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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.

Network25.78.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
25.78.0.0
Broadcast address
25.79.255.255
First usable
25.78.0.1
Last usable
25.79.255.254
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 194E0000 · Integer 424542208 to 424673279
Reverse DNS zones
78.25.in-addr.arpa
79.25.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
Address00011001.01001110.00000000.0000000025.78.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00011001.01001110.00000000.0000000025.78.0.0
Broadcast00011001.01001111.11111111.1111111125.79.255.255
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)

25.78.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
125.78.0.0/2425.78.0.1 to 25.78.0.25425.78.0.255254
225.78.1.0/2425.78.1.1 to 25.78.1.25425.78.1.255254
325.78.2.0/2425.78.2.1 to 25.78.2.25425.78.2.255254
425.78.3.0/2425.78.3.1 to 25.78.3.25425.78.3.255254
525.78.4.0/2425.78.4.1 to 25.78.4.25425.78.4.255254
625.78.5.0/2425.78.5.1 to 25.78.5.25425.78.5.255254
725.78.6.0/2425.78.6.1 to 25.78.6.25425.78.6.255254
825.78.7.0/2425.78.7.1 to 25.78.7.25425.78.7.255254
925.78.8.0/2425.78.8.1 to 25.78.8.25425.78.8.255254
1025.78.9.0/2425.78.9.1 to 25.78.9.25425.78.9.255254
1125.78.10.0/2425.78.10.1 to 25.78.10.25425.78.10.255254
1225.78.11.0/2425.78.11.1 to 25.78.11.25425.78.11.255254
1325.78.12.0/2425.78.12.1 to 25.78.12.25425.78.12.255254
1425.78.13.0/2425.78.13.1 to 25.78.13.25425.78.13.255254
1525.78.14.0/2425.78.14.1 to 25.78.14.25425.78.14.255254
1625.78.15.0/2425.78.15.1 to 25.78.15.25425.78.15.255254
1725.78.16.0/2425.78.16.1 to 25.78.16.25425.78.16.255254
1825.78.17.0/2425.78.17.1 to 25.78.17.25425.78.17.255254
1925.78.18.0/2425.78.18.1 to 25.78.18.25425.78.18.255254
2025.78.19.0/2425.78.19.1 to 25.78.19.25425.78.19.255254
2125.78.20.0/2425.78.20.1 to 25.78.20.25425.78.20.255254
2225.78.21.0/2425.78.21.1 to 25.78.21.25425.78.21.255254
2325.78.22.0/2425.78.22.1 to 25.78.22.25425.78.22.255254
2425.78.23.0/2425.78.23.1 to 25.78.23.25425.78.23.255254
2525.78.24.0/2425.78.24.1 to 25.78.24.25425.78.24.255254
2625.78.25.0/2425.78.25.1 to 25.78.25.25425.78.25.255254
2725.78.26.0/2425.78.26.1 to 25.78.26.25425.78.26.255254
2825.78.27.0/2425.78.27.1 to 25.78.27.25425.78.27.255254
2925.78.28.0/2425.78.28.1 to 25.78.28.25425.78.28.255254
3025.78.29.0/2425.78.29.1 to 25.78.29.25425.78.29.255254
3125.78.30.0/2425.78.30.1 to 25.78.30.25425.78.30.255254
3225.78.31.0/2425.78.31.1 to 25.78.31.25425.78.31.255254
3325.78.32.0/2425.78.32.1 to 25.78.32.25425.78.32.255254
3425.78.33.0/2425.78.33.1 to 25.78.33.25425.78.33.255254
