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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.

Network85.0.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
85.0.0.0
Broadcast address
85.1.255.255
First usable
85.0.0.1
Last usable
85.1.255.254
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 55000000 · Integer 1426063360 to 1426194431
Reverse DNS zones
0.85.in-addr.arpa
1.85.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
Address01010101.00000000.00000000.0000000085.0.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01010101.00000000.00000000.0000000085.0.0.0
Broadcast01010101.00000001.11111111.1111111185.1.255.255
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)

85.0.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
185.0.0.0/2485.0.0.1 to 85.0.0.25485.0.0.255254
285.0.1.0/2485.0.1.1 to 85.0.1.25485.0.1.255254
385.0.2.0/2485.0.2.1 to 85.0.2.25485.0.2.255254
485.0.3.0/2485.0.3.1 to 85.0.3.25485.0.3.255254
585.0.4.0/2485.0.4.1 to 85.0.4.25485.0.4.255254
685.0.5.0/2485.0.5.1 to 85.0.5.25485.0.5.255254
785.0.6.0/2485.0.6.1 to 85.0.6.25485.0.6.255254
885.0.7.0/2485.0.7.1 to 85.0.7.25485.0.7.255254
985.0.8.0/2485.0.8.1 to 85.0.8.25485.0.8.255254
1085.0.9.0/2485.0.9.1 to 85.0.9.25485.0.9.255254
1185.0.10.0/2485.0.10.1 to 85.0.10.25485.0.10.255254
1285.0.11.0/2485.0.11.1 to 85.0.11.25485.0.11.255254
1385.0.12.0/2485.0.12.1 to 85.0.12.25485.0.12.255254
1485.0.13.0/2485.0.13.1 to 85.0.13.25485.0.13.255254
1585.0.14.0/2485.0.14.1 to 85.0.14.25485.0.14.255254
1685.0.15.0/2485.0.15.1 to 85.0.15.25485.0.15.255254
1785.0.16.0/2485.0.16.1 to 85.0.16.25485.0.16.255254
1885.0.17.0/2485.0.17.1 to 85.0.17.25485.0.17.255254
1985.0.18.0/2485.0.18.1 to 85.0.18.25485.0.18.255254
2085.0.19.0/2485.0.19.1 to 85.0.19.25485.0.19.255254
2185.0.20.0/2485.0.20.1 to 85.0.20.25485.0.20.255254
2285.0.21.0/2485.0.21.1 to 85.0.21.25485.0.21.255254
2385.0.22.0/2485.0.22.1 to 85.0.22.25485.0.22.255254
2485.0.23.0/2485.0.23.1 to 85.0.23.25485.0.23.255254
2585.0.24.0/2485.0.24.1 to 85.0.24.25485.0.24.255254
2685.0.25.0/2485.0.25.1 to 85.0.25.25485.0.25.255254
2785.0.26.0/2485.0.26.1 to 85.0.26.25485.0.26.255254
2885.0.27.0/2485.0.27.1 to 85.0.27.25485.0.27.255254
2985.0.28.0/2485.0.28.1 to 85.0.28.25485.0.28.255254
3085.0.29.0/2485.0.29.1 to 85.0.29.25485.0.29.255254
3185.0.30.0/2485.0.30.1 to 85.0.30.25485.0.30.255254
3285.0.31.0/2485.0.31.1 to 85.0.31.25485.0.31.255254
3385.0.32.0/2485.0.32.1 to 85.0.32.25485.0.32.255254
3485.0.33.0/2485.0.33.1 to 85.0.33.25485.0.33.255254
