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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.

Network68.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
68.0.0.0
Broadcast address
71.255.255.255
First usable
68.0.0.1
Last usable
71.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 44000000 · Integer 1140850688 to 1207959551
Reverse DNS zones
68.in-addr.arpa
69.in-addr.arpa
70.in-addr.arpa
71.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000100.00000000.00000000.0000000068.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01000100.00000000.00000000.0000000068.0.0.0
Broadcast01000111.11111111.11111111.1111111171.255.255.255
Split into smaller subnets/16
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

68.0.0.0/6 makes 1,024 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.0.0.0/1668.0.0.1 to 68.0.255.25468.0.255.25565,534
268.1.0.0/1668.1.0.1 to 68.1.255.25468.1.255.25565,534
368.2.0.0/1668.2.0.1 to 68.2.255.25468.2.255.25565,534
468.3.0.0/1668.3.0.1 to 68.3.255.25468.3.255.25565,534
568.4.0.0/1668.4.0.1 to 68.4.255.25468.4.255.25565,534
668.5.0.0/1668.5.0.1 to 68.5.255.25468.5.255.25565,534
768.6.0.0/1668.6.0.1 to 68.6.255.25468.6.255.25565,534
868.7.0.0/1668.7.0.1 to 68.7.255.25468.7.255.25565,534
968.8.0.0/1668.8.0.1 to 68.8.255.25468.8.255.25565,534
1068.9.0.0/1668.9.0.1 to 68.9.255.25468.9.255.25565,534
1168.10.0.0/1668.10.0.1 to 68.10.255.25468.10.255.25565,534
1268.11.0.0/1668.11.0.1 to 68.11.255.25468.11.255.25565,534
1368.12.0.0/1668.12.0.1 to 68.12.255.25468.12.255.25565,534
1468.13.0.0/1668.13.0.1 to 68.13.255.25468.13.255.25565,534
1568.14.0.0/1668.14.0.1 to 68.14.255.25468.14.255.25565,534
1668.15.0.0/1668.15.0.1 to 68.15.255.25468.15.255.25565,534
1768.16.0.0/1668.16.0.1 to 68.16.255.25468.16.255.25565,534
1868.17.0.0/1668.17.0.1 to 68.17.255.25468.17.255.25565,534
1968.18.0.0/1668.18.0.1 to 68.18.255.25468.18.255.25565,534
2068.19.0.0/1668.19.0.1 to 68.19.255.25468.19.255.25565,534
2168.20.0.0/1668.20.0.1 to 68.20.255.25468.20.255.25565,534
2268.21.0.0/1668.21.0.1 to 68.21.255.25468.21.255.25565,534
2368.22.0.0/1668.22.0.1 to 68.22.255.25468.22.255.25565,534
2468.23.0.0/1668.23.0.1 to 68.23.255.25468.23.255.25565,534
2568.24.0.0/1668.24.0.1 to 68.24.255.25468.24.255.25565,534
2668.25.0.0/1668.25.0.1 to 68.25.255.25468.25.255.25565,534
2768.26.0.0/1668.26.0.1 to 68.26.255.25468.26.255.25565,534
2868.27.0.0/1668.27.0.1 to 68.27.255.25468.27.255.25565,534
2968.28.0.0/1668.28.0.1 to 68.28.255.25468.28.255.25565,534
3068.29.0.0/1668.29.0.1 to 68.29.255.25468.29.255.25565,534
3168.30.0.0/1668.30.0.1 to 68.30.255.25468.30.255.25565,534
3268.31.0.0/1668.31.0.1 to 68.31.255.25468.31.255.25565,534
3368.32.0.0/1668.32.0.1 to 68.32.255.25468.32.255.25565,534
3468.33.0.0/1668.33.0.1 to 68.33.255.25468.33.255.25565,534