3525.78.34.0/2425.78.34.1 to 25.78.34.25425.78.34.255254
3625.78.35.0/2425.78.35.1 to 25.78.35.25425.78.35.255254
3725.78.36.0/2425.78.36.1 to 25.78.36.25425.78.36.255254
3825.78.37.0/2425.78.37.1 to 25.78.37.25425.78.37.255254
3925.78.38.0/2425.78.38.1 to 25.78.38.25425.78.38.255254
4025.78.39.0/2425.78.39.1 to 25.78.39.25425.78.39.255254
4125.78.40.0/2425.78.40.1 to 25.78.40.25425.78.40.255254
4225.78.41.0/2425.78.41.1 to 25.78.41.25425.78.41.255254
4325.78.42.0/2425.78.42.1 to 25.78.42.25425.78.42.255254
4425.78.43.0/2425.78.43.1 to 25.78.43.25425.78.43.255254
4525.78.44.0/2425.78.44.1 to 25.78.44.25425.78.44.255254
4625.78.45.0/2425.78.45.1 to 25.78.45.25425.78.45.255254
4725.78.46.0/2425.78.46.1 to 25.78.46.25425.78.46.255254
4825.78.47.0/2425.78.47.1 to 25.78.47.25425.78.47.255254
4925.78.48.0/2425.78.48.1 to 25.78.48.25425.78.48.255254
5025.78.49.0/2425.78.49.1 to 25.78.49.25425.78.49.255254
5125.78.50.0/2425.78.50.1 to 25.78.50.25425.78.50.255254
5225.78.51.0/2425.78.51.1 to 25.78.51.25425.78.51.255254
5325.78.52.0/2425.78.52.1 to 25.78.52.25425.78.52.255254
5425.78.53.0/2425.78.53.1 to 25.78.53.25425.78.53.255254
5525.78.54.0/2425.78.54.1 to 25.78.54.25425.78.54.255254
5625.78.55.0/2425.78.55.1 to 25.78.55.25425.78.55.255254
5725.78.56.0/2425.78.56.1 to 25.78.56.25425.78.56.255254
5825.78.57.0/2425.78.57.1 to 25.78.57.25425.78.57.255254
5925.78.58.0/2425.78.58.1 to 25.78.58.25425.78.58.255254
6025.78.59.0/2425.78.59.1 to 25.78.59.25425.78.59.255254
6125.78.60.0/2425.78.60.1 to 25.78.60.25425.78.60.255254
6225.78.61.0/2425.78.61.1 to 25.78.61.25425.78.61.255254
6325.78.62.0/2425.78.62.1 to 25.78.62.25425.78.62.255254
6425.78.63.0/2425.78.63.1 to 25.78.63.25425.78.63.255254
6525.78.64.0/2425.78.64.1 to 25.78.64.25425.78.64.255254
6625.78.65.0/2425.78.65.1 to 25.78.65.25425.78.65.255254
6725.78.66.0/2425.78.66.1 to 25.78.66.25425.78.66.255254
6825.78.67.0/2425.78.67.1 to 25.78.67.25425.78.67.255254
6925.78.68.0/2425.78.68.1 to 25.78.68.25425.78.68.255254
7025.78.69.0/2425.78.69.1 to 25.78.69.25425.78.69.255254
7125.78.70.0/2425.78.70.1 to 25.78.70.25425.78.70.255254
7225.78.71.0/2425.78.71.1 to 25.78.71.25425.78.71.255254
7325.78.72.0/2425.78.72.1 to 25.78.72.25425.78.72.255254
7425.78.73.0/2425.78.73.1 to 25.78.73.25425.78.73.255254
7525.78.74.0/2425.78.74.1 to 25.78.74.25425.78.74.255254
7625.78.75.0/2425.78.75.1 to 25.78.75.25425.78.75.255254
7725.78.76.0/2425.78.76.1 to 25.78.76.25425.78.76.255254
7825.78.77.0/2425.78.77.1 to 25.78.77.25425.78.77.255254
7925.78.78.0/2425.78.78.1 to 25.78.78.25425.78.78.255254
8025.78.79.0/2425.78.79.1 to 25.78.79.25425.78.79.255254
8125.78.80.0/2425.78.80.1 to 25.78.80.25425.78.80.255254
8225.78.81.0/2425.78.81.1 to 25.78.81.25425.78.81.255254
