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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.

Network36.7.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
36.7.0.0
Broadcast address
36.7.255.255
First usable
36.7.0.1
Last usable
36.7.255.254
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 24070000 · Integer 604438528 to 604504063
Reverse DNS zone
7.36.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100100.00000111..00000000.0000000036.7.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00100100.00000111..00000000.0000000036.7.0.0
Broadcast00100100.00000111..11111111.1111111136.7.255.255
Split into smaller subnets/24
/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)

36.7.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
136.7.0.0/2436.7.0.1 to 36.7.0.25436.7.0.255254
236.7.1.0/2436.7.1.1 to 36.7.1.25436.7.1.255254
336.7.2.0/2436.7.2.1 to 36.7.2.25436.7.2.255254
436.7.3.0/2436.7.3.1 to 36.7.3.25436.7.3.255254
536.7.4.0/2436.7.4.1 to 36.7.4.25436.7.4.255254
636.7.5.0/2436.7.5.1 to 36.7.5.25436.7.5.255254
736.7.6.0/2436.7.6.1 to 36.7.6.25436.7.6.255254
836.7.7.0/2436.7.7.1 to 36.7.7.25436.7.7.255254
936.7.8.0/2436.7.8.1 to 36.7.8.25436.7.8.255254
1036.7.9.0/2436.7.9.1 to 36.7.9.25436.7.9.255254
1136.7.10.0/2436.7.10.1 to 36.7.10.25436.7.10.255254
1236.7.11.0/2436.7.11.1 to 36.7.11.25436.7.11.255254
1336.7.12.0/2436.7.12.1 to 36.7.12.25436.7.12.255254
1436.7.13.0/2436.7.13.1 to 36.7.13.25436.7.13.255254
1536.7.14.0/2436.7.14.1 to 36.7.14.25436.7.14.255254
1636.7.15.0/2436.7.15.1 to 36.7.15.25436.7.15.255254
1736.7.16.0/2436.7.16.1 to 36.7.16.25436.7.16.255254
1836.7.17.0/2436.7.17.1 to 36.7.17.25436.7.17.255254
1936.7.18.0/2436.7.18.1 to 36.7.18.25436.7.18.255254
2036.7.19.0/2436.7.19.1 to 36.7.19.25436.7.19.255254
2136.7.20.0/2436.7.20.1 to 36.7.20.25436.7.20.255254
2236.7.21.0/2436.7.21.1 to 36.7.21.25436.7.21.255254
2336.7.22.0/2436.7.22.1 to 36.7.22.25436.7.22.255254
2436.7.23.0/2436.7.23.1 to 36.7.23.25436.7.23.255254
2536.7.24.0/2436.7.24.1 to 36.7.24.25436.7.24.255254
2636.7.25.0/2436.7.25.1 to 36.7.25.25436.7.25.255254
2736.7.26.0/2436.7.26.1 to 36.7.26.25436.7.26.255254
2836.7.27.0/2436.7.27.1 to 36.7.27.25436.7.27.255254
2936.7.28.0/2436.7.28.1 to 36.7.28.25436.7.28.255254
3036.7.29.0/2436.7.29.1 to 36.7.29.25436.7.29.255254
3136.7.30.0/2436.7.30.1 to 36.7.30.25436.7.30.255254
3236.7.31.0/2436.7.31.1 to 36.7.31.25436.7.31.255254
3336.7.32.0/2436.7.32.1 to 36.7.32.25436.7.32.255254
3436.7.33.0/2436.7.33.1 to 36.7.33.25436.7.33.255254