3585.0.34.0/2485.0.34.1 to 85.0.34.25485.0.34.255254
3685.0.35.0/2485.0.35.1 to 85.0.35.25485.0.35.255254
3785.0.36.0/2485.0.36.1 to 85.0.36.25485.0.36.255254
3885.0.37.0/2485.0.37.1 to 85.0.37.25485.0.37.255254
3985.0.38.0/2485.0.38.1 to 85.0.38.25485.0.38.255254
4085.0.39.0/2485.0.39.1 to 85.0.39.25485.0.39.255254
4185.0.40.0/2485.0.40.1 to 85.0.40.25485.0.40.255254
4285.0.41.0/2485.0.41.1 to 85.0.41.25485.0.41.255254
4385.0.42.0/2485.0.42.1 to 85.0.42.25485.0.42.255254
4485.0.43.0/2485.0.43.1 to 85.0.43.25485.0.43.255254
4585.0.44.0/2485.0.44.1 to 85.0.44.25485.0.44.255254
4685.0.45.0/2485.0.45.1 to 85.0.45.25485.0.45.255254
4785.0.46.0/2485.0.46.1 to 85.0.46.25485.0.46.255254
4885.0.47.0/2485.0.47.1 to 85.0.47.25485.0.47.255254
4985.0.48.0/2485.0.48.1 to 85.0.48.25485.0.48.255254
5085.0.49.0/2485.0.49.1 to 85.0.49.25485.0.49.255254
5185.0.50.0/2485.0.50.1 to 85.0.50.25485.0.50.255254
5285.0.51.0/2485.0.51.1 to 85.0.51.25485.0.51.255254
5385.0.52.0/2485.0.52.1 to 85.0.52.25485.0.52.255254
5485.0.53.0/2485.0.53.1 to 85.0.53.25485.0.53.255254
5585.0.54.0/2485.0.54.1 to 85.0.54.25485.0.54.255254
5685.0.55.0/2485.0.55.1 to 85.0.55.25485.0.55.255254
5785.0.56.0/2485.0.56.1 to 85.0.56.25485.0.56.255254
5885.0.57.0/2485.0.57.1 to 85.0.57.25485.0.57.255254
5985.0.58.0/2485.0.58.1 to 85.0.58.25485.0.58.255254
6085.0.59.0/2485.0.59.1 to 85.0.59.25485.0.59.255254
6185.0.60.0/2485.0.60.1 to 85.0.60.25485.0.60.255254
6285.0.61.0/2485.0.61.1 to 85.0.61.25485.0.61.255254
6385.0.62.0/2485.0.62.1 to 85.0.62.25485.0.62.255254
6485.0.63.0/2485.0.63.1 to 85.0.63.25485.0.63.255254
6585.0.64.0/2485.0.64.1 to 85.0.64.25485.0.64.255254
6685.0.65.0/2485.0.65.1 to 85.0.65.25485.0.65.255254
6785.0.66.0/2485.0.66.1 to 85.0.66.25485.0.66.255254
6885.0.67.0/2485.0.67.1 to 85.0.67.25485.0.67.255254
6985.0.68.0/2485.0.68.1 to 85.0.68.25485.0.68.255254
7085.0.69.0/2485.0.69.1 to 85.0.69.25485.0.69.255254
7185.0.70.0/2485.0.70.1 to 85.0.70.25485.0.70.255254
7285.0.71.0/2485.0.71.1 to 85.0.71.25485.0.71.255254
7385.0.72.0/2485.0.72.1 to 85.0.72.25485.0.72.255254
7485.0.73.0/2485.0.73.1 to 85.0.73.25485.0.73.255254
7585.0.74.0/2485.0.74.1 to 85.0.74.25485.0.74.255254
7685.0.75.0/2485.0.75.1 to 85.0.75.25485.0.75.255254
7785.0.76.0/2485.0.76.1 to 85.0.76.25485.0.76.255254
7885.0.77.0/2485.0.77.1 to 85.0.77.25485.0.77.255254
7985.0.78.0/2485.0.78.1 to 85.0.78.25485.0.78.255254
8085.0.79.0/2485.0.79.1 to 85.0.79.25485.0.79.255254
8185.0.80.0/2485.0.80.1 to 85.0.80.25485.0.80.255254
8285.0.81.0/2485.0.81.1 to 85.0.81.25485.0.81.255254
