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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.

Network52.12.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
52.12.0.0
Broadcast address
52.13.255.255
First usable
52.12.0.1
Last usable
52.13.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 340C0000 · Integer 873201664 to 873332735
Reverse DNS zones
12.52.in-addr.arpa
13.52.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110100.00001100.00000000.0000000052.12.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00110100.00001100.00000000.0000000052.12.0.0
Broadcast00110100.00001101.11111111.1111111152.13.255.255
Split into smaller subnets/24
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

52.12.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
152.12.0.0/2452.12.0.1 to 52.12.0.25452.12.0.255254
252.12.1.0/2452.12.1.1 to 52.12.1.25452.12.1.255254
352.12.2.0/2452.12.2.1 to 52.12.2.25452.12.2.255254
452.12.3.0/2452.12.3.1 to 52.12.3.25452.12.3.255254
552.12.4.0/2452.12.4.1 to 52.12.4.25452.12.4.255254
652.12.5.0/2452.12.5.1 to 52.12.5.25452.12.5.255254
752.12.6.0/2452.12.6.1 to 52.12.6.25452.12.6.255254
852.12.7.0/2452.12.7.1 to 52.12.7.25452.12.7.255254
952.12.8.0/2452.12.8.1 to 52.12.8.25452.12.8.255254
1052.12.9.0/2452.12.9.1 to 52.12.9.25452.12.9.255254
1152.12.10.0/2452.12.10.1 to 52.12.10.25452.12.10.255254
1252.12.11.0/2452.12.11.1 to 52.12.11.25452.12.11.255254
1352.12.12.0/2452.12.12.1 to 52.12.12.25452.12.12.255254
1452.12.13.0/2452.12.13.1 to 52.12.13.25452.12.13.255254
1552.12.14.0/2452.12.14.1 to 52.12.14.25452.12.14.255254
1652.12.15.0/2452.12.15.1 to 52.12.15.25452.12.15.255254
1752.12.16.0/2452.12.16.1 to 52.12.16.25452.12.16.255254
1852.12.17.0/2452.12.17.1 to 52.12.17.25452.12.17.255254
1952.12.18.0/2452.12.18.1 to 52.12.18.25452.12.18.255254
2052.12.19.0/2452.12.19.1 to 52.12.19.25452.12.19.255254
2152.12.20.0/2452.12.20.1 to 52.12.20.25452.12.20.255254
2252.12.21.0/2452.12.21.1 to 52.12.21.25452.12.21.255254
2352.12.22.0/2452.12.22.1 to 52.12.22.25452.12.22.255254
2452.12.23.0/2452.12.23.1 to 52.12.23.25452.12.23.255254
2552.12.24.0/2452.12.24.1 to 52.12.24.25452.12.24.255254
2652.12.25.0/2452.12.25.1 to 52.12.25.25452.12.25.255254
2752.12.26.0/2452.12.26.1 to 52.12.26.25452.12.26.255254
2852.12.27.0/2452.12.27.1 to 52.12.27.25452.12.27.255254
2952.12.28.0/2452.12.28.1 to 52.12.28.25452.12.28.255254
3052.12.29.0/2452.12.29.1 to 52.12.29.25452.12.29.255254
3152.12.30.0/2452.12.30.1 to 52.12.30.25452.12.30.255254
3252.12.31.0/2452.12.31.1 to 52.12.31.25452.12.31.255254
3352.12.32.0/2452.12.32.1 to 52.12.32.25452.12.32.255254
3452.12.33.0/2452.12.33.1 to 52.12.33.25452.12.33.255254