3536.7.34.0/2436.7.34.1 to 36.7.34.25436.7.34.255254
3636.7.35.0/2436.7.35.1 to 36.7.35.25436.7.35.255254
3736.7.36.0/2436.7.36.1 to 36.7.36.25436.7.36.255254
3836.7.37.0/2436.7.37.1 to 36.7.37.25436.7.37.255254
3936.7.38.0/2436.7.38.1 to 36.7.38.25436.7.38.255254
4036.7.39.0/2436.7.39.1 to 36.7.39.25436.7.39.255254
4136.7.40.0/2436.7.40.1 to 36.7.40.25436.7.40.255254
4236.7.41.0/2436.7.41.1 to 36.7.41.25436.7.41.255254
4336.7.42.0/2436.7.42.1 to 36.7.42.25436.7.42.255254
4436.7.43.0/2436.7.43.1 to 36.7.43.25436.7.43.255254
4536.7.44.0/2436.7.44.1 to 36.7.44.25436.7.44.255254
4636.7.45.0/2436.7.45.1 to 36.7.45.25436.7.45.255254
4736.7.46.0/2436.7.46.1 to 36.7.46.25436.7.46.255254
4836.7.47.0/2436.7.47.1 to 36.7.47.25436.7.47.255254
4936.7.48.0/2436.7.48.1 to 36.7.48.25436.7.48.255254
5036.7.49.0/2436.7.49.1 to 36.7.49.25436.7.49.255254
5136.7.50.0/2436.7.50.1 to 36.7.50.25436.7.50.255254
5236.7.51.0/2436.7.51.1 to 36.7.51.25436.7.51.255254
5336.7.52.0/2436.7.52.1 to 36.7.52.25436.7.52.255254
5436.7.53.0/2436.7.53.1 to 36.7.53.25436.7.53.255254
5536.7.54.0/2436.7.54.1 to 36.7.54.25436.7.54.255254
5636.7.55.0/2436.7.55.1 to 36.7.55.25436.7.55.255254
5736.7.56.0/2436.7.56.1 to 36.7.56.25436.7.56.255254
5836.7.57.0/2436.7.57.1 to 36.7.57.25436.7.57.255254
5936.7.58.0/2436.7.58.1 to 36.7.58.25436.7.58.255254
6036.7.59.0/2436.7.59.1 to 36.7.59.25436.7.59.255254
6136.7.60.0/2436.7.60.1 to 36.7.60.25436.7.60.255254
6236.7.61.0/2436.7.61.1 to 36.7.61.25436.7.61.255254
6336.7.62.0/2436.7.62.1 to 36.7.62.25436.7.62.255254
6436.7.63.0/2436.7.63.1 to 36.7.63.25436.7.63.255254
6536.7.64.0/2436.7.64.1 to 36.7.64.25436.7.64.255254
6636.7.65.0/2436.7.65.1 to 36.7.65.25436.7.65.255254
6736.7.66.0/2436.7.66.1 to 36.7.66.25436.7.66.255254
6836.7.67.0/2436.7.67.1 to 36.7.67.25436.7.67.255254
6936.7.68.0/2436.7.68.1 to 36.7.68.25436.7.68.255254
7036.7.69.0/2436.7.69.1 to 36.7.69.25436.7.69.255254
7136.7.70.0/2436.7.70.1 to 36.7.70.25436.7.70.255254
7236.7.71.0/2436.7.71.1 to 36.7.71.25436.7.71.255254
7336.7.72.0/2436.7.72.1 to 36.7.72.25436.7.72.255254
7436.7.73.0/2436.7.73.1 to 36.7.73.25436.7.73.255254
7536.7.74.0/2436.7.74.1 to 36.7.74.25436.7.74.255254
7636.7.75.0/2436.7.75.1 to 36.7.75.25436.7.75.255254
7736.7.76.0/2436.7.76.1 to 36.7.76.25436.7.76.255254
7836.7.77.0/2436.7.77.1 to 36.7.77.25436.7.77.255254
7936.7.78.0/2436.7.78.1 to 36.7.78.25436.7.78.255254
8036.7.79.0/2436.7.79.1 to 36.7.79.25436.7.79.255254
8136.7.80.0/2436.7.80.1 to 36.7.80.25436.7.80.255254
