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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.

Network79.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
79.128.0.0
Broadcast address
79.255.255.255
First usable
79.128.0.1
Last usable
79.255.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 4F800000 · Integer 1333788672 to 1342177279
Reverse DNS zones
128.79.in-addr.arpa
129.79.in-addr.arpa
130.79.in-addr.arpa
131.79.in-addr.arpa
132.79.in-addr.arpa
133.79.in-addr.arpa
134.79.in-addr.arpa
135.79.in-addr.arpa
136.79.in-addr.arpa
137.79.in-addr.arpa
138.79.in-addr.arpa
139.79.in-addr.arpa
140.79.in-addr.arpa
141.79.in-addr.arpa
142.79.in-addr.arpa
143.79.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001111.10000000.00000000.0000000079.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01001111.10000000.00000000.0000000079.128.0.0
Broadcast01001111.11111111.11111111.1111111179.255.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

79.128.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
179.128.0.0/1779.128.0.1 to 79.128.127.25479.128.127.25532,766
279.128.128.0/1779.128.128.1 to 79.128.255.25479.128.255.25532,766
379.129.0.0/1779.129.0.1 to 79.129.127.25479.129.127.25532,766
479.129.128.0/1779.129.128.1 to 79.129.255.25479.129.255.25532,766
579.130.0.0/1779.130.0.1 to 79.130.127.25479.130.127.25532,766
679.130.128.0/1779.130.128.1 to 79.130.255.25479.130.255.25532,766
779.131.0.0/1779.131.0.1 to 79.131.127.25479.131.127.25532,766
879.131.128.0/1779.131.128.1 to 79.131.255.25479.131.255.25532,766
979.132.0.0/1779.132.0.1 to 79.132.127.25479.132.127.25532,766
1079.132.128.0/1779.132.128.1 to 79.132.255.25479.132.255.25532,766
1179.133.0.0/1779.133.0.1 to 79.133.127.25479.133.127.25532,766
1279.133.128.0/1779.133.128.1 to 79.133.255.25479.133.255.25532,766
1379.134.0.0/1779.134.0.1 to 79.134.127.25479.134.127.25532,766
1479.134.128.0/1779.134.128.1 to 79.134.255.25479.134.255.25532,766
1579.135.0.0/1779.135.0.1 to 79.135.127.25479.135.127.25532,766
1679.135.128.0/1779.135.128.1 to 79.135.255.25479.135.255.25532,766
1779.136.0.0/1779.136.0.1 to 79.136.127.25479.136.127.25532,766
1879.136.128.0/1779.136.128.1 to 79.136.255.25479.136.255.25532,766
1979.137.0.0/1779.137.0.1 to 79.137.127.25479.137.127.25532,766
2079.137.128.0/1779.137.128.1 to 79.137.255.25479.137.255.25532,766
2179.138.0.0/1779.138.0.1 to 79.138.127.25479.138.127.25532,766
2279.138.128.0/1779.138.128.1 to 79.138.255.25479.138.255.25532,766
2379.139.0.0/1779.139.0.1 to 79.139.127.25479.139.127.25532,766
2479.139.128.0/1779.139.128.1 to 79.139.255.25479.139.255.25532,766
2579.140.0.0/1779.140.0.1 to 79.140.127.25479.140.127.25532,766
2679.140.128.0/1779.140.128.1 to 79.140.255.25479.140.255.25532,766
2779.141.0.0/1779.141.0.1 to 79.141.127.25479.141.127.25532,766
2879.141.128.0/1779.141.128.1 to 79.141.255.25479.141.255.25532,766
2979.142.0.0/1779.142.0.1 to 79.142.127.25479.142.127.25532,766
3079.142.128.0/1779.142.128.1 to 79.142.255.25479.142.255.25532,766
