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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.

Network38.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
38.128.0.0
Broadcast address
38.255.255.255
First usable
38.128.0.1
Last usable
38.255.255.254
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 26800000 · Integer 645922816 to 654311423
Reverse DNS zones
128.38.in-addr.arpa
129.38.in-addr.arpa
130.38.in-addr.arpa
131.38.in-addr.arpa
132.38.in-addr.arpa
133.38.in-addr.arpa
134.38.in-addr.arpa
135.38.in-addr.arpa
136.38.in-addr.arpa
137.38.in-addr.arpa
138.38.in-addr.arpa
139.38.in-addr.arpa
140.38.in-addr.arpa
141.38.in-addr.arpa
142.38.in-addr.arpa
143.38.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
Address00100110.10000000.00000000.0000000038.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00100110.10000000.00000000.0000000038.128.0.0
Broadcast00100110.11111111.11111111.1111111138.255.255.255
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)

38.128.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
138.128.0.0/1738.128.0.1 to 38.128.127.25438.128.127.25532,766
238.128.128.0/1738.128.128.1 to 38.128.255.25438.128.255.25532,766
338.129.0.0/1738.129.0.1 to 38.129.127.25438.129.127.25532,766
438.129.128.0/1738.129.128.1 to 38.129.255.25438.129.255.25532,766
538.130.0.0/1738.130.0.1 to 38.130.127.25438.130.127.25532,766
638.130.128.0/1738.130.128.1 to 38.130.255.25438.130.255.25532,766
738.131.0.0/1738.131.0.1 to 38.131.127.25438.131.127.25532,766
838.131.128.0/1738.131.128.1 to 38.131.255.25438.131.255.25532,766
938.132.0.0/1738.132.0.1 to 38.132.127.25438.132.127.25532,766
1038.132.128.0/1738.132.128.1 to 38.132.255.25438.132.255.25532,766
1138.133.0.0/1738.133.0.1 to 38.133.127.25438.133.127.25532,766
1238.133.128.0/1738.133.128.1 to 38.133.255.25438.133.255.25532,766
1338.134.0.0/1738.134.0.1 to 38.134.127.25438.134.127.25532,766
1438.134.128.0/1738.134.128.1 to 38.134.255.25438.134.255.25532,766
1538.135.0.0/1738.135.0.1 to 38.135.127.25438.135.127.25532,766
1638.135.128.0/1738.135.128.1 to 38.135.255.25438.135.255.25532,766
1738.136.0.0/1738.136.0.1 to 38.136.127.25438.136.127.25532,766
1838.136.128.0/1738.136.128.1 to 38.136.255.25438.136.255.25532,766
1938.137.0.0/1738.137.0.1 to 38.137.127.25438.137.127.25532,766
2038.137.128.0/1738.137.128.1 to 38.137.255.25438.137.255.25532,766
2138.138.0.0/1738.138.0.1 to 38.138.127.25438.138.127.25532,766
2238.138.128.0/1738.138.128.1 to 38.138.255.25438.138.255.25532,766
2338.139.0.0/1738.139.0.1 to 38.139.127.25438.139.127.25532,766
2438.139.128.0/1738.139.128.1 to 38.139.255.25438.139.255.25532,766
2538.140.0.0/1738.140.0.1 to 38.140.127.25438.140.127.25532,766
2638.140.128.0/1738.140.128.1 to 38.140.255.25438.140.255.25532,766
2738.141.0.0/1738.141.0.1 to 38.141.127.25438.141.127.25532,766
2838.141.128.0/1738.141.128.1 to 38.141.255.25438.141.255.25532,766