8325.78.82.0/2425.78.82.1 to 25.78.82.25425.78.82.255254
8425.78.83.0/2425.78.83.1 to 25.78.83.25425.78.83.255254
8525.78.84.0/2425.78.84.1 to 25.78.84.25425.78.84.255254
8625.78.85.0/2425.78.85.1 to 25.78.85.25425.78.85.255254
8725.78.86.0/2425.78.86.1 to 25.78.86.25425.78.86.255254
8825.78.87.0/2425.78.87.1 to 25.78.87.25425.78.87.255254
8925.78.88.0/2425.78.88.1 to 25.78.88.25425.78.88.255254
9025.78.89.0/2425.78.89.1 to 25.78.89.25425.78.89.255254
9125.78.90.0/2425.78.90.1 to 25.78.90.25425.78.90.255254
9225.78.91.0/2425.78.91.1 to 25.78.91.25425.78.91.255254
9325.78.92.0/2425.78.92.1 to 25.78.92.25425.78.92.255254
9425.78.93.0/2425.78.93.1 to 25.78.93.25425.78.93.255254
9525.78.94.0/2425.78.94.1 to 25.78.94.25425.78.94.255254
9625.78.95.0/2425.78.95.1 to 25.78.95.25425.78.95.255254
9725.78.96.0/2425.78.96.1 to 25.78.96.25425.78.96.255254
9825.78.97.0/2425.78.97.1 to 25.78.97.25425.78.97.255254
9925.78.98.0/2425.78.98.1 to 25.78.98.25425.78.98.255254
10025.78.99.0/2425.78.99.1 to 25.78.99.25425.78.99.255254
10125.78.100.0/2425.78.100.1 to 25.78.100.25425.78.100.255254
10225.78.101.0/2425.78.101.1 to 25.78.101.25425.78.101.255254
10325.78.102.0/2425.78.102.1 to 25.78.102.25425.78.102.255254
10425.78.103.0/2425.78.103.1 to 25.78.103.25425.78.103.255254
10525.78.104.0/2425.78.104.1 to 25.78.104.25425.78.104.255254
10625.78.105.0/2425.78.105.1 to 25.78.105.25425.78.105.255254
10725.78.106.0/2425.78.106.1 to 25.78.106.25425.78.106.255254
10825.78.107.0/2425.78.107.1 to 25.78.107.25425.78.107.255254
10925.78.108.0/2425.78.108.1 to 25.78.108.25425.78.108.255254
11025.78.109.0/2425.78.109.1 to 25.78.109.25425.78.109.255254
11125.78.110.0/2425.78.110.1 to 25.78.110.25425.78.110.255254
11225.78.111.0/2425.78.111.1 to 25.78.111.25425.78.111.255254
11325.78.112.0/2425.78.112.1 to 25.78.112.25425.78.112.255254
11425.78.113.0/2425.78.113.1 to 25.78.113.25425.78.113.255254
11525.78.114.0/2425.78.114.1 to 25.78.114.25425.78.114.255254
11625.78.115.0/2425.78.115.1 to 25.78.115.25425.78.115.255254
11725.78.116.0/2425.78.116.1 to 25.78.116.25425.78.116.255254
11825.78.117.0/2425.78.117.1 to 25.78.117.25425.78.117.255254
11925.78.118.0/2425.78.118.1 to 25.78.118.25425.78.118.255254
12025.78.119.0/2425.78.119.1 to 25.78.119.25425.78.119.255254
12125.78.120.0/2425.78.120.1 to 25.78.120.25425.78.120.255254
12225.78.121.0/2425.78.121.1 to 25.78.121.25425.78.121.255254
12325.78.122.0/2425.78.122.1 to 25.78.122.25425.78.122.255254
12425.78.123.0/2425.78.123.1 to 25.78.123.25425.78.123.255254
12525.78.124.0/2425.78.124.1 to 25.78.124.25425.78.124.255254
12625.78.125.0/2425.78.125.1 to 25.78.125.25425.78.125.255254
12725.78.126.0/2425.78.126.1 to 25.78.126.25425.78.126.255254