3552.12.34.0/2452.12.34.1 to 52.12.34.25452.12.34.255254
3652.12.35.0/2452.12.35.1 to 52.12.35.25452.12.35.255254
3752.12.36.0/2452.12.36.1 to 52.12.36.25452.12.36.255254
3852.12.37.0/2452.12.37.1 to 52.12.37.25452.12.37.255254
3952.12.38.0/2452.12.38.1 to 52.12.38.25452.12.38.255254
4052.12.39.0/2452.12.39.1 to 52.12.39.25452.12.39.255254
4152.12.40.0/2452.12.40.1 to 52.12.40.25452.12.40.255254
4252.12.41.0/2452.12.41.1 to 52.12.41.25452.12.41.255254
4352.12.42.0/2452.12.42.1 to 52.12.42.25452.12.42.255254
4452.12.43.0/2452.12.43.1 to 52.12.43.25452.12.43.255254
4552.12.44.0/2452.12.44.1 to 52.12.44.25452.12.44.255254
4652.12.45.0/2452.12.45.1 to 52.12.45.25452.12.45.255254
4752.12.46.0/2452.12.46.1 to 52.12.46.25452.12.46.255254
4852.12.47.0/2452.12.47.1 to 52.12.47.25452.12.47.255254
4952.12.48.0/2452.12.48.1 to 52.12.48.25452.12.48.255254
5052.12.49.0/2452.12.49.1 to 52.12.49.25452.12.49.255254
5152.12.50.0/2452.12.50.1 to 52.12.50.25452.12.50.255254
5252.12.51.0/2452.12.51.1 to 52.12.51.25452.12.51.255254
5352.12.52.0/2452.12.52.1 to 52.12.52.25452.12.52.255254
5452.12.53.0/2452.12.53.1 to 52.12.53.25452.12.53.255254
5552.12.54.0/2452.12.54.1 to 52.12.54.25452.12.54.255254
5652.12.55.0/2452.12.55.1 to 52.12.55.25452.12.55.255254
5752.12.56.0/2452.12.56.1 to 52.12.56.25452.12.56.255254
5852.12.57.0/2452.12.57.1 to 52.12.57.25452.12.57.255254
5952.12.58.0/2452.12.58.1 to 52.12.58.25452.12.58.255254
6052.12.59.0/2452.12.59.1 to 52.12.59.25452.12.59.255254
6152.12.60.0/2452.12.60.1 to 52.12.60.25452.12.60.255254
6252.12.61.0/2452.12.61.1 to 52.12.61.25452.12.61.255254
6352.12.62.0/2452.12.62.1 to 52.12.62.25452.12.62.255254
6452.12.63.0/2452.12.63.1 to 52.12.63.25452.12.63.255254
6552.12.64.0/2452.12.64.1 to 52.12.64.25452.12.64.255254
6652.12.65.0/2452.12.65.1 to 52.12.65.25452.12.65.255254
6752.12.66.0/2452.12.66.1 to 52.12.66.25452.12.66.255254
6852.12.67.0/2452.12.67.1 to 52.12.67.25452.12.67.255254
6952.12.68.0/2452.12.68.1 to 52.12.68.25452.12.68.255254
7052.12.69.0/2452.12.69.1 to 52.12.69.25452.12.69.255254
7152.12.70.0/2452.12.70.1 to 52.12.70.25452.12.70.255254
7252.12.71.0/2452.12.71.1 to 52.12.71.25452.12.71.255254
7352.12.72.0/2452.12.72.1 to 52.12.72.25452.12.72.255254
7452.12.73.0/2452.12.73.1 to 52.12.73.25452.12.73.255254
7552.12.74.0/2452.12.74.1 to 52.12.74.25452.12.74.255254
7652.12.75.0/2452.12.75.1 to 52.12.75.25452.12.75.255254
7752.12.76.0/2452.12.76.1 to 52.12.76.25452.12.76.255254
7852.12.77.0/2452.12.77.1 to 52.12.77.25452.12.77.255254
7952.12.78.0/2452.12.78.1 to 52.12.78.25452.12.78.255254
8052.12.79.0/2452.12.79.1 to 52.12.79.25452.12.79.255254
8152.12.80.0/2452.12.80.1 to 52.12.80.25452.12.80.255254
8252.12.81.0/2452.12.81.1 to 52.12.81.25452.12.81.255254