8236.7.81.0/2436.7.81.1 to 36.7.81.25436.7.81.255254
8336.7.82.0/2436.7.82.1 to 36.7.82.25436.7.82.255254
8436.7.83.0/2436.7.83.1 to 36.7.83.25436.7.83.255254
8536.7.84.0/2436.7.84.1 to 36.7.84.25436.7.84.255254
8636.7.85.0/2436.7.85.1 to 36.7.85.25436.7.85.255254
8736.7.86.0/2436.7.86.1 to 36.7.86.25436.7.86.255254
8836.7.87.0/2436.7.87.1 to 36.7.87.25436.7.87.255254
8936.7.88.0/2436.7.88.1 to 36.7.88.25436.7.88.255254
9036.7.89.0/2436.7.89.1 to 36.7.89.25436.7.89.255254
9136.7.90.0/2436.7.90.1 to 36.7.90.25436.7.90.255254
9236.7.91.0/2436.7.91.1 to 36.7.91.25436.7.91.255254
9336.7.92.0/2436.7.92.1 to 36.7.92.25436.7.92.255254
9436.7.93.0/2436.7.93.1 to 36.7.93.25436.7.93.255254
9536.7.94.0/2436.7.94.1 to 36.7.94.25436.7.94.255254
9636.7.95.0/2436.7.95.1 to 36.7.95.25436.7.95.255254
9736.7.96.0/2436.7.96.1 to 36.7.96.25436.7.96.255254
9836.7.97.0/2436.7.97.1 to 36.7.97.25436.7.97.255254
9936.7.98.0/2436.7.98.1 to 36.7.98.25436.7.98.255254
10036.7.99.0/2436.7.99.1 to 36.7.99.25436.7.99.255254
10136.7.100.0/2436.7.100.1 to 36.7.100.25436.7.100.255254
10236.7.101.0/2436.7.101.1 to 36.7.101.25436.7.101.255254
10336.7.102.0/2436.7.102.1 to 36.7.102.25436.7.102.255254
10436.7.103.0/2436.7.103.1 to 36.7.103.25436.7.103.255254
10536.7.104.0/2436.7.104.1 to 36.7.104.25436.7.104.255254
10636.7.105.0/2436.7.105.1 to 36.7.105.25436.7.105.255254
10736.7.106.0/2436.7.106.1 to 36.7.106.25436.7.106.255254
10836.7.107.0/2436.7.107.1 to 36.7.107.25436.7.107.255254
10936.7.108.0/2436.7.108.1 to 36.7.108.25436.7.108.255254
11036.7.109.0/2436.7.109.1 to 36.7.109.25436.7.109.255254
11136.7.110.0/2436.7.110.1 to 36.7.110.25436.7.110.255254
11236.7.111.0/2436.7.111.1 to 36.7.111.25436.7.111.255254
11336.7.112.0/2436.7.112.1 to 36.7.112.25436.7.112.255254
11436.7.113.0/2436.7.113.1 to 36.7.113.25436.7.113.255254
11536.7.114.0/2436.7.114.1 to 36.7.114.25436.7.114.255254
11636.7.115.0/2436.7.115.1 to 36.7.115.25436.7.115.255254
11736.7.116.0/2436.7.116.1 to 36.7.116.25436.7.116.255254
11836.7.117.0/2436.7.117.1 to 36.7.117.25436.7.117.255254
11936.7.118.0/2436.7.118.1 to 36.7.118.25436.7.118.255254
12036.7.119.0/2436.7.119.1 to 36.7.119.25436.7.119.255254
12136.7.120.0/2436.7.120.1 to 36.7.120.25436.7.120.255254
12236.7.121.0/2436.7.121.1 to 36.7.121.25436.7.121.255254
12336.7.122.0/2436.7.122.1 to 36.7.122.25436.7.122.255254
12436.7.123.0/2436.7.123.1 to 36.7.123.25436.7.123.255254
12536.7.124.0/2436.7.124.1 to 36.7.124.25436.7.124.255254
12636.7.125.0/2436.7.125.1 to 36.7.125.25436.7.125.255254
12736.7.126.0/2436.7.126.1 to 36.7.126.25436.7.126.255254
