.84.9.1 to 20.84.9.12620.84.9.127126
2020.84.9.128/2520.84.9.129 to 20.84.9.25420.84.9.255126
2120.84.10.0/2520.84.10.1 to 20.84.10.12620.84.10.127126
2220.84.10.128/2520.84.10.129 to 20.84.10.25420.84.10.255126
2320.84.11.0/2520.84.11.1 to 20.84.11.12620.84.11.127126
2420.84.11.128/2520.84.11.129 to 20.84.11.25420.84.11.255126
2520.84.12.0/2520.84.12.1 to 20.84.12.12620.84.12.127126
2620.84.12.128/2520.84.12.129 to 20.84.12.25420.84.12.255126
2720.84.13.0/2520.84.13.1 to 20.84.13.12620.84.13.127126
2820.84.13.128/2520.84.13.129 to 20.84.13.25420.84.13.255126
2920.84.14.0/2520.84.14.1 to 20.84.14.12620.84.14.127126
3020.84.14.128/2520.84.14.129 to 20.84.14.25420.84.14.255126
3120.84.15.0/2520.84.15.1 to 20.84.15.12620.84.15.127126
3220.84.15.128/2520.84.15.129 to 20.84.15.25420.84.15.255126
3320.84.16.0/2520.84.16.1 to 20.84.16.12620.84.16.127126
3420.84.16.128/2520.84.16.129 to 20.84.16.25420.84.16.255126
3520.84.17.0/2520.84.17.1 to 20.84.17.12620.84.17.127126
3620.84.17.128/2520.84.17.129 to 20.84.17.25420.84.17.255126
3720.84.18.0/2520.84.18.1 to 20.84.18.12620.84.18.127126
3820.84.18.128/2520.84.18.129 to 20.84.18.25420.84.18.255126
3920.84.19.0/2520.84.19.1 to 20.84.19.12620.84.19.127126
4020.84.19.128/2520.84.19.129 to 20.84.19.25420.84.19.255126
4120.84.20.0/2520.84.20.1 to 20.84.20.12620.84.20.127126
4220.84.20.128/2520.84.20.129 to 20.84.20.25420.84.20.255126
4320.84.21.0/2520.84.21.1 to 20.84.21.12620.84.21.127126
4420.84.21.128/2520.84.21.129 to 20.84.21.25420.84.21.255126
4520.84.22.0/2520.84.22.1 to 20.84.22.12620.84.22.127126
4620.84.22.128/2520.84.22.129 to 20.84.22.25420.84.22.255126
4720.84.23.0/2520.84.23.1 to 20.84.23.12620.84.23.127126
4820.84.23.128/2520.84.23.129 to 20.84.23.25420.84.23.255126
4920.84.24.0/2520.84.24.1 to 20.84.24.12620.84.24.127126
5020.84.24.128/2520.84.24.129 to 20.84.24.25420.84.24.255126
5120.84.25.0/2520.84.25.1 to 20.84.25.12620.84.25.127126
5220.84.25.128/2520.84.25.129 to 20.84.25.25420.84.25.255126
5320.84.26.0/2520.84.26.1 to 20.84.26.12620.84.26.127126
5420.84.26.128/2520.84.26.129 to 20.84.26.25420.84.26.255126
5520.84.27.0/2520.84.27.1 to 20.84.27.12620.84.27.127126
5620.84.27.128/2520.84.27.129 to 20.84.27.25420.84.27.255126
5720.84.28.0/2520.84.28.1 to 20.84.28.12620.84.28.127126
5820.84.28.128/2520.84.28.129 to 20.84.28.25420.84.28.255126
5920.84.29.0/2520.84.29.1 to 20.84.29.12620.84.29.127126
6020.84.29.128/2520.84.29.129 to 20.84.29.25420.84.29.255126
6120.84.30.0/2520.84.30.1 to 20.84.30.12620.84.30.127126
6220.84.30.128/2520.84.30.129 to 20.84.30.25420.84.30.255126
6320.84.31.0/2520.84.31.1 to 20.84.31.12620.84.31.127126
6420.84.31.128/2520.84.31.129 to 20.84.31.25420.84.31.255126
6520.84.32.0/2520.84.32.1 to 20.84.32.12620.84.32.127126
6620.84.32.128/2520.84.32.129 to 20.84.32.25420.84.32.255126
6720.84.33.0/2520.84.33.1 to 20.84.33.12620.84.33.127126