8352.12.82.0/2452.12.82.1 to 52.12.82.25452.12.82.255254
8452.12.83.0/2452.12.83.1 to 52.12.83.25452.12.83.255254
8552.12.84.0/2452.12.84.1 to 52.12.84.25452.12.84.255254
8652.12.85.0/2452.12.85.1 to 52.12.85.25452.12.85.255254
8752.12.86.0/2452.12.86.1 to 52.12.86.25452.12.86.255254
8852.12.87.0/2452.12.87.1 to 52.12.87.25452.12.87.255254
8952.12.88.0/2452.12.88.1 to 52.12.88.25452.12.88.255254
9052.12.89.0/2452.12.89.1 to 52.12.89.25452.12.89.255254
9152.12.90.0/2452.12.90.1 to 52.12.90.25452.12.90.255254
9252.12.91.0/2452.12.91.1 to 52.12.91.25452.12.91.255254
9352.12.92.0/2452.12.92.1 to 52.12.92.25452.12.92.255254
9452.12.93.0/2452.12.93.1 to 52.12.93.25452.12.93.255254
9552.12.94.0/2452.12.94.1 to 52.12.94.25452.12.94.255254
9652.12.95.0/2452.12.95.1 to 52.12.95.25452.12.95.255254
9752.12.96.0/2452.12.96.1 to 52.12.96.25452.12.96.255254
9852.12.97.0/2452.12.97.1 to 52.12.97.25452.12.97.255254
9952.12.98.0/2452.12.98.1 to 52.12.98.25452.12.98.255254
10052.12.99.0/2452.12.99.1 to 52.12.99.25452.12.99.255254
10152.12.100.0/2452.12.100.1 to 52.12.100.25452.12.100.255254
10252.12.101.0/2452.12.101.1 to 52.12.101.25452.12.101.255254
10352.12.102.0/2452.12.102.1 to 52.12.102.25452.12.102.255254
10452.12.103.0/2452.12.103.1 to 52.12.103.25452.12.103.255254
10552.12.104.0/2452.12.104.1 to 52.12.104.25452.12.104.255254
10652.12.105.0/2452.12.105.1 to 52.12.105.25452.12.105.255254
10752.12.106.0/2452.12.106.1 to 52.12.106.25452.12.106.255254
10852.12.107.0/2452.12.107.1 to 52.12.107.25452.12.107.255254
10952.12.108.0/2452.12.108.1 to 52.12.108.25452.12.108.255254
11052.12.109.0/2452.12.109.1 to 52.12.109.25452.12.109.255254
11152.12.110.0/2452.12.110.1 to 52.12.110.25452.12.110.255254
11252.12.111.0/2452.12.111.1 to 52.12.111.25452.12.111.255254
11352.12.112.0/2452.12.112.1 to 52.12.112.25452.12.112.255254
11452.12.113.0/2452.12.113.1 to 52.12.113.25452.12.113.255254
11552.12.114.0/2452.12.114.1 to 52.12.114.25452.12.114.255254
11652.12.115.0/2452.12.115.1 to 52.12.115.25452.12.115.255254
11752.12.116.0/2452.12.116.1 to 52.12.116.25452.12.116.255254
11852.12.117.0/2452.12.117.1 to 52.12.117.25452.12.117.255254
11952.12.118.0/2452.12.118.1 to 52.12.118.25452.12.118.255254
12052.12.119.0/2452.12.119.1 to 52.12.119.25452.12.119.255254
12152.12.120.0/2452.12.120.1 to 52.12.120.25452.12.120.255254
12252.12.121.0/2452.12.121.1 to 52.12.121.25452.12.121.255254
12352.12.122.0/2452.12.122.1 to 52.12.122.25452.12.122.255254
12452.12.123.0/2452.12.123.1 to 52.12.123.25452.12.123.255254
12552.12.124.0/2452.12.124.1 to 52.12.124.25452.12.124.255254
12652.12.125.0/2452.12.125.1 to 52.12.125.25452.12.125.255254