2938.142.0.0/1738.142.0.1 to 38.142.127.25438.142.127.25532,766
3038.142.128.0/1738.142.128.1 to 38.142.255.25438.142.255.25532,766
3138.143.0.0/1738.143.0.1 to 38.143.127.25438.143.127.25532,766
3238.143.128.0/1738.143.128.1 to 38.143.255.25438.143.255.25532,766
3338.144.0.0/1738.144.0.1 to 38.144.127.25438.144.127.25532,766
3438.144.128.0/1738.144.128.1 to 38.144.255.25438.144.255.25532,766
3538.145.0.0/1738.145.0.1 to 38.145.127.25438.145.127.25532,766
3638.145.128.0/1738.145.128.1 to 38.145.255.25438.145.255.25532,766
3738.146.0.0/1738.146.0.1 to 38.146.127.25438.146.127.25532,766
3838.146.128.0/1738.146.128.1 to 38.146.255.25438.146.255.25532,766
3938.147.0.0/1738.147.0.1 to 38.147.127.25438.147.127.25532,766
4038.147.128.0/1738.147.128.1 to 38.147.255.25438.147.255.25532,766
4138.148.0.0/1738.148.0.1 to 38.148.127.25438.148.127.25532,766
4238.148.128.0/1738.148.128.1 to 38.148.255.25438.148.255.25532,766
4338.149.0.0/1738.149.0.1 to 38.149.127.25438.149.127.25532,766
4438.149.128.0/1738.149.128.1 to 38.149.255.25438.149.255.25532,766
4538.150.0.0/1738.150.0.1 to 38.150.127.25438.150.127.25532,766
4638.150.128.0/1738.150.128.1 to 38.150.255.25438.150.255.25532,766
4738.151.0.0/1738.151.0.1 to 38.151.127.25438.151.127.25532,766
4838.151.128.0/1738.151.128.1 to 38.151.255.25438.151.255.25532,766
4938.152.0.0/1738.152.0.1 to 38.152.127.25438.152.127.25532,766
5038.152.128.0/1738.152.128.1 to 38.152.255.25438.152.255.25532,766
5138.153.0.0/1738.153.0.1 to 38.153.127.25438.153.127.25532,766
5238.153.128.0/1738.153.128.1 to 38.153.255.25438.153.255.25532,766
5338.154.0.0/1738.154.0.1 to 38.154.127.25438.154.127.25532,766
5438.154.128.0/1738.154.128.1 to 38.154.255.25438.154.255.25532,766
5538.155.0.0/1738.155.0.1 to 38.155.127.25438.155.127.25532,766
5638.155.128.0/1738.155.128.1 to 38.155.255.25438.155.255.25532,766
5738.156.0.0/1738.156.0.1 to 38.156.127.25438.156.127.25532,766
5838.156.128.0/1738.156.128.1 to 38.156.255.25438.156.255.25532,766
5938.157.0.0/1738.157.0.1 to 38.157.127.25438.157.127.25532,766
6038.157.128.0/1738.157.128.1 to 38.157.255.25438.157.255.25532,766
6138.158.0.0/1738.158.0.1 to 38.158.127.25438.158.127.25532,766
6238.158.128.0/1738.158.128.1 to 38.158.255.25438.158.255.25532,766
6338.159.0.0/1738.159.0.1 to 38.159.127.25438.159.127.25532,766
6438.159.128.0/1738.159.128.1 to 38.159.255.25438.159.255.25532,766
6538.160.0.0/1738.160.0.1 to 38.160.127.25438.160.127.25532,766
6638.160.128.0/1738.160.128.1 to 38.160.255.25438.160.255.25532,766
6738.161.0.0/1738.161.0.1 to 38.161.127.25438.161.127.25532,766
6838.161.128.0/1738.161.128.1 to 38.161.255.25438.161.255.25532,766
6938.162.0.0/1738.162.0.1 to 38.162.127.25438.162.127.25532,766
7038.162.128.0/1738.162.128.1 to 38.162.255.25438.162.255.25532,766
7138.163.0.0/1738.163.0.1 to 38.163.127.25438.163.127.25532,766
7238.163.128.0/1738.163.128.1 to 38.163.255.25438.163.255.25532,766
