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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.

Network45.78.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
45.78.0.0
Broadcast address
45.79.255.255
First usable
45.78.0.1
Last usable
45.79.255.254
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 2D4E0000 · Integer 760086528 to 760217599
Reverse DNS zones
78.45.in-addr.arpa
79.45.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
Address00101101.01001110.00000000.0000000045.78.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00101101.01001110.00000000.0000000045.78.0.0
Broadcast00101101.01001111.11111111.1111111145.79.255.255
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)

45.78.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
145.78.0.0/2445.78.0.1 to 45.78.0.25445.78.0.255254
245.78.1.0/2445.78.1.1 to 45.78.1.25445.78.1.255254
345.78.2.0/2445.78.2.1 to 45.78.2.25445.78.2.255254
445.78.3.0/2445.78.3.1 to 45.78.3.25445.78.3.255254
545.78.4.0/2445.78.4.1 to 45.78.4.25445.78.4.255254
645.78.5.0/2445.78.5.1 to 45.78.5.25445.78.5.255254
745.78.6.0/2445.78.6.1 to 45.78.6.25445.78.6.255254
845.78.7.0/2445.78.7.1 to 45.78.7.25445.78.7.255254
945.78.8.0/2445.78.8.1 to 45.78.8.25445.78.8.255254
1045.78.9.0/2445.78.9.1 to 45.78.9.25445.78.9.255254
1145.78.10.0/2445.78.10.1 to 45.78.10.25445.78.10.255254
1245.78.11.0/2445.78.11.1 to 45.78.11.25445.78.11.255254
1345.78.12.0/2445.78.12.1 to 45.78.12.25445.78.12.255254
1445.78.13.0/2445.78.13.1 to 45.78.13.25445.78.13.255254
1545.78.14.0/2445.78.14.1 to 45.78.14.25445.78.14.255254
1645.78.15.0/2445.78.15.1 to 45.78.15.25445.78.15.255254
1745.78.16.0/2445.78.16.1 to 45.78.16.25445.78.16.255254
1845.78.17.0/2445.78.17.1 to 45.78.17.25445.78.17.255254
1945.78.18.0/2445.78.18.1 to 45.78.18.25445.78.18.255254
2045.78.19.0/2445.78.19.1 to 45.78.19.25445.78.19.255254
2145.78.20.0/2445.78.20.1 to 45.78.20.25445.78.20.255254
2245.78.21.0/2445.78.21.1 to 45.78.21.25445.78.21.255254
2345.78.22.0/2445.78.22.1 to 45.78.22.25445.78.22.255254
2445.78.23.0/2445.78.23.1 to 45.78.23.25445.78.23.255254
2545.78.24.0/2445.78.24.1 to 45.78.24.25445.78.24.255254
2645.78.25.0/2445.78.25.1 to 45.78.25.25445.78.25.255254
2745.78.26.0/2445.78.26.1 to 45.78.26.25445.78.26.255254
2845.78.27.0/2445.78.27.1 to 45.78.27.25445.78.27.255254
2945.78.28.0/2445.78.28.1 to 45.78.28.25445.78.28.255254
3045.78.29.0/2445.78.29.1 to 45.78.29.25445.78.29.255254
3145.78.30.0/2445.78.30.1 to 45.78.30.25445.78.30.255254
3245.78.31.0/2445.78.31.1 to 45.78.31.25445.78.31.255254
3345.78.32.0/2445.78.32.1 to 45.78.32.25445.78.32.255254
3445.78.33.0/2445.78.33.1 to 45.78.33.25445.78.33.255254