12836.7.127.0/2436.7.127.1 to 36.7.127.25436.7.127.255254
12936.7.128.0/2436.7.128.1 to 36.7.128.25436.7.128.255254
13036.7.129.0/2436.7.129.1 to 36.7.129.25436.7.129.255254
13136.7.130.0/2436.7.130.1 to 36.7.130.25436.7.130.255254
13236.7.131.0/2436.7.131.1 to 36.7.131.25436.7.131.255254
13336.7.132.0/2436.7.132.1 to 36.7.132.25436.7.132.255254
13436.7.133.0/2436.7.133.1 to 36.7.133.25436.7.133.255254
13536.7.134.0/2436.7.134.1 to 36.7.134.25436.7.134.255254
13636.7.135.0/2436.7.135.1 to 36.7.135.25436.7.135.255254
13736.7.136.0/2436.7.136.1 to 36.7.136.25436.7.136.255254
13836.7.137.0/2436.7.137.1 to 36.7.137.25436.7.137.255254
13936.7.138.0/2436.7.138.1 to 36.7.138.25436.7.138.255254
14036.7.139.0/2436.7.139.1 to 36.7.139.25436.7.139.255254
14136.7.140.0/2436.7.140.1 to 36.7.140.25436.7.140.255254
14236.7.141.0/2436.7.141.1 to 36.7.141.25436.7.141.255254
14336.7.142.0/2436.7.142.1 to 36.7.142.25436.7.142.255254
14436.7.143.0/2436.7.143.1 to 36.7.143.25436.7.143.255254
14536.7.144.0/2436.7.144.1 to 36.7.144.25436.7.144.255254
14636.7.145.0/2436.7.145.1 to 36.7.145.25436.7.145.255254
14736.7.146.0/2436.7.146.1 to 36.7.146.25436.7.146.255254
14836.7.147.0/2436.7.147.1 to 36.7.147.25436.7.147.255254
14936.7.148.0/2436.7.148.1 to 36.7.148.25436.7.148.255254
15036.7.149.0/2436.7.149.1 to 36.7.149.25436.7.149.255254
15136.7.150.0/2436.7.150.1 to 36.7.150.25436.7.150.255254
15236.7.151.0/2436.7.151.1 to 36.7.151.25436.7.151.255254
15336.7.152.0/2436.7.152.1 to 36.7.152.25436.7.152.255254
15436.7.153.0/2436.7.153.1 to 36.7.153.25436.7.153.255254
15536.7.154.0/2436.7.154.1 to 36.7.154.25436.7.154.255254
15636.7.155.0/2436.7.155.1 to 36.7.155.25436.7.155.255254
15736.7.156.0/2436.7.156.1 to 36.7.156.25436.7.156.255254
15836.7.157.0/2436.7.157.1 to 36.7.157.25436.7.157.255254
15936.7.158.0/2436.7.158.1 to 36.7.158.25436.7.158.255254
16036.7.159.0/2436.7.159.1 to 36.7.159.25436.7.159.255254
16136.7.160.0/2436.7.160.1 to 36.7.160.25436.7.160.255254
16236.7.161.0/2436.7.161.1 to 36.7.161.25436.7.161.255254
16336.7.162.0/2436.7.162.1 to 36.7.162.25436.7.162.255254
16436.7.163.0/2436.7.163.1 to 36.7.163.25436.7.163.255254
16536.7.164.0/2436.7.164.1 to 36.7.164.25436.7.164.255254
16636.7.165.0/2436.7.165.1 to 36.7.165.25436.7.165.255254
16736.7.166.0/2436.7.166.1 to 36.7.166.25436.7.166.255254
16836.7.167.0/2436.7.167.1 to 36.7.167.25436.7.167.255254
16936.7.168.0/2436.7.168.1 to 36.7.168.25436.7.168.255254
17036.7.169.0/2436.7.169.1 to 36.7.169.25436.7.169.255254