7338.164.0.0/1738.164.0.1 to 38.164.127.25438.164.127.25532,766
7438.164.128.0/1738.164.128.1 to 38.164.255.25438.164.255.25532,766
7538.165.0.0/1738.165.0.1 to 38.165.127.25438.165.127.25532,766
7638.165.128.0/1738.165.128.1 to 38.165.255.25438.165.255.25532,766
7738.166.0.0/1738.166.0.1 to 38.166.127.25438.166.127.25532,766
7838.166.128.0/1738.166.128.1 to 38.166.255.25438.166.255.25532,766
7938.167.0.0/1738.167.0.1 to 38.167.127.25438.167.127.25532,766
8038.167.128.0/1738.167.128.1 to 38.167.255.25438.167.255.25532,766
8138.168.0.0/1738.168.0.1 to 38.168.127.25438.168.127.25532,766
8238.168.128.0/1738.168.128.1 to 38.168.255.25438.168.255.25532,766
8338.169.0.0/1738.169.0.1 to 38.169.127.25438.169.127.25532,766
8438.169.128.0/1738.169.128.1 to 38.169.255.25438.169.255.25532,766
8538.170.0.0/1738.170.0.1 to 38.170.127.25438.170.127.25532,766
8638.170.128.0/1738.170.128.1 to 38.170.255.25438.170.255.25532,766
8738.171.0.0/1738.171.0.1 to 38.171.127.25438.171.127.25532,766
8838.171.128.0/1738.171.128.1 to 38.171.255.25438.171.255.25532,766
8938.172.0.0/1738.172.0.1 to 38.172.127.25438.172.127.25532,766
9038.172.128.0/1738.172.128.1 to 38.172.255.25438.172.255.25532,766
9138.173.0.0/1738.173.0.1 to 38.173.127.25438.173.127.25532,766
9238.173.128.0/1738.173.128.1 to 38.173.255.25438.173.255.25532,766
9338.174.0.0/1738.174.0.1 to 38.174.127.25438.174.127.25532,766
9438.174.128.0/1738.174.128.1 to 38.174.255.25438.174.255.25532,766
9538.175.0.0/1738.175.0.1 to 38.175.127.25438.175.127.25532,766
9638.175.128.0/1738.175.128.1 to 38.175.255.25438.175.255.25532,766
9738.176.0.0/1738.176.0.1 to 38.176.127.25438.176.127.25532,766
9838.176.128.0/1738.176.128.1 to 38.176.255.25438.176.255.25532,766
9938.177.0.0/1738.177.0.1 to 38.177.127.25438.177.127.25532,766
10038.177.128.0/1738.177.128.1 to 38.177.255.25438.177.255.25532,766
10138.178.0.0/1738.178.0.1 to 38.178.127.25438.178.127.25532,766
10238.178.128.0/1738.178.128.1 to 38.178.255.25438.178.255.25532,766
10338.179.0.0/1738.179.0.1 to 38.179.127.25438.179.127.25532,766
10438.179.128.0/1738.179.128.1 to 38.179.255.25438.179.255.25532,766
10538.180.0.0/1738.180.0.1 to 38.180.127.25438.180.127.25532,766
10638.180.128.0/1738.180.128.1 to 38.180.255.25438.180.255.25532,766
10738.181.0.0/1738.181.0.1 to 38.181.127.25438.181.127.25532,766
10838.181.128.0/1738.181.128.1 to 38.181.255.25438.181.255.25532,766
10938.182.0.0/1738.182.0.1 to 38.182.127.25438.182.127.25532,766
11038.182.128.0/1738.182.128.1 to 38.182.255.25438.182.255.25532,766
11138.183.0.0/1738.183.0.1 to 38.183.127.25438.183.127.25532,766
11238.183.128.0/1738.183.128.1 to 38.183.255.25438.183.255.25532,766
11338.184.0.0/1738.184.0.1 to 38.184.127.25438.184.127.25532,766
11438.184.128.0/1738.184.128.1 to 38.184.255.25438.184.255.25532,766
11538.185.0.0/1738.185.0.1 to 38.185.127.25438.185.127.25532,766
11638.185.128.0/1738.185.128.1 to 38.185.255.25438.185.255.25532,766
