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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.

Network61.72.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
61.72.0.0
Broadcast address
61.73.255.255
First usable
61.72.0.1
Last usable
61.73.255.254
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 3D480000 · Integer 1028128768 to 1028259839
Reverse DNS zones
72.61.in-addr.arpa
73.61.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
Address00111101.01001000.00000000.0000000061.72.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00111101.01001000.00000000.0000000061.72.0.0
Broadcast00111101.01001001.11111111.1111111161.73.255.255
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)

61.72.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
161.72.0.0/2461.72.0.1 to 61.72.0.25461.72.0.255254
261.72.1.0/2461.72.1.1 to 61.72.1.25461.72.1.255254
361.72.2.0/2461.72.2.1 to 61.72.2.25461.72.2.255254
461.72.3.0/2461.72.3.1 to 61.72.3.25461.72.3.255254
561.72.4.0/2461.72.4.1 to 61.72.4.25461.72.4.255254
661.72.5.0/2461.72.5.1 to 61.72.5.25461.72.5.255254
761.72.6.0/2461.72.6.1 to 61.72.6.25461.72.6.255254
861.72.7.0/2461.72.7.1 to 61.72.7.25461.72.7.255254
961.72.8.0/2461.72.8.1 to 61.72.8.25461.72.8.255254
1061.72.9.0/2461.72.9.1 to 61.72.9.25461.72.9.255254
1161.72.10.0/2461.72.10.1 to 61.72.10.25461.72.10.255254
1261.72.11.0/2461.72.11.1 to 61.72.11.25461.72.11.255254
1361.72.12.0/2461.72.12.1 to 61.72.12.25461.72.12.255254
1461.72.13.0/2461.72.13.1 to 61.72.13.25461.72.13.255254
1561.72.14.0/2461.72.14.1 to 61.72.14.25461.72.14.255254
1661.72.15.0/2461.72.15.1 to 61.72.15.25461.72.15.255254
1761.72.16.0/2461.72.16.1 to 61.72.16.25461.72.16.255254
1861.72.17.0/2461.72.17.1 to 61.72.17.25461.72.17.255254
1961.72.18.0/2461.72.18.1 to 61.72.18.25461.72.18.255254
2061.72.19.0/2461.72.19.1 to 61.72.19.25461.72.19.255254
2161.72.20.0/2461.72.20.1 to 61.72.20.25461.72.20.255254
2261.72.21.0/2461.72.21.1 to 61.72.21.25461.72.21.255254
2361.72.22.0/2461.72.22.1 to 61.72.22.25461.72.22.255254
2461.72.23.0/2461.72.23.1 to 61.72.23.25461.72.23.255254
2561.72.24.0/2461.72.24.1 to 61.72.24.25461.72.24.255254
2661.72.25.0/2461.72.25.1 to 61.72.25.25461.72.25.255254
2761.72.26.0/2461.72.26.1 to 61.72.26.25461.72.26.255254
2861.72.27.0/2461.72.27.1 to 61.72.27.25461.72.27.255254
2961.72.28.0/2461.72.28.1 to 61.72.28.25461.72.28.255254
3061.72.29.0/2461.72.29.1 to 61.72.29.25461.72.29.255254
3161.72.30.0/2461.72.30.1 to 61.72.30.25461.72.30.255254
3261.72.31.0/2461.72.31.1 to 61.72.31.25461.72.31.255254
3361.72.32.0/2461.72.32.1 to 61.72.32.25461.72.32.255254
3461.72.33.0/2461.72.33.1 to 61.72.33.25461.72.33.255254