12752.12.126.0/2452.12.126.1 to 52.12.126.25452.12.126.255254
12852.12.127.0/2452.12.127.1 to 52.12.127.25452.12.127.255254
12952.12.128.0/2452.12.128.1 to 52.12.128.25452.12.128.255254
13052.12.129.0/2452.12.129.1 to 52.12.129.25452.12.129.255254
13152.12.130.0/2452.12.130.1 to 52.12.130.25452.12.130.255254
13252.12.131.0/2452.12.131.1 to 52.12.131.25452.12.131.255254
13352.12.132.0/2452.12.132.1 to 52.12.132.25452.12.132.255254
13452.12.133.0/2452.12.133.1 to 52.12.133.25452.12.133.255254
13552.12.134.0/2452.12.134.1 to 52.12.134.25452.12.134.255254
13652.12.135.0/2452.12.135.1 to 52.12.135.25452.12.135.255254
13752.12.136.0/2452.12.136.1 to 52.12.136.25452.12.136.255254
13852.12.137.0/2452.12.137.1 to 52.12.137.25452.12.137.255254
13952.12.138.0/2452.12.138.1 to 52.12.138.25452.12.138.255254
14052.12.139.0/2452.12.139.1 to 52.12.139.25452.12.139.255254
14152.12.140.0/2452.12.140.1 to 52.12.140.25452.12.140.255254
14252.12.141.0/2452.12.141.1 to 52.12.141.25452.12.141.255254
14352.12.142.0/2452.12.142.1 to 52.12.142.25452.12.142.255254
14452.12.143.0/2452.12.143.1 to 52.12.143.25452.12.143.255254
14552.12.144.0/2452.12.144.1 to 52.12.144.25452.12.144.255254
14652.12.145.0/2452.12.145.1 to 52.12.145.25452.12.145.255254
14752.12.146.0/2452.12.146.1 to 52.12.146.25452.12.146.255254
14852.12.147.0/2452.12.147.1 to 52.12.147.25452.12.147.255254
14952.12.148.0/2452.12.148.1 to 52.12.148.25452.12.148.255254
15052.12.149.0/2452.12.149.1 to 52.12.149.25452.12.149.255254
15152.12.150.0/2452.12.150.1 to 52.12.150.25452.12.150.255254
15252.12.151.0/2452.12.151.1 to 52.12.151.25452.12.151.255254
15352.12.152.0/2452.12.152.1 to 52.12.152.25452.12.152.255254
15452.12.153.0/2452.12.153.1 to 52.12.153.25452.12.153.255254
15552.12.154.0/2452.12.154.1 to 52.12.154.25452.12.154.255254
15652.12.155.0/2452.12.155.1 to 52.12.155.25452.12.155.255254
15752.12.156.0/2452.12.156.1 to 52.12.156.25452.12.156.255254
15852.12.157.0/2452.12.157.1 to 52.12.157.25452.12.157.255254
15952.12.158.0/2452.12.158.1 to 52.12.158.25452.12.158.255254
16052.12.159.0/2452.12.159.1 to 52.12.159.25452.12.159.255254
16152.12.160.0/2452.12.160.1 to 52.12.160.25452.12.160.255254
16252.12.161.0/2452.12.161.1 to 52.12.161.25452.12.161.255254
16352.12.162.0/2452.12.162.1 to 52.12.162.25452.12.162.255254
16452.12.163.0/2452.12.163.1 to 52.12.163.25452.12.163.255254
16552.12.164.0/2452.12.164.1 to 52.12.164.25452.12.164.255254
16652.12.165.0/2452.12.165.1 to 52.12.165.25452.12.165.255254
16752.12.166.0/2452.12.166.1 to 52.12.166.25452.12.166.255254
16852.12.167.0/2452.12.167.1 to 52.12.167.25452.12.167.255254
16952.12.168.0/2452.12.168.1 to 52.12.168.25452.12.168.255254
17052.12.169.0/2452.12.169.1 to 52.12.169.25452.12.169.255254