3179.143.0.0/1779.143.0.1 to 79.143.127.25479.143.127.25532,766
3279.143.128.0/1779.143.128.1 to 79.143.255.25479.143.255.25532,766
3379.144.0.0/1779.144.0.1 to 79.144.127.25479.144.127.25532,766
3479.144.128.0/1779.144.128.1 to 79.144.255.25479.144.255.25532,766
3579.145.0.0/1779.145.0.1 to 79.145.127.25479.145.127.25532,766
3679.145.128.0/1779.145.128.1 to 79.145.255.25479.145.255.25532,766
3779.146.0.0/1779.146.0.1 to 79.146.127.25479.146.127.25532,766
3879.146.128.0/1779.146.128.1 to 79.146.255.25479.146.255.25532,766
3979.147.0.0/1779.147.0.1 to 79.147.127.25479.147.127.25532,766
4079.147.128.0/1779.147.128.1 to 79.147.255.25479.147.255.25532,766
4179.148.0.0/1779.148.0.1 to 79.148.127.25479.148.127.25532,766
4279.148.128.0/1779.148.128.1 to 79.148.255.25479.148.255.25532,766
4379.149.0.0/1779.149.0.1 to 79.149.127.25479.149.127.25532,766
4479.149.128.0/1779.149.128.1 to 79.149.255.25479.149.255.25532,766
4579.150.0.0/1779.150.0.1 to 79.150.127.25479.150.127.25532,766
4679.150.128.0/1779.150.128.1 to 79.150.255.25479.150.255.25532,766
4779.151.0.0/1779.151.0.1 to 79.151.127.25479.151.127.25532,766
4879.151.128.0/1779.151.128.1 to 79.151.255.25479.151.255.25532,766
4979.152.0.0/1779.152.0.1 to 79.152.127.25479.152.127.25532,766
5079.152.128.0/1779.152.128.1 to 79.152.255.25479.152.255.25532,766
5179.153.0.0/1779.153.0.1 to 79.153.127.25479.153.127.25532,766
5279.153.128.0/1779.153.128.1 to 79.153.255.25479.153.255.25532,766
5379.154.0.0/1779.154.0.1 to 79.154.127.25479.154.127.25532,766
5479.154.128.0/1779.154.128.1 to 79.154.255.25479.154.255.25532,766
5579.155.0.0/1779.155.0.1 to 79.155.127.25479.155.127.25532,766
5679.155.128.0/1779.155.128.1 to 79.155.255.25479.155.255.25532,766
5779.156.0.0/1779.156.0.1 to 79.156.127.25479.156.127.25532,766
5879.156.128.0/1779.156.128.1 to 79.156.255.25479.156.255.25532,766
5979.157.0.0/1779.157.0.1 to 79.157.127.25479.157.127.25532,766
6079.157.128.0/1779.157.128.1 to 79.157.255.25479.157.255.25532,766
6179.158.0.0/1779.158.0.1 to 79.158.127.25479.158.127.25532,766
6279.158.128.0/1779.158.128.1 to 79.158.255.25479.158.255.25532,766
6379.159.0.0/1779.159.0.1 to 79.159.127.25479.159.127.25532,766
6479.159.128.0/1779.159.128.1 to 79.159.255.25479.159.255.25532,766
6579.160.0.0/1779.160.0.1 to 79.160.127.25479.160.127.25532,766
6679.160.128.0/1779.160.128.1 to 79.160.255.25479.160.255.25532,766
6779.161.0.0/1779.161.0.1 to 79.161.127.25479.161.127.25532,766
6879.161.128.0/1779.161.128.1 to 79.161.255.25479.161.255.25532,766
6979.162.0.0/1779.162.0.1 to 79.162.127.25479.162.127.25532,766
7079.162.128.0/1779.162.128.1 to 79.162.255.25479.162.255.25532,766
7179.163.0.0/1779.163.0.1 to 79.163.127.25479.163.127.25532,766
7279.163.128.0/1779.163.128.1 to 79.163.255.25479.163.255.25532,766
7379.164.0.0/1779.164.0.1 to 79.164.127.25479.164.127.25532,766
7479.164.128.0/1779.164.128.1 to 79.164.255.25479.164.255.25532,766
7579.165.0.0/1779.165.0.1 to 79.165.127.25479.165.127.25532,766
7679.165.128.0/1779.165.128.1 to 79.165.255.25479.165.255.25532,766
