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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/15
/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 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.0.0.0/1568.0.0.1 to 68.1.255.25468.1.255.255131,070
268.2.0.0/1568.2.0.1 to 68.3.255.25468.3.255.255131,070
368.4.0.0/1568.4.0.1 to 68.5.255.25468.5.255.255131,070
468.6.0.0/1568.6.0.1 to 68.7.255.25468.7.255.255131,070
568.8.0.0/1568.8.0.1 to 68.9.255.25468.9.255.255131,070
668.10.0.0/1568.10.0.1 to 68.11.255.25468.11.255.255131,070
768.12.0.0/1568.12.0.1 to 68.13.255.25468.13.255.255131,070
868.14.0.0/1568.14.0.1 to 68.15.255.25468.15.255.255131,070
968.16.0.0/1568.16.0.1 to 68.17.255.25468.17.255.255131,070
1068.18.0.0/1568.18.0.1 to 68.19.255.25468.19.255.255131,070
1168.20.0.0/1568.20.0.1 to 68.21.255.25468.21.255.255131,070
1268.22.0.0/1568.22.0.1 to 68.23.255.25468.23.255.255131,070
1368.24.0.0/1568.24.0.1 to 68.25.255.25468.25.255.255131,070
1468.26.0.0/1568.26.0.1 to 68.27.255.25468.27.255.255131,070
1568.28.0.0/1568.28.0.1 to 68.29.255.25468.29.255.255131,070
1668.30.0.0/1568.30.0.1 to 68.31.255.25468.31.255.255131,070
1768.32.0.0/1568.32.0.1 to 68.33.255.25468.33.255.255131,070
1868.34.0.0/1568.34.0.1 to 68.35.255.25468.35.255.255131,070
1968.36.0.0/1568.36.0.1 to 68.37.255.25468.37.255.255131,070
2068.38.0.0/1568.38.0.1 to 68.39.255.25468.39.255.255131,070
2168.40.0.0/1568.40.0.1 to 68.41.255.25468.41.255.255131,070
2268.42.0.0/1568.42.0.1 to 68.43.255.25468.43.255.255131,070
2368.44.0.0/1568.44.0.1 to 68.45.255.25468.45.255.255131,070
2468.46.0.0/1568.46.0.1 to 68.47.255.25468.47.255.255131,070
2568.48.0.0/1568.48.0.1 to 68.49.255.25468.49.255.255131,070
2668.50.0.0/1568.50.0.1 to 68.51.255.25468.51.255.255131,070
2768.52.0.0/1568.52.0.1 to 68.53.255.25468.53.255.255131,070
2868.54.0.0/1568.54.0.1 to 68.55.255.25468.55.255.255131,070
2968.56.0.0/1568.56.0.1 to 68.57.255.25468.57.255.255131,070
3068.58.0.0/1568.58.0.1 to 68.59.255.25468.59.255.255131,070
3168.60.0.0/1568.60.0.1 to 68.61.255.25468.61.255.255131,070
3268.62.0.0/1568.62.0.1 to 68.63.255.25468.63.255.255131,070
3368.64.0.0/1568.64.0.1 to 68.65.255.25468.65.255.255131,070
3468.66.0.0/1568.66.0.1 to 68.67.255.25468.67.255.255131,070
3568.68.0.0/1568.68.0.1 to 68.69.255.25468.69.255.255131,070
3668.70.0.0/1568.70.0.1 to 68.71.255.25468.71.255.255131,070
3768.72.0.0/1568.72.0.1 to 68.73.255.25468.73.255.255131,070
3868.74.0.0/1568.74.0.1 to 68.75.255.25468.75.255.255131,070
3968.76.0.0/1568.76.0.1 to 68.77.255.25468.77.255.255131,070
4068.78.0.0/1568.78.0.1 to 68.79.255.25468.79.255.255131,070
4168.80.0.0/1568.80.0.1 to 68.81.255.25468.81.255.255131,070
4268.82.0.0/1568.82.0.1 to 68.83.255.25468.83.255.255131,070