3561.72.34.0/2461.72.34.1 to 61.72.34.25461.72.34.255254
3661.72.35.0/2461.72.35.1 to 61.72.35.25461.72.35.255254
3761.72.36.0/2461.72.36.1 to 61.72.36.25461.72.36.255254
3861.72.37.0/2461.72.37.1 to 61.72.37.25461.72.37.255254
3961.72.38.0/2461.72.38.1 to 61.72.38.25461.72.38.255254
4061.72.39.0/2461.72.39.1 to 61.72.39.25461.72.39.255254
4161.72.40.0/2461.72.40.1 to 61.72.40.25461.72.40.255254
4261.72.41.0/2461.72.41.1 to 61.72.41.25461.72.41.255254
4361.72.42.0/2461.72.42.1 to 61.72.42.25461.72.42.255254
4461.72.43.0/2461.72.43.1 to 61.72.43.25461.72.43.255254
4561.72.44.0/2461.72.44.1 to 61.72.44.25461.72.44.255254
4661.72.45.0/2461.72.45.1 to 61.72.45.25461.72.45.255254
4761.72.46.0/2461.72.46.1 to 61.72.46.25461.72.46.255254
4861.72.47.0/2461.72.47.1 to 61.72.47.25461.72.47.255254
4961.72.48.0/2461.72.48.1 to 61.72.48.25461.72.48.255254
5061.72.49.0/2461.72.49.1 to 61.72.49.25461.72.49.255254
5161.72.50.0/2461.72.50.1 to 61.72.50.25461.72.50.255254
5261.72.51.0/2461.72.51.1 to 61.72.51.25461.72.51.255254
5361.72.52.0/2461.72.52.1 to 61.72.52.25461.72.52.255254
5461.72.53.0/2461.72.53.1 to 61.72.53.25461.72.53.255254
5561.72.54.0/2461.72.54.1 to 61.72.54.25461.72.54.255254
5661.72.55.0/2461.72.55.1 to 61.72.55.25461.72.55.255254
5761.72.56.0/2461.72.56.1 to 61.72.56.25461.72.56.255254
5861.72.57.0/2461.72.57.1 to 61.72.57.25461.72.57.255254
5961.72.58.0/2461.72.58.1 to 61.72.58.25461.72.58.255254
6061.72.59.0/2461.72.59.1 to 61.72.59.25461.72.59.255254
6161.72.60.0/2461.72.60.1 to 61.72.60.25461.72.60.255254
6261.72.61.0/2461.72.61.1 to 61.72.61.25461.72.61.255254
6361.72.62.0/2461.72.62.1 to 61.72.62.25461.72.62.255254
6461.72.63.0/2461.72.63.1 to 61.72.63.25461.72.63.255254
6561.72.64.0/2461.72.64.1 to 61.72.64.25461.72.64.255254
6661.72.65.0/2461.72.65.1 to 61.72.65.25461.72.65.255254
6761.72.66.0/2461.72.66.1 to 61.72.66.25461.72.66.255254
6861.72.67.0/2461.72.67.1 to 61.72.67.25461.72.67.255254
6961.72.68.0/2461.72.68.1 to 61.72.68.25461.72.68.255254
7061.72.69.0/2461.72.69.1 to 61.72.69.25461.72.69.255254
7161.72.70.0/2461.72.70.1 to 61.72.70.25461.72.70.255254
7261.72.71.0/2461.72.71.1 to 61.72.71.25461.72.71.255254
7361.72.72.0/2461.72.72.1 to 61.72.72.25461.72.72.255254
7461.72.73.0/2461.72.73.1 to 61.72.73.25461.72.73.255254
7561.72.74.0/2461.72.74.1 to 61.72.74.25461.72.74.255254
7661.72.75.0/2461.72.75.1 to 61.72.75.25461.72.75.255254
7761.72.76.0/2461.72.76.1 to 61.72.76.25461.72.76.255254
7861.72.77.0/2461.72.77.1 to 61.72.77.25461.72.77.255254
7961.72.78.0/2461.72.78.1 to 61.72.78.25461.72.78.255254
8061.72.79.0/2461.72.79.1 to 61.72.79.25461.72.79.255254
8161.72.80.0/2461.72.80.1 to 61.72.80.25461.72.80.255254
8261.72.81.0/2461.72.81.1 to 61.72.81.25461.72.81.255254