3545.78.34.0/2445.78.34.1 to 45.78.34.25445.78.34.255254
3645.78.35.0/2445.78.35.1 to 45.78.35.25445.78.35.255254
3745.78.36.0/2445.78.36.1 to 45.78.36.25445.78.36.255254
3845.78.37.0/2445.78.37.1 to 45.78.37.25445.78.37.255254
3945.78.38.0/2445.78.38.1 to 45.78.38.25445.78.38.255254
4045.78.39.0/2445.78.39.1 to 45.78.39.25445.78.39.255254
4145.78.40.0/2445.78.40.1 to 45.78.40.25445.78.40.255254
4245.78.41.0/2445.78.41.1 to 45.78.41.25445.78.41.255254
4345.78.42.0/2445.78.42.1 to 45.78.42.25445.78.42.255254
4445.78.43.0/2445.78.43.1 to 45.78.43.25445.78.43.255254
4545.78.44.0/2445.78.44.1 to 45.78.44.25445.78.44.255254
4645.78.45.0/2445.78.45.1 to 45.78.45.25445.78.45.255254
4745.78.46.0/2445.78.46.1 to 45.78.46.25445.78.46.255254
4845.78.47.0/2445.78.47.1 to 45.78.47.25445.78.47.255254
4945.78.48.0/2445.78.48.1 to 45.78.48.25445.78.48.255254
5045.78.49.0/2445.78.49.1 to 45.78.49.25445.78.49.255254
5145.78.50.0/2445.78.50.1 to 45.78.50.25445.78.50.255254
5245.78.51.0/2445.78.51.1 to 45.78.51.25445.78.51.255254
5345.78.52.0/2445.78.52.1 to 45.78.52.25445.78.52.255254
5445.78.53.0/2445.78.53.1 to 45.78.53.25445.78.53.255254
5545.78.54.0/2445.78.54.1 to 45.78.54.25445.78.54.255254
5645.78.55.0/2445.78.55.1 to 45.78.55.25445.78.55.255254
5745.78.56.0/2445.78.56.1 to 45.78.56.25445.78.56.255254
5845.78.57.0/2445.78.57.1 to 45.78.57.25445.78.57.255254
5945.78.58.0/2445.78.58.1 to 45.78.58.25445.78.58.255254
6045.78.59.0/2445.78.59.1 to 45.78.59.25445.78.59.255254
6145.78.60.0/2445.78.60.1 to 45.78.60.25445.78.60.255254
6245.78.61.0/2445.78.61.1 to 45.78.61.25445.78.61.255254
6345.78.62.0/2445.78.62.1 to 45.78.62.25445.78.62.255254
6445.78.63.0/2445.78.63.1 to 45.78.63.25445.78.63.255254
6545.78.64.0/2445.78.64.1 to 45.78.64.25445.78.64.255254
6645.78.65.0/2445.78.65.1 to 45.78.65.25445.78.65.255254
6745.78.66.0/2445.78.66.1 to 45.78.66.25445.78.66.255254
6845.78.67.0/2445.78.67.1 to 45.78.67.25445.78.67.255254
6945.78.68.0/2445.78.68.1 to 45.78.68.25445.78.68.255254
7045.78.69.0/2445.78.69.1 to 45.78.69.25445.78.69.255254
7145.78.70.0/2445.78.70.1 to 45.78.70.25445.78.70.255254
7245.78.71.0/2445.78.71.1 to 45.78.71.25445.78.71.255254
7345.78.72.0/2445.78.72.1 to 45.78.72.25445.78.72.255254
7445.78.73.0/2445.78.73.1 to 45.78.73.25445.78.73.255254
7545.78.74.0/2445.78.74.1 to 45.78.74.25445.78.74.255254
7645.78.75.0/2445.78.75.1 to 45.78.75.25445.78.75.255254
7745.78.76.0/2445.78.76.1 to 45.78.76.25445.78.76.255254
7845.78.77.0/2445.78.77.1 to 45.78.77.25445.78.77.255254
7945.78.78.0/2445.78.78.1 to 45.78.78.25445.78.78.255254
8045.78.79.0/2445.78.79.1 to 45.78.79.25445.78.79.255254
8145.78.80.0/2445.78.80.1 to 45.78.80.25445.78.80.255254
8245.78.81.0/2445.78.81.1 to 45.78.81.25445.78.81.255254