17152.12.170.0/2452.12.170.1 to 52.12.170.25452.12.170.255254
17252.12.171.0/2452.12.171.1 to 52.12.171.25452.12.171.255254
17352.12.172.0/2452.12.172.1 to 52.12.172.25452.12.172.255254
17452.12.173.0/2452.12.173.1 to 52.12.173.25452.12.173.255254
17552.12.174.0/2452.12.174.1 to 52.12.174.25452.12.174.255254
17652.12.175.0/2452.12.175.1 to 52.12.175.25452.12.175.255254
17752.12.176.0/2452.12.176.1 to 52.12.176.25452.12.176.255254
17852.12.177.0/2452.12.177.1 to 52.12.177.25452.12.177.255254
17952.12.178.0/2452.12.178.1 to 52.12.178.25452.12.178.255254
18052.12.179.0/2452.12.179.1 to 52.12.179.25452.12.179.255254
18152.12.180.0/2452.12.180.1 to 52.12.180.25452.12.180.255254
18252.12.181.0/2452.12.181.1 to 52.12.181.25452.12.181.255254
18352.12.182.0/2452.12.182.1 to 52.12.182.25452.12.182.255254
18452.12.183.0/2452.12.183.1 to 52.12.183.25452.12.183.255254
18552.12.184.0/2452.12.184.1 to 52.12.184.25452.12.184.255254
18652.12.185.0/2452.12.185.1 to 52.12.185.25452.12.185.255254
18752.12.186.0/2452.12.186.1 to 52.12.186.25452.12.186.255254
18852.12.187.0/2452.12.187.1 to 52.12.187.25452.12.187.255254
18952.12.188.0/2452.12.188.1 to 52.12.188.25452.12.188.255254
19052.12.189.0/2452.12.189.1 to 52.12.189.25452.12.189.255254
19152.12.190.0/2452.12.190.1 to 52.12.190.25452.12.190.255254
19252.12.191.0/2452.12.191.1 to 52.12.191.25452.12.191.255254
19352.12.192.0/2452.12.192.1 to 52.12.192.25452.12.192.255254
19452.12.193.0/2452.12.193.1 to 52.12.193.25452.12.193.255254
19552.12.194.0/2452.12.194.1 to 52.12.194.25452.12.194.255254
19652.12.195.0/2452.12.195.1 to 52.12.195.25452.12.195.255254
19752.12.196.0/2452.12.196.1 to 52.12.196.25452.12.196.255254
19852.12.197.0/2452.12.197.1 to 52.12.197.25452.12.197.255254
19952.12.198.0/2452.12.198.1 to 52.12.198.25452.12.198.255254
20052.12.199.0/2452.12.199.1 to 52.12.199.25452.12.199.255254
20152.12.200.0/2452.12.200.1 to 52.12.200.25452.12.200.255254
20252.12.201.0/2452.12.201.1 to 52.12.201.25452.12.201.255254
20352.12.202.0/2452.12.202.1 to 52.12.202.25452.12.202.255254
20452.12.203.0/2452.12.203.1 to 52.12.203.25452.12.203.255254
20552.12.204.0/2452.12.204.1 to 52.12.204.25452.12.204.255254
20652.12.205.0/2452.12.205.1 to 52.12.205.25452.12.205.255254
20752.12.206.0/2452.12.206.1 to 52.12.206.25452.12.206.255254
20852.12.207.0/2452.12.207.1 to 52.12.207.25452.12.207.255254
20952.12.208.0/2452.12.208.1 to 52.12.208.25452.12.208.255254
21052.12.209.0/2452.12.209.1 to 52.12.209.25452.12.209.255254
21152.12.210.0/2452.12.210.1 to 52.12.210.25452.12.210.255254
21252.12.211.0/2452.12.211.1 to 52.12.211.25452.12.211.255254
21352.12.212.0/2452.12.212.1 to 52.12.212.25452.12.212.255254