4368.84.0.0/1568.84.0.1 to 68.85.255.25468.85.255.255131,070
4468.86.0.0/1568.86.0.1 to 68.87.255.25468.87.255.255131,070
4568.88.0.0/1568.88.0.1 to 68.89.255.25468.89.255.255131,070
4668.90.0.0/1568.90.0.1 to 68.91.255.25468.91.255.255131,070
4768.92.0.0/1568.92.0.1 to 68.93.255.25468.93.255.255131,070
4868.94.0.0/1568.94.0.1 to 68.95.255.25468.95.255.255131,070
4968.96.0.0/1568.96.0.1 to 68.97.255.25468.97.255.255131,070
5068.98.0.0/1568.98.0.1 to 68.99.255.25468.99.255.255131,070
5168.100.0.0/1568.100.0.1 to 68.101.255.25468.101.255.255131,070
5268.102.0.0/1568.102.0.1 to 68.103.255.25468.103.255.255131,070
5368.104.0.0/1568.104.0.1 to 68.105.255.25468.105.255.255131,070
5468.106.0.0/1568.106.0.1 to 68.107.255.25468.107.255.255131,070
5568.108.0.0/1568.108.0.1 to 68.109.255.25468.109.255.255131,070
5668.110.0.0/1568.110.0.1 to 68.111.255.25468.111.255.255131,070
5768.112.0.0/1568.112.0.1 to 68.113.255.25468.113.255.255131,070
5868.114.0.0/1568.114.0.1 to 68.115.255.25468.115.255.255131,070
5968.116.0.0/1568.116.0.1 to 68.117.255.25468.117.255.255131,070
6068.118.0.0/1568.118.0.1 to 68.119.255.25468.119.255.255131,070
6168.120.0.0/1568.120.0.1 to 68.121.255.25468.121.255.255131,070
6268.122.0.0/1568.122.0.1 to 68.123.255.25468.123.255.255131,070
6368.124.0.0/1568.124.0.1 to 68.125.255.25468.125.255.255131,070
6468.126.0.0/1568.126.0.1 to 68.127.255.25468.127.255.255131,070
6568.128.0.0/1568.128.0.1 to 68.129.255.25468.129.255.255131,070
6668.130.0.0/1568.130.0.1 to 68.131.255.25468.131.255.255131,070
6768.132.0.0/1568.132.0.1 to 68.133.255.25468.133.255.255131,070
6868.134.0.0/1568.134.0.1 to 68.135.255.25468.135.255.255131,070
6968.136.0.0/1568.136.0.1 to 68.137.255.25468.137.255.255131,070
7068.138.0.0/1568.138.0.1 to 68.139.255.25468.139.255.255131,070
7168.140.0.0/1568.140.0.1 to 68.141.255.25468.141.255.255131,070
7268.142.0.0/1568.142.0.1 to 68.143.255.25468.143.255.255131,070
7368.144.0.0/1568.144.0.1 to 68.145.255.25468.145.255.255131,070
7468.146.0.0/1568.146.0.1 to 68.147.255.25468.147.255.255131,070
7568.148.0.0/1568.148.0.1 to 68.149.255.25468.149.255.255131,070
7668.150.0.0/1568.150.0.1 to 68.151.255.25468.151.255.255131,070
7768.152.0.0/1568.152.0.1 to 68.153.255.25468.153.255.255131,070
7868.154.0.0/1568.154.0.1 to 68.155.255.25468.155.255.255131,070
7968.156.0.0/1568.156.0.1 to 68.157.255.25468.157.255.255131,070
8068.158.0.0/1568.158.0.1 to 68.159.255.25468.159.255.255131,070
8168.160.0.0/1568.160.0.1 to 68.161.255.25468.161.255.255131,070
8268.162.0.0/1568.162.0.1 to 68.163.255.25468.163.255.255131,070
8368.164.0.0/1568.164.0.1 to 68.165.255.25468.165.255.255131,070
8468.166.0.0/1568.166.0.1 to 68.167.255.25468.167.255.255131,070
8568.168.0.0/1568.168.0.1 to 68.169.255.25468.169.255.255131,070