8345.78.82.0/2445.78.82.1 to 45.78.82.25445.78.82.255254
8445.78.83.0/2445.78.83.1 to 45.78.83.25445.78.83.255254
8545.78.84.0/2445.78.84.1 to 45.78.84.25445.78.84.255254
8645.78.85.0/2445.78.85.1 to 45.78.85.25445.78.85.255254
8745.78.86.0/2445.78.86.1 to 45.78.86.25445.78.86.255254
8845.78.87.0/2445.78.87.1 to 45.78.87.25445.78.87.255254
8945.78.88.0/2445.78.88.1 to 45.78.88.25445.78.88.255254
9045.78.89.0/2445.78.89.1 to 45.78.89.25445.78.89.255254
9145.78.90.0/2445.78.90.1 to 45.78.90.25445.78.90.255254
9245.78.91.0/2445.78.91.1 to 45.78.91.25445.78.91.255254
9345.78.92.0/2445.78.92.1 to 45.78.92.25445.78.92.255254
9445.78.93.0/2445.78.93.1 to 45.78.93.25445.78.93.255254
9545.78.94.0/2445.78.94.1 to 45.78.94.25445.78.94.255254
9645.78.95.0/2445.78.95.1 to 45.78.95.25445.78.95.255254
9745.78.96.0/2445.78.96.1 to 45.78.96.25445.78.96.255254
9845.78.97.0/2445.78.97.1 to 45.78.97.25445.78.97.255254
9945.78.98.0/2445.78.98.1 to 45.78.98.25445.78.98.255254
10045.78.99.0/2445.78.99.1 to 45.78.99.25445.78.99.255254
10145.78.100.0/2445.78.100.1 to 45.78.100.25445.78.100.255254
10245.78.101.0/2445.78.101.1 to 45.78.101.25445.78.101.255254
10345.78.102.0/2445.78.102.1 to 45.78.102.25445.78.102.255254
10445.78.103.0/2445.78.103.1 to 45.78.103.25445.78.103.255254
10545.78.104.0/2445.78.104.1 to 45.78.104.25445.78.104.255254
10645.78.105.0/2445.78.105.1 to 45.78.105.25445.78.105.255254
10745.78.106.0/2445.78.106.1 to 45.78.106.25445.78.106.255254
10845.78.107.0/2445.78.107.1 to 45.78.107.25445.78.107.255254
10945.78.108.0/2445.78.108.1 to 45.78.108.25445.78.108.255254
11045.78.109.0/2445.78.109.1 to 45.78.109.25445.78.109.255254
11145.78.110.0/2445.78.110.1 to 45.78.110.25445.78.110.255254
11245.78.111.0/2445.78.111.1 to 45.78.111.25445.78.111.255254
11345.78.112.0/2445.78.112.1 to 45.78.112.25445.78.112.255254
11445.78.113.0/2445.78.113.1 to 45.78.113.25445.78.113.255254
11545.78.114.0/2445.78.114.1 to 45.78.114.25445.78.114.255254
11645.78.115.0/2445.78.115.1 to 45.78.115.25445.78.115.255254
11745.78.116.0/2445.78.116.1 to 45.78.116.25445.78.116.255254
11845.78.117.0/2445.78.117.1 to 45.78.117.25445.78.117.255254
11945.78.118.0/2445.78.118.1 to 45.78.118.25445.78.118.255254
12045.78.119.0/2445.78.119.1 to 45.78.119.25445.78.119.255254
12145.78.120.0/2445.78.120.1 to 45.78.120.25445.78.120.255254
12245.78.121.0/2445.78.121.1 to 45.78.121.25445.78.121.255254
12345.78.122.0/2445.78.122.1 to 45.78.122.25445.78.122.255254
12445.78.123.0/2445.78.123.1 to 45.78.123.25445.78.123.255254
12545.78.124.0/2445.78.124.1 to 45.78.124.25445.78.124.255254
12645.78.125.0/2445.78.125.1 to 45.78.125.25445.78.125.255254
12745.78.126.0/2445.78.126.1 to 45.78.126.25445.78.126.255254