7779.166.0.0/1779.166.0.1 to 79.166.127.25479.166.127.25532,766
7879.166.128.0/1779.166.128.1 to 79.166.255.25479.166.255.25532,766
7979.167.0.0/1779.167.0.1 to 79.167.127.25479.167.127.25532,766
8079.167.128.0/1779.167.128.1 to 79.167.255.25479.167.255.25532,766
8179.168.0.0/1779.168.0.1 to 79.168.127.25479.168.127.25532,766
8279.168.128.0/1779.168.128.1 to 79.168.255.25479.168.255.25532,766
8379.169.0.0/1779.169.0.1 to 79.169.127.25479.169.127.25532,766
8479.169.128.0/1779.169.128.1 to 79.169.255.25479.169.255.25532,766
8579.170.0.0/1779.170.0.1 to 79.170.127.25479.170.127.25532,766
8679.170.128.0/1779.170.128.1 to 79.170.255.25479.170.255.25532,766
8779.171.0.0/1779.171.0.1 to 79.171.127.25479.171.127.25532,766
8879.171.128.0/1779.171.128.1 to 79.171.255.25479.171.255.25532,766
8979.172.0.0/1779.172.0.1 to 79.172.127.25479.172.127.25532,766
9079.172.128.0/1779.172.128.1 to 79.172.255.25479.172.255.25532,766
9179.173.0.0/1779.173.0.1 to 79.173.127.25479.173.127.25532,766
9279.173.128.0/1779.173.128.1 to 79.173.255.25479.173.255.25532,766
9379.174.0.0/1779.174.0.1 to 79.174.127.25479.174.127.25532,766
9479.174.128.0/1779.174.128.1 to 79.174.255.25479.174.255.25532,766
9579.175.0.0/1779.175.0.1 to 79.175.127.25479.175.127.25532,766
9679.175.128.0/1779.175.128.1 to 79.175.255.25479.175.255.25532,766
9779.176.0.0/1779.176.0.1 to 79.176.127.25479.176.127.25532,766
9879.176.128.0/1779.176.128.1 to 79.176.255.25479.176.255.25532,766
9979.177.0.0/1779.177.0.1 to 79.177.127.25479.177.127.25532,766
10079.177.128.0/1779.177.128.1 to 79.177.255.25479.177.255.25532,766
10179.178.0.0/1779.178.0.1 to 79.178.127.25479.178.127.25532,766
10279.178.128.0/1779.178.128.1 to 79.178.255.25479.178.255.25532,766
10379.179.0.0/1779.179.0.1 to 79.179.127.25479.179.127.25532,766
10479.179.128.0/1779.179.128.1 to 79.179.255.25479.179.255.25532,766
10579.180.0.0/1779.180.0.1 to 79.180.127.25479.180.127.25532,766
10679.180.128.0/1779.180.128.1 to 79.180.255.25479.180.255.25532,766
10779.181.0.0/1779.181.0.1 to 79.181.127.25479.181.127.25532,766
10879.181.128.0/1779.181.128.1 to 79.181.255.25479.181.255.25532,766
10979.182.0.0/1779.182.0.1 to 79.182.127.25479.182.127.25532,766
11079.182.128.0/1779.182.128.1 to 79.182.255.25479.182.255.25532,766
11179.183.0.0/1779.183.0.1 to 79.183.127.25479.183.127.25532,766
11279.183.128.0/1779.183.128.1 to 79.183.255.25479.183.255.25532,766
11379.184.0.0/1779.184.0.1 to 79.184.127.25479.184.127.25532,766
11479.184.128.0/1779.184.128.1 to 79.184.255.25479.184.255.25532,766
11579.185.0.0/1779.185.0.1 to 79.185.127.25479.185.127.25532,766
11679.185.128.0/1779.185.128.1 to 79.185.255.25479.185.255.25532,766
11779.186.0.0/1779.186.0.1 to 79.186.127.25479.186.127.25532,766
11879.186.128.0/1779.186.128.1 to 79.186.255.25479.186.255.25532,766
11979.187.0.0/1779.187.0.1 to 79.187.127.25479.187.127.25532,766
12079.187.128.0/1779.187.128.1 to 79.187.255.25479.187.255.25532,766
12179.188.0.0/1779.188.0.1 to 79.188.127.25479.188.127.25532,766