8385.0.82.0/2485.0.82.1 to 85.0.82.25485.0.82.255254
8485.0.83.0/2485.0.83.1 to 85.0.83.25485.0.83.255254
8585.0.84.0/2485.0.84.1 to 85.0.84.25485.0.84.255254
8685.0.85.0/2485.0.85.1 to 85.0.85.25485.0.85.255254
8785.0.86.0/2485.0.86.1 to 85.0.86.25485.0.86.255254
8885.0.87.0/2485.0.87.1 to 85.0.87.25485.0.87.255254
8985.0.88.0/2485.0.88.1 to 85.0.88.25485.0.88.255254
9085.0.89.0/2485.0.89.1 to 85.0.89.25485.0.89.255254
9185.0.90.0/2485.0.90.1 to 85.0.90.25485.0.90.255254
9285.0.91.0/2485.0.91.1 to 85.0.91.25485.0.91.255254
9385.0.92.0/2485.0.92.1 to 85.0.92.25485.0.92.255254
9485.0.93.0/2485.0.93.1 to 85.0.93.25485.0.93.255254
9585.0.94.0/2485.0.94.1 to 85.0.94.25485.0.94.255254
9685.0.95.0/2485.0.95.1 to 85.0.95.25485.0.95.255254
9785.0.96.0/2485.0.96.1 to 85.0.96.25485.0.96.255254
9885.0.97.0/2485.0.97.1 to 85.0.97.25485.0.97.255254
9985.0.98.0/2485.0.98.1 to 85.0.98.25485.0.98.255254
10085.0.99.0/2485.0.99.1 to 85.0.99.25485.0.99.255254
10185.0.100.0/2485.0.100.1 to 85.0.100.25485.0.100.255254
10285.0.101.0/2485.0.101.1 to 85.0.101.25485.0.101.255254
10385.0.102.0/2485.0.102.1 to 85.0.102.25485.0.102.255254
10485.0.103.0/2485.0.103.1 to 85.0.103.25485.0.103.255254
10585.0.104.0/2485.0.104.1 to 85.0.104.25485.0.104.255254
10685.0.105.0/2485.0.105.1 to 85.0.105.25485.0.105.255254
10785.0.106.0/2485.0.106.1 to 85.0.106.25485.0.106.255254
10885.0.107.0/2485.0.107.1 to 85.0.107.25485.0.107.255254
10985.0.108.0/2485.0.108.1 to 85.0.108.25485.0.108.255254
11085.0.109.0/2485.0.109.1 to 85.0.109.25485.0.109.255254
11185.0.110.0/2485.0.110.1 to 85.0.110.25485.0.110.255254
11285.0.111.0/2485.0.111.1 to 85.0.111.25485.0.111.255254
11385.0.112.0/2485.0.112.1 to 85.0.112.25485.0.112.255254
11485.0.113.0/2485.0.113.1 to 85.0.113.25485.0.113.255254
11585.0.114.0/2485.0.114.1 to 85.0.114.25485.0.114.255254
11685.0.115.0/2485.0.115.1 to 85.0.115.25485.0.115.255254
11785.0.116.0/2485.0.116.1 to 85.0.116.25485.0.116.255254
11885.0.117.0/2485.0.117.1 to 85.0.117.25485.0.117.255254
11985.0.118.0/2485.0.118.1 to 85.0.118.25485.0.118.255254
12085.0.119.0/2485.0.119.1 to 85.0.119.25485.0.119.255254
12185.0.120.0/2485.0.120.1 to 85.0.120.25485.0.120.255254
12285.0.121.0/2485.0.121.1 to 85.0.121.25485.0.121.255254
12385.0.122.0/2485.0.122.1 to 85.0.122.25485.0.122.255254
12485.0.123.0/2485.0.123.1 to 85.0.123.25485.0.123.255254
12585.0.124.0/2485.0.124.1 to 85.0.124.25485.0.124.255254
12685.0.125.0/2485.0.125.1 to 85.0.125.25485.0.125.255254
12785.0.126.0/2485.0.126.1 to 85.0.126.25485.0.126.255254