6820.84.33.128/2520.84.33.129 to 20.84.33.25420.84.33.255126
6920.84.34.0/2520.84.34.1 to 20.84.34.12620.84.34.127126
7020.84.34.128/2520.84.34.129 to 20.84.34.25420.84.34.255126
7120.84.35.0/2520.84.35.1 to 20.84.35.12620.84.35.127126
7220.84.35.128/2520.84.35.129 to 20.84.35.25420.84.35.255126
7320.84.36.0/2520.84.36.1 to 20.84.36.12620.84.36.127126
7420.84.36.128/2520.84.36.129 to 20.84.36.25420.84.36.255126
7520.84.37.0/2520.84.37.1 to 20.84.37.12620.84.37.127126
7620.84.37.128/2520.84.37.129 to 20.84.37.25420.84.37.255126
7720.84.38.0/2520.84.38.1 to 20.84.38.12620.84.38.127126
7820.84.38.128/2520.84.38.129 to 20.84.38.25420.84.38.255126
7920.84.39.0/2520.84.39.1 to 20.84.39.12620.84.39.127126
8020.84.39.128/2520.84.39.129 to 20.84.39.25420.84.39.255126
8120.84.40.0/2520.84.40.1 to 20.84.40.12620.84.40.127126
8220.84.40.128/2520.84.40.129 to 20.84.40.25420.84.40.255126
8320.84.41.0/2520.84.41.1 to 20.84.41.12620.84.41.127126
8420.84.41.128/2520.84.41.129 to 20.84.41.25420.84.41.255126
8520.84.42.0/2520.84.42.1 to 20.84.42.12620.84.42.127126
8620.84.42.128/2520.84.42.129 to 20.84.42.25420.84.42.255126
8720.84.43.0/2520.84.43.1 to 20.84.43.12620.84.43.127126
8820.84.43.128/2520.84.43.129 to 20.84.43.25420.84.43.255126
8920.84.44.0/2520.84.44.1 to 20.84.44.12620.84.44.127126
9020.84.44.128/2520.84.44.129 to 20.84.44.25420.84.44.255126
9120.84.45.0/2520.84.45.1 to 20.84.45.12620.84.45.127126
9220.84.45.128/2520.84.45.129 to 20.84.45.25420.84.45.255126
9320.84.46.0/2520.84.46.1 to 20.84.46.12620.84.46.127126
9420.84.46.128/2520.84.46.129 to 20.84.46.25420.84.46.255126
9520.84.47.0/2520.84.47.1 to 20.84.47.12620.84.47.127126
9620.84.47.128/2520.84.47.129 to 20.84.47.25420.84.47.255126
9720.84.48.0/2520.84.48.1 to 20.84.48.12620.84.48.127126
9820.84.48.128/2520.84.48.129 to 20.84.48.25420.84.48.255126
9920.84.49.0/2520.84.49.1 to 20.84.49.12620.84.49.127126
10020.84.49.128/2520.84.49.129 to 20.84.49.25420.84.49.255126
10120.84.50.0/2520.84.50.1 to 20.84.50.12620.84.50.127126
10220.84.50.128/2520.84.50.129 to 20.84.50.25420.84.50.255126
10320.84.51.0/2520.84.51.1 to 20.84.51.12620.84.51.127126
10420.84.51.128/2520.84.51.129 to 20.84.51.25420.84.51.255126
10520.84.52.0/2520.84.52.1 to 20.84.52.12620.84.52.127126
10620.84.52.128/2520.84.52.129 to 20.84.52.25420.84.52.255126
10720.84.53.0/2520.84.53.1 to 20.84.53.12620.84.53.127126
10820.84.53.128/2520.84.53.129 to 20.84.53.25420.84.53.255126
10920.84.54.0/2520.84.54.1 to 20.84.54.12620.84.54.127126
11020.84.54.128/2520.84.54.129 to 20.84.54.25420.84.54.255126
11120.84.55.0/2520.84.55.1 to 20.84.55.12620.84.55.127126
11220.84.55.128/2520.84.55.129 to 20.84.55.25420.84.55.255126
11320.84.56.0/2520.84.56.1 to 20.84.56.12620.84.56.127126
11420.84.56.128/2520.84.56.129 to 20.84.56.25420.84.56.255126
11520.84.57.0/2520.84.57.1 to 20.84.57.12620.84.57.127126
11620.84.57.128/2520.84.57.129 to 20.84.57.25420.84.57.255126