12845.78.127.0/2445.78.127.1 to 45.78.127.25445.78.127.255254
12945.78.128.0/2445.78.128.1 to 45.78.128.25445.78.128.255254
13045.78.129.0/2445.78.129.1 to 45.78.129.25445.78.129.255254
13145.78.130.0/2445.78.130.1 to 45.78.130.25445.78.130.255254
13245.78.131.0/2445.78.131.1 to 45.78.131.25445.78.131.255254
13345.78.132.0/2445.78.132.1 to 45.78.132.25445.78.132.255254
13445.78.133.0/2445.78.133.1 to 45.78.133.25445.78.133.255254
13545.78.134.0/2445.78.134.1 to 45.78.134.25445.78.134.255254
13645.78.135.0/2445.78.135.1 to 45.78.135.25445.78.135.255254
13745.78.136.0/2445.78.136.1 to 45.78.136.25445.78.136.255254
13845.78.137.0/2445.78.137.1 to 45.78.137.25445.78.137.255254
13945.78.138.0/2445.78.138.1 to 45.78.138.25445.78.138.255254
14045.78.139.0/2445.78.139.1 to 45.78.139.25445.78.139.255254
14145.78.140.0/2445.78.140.1 to 45.78.140.25445.78.140.255254
14245.78.141.0/2445.78.141.1 to 45.78.141.25445.78.141.255254
14345.78.142.0/2445.78.142.1 to 45.78.142.25445.78.142.255254
14445.78.143.0/2445.78.143.1 to 45.78.143.25445.78.143.255254
14545.78.144.0/2445.78.144.1 to 45.78.144.25445.78.144.255254
14645.78.145.0/2445.78.145.1 to 45.78.145.25445.78.145.255254
14745.78.146.0/2445.78.146.1 to 45.78.146.25445.78.146.255254
14845.78.147.0/2445.78.147.1 to 45.78.147.25445.78.147.255254
14945.78.148.0/2445.78.148.1 to 45.78.148.25445.78.148.255254
15045.78.149.0/2445.78.149.1 to 45.78.149.25445.78.149.255254
15145.78.150.0/2445.78.150.1 to 45.78.150.25445.78.150.255254
15245.78.151.0/2445.78.151.1 to 45.78.151.25445.78.151.255254
15345.78.152.0/2445.78.152.1 to 45.78.152.25445.78.152.255254
15445.78.153.0/2445.78.153.1 to 45.78.153.25445.78.153.255254
15545.78.154.0/2445.78.154.1 to 45.78.154.25445.78.154.255254
15645.78.155.0/2445.78.155.1 to 45.78.155.25445.78.155.255254
15745.78.156.0/2445.78.156.1 to 45.78.156.25445.78.156.255254
15845.78.157.0/2445.78.157.1 to 45.78.157.25445.78.157.255254
15945.78.158.0/2445.78.158.1 to 45.78.158.25445.78.158.255254
16045.78.159.0/2445.78.159.1 to 45.78.159.25445.78.159.255254
16145.78.160.0/2445.78.160.1 to 45.78.160.25445.78.160.255254
16245.78.161.0/2445.78.161.1 to 45.78.161.25445.78.161.255254
16345.78.162.0/2445.78.162.1 to 45.78.162.25445.78.162.255254
16445.78.163.0/2445.78.163.1 to 45.78.163.25445.78.163.255254
16545.78.164.0/2445.78.164.1 to 45.78.164.25445.78.164.255254
16645.78.165.0/2445.78.165.1 to 45.78.165.25445.78.165.255254
16745.78.166.0/2445.78.166.1 to 45.78.166.25445.78.166.255254
16845.78.167.0/2445.78.167.1 to 45.78.167.25445.78.167.255254
16945.78.168.0/2445.78.168.1 to 45.78.168.25445.78.168.255254
17045.78.169.0/2445.78.169.1 to 45.78.169.25445.78.169.255254