12885.0.127.0/2485.0.127.1 to 85.0.127.25485.0.127.255254
12985.0.128.0/2485.0.128.1 to 85.0.128.25485.0.128.255254
13085.0.129.0/2485.0.129.1 to 85.0.129.25485.0.129.255254
13185.0.130.0/2485.0.130.1 to 85.0.130.25485.0.130.255254
13285.0.131.0/2485.0.131.1 to 85.0.131.25485.0.131.255254
13385.0.132.0/2485.0.132.1 to 85.0.132.25485.0.132.255254
13485.0.133.0/2485.0.133.1 to 85.0.133.25485.0.133.255254
13585.0.134.0/2485.0.134.1 to 85.0.134.25485.0.134.255254
13685.0.135.0/2485.0.135.1 to 85.0.135.25485.0.135.255254
13785.0.136.0/2485.0.136.1 to 85.0.136.25485.0.136.255254
13885.0.137.0/2485.0.137.1 to 85.0.137.25485.0.137.255254
13985.0.138.0/2485.0.138.1 to 85.0.138.25485.0.138.255254
14085.0.139.0/2485.0.139.1 to 85.0.139.25485.0.139.255254
14185.0.140.0/2485.0.140.1 to 85.0.140.25485.0.140.255254
14285.0.141.0/2485.0.141.1 to 85.0.141.25485.0.141.255254
14385.0.142.0/2485.0.142.1 to 85.0.142.25485.0.142.255254
14485.0.143.0/2485.0.143.1 to 85.0.143.25485.0.143.255254
14585.0.144.0/2485.0.144.1 to 85.0.144.25485.0.144.255254
14685.0.145.0/2485.0.145.1 to 85.0.145.25485.0.145.255254
14785.0.146.0/2485.0.146.1 to 85.0.146.25485.0.146.255254
14885.0.147.0/2485.0.147.1 to 85.0.147.25485.0.147.255254
14985.0.148.0/2485.0.148.1 to 85.0.148.25485.0.148.255254
15085.0.149.0/2485.0.149.1 to 85.0.149.25485.0.149.255254
15185.0.150.0/2485.0.150.1 to 85.0.150.25485.0.150.255254
15285.0.151.0/2485.0.151.1 to 85.0.151.25485.0.151.255254
15385.0.152.0/2485.0.152.1 to 85.0.152.25485.0.152.255254
15485.0.153.0/2485.0.153.1 to 85.0.153.25485.0.153.255254
15585.0.154.0/2485.0.154.1 to 85.0.154.25485.0.154.255254
15685.0.155.0/2485.0.155.1 to 85.0.155.25485.0.155.255254
15785.0.156.0/2485.0.156.1 to 85.0.156.25485.0.156.255254
15885.0.157.0/2485.0.157.1 to 85.0.157.25485.0.157.255254
15985.0.158.0/2485.0.158.1 to 85.0.158.25485.0.158.255254
16085.0.159.0/2485.0.159.1 to 85.0.159.25485.0.159.255254
16185.0.160.0/2485.0.160.1 to 85.0.160.25485.0.160.255254
16285.0.161.0/2485.0.161.1 to 85.0.161.25485.0.161.255254
16385.0.162.0/2485.0.162.1 to 85.0.162.25485.0.162.255254
16485.0.163.0/2485.0.163.1 to 85.0.163.25485.0.163.255254
16585.0.164.0/2485.0.164.1 to 85.0.164.25485.0.164.255254
16685.0.165.0/2485.0.165.1 to 85.0.165.25485.0.165.255254
16785.0.166.0/2485.0.166.1 to 85.0.166.25485.0.166.255254
16885.0.167.0/2485.0.167.1 to 85.0.167.25485.0.167.255254
16985.0.168.0/2485.0.168.1 to 85.0.168.25485.0.168.255254
17085.0.169.0/2485.0.169.1 to 85.0.169.25485.0.169.255254