3568.34.0.0/1668.34.0.1 to 68.34.255.25468.34.255.25565,534
3668.35.0.0/1668.35.0.1 to 68.35.255.25468.35.255.25565,534
3768.36.0.0/1668.36.0.1 to 68.36.255.25468.36.255.25565,534
3868.37.0.0/1668.37.0.1 to 68.37.255.25468.37.255.25565,534
3968.38.0.0/1668.38.0.1 to 68.38.255.25468.38.255.25565,534
4068.39.0.0/1668.39.0.1 to 68.39.255.25468.39.255.25565,534
4168.40.0.0/1668.40.0.1 to 68.40.255.25468.40.255.25565,534
4268.41.0.0/1668.41.0.1 to 68.41.255.25468.41.255.25565,534
4368.42.0.0/1668.42.0.1 to 68.42.255.25468.42.255.25565,534
4468.43.0.0/1668.43.0.1 to 68.43.255.25468.43.255.25565,534
4568.44.0.0/1668.44.0.1 to 68.44.255.25468.44.255.25565,534
4668.45.0.0/1668.45.0.1 to 68.45.255.25468.45.255.25565,534
4768.46.0.0/1668.46.0.1 to 68.46.255.25468.46.255.25565,534
4868.47.0.0/1668.47.0.1 to 68.47.255.25468.47.255.25565,534
4968.48.0.0/1668.48.0.1 to 68.48.255.25468.48.255.25565,534
5068.49.0.0/1668.49.0.1 to 68.49.255.25468.49.255.25565,534
5168.50.0.0/1668.50.0.1 to 68.50.255.25468.50.255.25565,534
5268.51.0.0/1668.51.0.1 to 68.51.255.25468.51.255.25565,534
5368.52.0.0/1668.52.0.1 to 68.52.255.25468.52.255.25565,534
5468.53.0.0/1668.53.0.1 to 68.53.255.25468.53.255.25565,534
5568.54.0.0/1668.54.0.1 to 68.54.255.25468.54.255.25565,534
5668.55.0.0/1668.55.0.1 to 68.55.255.25468.55.255.25565,534
5768.56.0.0/1668.56.0.1 to 68.56.255.25468.56.255.25565,534
5868.57.0.0/1668.57.0.1 to 68.57.255.25468.57.255.25565,534
5968.58.0.0/1668.58.0.1 to 68.58.255.25468.58.255.25565,534
6068.59.0.0/1668.59.0.1 to 68.59.255.25468.59.255.25565,534
6168.60.0.0/1668.60.0.1 to 68.60.255.25468.60.255.25565,534
6268.61.0.0/1668.61.0.1 to 68.61.255.25468.61.255.25565,534
6368.62.0.0/1668.62.0.1 to 68.62.255.25468.62.255.25565,534
6468.63.0.0/1668.63.0.1 to 68.63.255.25468.63.255.25565,534
6568.64.0.0/1668.64.0.1 to 68.64.255.25468.64.255.25565,534
6668.65.0.0/1668.65.0.1 to 68.65.255.25468.65.255.25565,534
6768.66.0.0/1668.66.0.1 to 68.66.255.25468.66.255.25565,534
6868.67.0.0/1668.67.0.1 to 68.67.255.25468.67.255.25565,534
6968.68.0.0/1668.68.0.1 to 68.68.255.25468.68.255.25565,534
7068.69.0.0/1668.69.0.1 to 68.69.255.25468.69.255.25565,534
7168.70.0.0/1668.70.0.1 to 68.70.255.25468.70.255.25565,534
7268.71.0.0/1668.71.0.1 to 68.71.255.25468.71.255.25565,534
7368.72.0.0/1668.72.0.1 to 68.72.255.25468.72.255.25565,534
7468.73.0.0/1668.73.0.1 to 68.73.255.25468.73.255.25565,534
7568.74.0.0/1668.74.0.1 to 68.74.255.25468.74.255.25565,534
7668.75.0.0/1668.75.0.1 to 68.75.255.25468.75.255.25565,534
7768.76.0.0/1668.76.0.1 to 68.76.255.25468.76.255.25565,534
7868.77.0.0/1668.77.0.1 to 68.77.255.25468.77.255.25565,534
7968.78.0.0/1668.78.0.1 to 68.78.255.25468.78.255.25565,534
8068.79.0.0/1668.79.0.1 to 68.79.255.25468.79.255.25565,534
8168.80.0.0/1668.80.0.1 to 68.80.255.25468.80.255.25565,534