17145.78.170.0/2445.78.170.1 to 45.78.170.25445.78.170.255254
17245.78.171.0/2445.78.171.1 to 45.78.171.25445.78.171.255254
17345.78.172.0/2445.78.172.1 to 45.78.172.25445.78.172.255254
17445.78.173.0/2445.78.173.1 to 45.78.173.25445.78.173.255254
17545.78.174.0/2445.78.174.1 to 45.78.174.25445.78.174.255254
17645.78.175.0/2445.78.175.1 to 45.78.175.25445.78.175.255254
17745.78.176.0/2445.78.176.1 to 45.78.176.25445.78.176.255254
17845.78.177.0/2445.78.177.1 to 45.78.177.25445.78.177.255254
17945.78.178.0/2445.78.178.1 to 45.78.178.25445.78.178.255254
18045.78.179.0/2445.78.179.1 to 45.78.179.25445.78.179.255254
18145.78.180.0/2445.78.180.1 to 45.78.180.25445.78.180.255254
18245.78.181.0/2445.78.181.1 to 45.78.181.25445.78.181.255254
18345.78.182.0/2445.78.182.1 to 45.78.182.25445.78.182.255254
18445.78.183.0/2445.78.183.1 to 45.78.183.25445.78.183.255254
18545.78.184.0/2445.78.184.1 to 45.78.184.25445.78.184.255254
18645.78.185.0/2445.78.185.1 to 45.78.185.25445.78.185.255254
18745.78.186.0/2445.78.186.1 to 45.78.186.25445.78.186.255254
18845.78.187.0/2445.78.187.1 to 45.78.187.25445.78.187.255254
18945.78.188.0/2445.78.188.1 to 45.78.188.25445.78.188.255254
19045.78.189.0/2445.78.189.1 to 45.78.189.25445.78.189.255254
19145.78.190.0/2445.78.190.1 to 45.78.190.25445.78.190.255254
19245.78.191.0/2445.78.191.1 to 45.78.191.25445.78.191.255254
19345.78.192.0/2445.78.192.1 to 45.78.192.25445.78.192.255254
19445.78.193.0/2445.78.193.1 to 45.78.193.25445.78.193.255254
19545.78.194.0/2445.78.194.1 to 45.78.194.25445.78.194.255254
19645.78.195.0/2445.78.195.1 to 45.78.195.25445.78.195.255254
19745.78.196.0/2445.78.196.1 to 45.78.196.25445.78.196.255254
19845.78.197.0/2445.78.197.1 to 45.78.197.25445.78.197.255254
19945.78.198.0/2445.78.198.1 to 45.78.198.25445.78.198.255254
20045.78.199.0/2445.78.199.1 to 45.78.199.25445.78.199.255254
20145.78.200.0/2445.78.200.1 to 45.78.200.25445.78.200.255254
20245.78.201.0/2445.78.201.1 to 45.78.201.25445.78.201.255254
20345.78.202.0/2445.78.202.1 to 45.78.202.25445.78.202.255254
20445.78.203.0/2445.78.203.1 to 45.78.203.25445.78.203.255254
20545.78.204.0/2445.78.204.1 to 45.78.204.25445.78.204.255254
20645.78.205.0/2445.78.205.1 to 45.78.205.25445.78.205.255254
20745.78.206.0/2445.78.206.1 to 45.78.206.25445.78.206.255254
20845.78.207.0/2445.78.207.1 to 45.78.207.25445.78.207.255254
20945.78.208.0/2445.78.208.1 to 45.78.208.25445.78.208.255254
21045.78.209.0/2445.78.209.1 to 45.78.209.25445.78.209.255254
21145.78.210.0/2445.78.210.1 to 45.78.210.25445.78.210.255254
21245.78.211.0/2445.78.211.1 to 45.78.211.25445.78.211.255254
21345.78.212.0/2445.78.212.1 to 45.78.212.25445.78.212.255254