8668.170.0.0/1568.170.0.1 to 68.171.255.25468.171.255.255131,070
8768.172.0.0/1568.172.0.1 to 68.173.255.25468.173.255.255131,070
8868.174.0.0/1568.174.0.1 to 68.175.255.25468.175.255.255131,070
8968.176.0.0/1568.176.0.1 to 68.177.255.25468.177.255.255131,070
9068.178.0.0/1568.178.0.1 to 68.179.255.25468.179.255.255131,070
9168.180.0.0/1568.180.0.1 to 68.181.255.25468.181.255.255131,070
9268.182.0.0/1568.182.0.1 to 68.183.255.25468.183.255.255131,070
9368.184.0.0/1568.184.0.1 to 68.185.255.25468.185.255.255131,070
9468.186.0.0/1568.186.0.1 to 68.187.255.25468.187.255.255131,070
9568.188.0.0/1568.188.0.1 to 68.189.255.25468.189.255.255131,070
9668.190.0.0/1568.190.0.1 to 68.191.255.25468.191.255.255131,070
9768.192.0.0/1568.192.0.1 to 68.193.255.25468.193.255.255131,070
9868.194.0.0/1568.194.0.1 to 68.195.255.25468.195.255.255131,070
9968.196.0.0/1568.196.0.1 to 68.197.255.25468.197.255.255131,070
10068.198.0.0/1568.198.0.1 to 68.199.255.25468.199.255.255131,070
10168.200.0.0/1568.200.0.1 to 68.201.255.25468.201.255.255131,070
10268.202.0.0/1568.202.0.1 to 68.203.255.25468.203.255.255131,070
10368.204.0.0/1568.204.0.1 to 68.205.255.25468.205.255.255131,070
10468.206.0.0/1568.206.0.1 to 68.207.255.25468.207.255.255131,070
10568.208.0.0/1568.208.0.1 to 68.209.255.25468.209.255.255131,070
10668.210.0.0/1568.210.0.1 to 68.211.255.25468.211.255.255131,070
10768.212.0.0/1568.212.0.1 to 68.213.255.25468.213.255.255131,070
10868.214.0.0/1568.214.0.1 to 68.215.255.25468.215.255.255131,070
10968.216.0.0/1568.216.0.1 to 68.217.255.25468.217.255.255131,070
11068.218.0.0/1568.218.0.1 to 68.219.255.25468.219.255.255131,070
11168.220.0.0/1568.220.0.1 to 68.221.255.25468.221.255.255131,070
11268.222.0.0/1568.222.0.1 to 68.223.255.25468.223.255.255131,070
11368.224.0.0/1568.224.0.1 to 68.225.255.25468.225.255.255131,070
11468.226.0.0/1568.226.0.1 to 68.227.255.25468.227.255.255131,070
11568.228.0.0/1568.228.0.1 to 68.229.255.25468.229.255.255131,070
11668.230.0.0/1568.230.0.1 to 68.231.255.25468.231.255.255131,070
11768.232.0.0/1568.232.0.1 to 68.233.255.25468.233.255.255131,070
11868.234.0.0/1568.234.0.1 to 68.235.255.25468.235.255.255131,070
11968.236.0.0/1568.236.0.1 to 68.237.255.25468.237.255.255131,070
12068.238.0.0/1568.238.0.1 to 68.239.255.25468.239.255.255131,070
12168.240.0.0/1568.240.0.1 to 68.241.255.25468.241.255.255131,070
12268.242.0.0/1568.242.0.1 to 68.243.255.25468.243.255.255131,070
12368.244.0.0/1568.244.0.1 to 68.245.255.25468.245.255.255131,070
12468.246.0.0/1568.246.0.1 to 68.247.255.25468.247.255.255131,070
12568.248.0.0/1568.248.0.1 to 68.249.255.25468.249.255.255131,070
12668.250.0.0/1568.250.0.1 to 68.251.255.25468.251.255.255131,070
12768.252.0.0/1568.252.0.1 to 68.253.255.25468.253.255.255131,070
12868.254.0.0/1568.254.0.1 to 68.255.255.25468.255.255.255131,070