8268.81.0.0/1668.81.0.1 to 68.81.255.25468.81.255.25565,534
8368.82.0.0/1668.82.0.1 to 68.82.255.25468.82.255.25565,534
8468.83.0.0/1668.83.0.1 to 68.83.255.25468.83.255.25565,534
8568.84.0.0/1668.84.0.1 to 68.84.255.25468.84.255.25565,534
8668.85.0.0/1668.85.0.1 to 68.85.255.25468.85.255.25565,534
8768.86.0.0/1668.86.0.1 to 68.86.255.25468.86.255.25565,534
8868.87.0.0/1668.87.0.1 to 68.87.255.25468.87.255.25565,534
8968.88.0.0/1668.88.0.1 to 68.88.255.25468.88.255.25565,534
9068.89.0.0/1668.89.0.1 to 68.89.255.25468.89.255.25565,534
9168.90.0.0/1668.90.0.1 to 68.90.255.25468.90.255.25565,534
9268.91.0.0/1668.91.0.1 to 68.91.255.25468.91.255.25565,534
9368.92.0.0/1668.92.0.1 to 68.92.255.25468.92.255.25565,534
9468.93.0.0/1668.93.0.1 to 68.93.255.25468.93.255.25565,534
9568.94.0.0/1668.94.0.1 to 68.94.255.25468.94.255.25565,534
9668.95.0.0/1668.95.0.1 to 68.95.255.25468.95.255.25565,534
9768.96.0.0/1668.96.0.1 to 68.96.255.25468.96.255.25565,534
9868.97.0.0/1668.97.0.1 to 68.97.255.25468.97.255.25565,534
9968.98.0.0/1668.98.0.1 to 68.98.255.25468.98.255.25565,534
10068.99.0.0/1668.99.0.1 to 68.99.255.25468.99.255.25565,534
10168.100.0.0/1668.100.0.1 to 68.100.255.25468.100.255.25565,534
10268.101.0.0/1668.101.0.1 to 68.101.255.25468.101.255.25565,534
10368.102.0.0/1668.102.0.1 to 68.102.255.25468.102.255.25565,534
10468.103.0.0/1668.103.0.1 to 68.103.255.25468.103.255.25565,534
10568.104.0.0/1668.104.0.1 to 68.104.255.25468.104.255.25565,534
10668.105.0.0/1668.105.0.1 to 68.105.255.25468.105.255.25565,534
10768.106.0.0/1668.106.0.1 to 68.106.255.25468.106.255.25565,534
10868.107.0.0/1668.107.0.1 to 68.107.255.25468.107.255.25565,534
10968.108.0.0/1668.108.0.1 to 68.108.255.25468.108.255.25565,534
11068.109.0.0/1668.109.0.1 to 68.109.255.25468.109.255.25565,534
11168.110.0.0/1668.110.0.1 to 68.110.255.25468.110.255.25565,534
11268.111.0.0/1668.111.0.1 to 68.111.255.25468.111.255.25565,534
11368.112.0.0/1668.112.0.1 to 68.112.255.25468.112.255.25565,534
11468.113.0.0/1668.113.0.1 to 68.113.255.25468.113.255.25565,534
11568.114.0.0/1668.114.0.1 to 68.114.255.25468.114.255.25565,534
11668.115.0.0/1668.115.0.1 to 68.115.255.25468.115.255.25565,534
11768.116.0.0/1668.116.0.1 to 68.116.255.25468.116.255.25565,534
11868.117.0.0/1668.117.0.1 to 68.117.255.25468.117.255.25565,534
11968.118.0.0/1668.118.0.1 to 68.118.255.25468.118.255.25565,534
12068.119.0.0/1668.119.0.1 to 68.119.255.25468.119.255.25565,534
12168.120.0.0/1668.120.0.1 to 68.120.255.25468.120.255.25565,534
12268.121.0.0/1668.121.0.1 to 68.121.255.25468.121.255.25565,534
12368.122.0.0/1668.122.0.1 to 68.122.255.25468.122.255.25565,534
12468.123.0.0/1668.123.0.1 to 68.123.255.25468.123.255.25565,534
12568.124.0.0/1668.124.0.1 to 68.124.255.25468.124.255.25565,534
12668.125.0.0/1668.125.0.1 to 68.125.255.25468.125.255.25565,534