21445.78.213.0/2445.78.213.1 to 45.78.213.25445.78.213.255254
21545.78.214.0/2445.78.214.1 to 45.78.214.25445.78.214.255254
21645.78.215.0/2445.78.215.1 to 45.78.215.25445.78.215.255254
21745.78.216.0/2445.78.216.1 to 45.78.216.25445.78.216.255254
21845.78.217.0/2445.78.217.1 to 45.78.217.25445.78.217.255254
21945.78.218.0/2445.78.218.1 to 45.78.218.25445.78.218.255254
22045.78.219.0/2445.78.219.1 to 45.78.219.25445.78.219.255254
22145.78.220.0/2445.78.220.1 to 45.78.220.25445.78.220.255254
22245.78.221.0/2445.78.221.1 to 45.78.221.25445.78.221.255254
22345.78.222.0/2445.78.222.1 to 45.78.222.25445.78.222.255254
22445.78.223.0/2445.78.223.1 to 45.78.223.25445.78.223.255254
22545.78.224.0/2445.78.224.1 to 45.78.224.25445.78.224.255254
22645.78.225.0/2445.78.225.1 to 45.78.225.25445.78.225.255254
22745.78.226.0/2445.78.226.1 to 45.78.226.25445.78.226.255254
22845.78.227.0/2445.78.227.1 to 45.78.227.25445.78.227.255254
22945.78.228.0/2445.78.228.1 to 45.78.228.25445.78.228.255254
23045.78.229.0/2445.78.229.1 to 45.78.229.25445.78.229.255254
23145.78.230.0/2445.78.230.1 to 45.78.230.25445.78.230.255254
23245.78.231.0/2445.78.231.1 to 45.78.231.25445.78.231.255254
23345.78.232.0/2445.78.232.1 to 45.78.232.25445.78.232.255254
23445.78.233.0/2445.78.233.1 to 45.78.233.25445.78.233.255254
23545.78.234.0/2445.78.234.1 to 45.78.234.25445.78.234.255254
23645.78.235.0/2445.78.235.1 to 45.78.235.25445.78.235.255254
23745.78.236.0/2445.78.236.1 to 45.78.236.25445.78.236.255254
23845.78.237.0/2445.78.237.1 to 45.78.237.25445.78.237.255254
23945.78.238.0/2445.78.238.1 to 45.78.238.25445.78.238.255254
24045.78.239.0/2445.78.239.1 to 45.78.239.25445.78.239.255254
24145.78.240.0/2445.78.240.1 to 45.78.240.25445.78.240.255254
24245.78.241.0/2445.78.241.1 to 45.78.241.25445.78.241.255254
24345.78.242.0/2445.78.242.1 to 45.78.242.25445.78.242.255254
24445.78.243.0/2445.78.243.1 to 45.78.243.25445.78.243.255254
24545.78.244.0/2445.78.244.1 to 45.78.244.25445.78.244.255254
24645.78.245.0/2445.78.245.1 to 45.78.245.25445.78.245.255254
24745.78.246.0/2445.78.246.1 to 45.78.246.25445.78.246.255254
24845.78.247.0/2445.78.247.1 to 45.78.247.25445.78.247.255254
24945.78.248.0/2445.78.248.1 to 45.78.248.25445.78.248.255254
25045.78.249.0/2445.78.249.1 to 45.78.249.25445.78.249.255254
25145.78.250.0/2445.78.250.1 to 45.78.250.25445.78.250.255254
25245.78.251.0/2445.78.251.1 to 45.78.251.25445.78.251.255254
25345.78.252.0/2445.78.252.1 to 45.78.252.25445.78.252.255254
25445.78.253.0/2445.78.253.1 to 45.78.253.25445.78.253.255254
25545.78.254.0/2445.78.254.1 to 45.78.254.25445.78.254.255254
25645.78.255.0/2445.78.255.1 to 45.78.255.25445.78.255.255254

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.