12969.0.0.0/1569.0.0.1 to 69.1.255.25469.1.255.255131,070
13069.2.0.0/1569.2.0.1 to 69.3.255.25469.3.255.255131,070
13169.4.0.0/1569.4.0.1 to 69.5.255.25469.5.255.255131,070
13269.6.0.0/1569.6.0.1 to 69.7.255.25469.7.255.255131,070
13369.8.0.0/1569.8.0.1 to 69.9.255.25469.9.255.255131,070
13469.10.0.0/1569.10.0.1 to 69.11.255.25469.11.255.255131,070
13569.12.0.0/1569.12.0.1 to 69.13.255.25469.13.255.255131,070
13669.14.0.0/1569.14.0.1 to 69.15.255.25469.15.255.255131,070
13769.16.0.0/1569.16.0.1 to 69.17.255.25469.17.255.255131,070
13869.18.0.0/1569.18.0.1 to 69.19.255.25469.19.255.255131,070
13969.20.0.0/1569.20.0.1 to 69.21.255.25469.21.255.255131,070
14069.22.0.0/1569.22.0.1 to 69.23.255.25469.23.255.255131,070
14169.24.0.0/1569.24.0.1 to 69.25.255.25469.25.255.255131,070
14269.26.0.0/1569.26.0.1 to 69.27.255.25469.27.255.255131,070
14369.28.0.0/1569.28.0.1 to 69.29.255.25469.29.255.255131,070
14469.30.0.0/1569.30.0.1 to 69.31.255.25469.31.255.255131,070
14569.32.0.0/1569.32.0.1 to 69.33.255.25469.33.255.255131,070
14669.34.0.0/1569.34.0.1 to 69.35.255.25469.35.255.255131,070
14769.36.0.0/1569.36.0.1 to 69.37.255.25469.37.255.255131,070
14869.38.0.0/1569.38.0.1 to 69.39.255.25469.39.255.255131,070
14969.40.0.0/1569.40.0.1 to 69.41.255.25469.41.255.255131,070
15069.42.0.0/1569.42.0.1 to 69.43.255.25469.43.255.255131,070
15169.44.0.0/1569.44.0.1 to 69.45.255.25469.45.255.255131,070
15269.46.0.0/1569.46.0.1 to 69.47.255.25469.47.255.255131,070
15369.48.0.0/1569.48.0.1 to 69.49.255.25469.49.255.255131,070
15469.50.0.0/1569.50.0.1 to 69.51.255.25469.51.255.255131,070
15569.52.0.0/1569.52.0.1 to 69.53.255.25469.53.255.255131,070
15669.54.0.0/1569.54.0.1 to 69.55.255.25469.55.255.255131,070
15769.56.0.0/1569.56.0.1 to 69.57.255.25469.57.255.255131,070
15869.58.0.0/1569.58.0.1 to 69.59.255.25469.59.255.255131,070
15969.60.0.0/1569.60.0.1 to 69.61.255.25469.61.255.255131,070
16069.62.0.0/1569.62.0.1 to 69.63.255.25469.63.255.255131,070
16169.64.0.0/1569.64.0.1 to 69.65.255.25469.65.255.255131,070
16269.66.0.0/1569.66.0.1 to 69.67.255.25469.67.255.255131,070
16369.68.0.0/1569.68.0.1 to 69.69.255.25469.69.255.255131,070
16469.70.0.0/1569.70.0.1 to 69.71.255.25469.71.255.255131,070
16569.72.0.0/1569.72.0.1 to 69.73.255.25469.73.255.255131,070
16669.74.0.0/1569.74.0.1 to 69.75.255.25469.75.255.255131,070
16769.76.0.0/1569.76.0.1 to 69.77.255.25469.77.255.255131,070
16869.78.0.0/1569.78.0.1 to 69.79.255.25469.79.255.255131,070
16969.80.0.0/1569.80.0.1 to 69.81.255.25469.81.255.255131,070
17069.82.0.0/1569.82.0.1 to 69.83.255.25469.83.255.255131,070
17169.84.0.0/1569.84.0.1 to 69.85.255.25469.85.255.255131,070
17269.86.0.0/1569.86.0.1 to 69.87.255.25469.87.255.255131,070
17369.88.0.0/1569.88.0.1 to 69.89.255.25469.89.255.255131,070