21452.12.213.0/2452.12.213.1 to 52.12.213.25452.12.213.255254
21552.12.214.0/2452.12.214.1 to 52.12.214.25452.12.214.255254
21652.12.215.0/2452.12.215.1 to 52.12.215.25452.12.215.255254
21752.12.216.0/2452.12.216.1 to 52.12.216.25452.12.216.255254
21852.12.217.0/2452.12.217.1 to 52.12.217.25452.12.217.255254
21952.12.218.0/2452.12.218.1 to 52.12.218.25452.12.218.255254
22052.12.219.0/2452.12.219.1 to 52.12.219.25452.12.219.255254
22152.12.220.0/2452.12.220.1 to 52.12.220.25452.12.220.255254
22252.12.221.0/2452.12.221.1 to 52.12.221.25452.12.221.255254
22352.12.222.0/2452.12.222.1 to 52.12.222.25452.12.222.255254
22452.12.223.0/2452.12.223.1 to 52.12.223.25452.12.223.255254
22552.12.224.0/2452.12.224.1 to 52.12.224.25452.12.224.255254
22652.12.225.0/2452.12.225.1 to 52.12.225.25452.12.225.255254
22752.12.226.0/2452.12.226.1 to 52.12.226.25452.12.226.255254
22852.12.227.0/2452.12.227.1 to 52.12.227.25452.12.227.255254
22952.12.228.0/2452.12.228.1 to 52.12.228.25452.12.228.255254
23052.12.229.0/2452.12.229.1 to 52.12.229.25452.12.229.255254
23152.12.230.0/2452.12.230.1 to 52.12.230.25452.12.230.255254
23252.12.231.0/2452.12.231.1 to 52.12.231.25452.12.231.255254
23352.12.232.0/2452.12.232.1 to 52.12.232.25452.12.232.255254
23452.12.233.0/2452.12.233.1 to 52.12.233.25452.12.233.255254
23552.12.234.0/2452.12.234.1 to 52.12.234.25452.12.234.255254
23652.12.235.0/2452.12.235.1 to 52.12.235.25452.12.235.255254
23752.12.236.0/2452.12.236.1 to 52.12.236.25452.12.236.255254
23852.12.237.0/2452.12.237.1 to 52.12.237.25452.12.237.255254
23952.12.238.0/2452.12.238.1 to 52.12.238.25452.12.238.255254
24052.12.239.0/2452.12.239.1 to 52.12.239.25452.12.239.255254
24152.12.240.0/2452.12.240.1 to 52.12.240.25452.12.240.255254
24252.12.241.0/2452.12.241.1 to 52.12.241.25452.12.241.255254
24352.12.242.0/2452.12.242.1 to 52.12.242.25452.12.242.255254
24452.12.243.0/2452.12.243.1 to 52.12.243.25452.12.243.255254
24552.12.244.0/2452.12.244.1 to 52.12.244.25452.12.244.255254
24652.12.245.0/2452.12.245.1 to 52.12.245.25452.12.245.255254
24752.12.246.0/2452.12.246.1 to 52.12.246.25452.12.246.255254
24852.12.247.0/2452.12.247.1 to 52.12.247.25452.12.247.255254
24952.12.248.0/2452.12.248.1 to 52.12.248.25452.12.248.255254
25052.12.249.0/2452.12.249.1 to 52.12.249.25452.12.249.255254
25152.12.250.0/2452.12.250.1 to 52.12.250.25452.12.250.255254
25252.12.251.0/2452.12.251.1 to 52.12.251.25452.12.251.255254
25352.12.252.0/2452.12.252.1 to 52.12.252.25452.12.252.255254
25452.12.253.0/2452.12.253.1 to 52.12.253.25452.12.253.255254
25552.12.254.0/2452.12.254.1 to 52.12.254.25452.12.254.255254
25652.12.255.0/2452.12.255.1 to 52.12.255.25452.12.255.255254

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.