11720.84.58.0/2520.84.58.1 to 20.84.58.12620.84.58.127126
11820.84.58.128/2520.84.58.129 to 20.84.58.25420.84.58.255126
11920.84.59.0/2520.84.59.1 to 20.84.59.12620.84.59.127126
12020.84.59.128/2520.84.59.129 to 20.84.59.25420.84.59.255126
12120.84.60.0/2520.84.60.1 to 20.84.60.12620.84.60.127126
12220.84.60.128/2520.84.60.129 to 20.84.60.25420.84.60.255126
12320.84.61.0/2520.84.61.1 to 20.84.61.12620.84.61.127126
12420.84.61.128/2520.84.61.129 to 20.84.61.25420.84.61.255126
12520.84.62.0/2520.84.62.1 to 20.84.62.12620.84.62.127126
12620.84.62.128/2520.84.62.129 to 20.84.62.25420.84.62.255126
12720.84.63.0/2520.84.63.1 to 20.84.63.12620.84.63.127126
12820.84.63.128/2520.84.63.129 to 20.84.63.25420.84.63.255126
12920.84.64.0/2520.84.64.1 to 20.84.64.12620.84.64.127126
13020.84.64.128/2520.84.64.129 to 20.84.64.25420.84.64.255126
13120.84.65.0/2520.84.65.1 to 20.84.65.12620.84.65.127126
13220.84.65.128/2520.84.65.129 to 20.84.65.25420.84.65.255126
13320.84.66.0/2520.84.66.1 to 20.84.66.12620.84.66.127126
13420.84.66.128/2520.84.66.129 to 20.84.66.25420.84.66.255126
13520.84.67.0/2520.84.67.1 to 20.84.67.12620.84.67.127126
13620.84.67.128/2520.84.67.129 to 20.84.67.25420.84.67.255126
13720.84.68.0/2520.84.68.1 to 20.84.68.12620.84.68.127126
13820.84.68.128/2520.84.68.129 to 20.84.68.25420.84.68.255126
13920.84.69.0/2520.84.69.1 to 20.84.69.12620.84.69.127126
14020.84.69.128/2520.84.69.129 to 20.84.69.25420.84.69.255126
14120.84.70.0/2520.84.70.1 to 20.84.70.12620.84.70.127126
14220.84.70.128/2520.84.70.129 to 20.84.70.25420.84.70.255126
14320.84.71.0/2520.84.71.1 to 20.84.71.12620.84.71.127126
14420.84.71.128/2520.84.71.129 to 20.84.71.25420.84.71.255126
14520.84.72.0/2520.84.72.1 to 20.84.72.12620.84.72.127126
14620.84.72.128/2520.84.72.129 to 20.84.72.25420.84.72.255126
14720.84.73.0/2520.84.73.1 to 20.84.73.12620.84.73.127126
14820.84.73.128/2520.84.73.129 to 20.84.73.25420.84.73.255126
14920.84.74.0/2520.84.74.1 to 20.84.74.12620.84.74.127126
15020.84.74.128/2520.84.74.129 to 20.84.74.25420.84.74.255126
15120.84.75.0/2520.84.75.1 to 20.84.75.12620.84.75.127126
15220.84.75.128/2520.84.75.129 to 20.84.75.25420.84.75.255126
15320.84.76.0/2520.84.76.1 to 20.84.76.12620.84.76.127126
15420.84.76.128/2520.84.76.129 to 20.84.76.25420.84.76.255126
15520.84.77.0/2520.84.77.1 to 20.84.77.12620.84.77.127126
15620.84.77.128/2520.84.77.129 to 20.84.77.25420.84.77.255126
15720.84.78.0/2520.84.78.1 to 20.84.78.12620.84.78.127126
15820.84.78.128/2520.84.78.129 to 20.84.78.25420.84.78.255126
15920.84.79.0/2520.84.79.1 to 20.84.79.12620.84.79.127126
16020.84.79.128/2520.84.79.129 to 20.84.79.25420.84.79.255126
16120.84.80.0/2520.84.80.1 to 20.84.80.12620.84.80.127126
16220.84.80.128/2520.84.80.129 to 20.84.80.25420.84.80.255126
16320.84.81.0/2520.84.81.1 to 20.84.81.12620.84.81.127126
16420.84.81.128/2520.84.81.129 to 20.84.81.25420.84.81.255126