12279.188.128.0/1779.188.128.1 to 79.188.255.25479.188.255.25532,766
12379.189.0.0/1779.189.0.1 to 79.189.127.25479.189.127.25532,766
12479.189.128.0/1779.189.128.1 to 79.189.255.25479.189.255.25532,766
12579.190.0.0/1779.190.0.1 to 79.190.127.25479.190.127.25532,766
12679.190.128.0/1779.190.128.1 to 79.190.255.25479.190.255.25532,766
12779.191.0.0/1779.191.0.1 to 79.191.127.25479.191.127.25532,766
12879.191.128.0/1779.191.128.1 to 79.191.255.25479.191.255.25532,766
12979.192.0.0/1779.192.0.1 to 79.192.127.25479.192.127.25532,766
13079.192.128.0/1779.192.128.1 to 79.192.255.25479.192.255.25532,766
13179.193.0.0/1779.193.0.1 to 79.193.127.25479.193.127.25532,766
13279.193.128.0/1779.193.128.1 to 79.193.255.25479.193.255.25532,766
13379.194.0.0/1779.194.0.1 to 79.194.127.25479.194.127.25532,766
13479.194.128.0/1779.194.128.1 to 79.194.255.25479.194.255.25532,766
13579.195.0.0/1779.195.0.1 to 79.195.127.25479.195.127.25532,766
13679.195.128.0/1779.195.128.1 to 79.195.255.25479.195.255.25532,766
13779.196.0.0/1779.196.0.1 to 79.196.127.25479.196.127.25532,766
13879.196.128.0/1779.196.128.1 to 79.196.255.25479.196.255.25532,766
13979.197.0.0/1779.197.0.1 to 79.197.127.25479.197.127.25532,766
14079.197.128.0/1779.197.128.1 to 79.197.255.25479.197.255.25532,766
14179.198.0.0/1779.198.0.1 to 79.198.127.25479.198.127.25532,766
14279.198.128.0/1779.198.128.1 to 79.198.255.25479.198.255.25532,766
14379.199.0.0/1779.199.0.1 to 79.199.127.25479.199.127.25532,766
14479.199.128.0/1779.199.128.1 to 79.199.255.25479.199.255.25532,766
14579.200.0.0/1779.200.0.1 to 79.200.127.25479.200.127.25532,766
14679.200.128.0/1779.200.128.1 to 79.200.255.25479.200.255.25532,766
14779.201.0.0/1779.201.0.1 to 79.201.127.25479.201.127.25532,766
14879.201.128.0/1779.201.128.1 to 79.201.255.25479.201.255.25532,766
14979.202.0.0/1779.202.0.1 to 79.202.127.25479.202.127.25532,766
15079.202.128.0/1779.202.128.1 to 79.202.255.25479.202.255.25532,766
15179.203.0.0/1779.203.0.1 to 79.203.127.25479.203.127.25532,766
15279.203.128.0/1779.203.128.1 to 79.203.255.25479.203.255.25532,766
15379.204.0.0/1779.204.0.1 to 79.204.127.25479.204.127.25532,766
15479.204.128.0/1779.204.128.1 to 79.204.255.25479.204.255.25532,766
15579.205.0.0/1779.205.0.1 to 79.205.127.25479.205.127.25532,766
15679.205.128.0/1779.205.128.1 to 79.205.255.25479.205.255.25532,766
15779.206.0.0/1779.206.0.1 to 79.206.127.25479.206.127.25532,766
15879.206.128.0/1779.206.128.1 to 79.206.255.25479.206.255.25532,766
15979.207.0.0/1779.207.0.1 to 79.207.127.25479.207.127.25532,766
16079.207.128.0/1779.207.128.1 to 79.207.255.25479.207.255.25532,766
16179.208.0.0/1779.208.0.1 to 79.208.127.25479.208.127.25532,766
16279.208.128.0/1779.208.128.1 to 79.208.255.25479.208.255.25532,766
16379.209.0.0/1779.209.0.1 to 79.209.127.25479.209.127.25532,766
16479.209.128.0/1779.209.128.1 to 79.209.255.25479.209.255.25532,766
16579.210.0.0/1779.210.0.1 to 79.210.127.25479.210.127.25532,766
16679.210.128.0/1779.210.128.1 to 79.210.255.25479.210.255.25532,766
16779.211.0.0/1779.211.0.1 to 79.211.127.25479.211.127.25532,766