17185.0.170.0/2485.0.170.1 to 85.0.170.25485.0.170.255254
17285.0.171.0/2485.0.171.1 to 85.0.171.25485.0.171.255254
17385.0.172.0/2485.0.172.1 to 85.0.172.25485.0.172.255254
17485.0.173.0/2485.0.173.1 to 85.0.173.25485.0.173.255254
17585.0.174.0/2485.0.174.1 to 85.0.174.25485.0.174.255254
17685.0.175.0/2485.0.175.1 to 85.0.175.25485.0.175.255254
17785.0.176.0/2485.0.176.1 to 85.0.176.25485.0.176.255254
17885.0.177.0/2485.0.177.1 to 85.0.177.25485.0.177.255254
17985.0.178.0/2485.0.178.1 to 85.0.178.25485.0.178.255254
18085.0.179.0/2485.0.179.1 to 85.0.179.25485.0.179.255254
18185.0.180.0/2485.0.180.1 to 85.0.180.25485.0.180.255254
18285.0.181.0/2485.0.181.1 to 85.0.181.25485.0.181.255254
18385.0.182.0/2485.0.182.1 to 85.0.182.25485.0.182.255254
18485.0.183.0/2485.0.183.1 to 85.0.183.25485.0.183.255254
18585.0.184.0/2485.0.184.1 to 85.0.184.25485.0.184.255254
18685.0.185.0/2485.0.185.1 to 85.0.185.25485.0.185.255254
18785.0.186.0/2485.0.186.1 to 85.0.186.25485.0.186.255254
18885.0.187.0/2485.0.187.1 to 85.0.187.25485.0.187.255254
18985.0.188.0/2485.0.188.1 to 85.0.188.25485.0.188.255254
19085.0.189.0/2485.0.189.1 to 85.0.189.25485.0.189.255254
19185.0.190.0/2485.0.190.1 to 85.0.190.25485.0.190.255254
19285.0.191.0/2485.0.191.1 to 85.0.191.25485.0.191.255254
19385.0.192.0/2485.0.192.1 to 85.0.192.25485.0.192.255254
19485.0.193.0/2485.0.193.1 to 85.0.193.25485.0.193.255254
19585.0.194.0/2485.0.194.1 to 85.0.194.25485.0.194.255254
19685.0.195.0/2485.0.195.1 to 85.0.195.25485.0.195.255254
19785.0.196.0/2485.0.196.1 to 85.0.196.25485.0.196.255254
19885.0.197.0/2485.0.197.1 to 85.0.197.25485.0.197.255254
19985.0.198.0/2485.0.198.1 to 85.0.198.25485.0.198.255254
20085.0.199.0/2485.0.199.1 to 85.0.199.25485.0.199.255254
20185.0.200.0/2485.0.200.1 to 85.0.200.25485.0.200.255254
20285.0.201.0/2485.0.201.1 to 85.0.201.25485.0.201.255254
20385.0.202.0/2485.0.202.1 to 85.0.202.25485.0.202.255254
20485.0.203.0/2485.0.203.1 to 85.0.203.25485.0.203.255254
20585.0.204.0/2485.0.204.1 to 85.0.204.25485.0.204.255254
20685.0.205.0/2485.0.205.1 to 85.0.205.25485.0.205.255254
20785.0.206.0/2485.0.206.1 to 85.0.206.25485.0.206.255254
20885.0.207.0/2485.0.207.1 to 85.0.207.25485.0.207.255254
20985.0.208.0/2485.0.208.1 to 85.0.208.25485.0.208.255254
21085.0.209.0/2485.0.209.1 to 85.0.209.25485.0.209.255254
21185.0.210.0/2485.0.210.1 to 85.0.210.25485.0.210.255254
21285.0.211.0/2485.0.211.1 to 85.0.211.25485.0.211.255254
21385.0.212.0/2485.0.212.1 to 85.0.212.25485.0.212.255254