17469.90.0.0/1569.90.0.1 to 69.91.255.25469.91.255.255131,070
17569.92.0.0/1569.92.0.1 to 69.93.255.25469.93.255.255131,070
17669.94.0.0/1569.94.0.1 to 69.95.255.25469.95.255.255131,070
17769.96.0.0/1569.96.0.1 to 69.97.255.25469.97.255.255131,070
17869.98.0.0/1569.98.0.1 to 69.99.255.25469.99.255.255131,070
17969.100.0.0/1569.100.0.1 to 69.101.255.25469.101.255.255131,070
18069.102.0.0/1569.102.0.1 to 69.103.255.25469.103.255.255131,070
18169.104.0.0/1569.104.0.1 to 69.105.255.25469.105.255.255131,070
18269.106.0.0/1569.106.0.1 to 69.107.255.25469.107.255.255131,070
18369.108.0.0/1569.108.0.1 to 69.109.255.25469.109.255.255131,070
18469.110.0.0/1569.110.0.1 to 69.111.255.25469.111.255.255131,070
18569.112.0.0/1569.112.0.1 to 69.113.255.25469.113.255.255131,070
18669.114.0.0/1569.114.0.1 to 69.115.255.25469.115.255.255131,070
18769.116.0.0/1569.116.0.1 to 69.117.255.25469.117.255.255131,070
18869.118.0.0/1569.118.0.1 to 69.119.255.25469.119.255.255131,070
18969.120.0.0/1569.120.0.1 to 69.121.255.25469.121.255.255131,070
19069.122.0.0/1569.122.0.1 to 69.123.255.25469.123.255.255131,070
19169.124.0.0/1569.124.0.1 to 69.125.255.25469.125.255.255131,070
19269.126.0.0/1569.126.0.1 to 69.127.255.25469.127.255.255131,070
19369.128.0.0/1569.128.0.1 to 69.129.255.25469.129.255.255131,070
19469.130.0.0/1569.130.0.1 to 69.131.255.25469.131.255.255131,070
19569.132.0.0/1569.132.0.1 to 69.133.255.25469.133.255.255131,070
19669.134.0.0/1569.134.0.1 to 69.135.255.25469.135.255.255131,070
19769.136.0.0/1569.136.0.1 to 69.137.255.25469.137.255.255131,070
19869.138.0.0/1569.138.0.1 to 69.139.255.25469.139.255.255131,070
19969.140.0.0/1569.140.0.1 to 69.141.255.25469.141.255.255131,070
20069.142.0.0/1569.142.0.1 to 69.143.255.25469.143.255.255131,070
20169.144.0.0/1569.144.0.1 to 69.145.255.25469.145.255.255131,070
20269.146.0.0/1569.146.0.1 to 69.147.255.25469.147.255.255131,070
20369.148.0.0/1569.148.0.1 to 69.149.255.25469.149.255.255131,070
20469.150.0.0/1569.150.0.1 to 69.151.255.25469.151.255.255131,070
20569.152.0.0/1569.152.0.1 to 69.153.255.25469.153.255.255131,070
20669.154.0.0/1569.154.0.1 to 69.155.255.25469.155.255.255131,070
20769.156.0.0/1569.156.0.1 to 69.157.255.25469.157.255.255131,070
20869.158.0.0/1569.158.0.1 to 69.159.255.25469.159.255.255131,070
20969.160.0.0/1569.160.0.1 to 69.161.255.25469.161.255.255131,070
21069.162.0.0/1569.162.0.1 to 69.163.255.25469.163.255.255131,070
21169.164.0.0/1569.164.0.1 to 69.165.255.25469.165.255.255131,070
21269.166.0.0/1569.166.0.1 to 69.167.255.25469.167.255.255131,070
21369.168.0.0/1569.168.0.1 to 69.169.255.25469.169.255.255131,070
21469.170.0.0/1569.170.0.1 to 69.171.255.25469.171.255.255131,070
21569.172.0.0/1569.172.0.1 to 69.173.255.25469.173.255.255131,070