16520.84.82.0/2520.84.82.1 to 20.84.82.12620.84.82.127126
16620.84.82.128/2520.84.82.129 to 20.84.82.25420.84.82.255126
16720.84.83.0/2520.84.83.1 to 20.84.83.12620.84.83.127126
16820.84.83.128/2520.84.83.129 to 20.84.83.25420.84.83.255126
16920.84.84.0/2520.84.84.1 to 20.84.84.12620.84.84.127126
17020.84.84.128/2520.84.84.129 to 20.84.84.25420.84.84.255126
17120.84.85.0/2520.84.85.1 to 20.84.85.12620.84.85.127126
17220.84.85.128/2520.84.85.129 to 20.84.85.25420.84.85.255126
17320.84.86.0/2520.84.86.1 to 20.84.86.12620.84.86.127126
17420.84.86.128/2520.84.86.129 to 20.84.86.25420.84.86.255126
17520.84.87.0/2520.84.87.1 to 20.84.87.12620.84.87.127126
17620.84.87.128/2520.84.87.129 to 20.84.87.25420.84.87.255126
17720.84.88.0/2520.84.88.1 to 20.84.88.12620.84.88.127126
17820.84.88.128/2520.84.88.129 to 20.84.88.25420.84.88.255126
17920.84.89.0/2520.84.89.1 to 20.84.89.12620.84.89.127126
18020.84.89.128/2520.84.89.129 to 20.84.89.25420.84.89.255126
18120.84.90.0/2520.84.90.1 to 20.84.90.12620.84.90.127126
18220.84.90.128/2520.84.90.129 to 20.84.90.25420.84.90.255126
18320.84.91.0/2520.84.91.1 to 20.84.91.12620.84.91.127126
18420.84.91.128/2520.84.91.129 to 20.84.91.25420.84.91.255126
18520.84.92.0/2520.84.92.1 to 20.84.92.12620.84.92.127126
18620.84.92.128/2520.84.92.129 to 20.84.92.25420.84.92.255126
18720.84.93.0/2520.84.93.1 to 20.84.93.12620.84.93.127126
18820.84.93.128/2520.84.93.129 to 20.84.93.25420.84.93.255126
18920.84.94.0/2520.84.94.1 to 20.84.94.12620.84.94.127126
19020.84.94.128/2520.84.94.129 to 20.84.94.25420.84.94.255126
19120.84.95.0/2520.84.95.1 to 20.84.95.12620.84.95.127126
19220.84.95.128/2520.84.95.129 to 20.84.95.25420.84.95.255126
19320.84.96.0/2520.84.96.1 to 20.84.96.12620.84.96.127126
19420.84.96.128/2520.84.96.129 to 20.84.96.25420.84.96.255126
19520.84.97.0/2520.84.97.1 to 20.84.97.12620.84.97.127126
19620.84.97.128/2520.84.97.129 to 20.84.97.25420.84.97.255126
19720.84.98.0/2520.84.98.1 to 20.84.98.12620.84.98.127126
19820.84.98.128/2520.84.98.129 to 20.84.98.25420.84.98.255126
19920.84.99.0/2520.84.99.1 to 20.84.99.12620.84.99.127126
20020.84.99.128/2520.84.99.129 to 20.84.99.25420.84.99.255126
20120.84.100.0/2520.84.100.1 to 20.84.100.12620.84.100.127126
20220.84.100.128/2520.84.100.129 to 20.84.100.25420.84.100.255126
20320.84.101.0/2520.84.101.1 to 20.84.101.12620.84.101.127126
20420.84.101.128/2520.84.101.129 to 20.84.101.25420.84.101.255126
20520.84.102.0/2520.84.102.1 to 20.84.102.12620.84.102.127126
20620.84.102.128/2520.84.102.129 to 20.84.102.25420.84.102.255126
20720.84.103.0/2520.84.103.1 to 20.84.103.12620.84.103.127126
20820.84.103.128/2520.84.103.129 to 20.84.103.25420.84.103.255126
20920.84.104.0/2520.84.104.1 to 20.84.104.12620.84.104.127126
21020.84.104.128/2520.84.104.129 to 20.84.104.25420.84.104.255126
21120.84.105.0/2520.84.105.1 to 20.84.105.12620.84.105.127126
21220.84.105.128/2520.84.105.129 to 20.84.105.25420.84.105.255126