16879.211.128.0/1779.211.128.1 to 79.211.255.25479.211.255.25532,766
16979.212.0.0/1779.212.0.1 to 79.212.127.25479.212.127.25532,766
17079.212.128.0/1779.212.128.1 to 79.212.255.25479.212.255.25532,766
17179.213.0.0/1779.213.0.1 to 79.213.127.25479.213.127.25532,766
17279.213.128.0/1779.213.128.1 to 79.213.255.25479.213.255.25532,766
17379.214.0.0/1779.214.0.1 to 79.214.127.25479.214.127.25532,766
17479.214.128.0/1779.214.128.1 to 79.214.255.25479.214.255.25532,766
17579.215.0.0/1779.215.0.1 to 79.215.127.25479.215.127.25532,766
17679.215.128.0/1779.215.128.1 to 79.215.255.25479.215.255.25532,766
17779.216.0.0/1779.216.0.1 to 79.216.127.25479.216.127.25532,766
17879.216.128.0/1779.216.128.1 to 79.216.255.25479.216.255.25532,766
17979.217.0.0/1779.217.0.1 to 79.217.127.25479.217.127.25532,766
18079.217.128.0/1779.217.128.1 to 79.217.255.25479.217.255.25532,766
18179.218.0.0/1779.218.0.1 to 79.218.127.25479.218.127.25532,766
18279.218.128.0/1779.218.128.1 to 79.218.255.25479.218.255.25532,766
18379.219.0.0/1779.219.0.1 to 79.219.127.25479.219.127.25532,766
18479.219.128.0/1779.219.128.1 to 79.219.255.25479.219.255.25532,766
18579.220.0.0/1779.220.0.1 to 79.220.127.25479.220.127.25532,766
18679.220.128.0/1779.220.128.1 to 79.220.255.25479.220.255.25532,766
18779.221.0.0/1779.221.0.1 to 79.221.127.25479.221.127.25532,766
18879.221.128.0/1779.221.128.1 to 79.221.255.25479.221.255.25532,766
18979.222.0.0/1779.222.0.1 to 79.222.127.25479.222.127.25532,766
19079.222.128.0/1779.222.128.1 to 79.222.255.25479.222.255.25532,766
19179.223.0.0/1779.223.0.1 to 79.223.127.25479.223.127.25532,766
19279.223.128.0/1779.223.128.1 to 79.223.255.25479.223.255.25532,766
19379.224.0.0/1779.224.0.1 to 79.224.127.25479.224.127.25532,766
19479.224.128.0/1779.224.128.1 to 79.224.255.25479.224.255.25532,766
19579.225.0.0/1779.225.0.1 to 79.225.127.25479.225.127.25532,766
19679.225.128.0/1779.225.128.1 to 79.225.255.25479.225.255.25532,766
19779.226.0.0/1779.226.0.1 to 79.226.127.25479.226.127.25532,766
19879.226.128.0/1779.226.128.1 to 79.226.255.25479.226.255.25532,766
19979.227.0.0/1779.227.0.1 to 79.227.127.25479.227.127.25532,766
20079.227.128.0/1779.227.128.1 to 79.227.255.25479.227.255.25532,766
20179.228.0.0/1779.228.0.1 to 79.228.127.25479.228.127.25532,766
20279.228.128.0/1779.228.128.1 to 79.228.255.25479.228.255.25532,766
20379.229.0.0/1779.229.0.1 to 79.229.127.25479.229.127.25532,766
20479.229.128.0/1779.229.128.1 to 79.229.255.25479.229.255.25532,766
20579.230.0.0/1779.230.0.1 to 79.230.127.25479.230.127.25532,766
20679.230.128.0/1779.230.128.1 to 79.230.255.25479.230.255.25532,766
20779.231.0.0/1779.231.0.1 to 79.231.127.25479.231.127.25532,766
20879.231.128.0/1779.231.128.1 to 79.231.255.25479.231.255.25532,766
20979.232.0.0/1779.232.0.1 to 79.232.127.25479.232.127.25532,766
21079.232.128.0/1779.232.128.1 to 79.232.255.25479.232.255.25532,766
21179.233.0.0/1779.233.0.1 to 79.233.127.25479.233.127.25532,766
21279.233.128.0/1779.233.128.1 to 79.233.255.25479.233.255.25532,766