12825.78.127.0/2425.78.127.1 to 25.78.127.25425.78.127.255254
12925.78.128.0/2425.78.128.1 to 25.78.128.25425.78.128.255254
13025.78.129.0/2425.78.129.1 to 25.78.129.25425.78.129.255254
13125.78.130.0/2425.78.130.1 to 25.78.130.25425.78.130.255254
13225.78.131.0/2425.78.131.1 to 25.78.131.25425.78.131.255254
13325.78.132.0/2425.78.132.1 to 25.78.132.25425.78.132.255254
13425.78.133.0/2425.78.133.1 to 25.78.133.25425.78.133.255254
13525.78.134.0/2425.78.134.1 to 25.78.134.25425.78.134.255254
13625.78.135.0/2425.78.135.1 to 25.78.135.25425.78.135.255254
13725.78.136.0/2425.78.136.1 to 25.78.136.25425.78.136.255254
13825.78.137.0/2425.78.137.1 to 25.78.137.25425.78.137.255254
13925.78.138.0/2425.78.138.1 to 25.78.138.25425.78.138.255254
14025.78.139.0/2425.78.139.1 to 25.78.139.25425.78.139.255254
14125.78.140.0/2425.78.140.1 to 25.78.140.25425.78.140.255254
14225.78.141.0/2425.78.141.1 to 25.78.141.25425.78.141.255254
14325.78.142.0/2425.78.142.1 to 25.78.142.25425.78.142.255254
14425.78.143.0/2425.78.143.1 to 25.78.143.25425.78.143.255254
14525.78.144.0/2425.78.144.1 to 25.78.144.25425.78.144.255254
14625.78.145.0/2425.78.145.1 to 25.78.145.25425.78.145.255254
14725.78.146.0/2425.78.146.1 to 25.78.146.25425.78.146.255254
14825.78.147.0/2425.78.147.1 to 25.78.147.25425.78.147.255254
14925.78.148.0/2425.78.148.1 to 25.78.148.25425.78.148.255254
15025.78.149.0/2425.78.149.1 to 25.78.149.25425.78.149.255254
15125.78.150.0/2425.78.150.1 to 25.78.150.25425.78.150.255254
15225.78.151.0/2425.78.151.1 to 25.78.151.25425.78.151.255254
15325.78.152.0/2425.78.152.1 to 25.78.152.25425.78.152.255254
15425.78.153.0/2425.78.153.1 to 25.78.153.25425.78.153.255254
15525.78.154.0/2425.78.154.1 to 25.78.154.25425.78.154.255254
15625.78.155.0/2425.78.155.1 to 25.78.155.25425.78.155.255254
15725.78.156.0/2425.78.156.1 to 25.78.156.25425.78.156.255254
15825.78.157.0/2425.78.157.1 to 25.78.157.25425.78.157.255254
15925.78.158.0/2425.78.158.1 to 25.78.158.25425.78.158.255254
16025.78.159.0/2425.78.159.1 to 25.78.159.25425.78.159.255254
16125.78.160.0/2425.78.160.1 to 25.78.160.25425.78.160.255254
16225.78.161.0/2425.78.161.1 to 25.78.161.25425.78.161.255254
16325.78.162.0/2425.78.162.1 to 25.78.162.25425.78.162.255254
16425.78.163.0/2425.78.163.1 to 25.78.163.25425.78.163.255254
16525.78.164.0/2425.78.164.1 to 25.78.164.25425.78.164.255254
16625.78.165.0/2425.78.165.1 to 25.78.165.25425.78.165.255254
16725.78.166.0/2425.78.166.1 to 25.78.166.25425.78.166.255254
16825.78.167.0/2425.78.167.1 to 25.78.167.25425.78.167.255254
16925.78.168.0/2425.78.168.1 to 25.78.168.25425.78.168.255254
17025.78.169.0/2425.78.169.1 to 25.78.169.25425.78.169.255254