8361.72.82.0/2461.72.82.1 to 61.72.82.25461.72.82.255254
8461.72.83.0/2461.72.83.1 to 61.72.83.25461.72.83.255254
8561.72.84.0/2461.72.84.1 to 61.72.84.25461.72.84.255254
8661.72.85.0/2461.72.85.1 to 61.72.85.25461.72.85.255254
8761.72.86.0/2461.72.86.1 to 61.72.86.25461.72.86.255254
8861.72.87.0/2461.72.87.1 to 61.72.87.25461.72.87.255254
8961.72.88.0/2461.72.88.1 to 61.72.88.25461.72.88.255254
9061.72.89.0/2461.72.89.1 to 61.72.89.25461.72.89.255254
9161.72.90.0/2461.72.90.1 to 61.72.90.25461.72.90.255254
9261.72.91.0/2461.72.91.1 to 61.72.91.25461.72.91.255254
9361.72.92.0/2461.72.92.1 to 61.72.92.25461.72.92.255254
9461.72.93.0/2461.72.93.1 to 61.72.93.25461.72.93.255254
9561.72.94.0/2461.72.94.1 to 61.72.94.25461.72.94.255254
9661.72.95.0/2461.72.95.1 to 61.72.95.25461.72.95.255254
9761.72.96.0/2461.72.96.1 to 61.72.96.25461.72.96.255254
9861.72.97.0/2461.72.97.1 to 61.72.97.25461.72.97.255254
9961.72.98.0/2461.72.98.1 to 61.72.98.25461.72.98.255254
10061.72.99.0/2461.72.99.1 to 61.72.99.25461.72.99.255254
10161.72.100.0/2461.72.100.1 to 61.72.100.25461.72.100.255254
10261.72.101.0/2461.72.101.1 to 61.72.101.25461.72.101.255254
10361.72.102.0/2461.72.102.1 to 61.72.102.25461.72.102.255254
10461.72.103.0/2461.72.103.1 to 61.72.103.25461.72.103.255254
10561.72.104.0/2461.72.104.1 to 61.72.104.25461.72.104.255254
10661.72.105.0/2461.72.105.1 to 61.72.105.25461.72.105.255254
10761.72.106.0/2461.72.106.1 to 61.72.106.25461.72.106.255254
10861.72.107.0/2461.72.107.1 to 61.72.107.25461.72.107.255254
10961.72.108.0/2461.72.108.1 to 61.72.108.25461.72.108.255254
11061.72.109.0/2461.72.109.1 to 61.72.109.25461.72.109.255254
11161.72.110.0/2461.72.110.1 to 61.72.110.25461.72.110.255254
11261.72.111.0/2461.72.111.1 to 61.72.111.25461.72.111.255254
11361.72.112.0/2461.72.112.1 to 61.72.112.25461.72.112.255254
11461.72.113.0/2461.72.113.1 to 61.72.113.25461.72.113.255254
11561.72.114.0/2461.72.114.1 to 61.72.114.25461.72.114.255254
11661.72.115.0/2461.72.115.1 to 61.72.115.25461.72.115.255254
11761.72.116.0/2461.72.116.1 to 61.72.116.25461.72.116.255254
11861.72.117.0/2461.72.117.1 to 61.72.117.25461.72.117.255254
11961.72.118.0/2461.72.118.1 to 61.72.118.25461.72.118.255254
12061.72.119.0/2461.72.119.1 to 61.72.119.25461.72.119.255254
12161.72.120.0/2461.72.120.1 to 61.72.120.25461.72.120.255254
12261.72.121.0/2461.72.121.1 to 61.72.121.25461.72.121.255254
12361.72.122.0/2461.72.122.1 to 61.72.122.25461.72.122.255254
12461.72.123.0/2461.72.123.1 to 61.72.123.25461.72.123.255254
12561.72.124.0/2461.72.124.1 to 61.72.124.25461.72.124.255254
12661.72.125.0/2461.72.125.1 to 61.72.125.25461.72.125.255254
12761.72.126.0/2461.72.126.1 to 61.72.126.25461.72.126.255254