21485.0.213.0/2485.0.213.1 to 85.0.213.25485.0.213.255254
21585.0.214.0/2485.0.214.1 to 85.0.214.25485.0.214.255254
21685.0.215.0/2485.0.215.1 to 85.0.215.25485.0.215.255254
21785.0.216.0/2485.0.216.1 to 85.0.216.25485.0.216.255254
21885.0.217.0/2485.0.217.1 to 85.0.217.25485.0.217.255254
21985.0.218.0/2485.0.218.1 to 85.0.218.25485.0.218.255254
22085.0.219.0/2485.0.219.1 to 85.0.219.25485.0.219.255254
22185.0.220.0/2485.0.220.1 to 85.0.220.25485.0.220.255254
22285.0.221.0/2485.0.221.1 to 85.0.221.25485.0.221.255254
22385.0.222.0/2485.0.222.1 to 85.0.222.25485.0.222.255254
22485.0.223.0/2485.0.223.1 to 85.0.223.25485.0.223.255254
22585.0.224.0/2485.0.224.1 to 85.0.224.25485.0.224.255254
22685.0.225.0/2485.0.225.1 to 85.0.225.25485.0.225.255254
22785.0.226.0/2485.0.226.1 to 85.0.226.25485.0.226.255254
22885.0.227.0/2485.0.227.1 to 85.0.227.25485.0.227.255254
22985.0.228.0/2485.0.228.1 to 85.0.228.25485.0.228.255254
23085.0.229.0/2485.0.229.1 to 85.0.229.25485.0.229.255254
23185.0.230.0/2485.0.230.1 to 85.0.230.25485.0.230.255254
23285.0.231.0/2485.0.231.1 to 85.0.231.25485.0.231.255254
23385.0.232.0/2485.0.232.1 to 85.0.232.25485.0.232.255254
23485.0.233.0/2485.0.233.1 to 85.0.233.25485.0.233.255254
23585.0.234.0/2485.0.234.1 to 85.0.234.25485.0.234.255254
23685.0.235.0/2485.0.235.1 to 85.0.235.25485.0.235.255254
23785.0.236.0/2485.0.236.1 to 85.0.236.25485.0.236.255254
23885.0.237.0/2485.0.237.1 to 85.0.237.25485.0.237.255254
23985.0.238.0/2485.0.238.1 to 85.0.238.25485.0.238.255254
24085.0.239.0/2485.0.239.1 to 85.0.239.25485.0.239.255254
24185.0.240.0/2485.0.240.1 to 85.0.240.25485.0.240.255254
24285.0.241.0/2485.0.241.1 to 85.0.241.25485.0.241.255254
24385.0.242.0/2485.0.242.1 to 85.0.242.25485.0.242.255254
24485.0.243.0/2485.0.243.1 to 85.0.243.25485.0.243.255254
24585.0.244.0/2485.0.244.1 to 85.0.244.25485.0.244.255254
24685.0.245.0/2485.0.245.1 to 85.0.245.25485.0.245.255254
24785.0.246.0/2485.0.246.1 to 85.0.246.25485.0.246.255254
24885.0.247.0/2485.0.247.1 to 85.0.247.25485.0.247.255254
24985.0.248.0/2485.0.248.1 to 85.0.248.25485.0.248.255254
25085.0.249.0/2485.0.249.1 to 85.0.249.25485.0.249.255254
25185.0.250.0/2485.0.250.1 to 85.0.250.25485.0.250.255254
25285.0.251.0/2485.0.251.1 to 85.0.251.25485.0.251.255254
25385.0.252.0/2485.0.252.1 to 85.0.252.25485.0.252.255254
25485.0.253.0/2485.0.253.1 to 85.0.253.25485.0.253.255254
25585.0.254.0/2485.0.254.1 to 85.0.254.25485.0.254.255254
25685.0.255.0/2485.0.255.1 to 85.0.255.25485.0.255.255254

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.