12768.126.0.0/1668.126.0.1 to 68.126.255.25468.126.255.25565,534
12868.127.0.0/1668.127.0.1 to 68.127.255.25468.127.255.25565,534
12968.128.0.0/1668.128.0.1 to 68.128.255.25468.128.255.25565,534
13068.129.0.0/1668.129.0.1 to 68.129.255.25468.129.255.25565,534
13168.130.0.0/1668.130.0.1 to 68.130.255.25468.130.255.25565,534
13268.131.0.0/1668.131.0.1 to 68.131.255.25468.131.255.25565,534
13368.132.0.0/1668.132.0.1 to 68.132.255.25468.132.255.25565,534
13468.133.0.0/1668.133.0.1 to 68.133.255.25468.133.255.25565,534
13568.134.0.0/1668.134.0.1 to 68.134.255.25468.134.255.25565,534
13668.135.0.0/1668.135.0.1 to 68.135.255.25468.135.255.25565,534
13768.136.0.0/1668.136.0.1 to 68.136.255.25468.136.255.25565,534
13868.137.0.0/1668.137.0.1 to 68.137.255.25468.137.255.25565,534
13968.138.0.0/1668.138.0.1 to 68.138.255.25468.138.255.25565,534
14068.139.0.0/1668.139.0.1 to 68.139.255.25468.139.255.25565,534
14168.140.0.0/1668.140.0.1 to 68.140.255.25468.140.255.25565,534
14268.141.0.0/1668.141.0.1 to 68.141.255.25468.141.255.25565,534
14368.142.0.0/1668.142.0.1 to 68.142.255.25468.142.255.25565,534
14468.143.0.0/1668.143.0.1 to 68.143.255.25468.143.255.25565,534
14568.144.0.0/1668.144.0.1 to 68.144.255.25468.144.255.25565,534
14668.145.0.0/1668.145.0.1 to 68.145.255.25468.145.255.25565,534
14768.146.0.0/1668.146.0.1 to 68.146.255.25468.146.255.25565,534
14868.147.0.0/1668.147.0.1 to 68.147.255.25468.147.255.25565,534
14968.148.0.0/1668.148.0.1 to 68.148.255.25468.148.255.25565,534
15068.149.0.0/1668.149.0.1 to 68.149.255.25468.149.255.25565,534
15168.150.0.0/1668.150.0.1 to 68.150.255.25468.150.255.25565,534
15268.151.0.0/1668.151.0.1 to 68.151.255.25468.151.255.25565,534
15368.152.0.0/1668.152.0.1 to 68.152.255.25468.152.255.25565,534
15468.153.0.0/1668.153.0.1 to 68.153.255.25468.153.255.25565,534
15568.154.0.0/1668.154.0.1 to 68.154.255.25468.154.255.25565,534
15668.155.0.0/1668.155.0.1 to 68.155.255.25468.155.255.25565,534
15768.156.0.0/1668.156.0.1 to 68.156.255.25468.156.255.25565,534
15868.157.0.0/1668.157.0.1 to 68.157.255.25468.157.255.25565,534
15968.158.0.0/1668.158.0.1 to 68.158.255.25468.158.255.25565,534
16068.159.0.0/1668.159.0.1 to 68.159.255.25468.159.255.25565,534
16168.160.0.0/1668.160.0.1 to 68.160.255.25468.160.255.25565,534
16268.161.0.0/1668.161.0.1 to 68.161.255.25468.161.255.25565,534
16368.162.0.0/1668.162.0.1 to 68.162.255.25468.162.255.25565,534
16468.163.0.0/1668.163.0.1 to 68.163.255.25468.163.255.25565,534
16568.164.0.0/1668.164.0.1 to 68.164.255.25468.164.255.25565,534
16668.165.0.0/1668.165.0.1 to 68.165.255.25468.165.255.25565,534
16768.166.0.0/1668.166.0.1 to 68.166.255.25468.166.255.25565,534
16868.167.0.0/1668.167.0.1 to 68.167.255.25468.167.255.25565,534
16968.168.0.0/1668.168.0.1 to 68.168.255.25468.168.255.25565,534
17068.169.0.0/1668.169.0.1 to 68.169.255.25468.169.255.25565,534