21320.84.106.0/2520.84.106.1 to 20.84.106.12620.84.106.127126
21420.84.106.128/2520.84.106.129 to 20.84.106.25420.84.106.255126
21520.84.107.0/2520.84.107.1 to 20.84.107.12620.84.107.127126
21620.84.107.128/2520.84.107.129 to 20.84.107.25420.84.107.255126
21720.84.108.0/2520.84.108.1 to 20.84.108.12620.84.108.127126
21820.84.108.128/2520.84.108.129 to 20.84.108.25420.84.108.255126
21920.84.109.0/2520.84.109.1 to 20.84.109.12620.84.109.127126
22020.84.109.128/2520.84.109.129 to 20.84.109.25420.84.109.255126
22120.84.110.0/2520.84.110.1 to 20.84.110.12620.84.110.127126
22220.84.110.128/2520.84.110.129 to 20.84.110.25420.84.110.255126
22320.84.111.0/2520.84.111.1 to 20.84.111.12620.84.111.127126
22420.84.111.128/2520.84.111.129 to 20.84.111.25420.84.111.255126
22520.84.112.0/2520.84.112.1 to 20.84.112.12620.84.112.127126
22620.84.112.128/2520.84.112.129 to 20.84.112.25420.84.112.255126
22720.84.113.0/2520.84.113.1 to 20.84.113.12620.84.113.127126
22820.84.113.128/2520.84.113.129 to 20.84.113.25420.84.113.255126
22920.84.114.0/2520.84.114.1 to 20.84.114.12620.84.114.127126
23020.84.114.128/2520.84.114.129 to 20.84.114.25420.84.114.255126
23120.84.115.0/2520.84.115.1 to 20.84.115.12620.84.115.127126
23220.84.115.128/2520.84.115.129 to 20.84.115.25420.84.115.255126
23320.84.116.0/2520.84.116.1 to 20.84.116.12620.84.116.127126
23420.84.116.128/2520.84.116.129 to 20.84.116.25420.84.116.255126
23520.84.117.0/2520.84.117.1 to 20.84.117.12620.84.117.127126
23620.84.117.128/2520.84.117.129 to 20.84.117.25420.84.117.255126
23720.84.118.0/2520.84.118.1 to 20.84.118.12620.84.118.127126
23820.84.118.128/2520.84.118.129 to 20.84.118.25420.84.118.255126
23920.84.119.0/2520.84.119.1 to 20.84.119.12620.84.119.127126
24020.84.119.128/2520.84.119.129 to 20.84.119.25420.84.119.255126
24120.84.120.0/2520.84.120.1 to 20.84.120.12620.84.120.127126
24220.84.120.128/2520.84.120.129 to 20.84.120.25420.84.120.255126
24320.84.121.0/2520.84.121.1 to 20.84.121.12620.84.121.127126
24420.84.121.128/2520.84.121.129 to 20.84.121.25420.84.121.255126
24520.84.122.0/2520.84.122.1 to 20.84.122.12620.84.122.127126
24620.84.122.128/2520.84.122.129 to 20.84.122.25420.84.122.255126
24720.84.123.0/2520.84.123.1 to 20.84.123.12620.84.123.127126
24820.84.123.128/2520.84.123.129 to 20.84.123.25420.84.123.255126
24920.84.124.0/2520.84.124.1 to 20.84.124.12620.84.124.127126
25020.84.124.128/2520.84.124.129 to 20.84.124.25420.84.124.255126
25120.84.125.0/2520.84.125.1 to 20.84.125.12620.84.125.127126
25220.84.125.128/2520.84.125.129 to 20.84.125.25420.84.125.255126
25320.84.126.0/2520.84.126.1 to 20.84.126.12620.84.126.127126
25420.84.126.128/2520.84.126.129 to 20.84.126.25420.84.126.255126
25520.84.127.0/2520.84.127.1 to 20.84.127.12620.84.127.127126
25620.84.127.128/2520.84.127.129 to 20.84.127.25420.84.127.255126

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.