12861.72.127.0/2461.72.127.1 to 61.72.127.25461.72.127.255254
12961.72.128.0/2461.72.128.1 to 61.72.128.25461.72.128.255254
13061.72.129.0/2461.72.129.1 to 61.72.129.25461.72.129.255254
13161.72.130.0/2461.72.130.1 to 61.72.130.25461.72.130.255254
13261.72.131.0/2461.72.131.1 to 61.72.131.25461.72.131.255254
13361.72.132.0/2461.72.132.1 to 61.72.132.25461.72.132.255254
13461.72.133.0/2461.72.133.1 to 61.72.133.25461.72.133.255254
13561.72.134.0/2461.72.134.1 to 61.72.134.25461.72.134.255254
13661.72.135.0/2461.72.135.1 to 61.72.135.25461.72.135.255254
13761.72.136.0/2461.72.136.1 to 61.72.136.25461.72.136.255254
13861.72.137.0/2461.72.137.1 to 61.72.137.25461.72.137.255254
13961.72.138.0/2461.72.138.1 to 61.72.138.25461.72.138.255254
14061.72.139.0/2461.72.139.1 to 61.72.139.25461.72.139.255254
14161.72.140.0/2461.72.140.1 to 61.72.140.25461.72.140.255254
14261.72.141.0/2461.72.141.1 to 61.72.141.25461.72.141.255254
14361.72.142.0/2461.72.142.1 to 61.72.142.25461.72.142.255254
14461.72.143.0/2461.72.143.1 to 61.72.143.25461.72.143.255254
14561.72.144.0/2461.72.144.1 to 61.72.144.25461.72.144.255254
14661.72.145.0/2461.72.145.1 to 61.72.145.25461.72.145.255254
14761.72.146.0/2461.72.146.1 to 61.72.146.25461.72.146.255254
14861.72.147.0/2461.72.147.1 to 61.72.147.25461.72.147.255254
14961.72.148.0/2461.72.148.1 to 61.72.148.25461.72.148.255254
15061.72.149.0/2461.72.149.1 to 61.72.149.25461.72.149.255254
15161.72.150.0/2461.72.150.1 to 61.72.150.25461.72.150.255254
15261.72.151.0/2461.72.151.1 to 61.72.151.25461.72.151.255254
15361.72.152.0/2461.72.152.1 to 61.72.152.25461.72.152.255254
15461.72.153.0/2461.72.153.1 to 61.72.153.25461.72.153.255254
15561.72.154.0/2461.72.154.1 to 61.72.154.25461.72.154.255254
15661.72.155.0/2461.72.155.1 to 61.72.155.25461.72.155.255254
15761.72.156.0/2461.72.156.1 to 61.72.156.25461.72.156.255254
15861.72.157.0/2461.72.157.1 to 61.72.157.25461.72.157.255254
15961.72.158.0/2461.72.158.1 to 61.72.158.25461.72.158.255254
16061.72.159.0/2461.72.159.1 to 61.72.159.25461.72.159.255254
16161.72.160.0/2461.72.160.1 to 61.72.160.25461.72.160.255254
16261.72.161.0/2461.72.161.1 to 61.72.161.25461.72.161.255254
16361.72.162.0/2461.72.162.1 to 61.72.162.25461.72.162.255254
16461.72.163.0/2461.72.163.1 to 61.72.163.25461.72.163.255254
16561.72.164.0/2461.72.164.1 to 61.72.164.25461.72.164.255254
16661.72.165.0/2461.72.165.1 to 61.72.165.25461.72.165.255254
16761.72.166.0/2461.72.166.1 to 61.72.166.25461.72.166.255254
16861.72.167.0/2461.72.167.1 to 61.72.167.25461.72.167.255254
16961.72.168.0/2461.72.168.1 to 61.72.168.25461.72.168.255254
17061.72.169.0/2461.72.169.1 to 61.72.169.25461.72.169.255254