17168.170.0.0/1668.170.0.1 to 68.170.255.25468.170.255.25565,534
17268.171.0.0/1668.171.0.1 to 68.171.255.25468.171.255.25565,534
17368.172.0.0/1668.172.0.1 to 68.172.255.25468.172.255.25565,534
17468.173.0.0/1668.173.0.1 to 68.173.255.25468.173.255.25565,534
17568.174.0.0/1668.174.0.1 to 68.174.255.25468.174.255.25565,534
17668.175.0.0/1668.175.0.1 to 68.175.255.25468.175.255.25565,534
17768.176.0.0/1668.176.0.1 to 68.176.255.25468.176.255.25565,534
17868.177.0.0/1668.177.0.1 to 68.177.255.25468.177.255.25565,534
17968.178.0.0/1668.178.0.1 to 68.178.255.25468.178.255.25565,534
18068.179.0.0/1668.179.0.1 to 68.179.255.25468.179.255.25565,534
18168.180.0.0/1668.180.0.1 to 68.180.255.25468.180.255.25565,534
18268.181.0.0/1668.181.0.1 to 68.181.255.25468.181.255.25565,534
18368.182.0.0/1668.182.0.1 to 68.182.255.25468.182.255.25565,534
18468.183.0.0/1668.183.0.1 to 68.183.255.25468.183.255.25565,534
18568.184.0.0/1668.184.0.1 to 68.184.255.25468.184.255.25565,534
18668.185.0.0/1668.185.0.1 to 68.185.255.25468.185.255.25565,534
18768.186.0.0/1668.186.0.1 to 68.186.255.25468.186.255.25565,534
18868.187.0.0/1668.187.0.1 to 68.187.255.25468.187.255.25565,534
18968.188.0.0/1668.188.0.1 to 68.188.255.25468.188.255.25565,534
19068.189.0.0/1668.189.0.1 to 68.189.255.25468.189.255.25565,534
19168.190.0.0/1668.190.0.1 to 68.190.255.25468.190.255.25565,534
19268.191.0.0/1668.191.0.1 to 68.191.255.25468.191.255.25565,534
19368.192.0.0/1668.192.0.1 to 68.192.255.25468.192.255.25565,534
19468.193.0.0/1668.193.0.1 to 68.193.255.25468.193.255.25565,534
19568.194.0.0/1668.194.0.1 to 68.194.255.25468.194.255.25565,534
19668.195.0.0/1668.195.0.1 to 68.195.255.25468.195.255.25565,534
19768.196.0.0/1668.196.0.1 to 68.196.255.25468.196.255.25565,534
19868.197.0.0/1668.197.0.1 to 68.197.255.25468.197.255.25565,534
19968.198.0.0/1668.198.0.1 to 68.198.255.25468.198.255.25565,534
20068.199.0.0/1668.199.0.1 to 68.199.255.25468.199.255.25565,534
20168.200.0.0/1668.200.0.1 to 68.200.255.25468.200.255.25565,534
20268.201.0.0/1668.201.0.1 to 68.201.255.25468.201.255.25565,534
20368.202.0.0/1668.202.0.1 to 68.202.255.25468.202.255.25565,534
20468.203.0.0/1668.203.0.1 to 68.203.255.25468.203.255.25565,534
20568.204.0.0/1668.204.0.1 to 68.204.255.25468.204.255.25565,534
20668.205.0.0/1668.205.0.1 to 68.205.255.25468.205.255.25565,534
20768.206.0.0/1668.206.0.1 to 68.206.255.25468.206.255.25565,534
20868.207.0.0/1668.207.0.1 to 68.207.255.25468.207.255.25565,534
20968.208.0.0/1668.208.0.1 to 68.208.255.25468.208.255.25565,534
21068.209.0.0/1668.209.0.1 to 68.209.255.25468.209.255.25565,534
21168.210.0.0/1668.210.0.1 to 68.210.255.25468.210.255.25565,534
21268.211.0.0/1668.211.0.1 to 68.211.255.25468.211.255.25565,534
21368.212.0.0/1668.212.0.1 to 68.212.255.25468.212.255.25565,534