17136.7.170.0/2436.7.170.1 to 36.7.170.25436.7.170.255254
17236.7.171.0/2436.7.171.1 to 36.7.171.25436.7.171.255254
17336.7.172.0/2436.7.172.1 to 36.7.172.25436.7.172.255254
17436.7.173.0/2436.7.173.1 to 36.7.173.25436.7.173.255254
17536.7.174.0/2436.7.174.1 to 36.7.174.25436.7.174.255254
17636.7.175.0/2436.7.175.1 to 36.7.175.25436.7.175.255254
17736.7.176.0/2436.7.176.1 to 36.7.176.25436.7.176.255254
17836.7.177.0/2436.7.177.1 to 36.7.177.25436.7.177.255254
17936.7.178.0/2436.7.178.1 to 36.7.178.25436.7.178.255254
18036.7.179.0/2436.7.179.1 to 36.7.179.25436.7.179.255254
18136.7.180.0/2436.7.180.1 to 36.7.180.25436.7.180.255254
18236.7.181.0/2436.7.181.1 to 36.7.181.25436.7.181.255254
18336.7.182.0/2436.7.182.1 to 36.7.182.25436.7.182.255254
18436.7.183.0/2436.7.183.1 to 36.7.183.25436.7.183.255254
18536.7.184.0/2436.7.184.1 to 36.7.184.25436.7.184.255254
18636.7.185.0/2436.7.185.1 to 36.7.185.25436.7.185.255254
18736.7.186.0/2436.7.186.1 to 36.7.186.25436.7.186.255254
18836.7.187.0/2436.7.187.1 to 36.7.187.25436.7.187.255254
18936.7.188.0/2436.7.188.1 to 36.7.188.25436.7.188.255254
19036.7.189.0/2436.7.189.1 to 36.7.189.25436.7.189.255254
19136.7.190.0/2436.7.190.1 to 36.7.190.25436.7.190.255254
19236.7.191.0/2436.7.191.1 to 36.7.191.25436.7.191.255254
19336.7.192.0/2436.7.192.1 to 36.7.192.25436.7.192.255254
19436.7.193.0/2436.7.193.1 to 36.7.193.25436.7.193.255254
19536.7.194.0/2436.7.194.1 to 36.7.194.25436.7.194.255254
19636.7.195.0/2436.7.195.1 to 36.7.195.25436.7.195.255254
19736.7.196.0/2436.7.196.1 to 36.7.196.25436.7.196.255254
19836.7.197.0/2436.7.197.1 to 36.7.197.25436.7.197.255254
19936.7.198.0/2436.7.198.1 to 36.7.198.25436.7.198.255254
20036.7.199.0/2436.7.199.1 to 36.7.199.25436.7.199.255254
20136.7.200.0/2436.7.200.1 to 36.7.200.25436.7.200.255254
20236.7.201.0/2436.7.201.1 to 36.7.201.25436.7.201.255254
20336.7.202.0/2436.7.202.1 to 36.7.202.25436.7.202.255254
20436.7.203.0/2436.7.203.1 to 36.7.203.25436.7.203.255254
20536.7.204.0/2436.7.204.1 to 36.7.204.25436.7.204.255254
20636.7.205.0/2436.7.205.1 to 36.7.205.25436.7.205.255254
20736.7.206.0/2436.7.206.1 to 36.7.206.25436.7.206.255254
20836.7.207.0/2436.7.207.1 to 36.7.207.25436.7.207.255254
20936.7.208.0/2436.7.208.1 to 36.7.208.25436.7.208.255254
21036.7.209.0/2436.7.209.1 to 36.7.209.25436.7.209.255254
21136.7.210.0/2436.7.210.1 to 36.7.210.25436.7.210.255254
21236.7.211.0/2436.7.211.1 to 36.7.211.25436.7.211.255254
21336.7.212.0/2436.7.212.1 to 36.7.212.25436.7.212.255254