17161.72.170.0/2461.72.170.1 to 61.72.170.25461.72.170.255254
17261.72.171.0/2461.72.171.1 to 61.72.171.25461.72.171.255254
17361.72.172.0/2461.72.172.1 to 61.72.172.25461.72.172.255254
17461.72.173.0/2461.72.173.1 to 61.72.173.25461.72.173.255254
17561.72.174.0/2461.72.174.1 to 61.72.174.25461.72.174.255254
17661.72.175.0/2461.72.175.1 to 61.72.175.25461.72.175.255254
17761.72.176.0/2461.72.176.1 to 61.72.176.25461.72.176.255254
17861.72.177.0/2461.72.177.1 to 61.72.177.25461.72.177.255254
17961.72.178.0/2461.72.178.1 to 61.72.178.25461.72.178.255254
18061.72.179.0/2461.72.179.1 to 61.72.179.25461.72.179.255254
18161.72.180.0/2461.72.180.1 to 61.72.180.25461.72.180.255254
18261.72.181.0/2461.72.181.1 to 61.72.181.25461.72.181.255254
18361.72.182.0/2461.72.182.1 to 61.72.182.25461.72.182.255254
18461.72.183.0/2461.72.183.1 to 61.72.183.25461.72.183.255254
18561.72.184.0/2461.72.184.1 to 61.72.184.25461.72.184.255254
18661.72.185.0/2461.72.185.1 to 61.72.185.25461.72.185.255254
18761.72.186.0/2461.72.186.1 to 61.72.186.25461.72.186.255254
18861.72.187.0/2461.72.187.1 to 61.72.187.25461.72.187.255254
18961.72.188.0/2461.72.188.1 to 61.72.188.25461.72.188.255254
19061.72.189.0/2461.72.189.1 to 61.72.189.25461.72.189.255254
19161.72.190.0/2461.72.190.1 to 61.72.190.25461.72.190.255254
19261.72.191.0/2461.72.191.1 to 61.72.191.25461.72.191.255254
19361.72.192.0/2461.72.192.1 to 61.72.192.25461.72.192.255254
19461.72.193.0/2461.72.193.1 to 61.72.193.25461.72.193.255254
19561.72.194.0/2461.72.194.1 to 61.72.194.25461.72.194.255254
19661.72.195.0/2461.72.195.1 to 61.72.195.25461.72.195.255254
19761.72.196.0/2461.72.196.1 to 61.72.196.25461.72.196.255254
19861.72.197.0/2461.72.197.1 to 61.72.197.25461.72.197.255254
19961.72.198.0/2461.72.198.1 to 61.72.198.25461.72.198.255254
20061.72.199.0/2461.72.199.1 to 61.72.199.25461.72.199.255254
20161.72.200.0/2461.72.200.1 to 61.72.200.25461.72.200.255254
20261.72.201.0/2461.72.201.1 to 61.72.201.25461.72.201.255254
20361.72.202.0/2461.72.202.1 to 61.72.202.25461.72.202.255254
20461.72.203.0/2461.72.203.1 to 61.72.203.25461.72.203.255254
20561.72.204.0/2461.72.204.1 to 61.72.204.25461.72.204.255254
20661.72.205.0/2461.72.205.1 to 61.72.205.25461.72.205.255254
20761.72.206.0/2461.72.206.1 to 61.72.206.25461.72.206.255254
20861.72.207.0/2461.72.207.1 to 61.72.207.25461.72.207.255254
20961.72.208.0/2461.72.208.1 to 61.72.208.25461.72.208.255254
21061.72.209.0/2461.72.209.1 to 61.72.209.25461.72.209.255254
21161.72.210.0/2461.72.210.1 to 61.72.210.25461.72.210.255254
21261.72.211.0/2461.72.211.1 to 61.72.211.25461.72.211.255254
21361.72.212.0/2461.72.212.1 to 61.72.212.25461.72.212.255254