21468.213.0.0/1668.213.0.1 to 68.213.255.25468.213.255.25565,534
21568.214.0.0/1668.214.0.1 to 68.214.255.25468.214.255.25565,534
21668.215.0.0/1668.215.0.1 to 68.215.255.25468.215.255.25565,534
21768.216.0.0/1668.216.0.1 to 68.216.255.25468.216.255.25565,534
21868.217.0.0/1668.217.0.1 to 68.217.255.25468.217.255.25565,534
21968.218.0.0/1668.218.0.1 to 68.218.255.25468.218.255.25565,534
22068.219.0.0/1668.219.0.1 to 68.219.255.25468.219.255.25565,534
22168.220.0.0/1668.220.0.1 to 68.220.255.25468.220.255.25565,534
22268.221.0.0/1668.221.0.1 to 68.221.255.25468.221.255.25565,534
22368.222.0.0/1668.222.0.1 to 68.222.255.25468.222.255.25565,534
22468.223.0.0/1668.223.0.1 to 68.223.255.25468.223.255.25565,534
22568.224.0.0/1668.224.0.1 to 68.224.255.25468.224.255.25565,534
22668.225.0.0/1668.225.0.1 to 68.225.255.25468.225.255.25565,534
22768.226.0.0/1668.226.0.1 to 68.226.255.25468.226.255.25565,534
22868.227.0.0/1668.227.0.1 to 68.227.255.25468.227.255.25565,534
22968.228.0.0/1668.228.0.1 to 68.228.255.25468.228.255.25565,534
23068.229.0.0/1668.229.0.1 to 68.229.255.25468.229.255.25565,534
23168.230.0.0/1668.230.0.1 to 68.230.255.25468.230.255.25565,534
23268.231.0.0/1668.231.0.1 to 68.231.255.25468.231.255.25565,534
23368.232.0.0/1668.232.0.1 to 68.232.255.25468.232.255.25565,534
23468.233.0.0/1668.233.0.1 to 68.233.255.25468.233.255.25565,534
23568.234.0.0/1668.234.0.1 to 68.234.255.25468.234.255.25565,534
23668.235.0.0/1668.235.0.1 to 68.235.255.25468.235.255.25565,534
23768.236.0.0/1668.236.0.1 to 68.236.255.25468.236.255.25565,534
23868.237.0.0/1668.237.0.1 to 68.237.255.25468.237.255.25565,534
23968.238.0.0/1668.238.0.1 to 68.238.255.25468.238.255.25565,534
24068.239.0.0/1668.239.0.1 to 68.239.255.25468.239.255.25565,534
24168.240.0.0/1668.240.0.1 to 68.240.255.25468.240.255.25565,534
24268.241.0.0/1668.241.0.1 to 68.241.255.25468.241.255.25565,534
24368.242.0.0/1668.242.0.1 to 68.242.255.25468.242.255.25565,534
24468.243.0.0/1668.243.0.1 to 68.243.255.25468.243.255.25565,534
24568.244.0.0/1668.244.0.1 to 68.244.255.25468.244.255.25565,534
24668.245.0.0/1668.245.0.1 to 68.245.255.25468.245.255.25565,534
24768.246.0.0/1668.246.0.1 to 68.246.255.25468.246.255.25565,534
24868.247.0.0/1668.247.0.1 to 68.247.255.25468.247.255.25565,534
24968.248.0.0/1668.248.0.1 to 68.248.255.25468.248.255.25565,534
25068.249.0.0/1668.249.0.1 to 68.249.255.25468.249.255.25565,534
25168.250.0.0/1668.250.0.1 to 68.250.255.25468.250.255.25565,534
25268.251.0.0/1668.251.0.1 to 68.251.255.25468.251.255.25565,534
25368.252.0.0/1668.252.0.1 to 68.252.255.25468.252.255.25565,534
25468.253.0.0/1668.253.0.1 to 68.253.255.25468.253.255.25565,534
25568.254.0.0/1668.254.0.1 to 68.254.255.25468.254.255.25565,534
25668.255.0.0/1668.255.0.1 to 68.255.255.25468.255.255.25565,534

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.