21379.234.0.0/1779.234.0.1 to 79.234.127.25479.234.127.25532,766
21479.234.128.0/1779.234.128.1 to 79.234.255.25479.234.255.25532,766
21579.235.0.0/1779.235.0.1 to 79.235.127.25479.235.127.25532,766
21679.235.128.0/1779.235.128.1 to 79.235.255.25479.235.255.25532,766
21779.236.0.0/1779.236.0.1 to 79.236.127.25479.236.127.25532,766
21879.236.128.0/1779.236.128.1 to 79.236.255.25479.236.255.25532,766
21979.237.0.0/1779.237.0.1 to 79.237.127.25479.237.127.25532,766
22079.237.128.0/1779.237.128.1 to 79.237.255.25479.237.255.25532,766
22179.238.0.0/1779.238.0.1 to 79.238.127.25479.238.127.25532,766
22279.238.128.0/1779.238.128.1 to 79.238.255.25479.238.255.25532,766
22379.239.0.0/1779.239.0.1 to 79.239.127.25479.239.127.25532,766
22479.239.128.0/1779.239.128.1 to 79.239.255.25479.239.255.25532,766
22579.240.0.0/1779.240.0.1 to 79.240.127.25479.240.127.25532,766
22679.240.128.0/1779.240.128.1 to 79.240.255.25479.240.255.25532,766
22779.241.0.0/1779.241.0.1 to 79.241.127.25479.241.127.25532,766
22879.241.128.0/1779.241.128.1 to 79.241.255.25479.241.255.25532,766
22979.242.0.0/1779.242.0.1 to 79.242.127.25479.242.127.25532,766
23079.242.128.0/1779.242.128.1 to 79.242.255.25479.242.255.25532,766
23179.243.0.0/1779.243.0.1 to 79.243.127.25479.243.127.25532,766
23279.243.128.0/1779.243.128.1 to 79.243.255.25479.243.255.25532,766
23379.244.0.0/1779.244.0.1 to 79.244.127.25479.244.127.25532,766
23479.244.128.0/1779.244.128.1 to 79.244.255.25479.244.255.25532,766
23579.245.0.0/1779.245.0.1 to 79.245.127.25479.245.127.25532,766
23679.245.128.0/1779.245.128.1 to 79.245.255.25479.245.255.25532,766
23779.246.0.0/1779.246.0.1 to 79.246.127.25479.246.127.25532,766
23879.246.128.0/1779.246.128.1 to 79.246.255.25479.246.255.25532,766
23979.247.0.0/1779.247.0.1 to 79.247.127.25479.247.127.25532,766
24079.247.128.0/1779.247.128.1 to 79.247.255.25479.247.255.25532,766
24179.248.0.0/1779.248.0.1 to 79.248.127.25479.248.127.25532,766
24279.248.128.0/1779.248.128.1 to 79.248.255.25479.248.255.25532,766
24379.249.0.0/1779.249.0.1 to 79.249.127.25479.249.127.25532,766
24479.249.128.0/1779.249.128.1 to 79.249.255.25479.249.255.25532,766
24579.250.0.0/1779.250.0.1 to 79.250.127.25479.250.127.25532,766
24679.250.128.0/1779.250.128.1 to 79.250.255.25479.250.255.25532,766
24779.251.0.0/1779.251.0.1 to 79.251.127.25479.251.127.25532,766
24879.251.128.0/1779.251.128.1 to 79.251.255.25479.251.255.25532,766
24979.252.0.0/1779.252.0.1 to 79.252.127.25479.252.127.25532,766
25079.252.128.0/1779.252.128.1 to 79.252.255.25479.252.255.25532,766
25179.253.0.0/1779.253.0.1 to 79.253.127.25479.253.127.25532,766
25279.253.128.0/1779.253.128.1 to 79.253.255.25479.253.255.25532,766
25379.254.0.0/1779.254.0.1 to 79.254.127.25479.254.127.25532,766
25479.254.128.0/1779.254.128.1 to 79.254.255.25479.254.255.25532,766
25579.255.0.0/1779.255.0.1 to 79.255.127.25479.255.127.25532,766
25679.255.128.0/1779.255.128.1 to 79.255.255.25479.255.255.25532,766

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.