21436.7.213.0/2436.7.213.1 to 36.7.213.25436.7.213.255254
21536.7.214.0/2436.7.214.1 to 36.7.214.25436.7.214.255254
21636.7.215.0/2436.7.215.1 to 36.7.215.25436.7.215.255254
21736.7.216.0/2436.7.216.1 to 36.7.216.25436.7.216.255254
21836.7.217.0/2436.7.217.1 to 36.7.217.25436.7.217.255254
21936.7.218.0/2436.7.218.1 to 36.7.218.25436.7.218.255254
22036.7.219.0/2436.7.219.1 to 36.7.219.25436.7.219.255254
22136.7.220.0/2436.7.220.1 to 36.7.220.25436.7.220.255254
22236.7.221.0/2436.7.221.1 to 36.7.221.25436.7.221.255254
22336.7.222.0/2436.7.222.1 to 36.7.222.25436.7.222.255254
22436.7.223.0/2436.7.223.1 to 36.7.223.25436.7.223.255254
22536.7.224.0/2436.7.224.1 to 36.7.224.25436.7.224.255254
22636.7.225.0/2436.7.225.1 to 36.7.225.25436.7.225.255254
22736.7.226.0/2436.7.226.1 to 36.7.226.25436.7.226.255254
22836.7.227.0/2436.7.227.1 to 36.7.227.25436.7.227.255254
22936.7.228.0/2436.7.228.1 to 36.7.228.25436.7.228.255254
23036.7.229.0/2436.7.229.1 to 36.7.229.25436.7.229.255254
23136.7.230.0/2436.7.230.1 to 36.7.230.25436.7.230.255254
23236.7.231.0/2436.7.231.1 to 36.7.231.25436.7.231.255254
23336.7.232.0/2436.7.232.1 to 36.7.232.25436.7.232.255254
23436.7.233.0/2436.7.233.1 to 36.7.233.25436.7.233.255254
23536.7.234.0/2436.7.234.1 to 36.7.234.25436.7.234.255254
23636.7.235.0/2436.7.235.1 to 36.7.235.25436.7.235.255254
23736.7.236.0/2436.7.236.1 to 36.7.236.25436.7.236.255254
23836.7.237.0/2436.7.237.1 to 36.7.237.25436.7.237.255254
23936.7.238.0/2436.7.238.1 to 36.7.238.25436.7.238.255254
24036.7.239.0/2436.7.239.1 to 36.7.239.25436.7.239.255254
24136.7.240.0/2436.7.240.1 to 36.7.240.25436.7.240.255254
24236.7.241.0/2436.7.241.1 to 36.7.241.25436.7.241.255254
24336.7.242.0/2436.7.242.1 to 36.7.242.25436.7.242.255254
24436.7.243.0/2436.7.243.1 to 36.7.243.25436.7.243.255254
24536.7.244.0/2436.7.244.1 to 36.7.244.25436.7.244.255254
24636.7.245.0/2436.7.245.1 to 36.7.245.25436.7.245.255254
24736.7.246.0/2436.7.246.1 to 36.7.246.25436.7.246.255254
24836.7.247.0/2436.7.247.1 to 36.7.247.25436.7.247.255254
24936.7.248.0/2436.7.248.1 to 36.7.248.25436.7.248.255254
25036.7.249.0/2436.7.249.1 to 36.7.249.25436.7.249.255254
25136.7.250.0/2436.7.250.1 to 36.7.250.25436.7.250.255254
25236.7.251.0/2436.7.251.1 to 36.7.251.25436.7.251.255254
25336.7.252.0/2436.7.252.1 to 36.7.252.25436.7.252.255254
25436.7.253.0/2436.7.253.1 to 36.7.253.25436.7.253.255254
25536.7.254.0/2436.7.254.1 to 36.7.254.25436.7.254.255254
25636.7.255.0/2436.7.255.1 to 36.7.255.25436.7.255.255254

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.