17125.78.170.0/2425.78.170.1 to 25.78.170.25425.78.170.255254
17225.78.171.0/2425.78.171.1 to 25.78.171.25425.78.171.255254
17325.78.172.0/2425.78.172.1 to 25.78.172.25425.78.172.255254
17425.78.173.0/2425.78.173.1 to 25.78.173.25425.78.173.255254
17525.78.174.0/2425.78.174.1 to 25.78.174.25425.78.174.255254
17625.78.175.0/2425.78.175.1 to 25.78.175.25425.78.175.255254
17725.78.176.0/2425.78.176.1 to 25.78.176.25425.78.176.255254
17825.78.177.0/2425.78.177.1 to 25.78.177.25425.78.177.255254
17925.78.178.0/2425.78.178.1 to 25.78.178.25425.78.178.255254
18025.78.179.0/2425.78.179.1 to 25.78.179.25425.78.179.255254
18125.78.180.0/2425.78.180.1 to 25.78.180.25425.78.180.255254
18225.78.181.0/2425.78.181.1 to 25.78.181.25425.78.181.255254
18325.78.182.0/2425.78.182.1 to 25.78.182.25425.78.182.255254
18425.78.183.0/2425.78.183.1 to 25.78.183.25425.78.183.255254
18525.78.184.0/2425.78.184.1 to 25.78.184.25425.78.184.255254
18625.78.185.0/2425.78.185.1 to 25.78.185.25425.78.185.255254
18725.78.186.0/2425.78.186.1 to 25.78.186.25425.78.186.255254
18825.78.187.0/2425.78.187.1 to 25.78.187.25425.78.187.255254
18925.78.188.0/2425.78.188.1 to 25.78.188.25425.78.188.255254
19025.78.189.0/2425.78.189.1 to 25.78.189.25425.78.189.255254
19125.78.190.0/2425.78.190.1 to 25.78.190.25425.78.190.255254
19225.78.191.0/2425.78.191.1 to 25.78.191.25425.78.191.255254
19325.78.192.0/2425.78.192.1 to 25.78.192.25425.78.192.255254
19425.78.193.0/2425.78.193.1 to 25.78.193.25425.78.193.255254
19525.78.194.0/2425.78.194.1 to 25.78.194.25425.78.194.255254
19625.78.195.0/2425.78.195.1 to 25.78.195.25425.78.195.255254
19725.78.196.0/2425.78.196.1 to 25.78.196.25425.78.196.255254
19825.78.197.0/2425.78.197.1 to 25.78.197.25425.78.197.255254
19925.78.198.0/2425.78.198.1 to 25.78.198.25425.78.198.255254
20025.78.199.0/2425.78.199.1 to 25.78.199.25425.78.199.255254
20125.78.200.0/2425.78.200.1 to 25.78.200.25425.78.200.255254
20225.78.201.0/2425.78.201.1 to 25.78.201.25425.78.201.255254
20325.78.202.0/2425.78.202.1 to 25.78.202.25425.78.202.255254
20425.78.203.0/2425.78.203.1 to 25.78.203.25425.78.203.255254
20525.78.204.0/2425.78.204.1 to 25.78.204.25425.78.204.255254
20625.78.205.0/2425.78.205.1 to 25.78.205.25425.78.205.255254
20725.78.206.0/2425.78.206.1 to 25.78.206.25425.78.206.255254
20825.78.207.0/2425.78.207.1 to 25.78.207.25425.78.207.255254
20925.78.208.0/2425.78.208.1 to 25.78.208.25425.78.208.255254
21025.78.209.0/2425.78.209.1 to 25.78.209.25425.78.209.255254
21125.78.210.0/2425.78.210.1 to 25.78.210.25425.78.210.255254
21225.78.211.0/2425.78.211.1 to 25.78.211.25425.78.211.255254
21325.78.212.0/2425.78.212.1 to 25.78.212.25425.78.212.255254