21669.174.0.0/1569.174.0.1 to 69.175.255.25469.175.255.255131,070
21769.176.0.0/1569.176.0.1 to 69.177.255.25469.177.255.255131,070
21869.178.0.0/1569.178.0.1 to 69.179.255.25469.179.255.255131,070
21969.180.0.0/1569.180.0.1 to 69.181.255.25469.181.255.255131,070
22069.182.0.0/1569.182.0.1 to 69.183.255.25469.183.255.255131,070
22169.184.0.0/1569.184.0.1 to 69.185.255.25469.185.255.255131,070
22269.186.0.0/1569.186.0.1 to 69.187.255.25469.187.255.255131,070
22369.188.0.0/1569.188.0.1 to 69.189.255.25469.189.255.255131,070
22469.190.0.0/1569.190.0.1 to 69.191.255.25469.191.255.255131,070
22569.192.0.0/1569.192.0.1 to 69.193.255.25469.193.255.255131,070
22669.194.0.0/1569.194.0.1 to 69.195.255.25469.195.255.255131,070
22769.196.0.0/1569.196.0.1 to 69.197.255.25469.197.255.255131,070
22869.198.0.0/1569.198.0.1 to 69.199.255.25469.199.255.255131,070
22969.200.0.0/1569.200.0.1 to 69.201.255.25469.201.255.255131,070
23069.202.0.0/1569.202.0.1 to 69.203.255.25469.203.255.255131,070
23169.204.0.0/1569.204.0.1 to 69.205.255.25469.205.255.255131,070
23269.206.0.0/1569.206.0.1 to 69.207.255.25469.207.255.255131,070
23369.208.0.0/1569.208.0.1 to 69.209.255.25469.209.255.255131,070
23469.210.0.0/1569.210.0.1 to 69.211.255.25469.211.255.255131,070
23569.212.0.0/1569.212.0.1 to 69.213.255.25469.213.255.255131,070
23669.214.0.0/1569.214.0.1 to 69.215.255.25469.215.255.255131,070
23769.216.0.0/1569.216.0.1 to 69.217.255.25469.217.255.255131,070
23869.218.0.0/1569.218.0.1 to 69.219.255.25469.219.255.255131,070
23969.220.0.0/1569.220.0.1 to 69.221.255.25469.221.255.255131,070
24069.222.0.0/1569.222.0.1 to 69.223.255.25469.223.255.255131,070
24169.224.0.0/1569.224.0.1 to 69.225.255.25469.225.255.255131,070
24269.226.0.0/1569.226.0.1 to 69.227.255.25469.227.255.255131,070
24369.228.0.0/1569.228.0.1 to 69.229.255.25469.229.255.255131,070
24469.230.0.0/1569.230.0.1 to 69.231.255.25469.231.255.255131,070
24569.232.0.0/1569.232.0.1 to 69.233.255.25469.233.255.255131,070
24669.234.0.0/1569.234.0.1 to 69.235.255.25469.235.255.255131,070
24769.236.0.0/1569.236.0.1 to 69.237.255.25469.237.255.255131,070
24869.238.0.0/1569.238.0.1 to 69.239.255.25469.239.255.255131,070
24969.240.0.0/1569.240.0.1 to 69.241.255.25469.241.255.255131,070
25069.242.0.0/1569.242.0.1 to 69.243.255.25469.243.255.255131,070
25169.244.0.0/1569.244.0.1 to 69.245.255.25469.245.255.255131,070
25269.246.0.0/1569.246.0.1 to 69.247.255.25469.247.255.255131,070
25369.248.0.0/1569.248.0.1 to 69.249.255.25469.249.255.255131,070
25469.250.0.0/1569.250.0.1 to 69.251.255.25469.251.255.255131,070
25569.252.0.0/1569.252.0.1 to 69.253.255.25469.253.255.255131,070
25669.254.0.0/1569.254.0.1 to 69.255.255.25469.255.255.255131,070

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.