21461.72.213.0/2461.72.213.1 to 61.72.213.25461.72.213.255254
21561.72.214.0/2461.72.214.1 to 61.72.214.25461.72.214.255254
21661.72.215.0/2461.72.215.1 to 61.72.215.25461.72.215.255254
21761.72.216.0/2461.72.216.1 to 61.72.216.25461.72.216.255254
21861.72.217.0/2461.72.217.1 to 61.72.217.25461.72.217.255254
21961.72.218.0/2461.72.218.1 to 61.72.218.25461.72.218.255254
22061.72.219.0/2461.72.219.1 to 61.72.219.25461.72.219.255254
22161.72.220.0/2461.72.220.1 to 61.72.220.25461.72.220.255254
22261.72.221.0/2461.72.221.1 to 61.72.221.25461.72.221.255254
22361.72.222.0/2461.72.222.1 to 61.72.222.25461.72.222.255254
22461.72.223.0/2461.72.223.1 to 61.72.223.25461.72.223.255254
22561.72.224.0/2461.72.224.1 to 61.72.224.25461.72.224.255254
22661.72.225.0/2461.72.225.1 to 61.72.225.25461.72.225.255254
22761.72.226.0/2461.72.226.1 to 61.72.226.25461.72.226.255254
22861.72.227.0/2461.72.227.1 to 61.72.227.25461.72.227.255254
22961.72.228.0/2461.72.228.1 to 61.72.228.25461.72.228.255254
23061.72.229.0/2461.72.229.1 to 61.72.229.25461.72.229.255254
23161.72.230.0/2461.72.230.1 to 61.72.230.25461.72.230.255254
23261.72.231.0/2461.72.231.1 to 61.72.231.25461.72.231.255254
23361.72.232.0/2461.72.232.1 to 61.72.232.25461.72.232.255254
23461.72.233.0/2461.72.233.1 to 61.72.233.25461.72.233.255254
23561.72.234.0/2461.72.234.1 to 61.72.234.25461.72.234.255254
23661.72.235.0/2461.72.235.1 to 61.72.235.25461.72.235.255254
23761.72.236.0/2461.72.236.1 to 61.72.236.25461.72.236.255254
23861.72.237.0/2461.72.237.1 to 61.72.237.25461.72.237.255254
23961.72.238.0/2461.72.238.1 to 61.72.238.25461.72.238.255254
24061.72.239.0/2461.72.239.1 to 61.72.239.25461.72.239.255254
24161.72.240.0/2461.72.240.1 to 61.72.240.25461.72.240.255254
24261.72.241.0/2461.72.241.1 to 61.72.241.25461.72.241.255254
24361.72.242.0/2461.72.242.1 to 61.72.242.25461.72.242.255254
24461.72.243.0/2461.72.243.1 to 61.72.243.25461.72.243.255254
24561.72.244.0/2461.72.244.1 to 61.72.244.25461.72.244.255254
24661.72.245.0/2461.72.245.1 to 61.72.245.25461.72.245.255254
24761.72.246.0/2461.72.246.1 to 61.72.246.25461.72.246.255254
24861.72.247.0/2461.72.247.1 to 61.72.247.25461.72.247.255254
24961.72.248.0/2461.72.248.1 to 61.72.248.25461.72.248.255254
25061.72.249.0/2461.72.249.1 to 61.72.249.25461.72.249.255254
25161.72.250.0/2461.72.250.1 to 61.72.250.25461.72.250.255254
25261.72.251.0/2461.72.251.1 to 61.72.251.25461.72.251.255254
25361.72.252.0/2461.72.252.1 to 61.72.252.25461.72.252.255254
25461.72.253.0/2461.72.253.1 to 61.72.253.25461.72.253.255254
25561.72.254.0/2461.72.254.1 to 61.72.254.25461.72.254.255254
25661.72.255.0/2461.72.255.1 to 61.72.255.25461.72.255.255254

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.