21425.78.213.0/2425.78.213.1 to 25.78.213.25425.78.213.255254
21525.78.214.0/2425.78.214.1 to 25.78.214.25425.78.214.255254
21625.78.215.0/2425.78.215.1 to 25.78.215.25425.78.215.255254
21725.78.216.0/2425.78.216.1 to 25.78.216.25425.78.216.255254
21825.78.217.0/2425.78.217.1 to 25.78.217.25425.78.217.255254
21925.78.218.0/2425.78.218.1 to 25.78.218.25425.78.218.255254
22025.78.219.0/2425.78.219.1 to 25.78.219.25425.78.219.255254
22125.78.220.0/2425.78.220.1 to 25.78.220.25425.78.220.255254
22225.78.221.0/2425.78.221.1 to 25.78.221.25425.78.221.255254
22325.78.222.0/2425.78.222.1 to 25.78.222.25425.78.222.255254
22425.78.223.0/2425.78.223.1 to 25.78.223.25425.78.223.255254
22525.78.224.0/2425.78.224.1 to 25.78.224.25425.78.224.255254
22625.78.225.0/2425.78.225.1 to 25.78.225.25425.78.225.255254
22725.78.226.0/2425.78.226.1 to 25.78.226.25425.78.226.255254
22825.78.227.0/2425.78.227.1 to 25.78.227.25425.78.227.255254
22925.78.228.0/2425.78.228.1 to 25.78.228.25425.78.228.255254
23025.78.229.0/2425.78.229.1 to 25.78.229.25425.78.229.255254
23125.78.230.0/2425.78.230.1 to 25.78.230.25425.78.230.255254
23225.78.231.0/2425.78.231.1 to 25.78.231.25425.78.231.255254
23325.78.232.0/2425.78.232.1 to 25.78.232.25425.78.232.255254
23425.78.233.0/2425.78.233.1 to 25.78.233.25425.78.233.255254
23525.78.234.0/2425.78.234.1 to 25.78.234.25425.78.234.255254
23625.78.235.0/2425.78.235.1 to 25.78.235.25425.78.235.255254
23725.78.236.0/2425.78.236.1 to 25.78.236.25425.78.236.255254
23825.78.237.0/2425.78.237.1 to 25.78.237.25425.78.237.255254
23925.78.238.0/2425.78.238.1 to 25.78.238.25425.78.238.255254
24025.78.239.0/2425.78.239.1 to 25.78.239.25425.78.239.255254
24125.78.240.0/2425.78.240.1 to 25.78.240.25425.78.240.255254
24225.78.241.0/2425.78.241.1 to 25.78.241.25425.78.241.255254
24325.78.242.0/2425.78.242.1 to 25.78.242.25425.78.242.255254
24425.78.243.0/2425.78.243.1 to 25.78.243.25425.78.243.255254
24525.78.244.0/2425.78.244.1 to 25.78.244.25425.78.244.255254
24625.78.245.0/2425.78.245.1 to 25.78.245.25425.78.245.255254
24725.78.246.0/2425.78.246.1 to 25.78.246.25425.78.246.255254
24825.78.247.0/2425.78.247.1 to 25.78.247.25425.78.247.255254
24925.78.248.0/2425.78.248.1 to 25.78.248.25425.78.248.255254
25025.78.249.0/2425.78.249.1 to 25.78.249.25425.78.249.255254
25125.78.250.0/2425.78.250.1 to 25.78.250.25425.78.250.255254
25225.78.251.0/2425.78.251.1 to 25.78.251.25425.78.251.255254
25325.78.252.0/2425.78.252.1 to 25.78.252.25425.78.252.255254
25425.78.253.0/2425.78.253.1 to 25.78.253.25425.78.253.255254
25525.78.254.0/2425.78.254.1 to 25.78.254.25425.78.254.255254
25625.78.255.0/2425.78.255.1 to 25.78.255.25425.78.255.255254

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.