11738.186.0.0/1738.186.0.1 to 38.186.127.25438.186.127.25532,766
11838.186.128.0/1738.186.128.1 to 38.186.255.25438.186.255.25532,766
11938.187.0.0/1738.187.0.1 to 38.187.127.25438.187.127.25532,766
12038.187.128.0/1738.187.128.1 to 38.187.255.25438.187.255.25532,766
12138.188.0.0/1738.188.0.1 to 38.188.127.25438.188.127.25532,766
12238.188.128.0/1738.188.128.1 to 38.188.255.25438.188.255.25532,766
12338.189.0.0/1738.189.0.1 to 38.189.127.25438.189.127.25532,766
12438.189.128.0/1738.189.128.1 to 38.189.255.25438.189.255.25532,766
12538.190.0.0/1738.190.0.1 to 38.190.127.25438.190.127.25532,766
12638.190.128.0/1738.190.128.1 to 38.190.255.25438.190.255.25532,766
12738.191.0.0/1738.191.0.1 to 38.191.127.25438.191.127.25532,766
12838.191.128.0/1738.191.128.1 to 38.191.255.25438.191.255.25532,766
12938.192.0.0/1738.192.0.1 to 38.192.127.25438.192.127.25532,766
13038.192.128.0/1738.192.128.1 to 38.192.255.25438.192.255.25532,766
13138.193.0.0/1738.193.0.1 to 38.193.127.25438.193.127.25532,766
13238.193.128.0/1738.193.128.1 to 38.193.255.25438.193.255.25532,766
13338.194.0.0/1738.194.0.1 to 38.194.127.25438.194.127.25532,766
13438.194.128.0/1738.194.128.1 to 38.194.255.25438.194.255.25532,766
13538.195.0.0/1738.195.0.1 to 38.195.127.25438.195.127.25532,766
13638.195.128.0/1738.195.128.1 to 38.195.255.25438.195.255.25532,766
13738.196.0.0/1738.196.0.1 to 38.196.127.25438.196.127.25532,766
13838.196.128.0/1738.196.128.1 to 38.196.255.25438.196.255.25532,766
13938.197.0.0/1738.197.0.1 to 38.197.127.25438.197.127.25532,766
14038.197.128.0/1738.197.128.1 to 38.197.255.25438.197.255.25532,766
14138.198.0.0/1738.198.0.1 to 38.198.127.25438.198.127.25532,766
14238.198.128.0/1738.198.128.1 to 38.198.255.25438.198.255.25532,766
14338.199.0.0/1738.199.0.1 to 38.199.127.25438.199.127.25532,766
14438.199.128.0/1738.199.128.1 to 38.199.255.25438.199.255.25532,766
14538.200.0.0/1738.200.0.1 to 38.200.127.25438.200.127.25532,766
14638.200.128.0/1738.200.128.1 to 38.200.255.25438.200.255.25532,766
14738.201.0.0/1738.201.0.1 to 38.201.127.25438.201.127.25532,766
14838.201.128.0/1738.201.128.1 to 38.201.255.25438.201.255.25532,766
14938.202.0.0/1738.202.0.1 to 38.202.127.25438.202.127.25532,766
15038.202.128.0/1738.202.128.1 to 38.202.255.25438.202.255.25532,766
15138.203.0.0/1738.203.0.1 to 38.203.127.25438.203.127.25532,766
15238.203.128.0/1738.203.128.1 to 38.203.255.25438.203.255.25532,766
15338.204.0.0/1738.204.0.1 to 38.204.127.25438.204.127.25532,766
15438.204.128.0/1738.204.128.1 to 38.204.255.25438.204.255.25532,766
15538.205.0.0/1738.205.0.1 to 38.205.127.25438.205.127.25532,766
15638.205.128.0/1738.205.128.1 to 38.205.255.25438.205.255.25532,766
15738.206.0.0/1738.206.0.1 to 38.206.127.25438.206.127.25532,766
15838.206.128.0/1738.206.128.1 to 38.206.255.25438.206.255.25532,766
15938.207.0.0/1738.207.0.1 to 38.207.127.25438.207.127.25532,766
16038.207.128.0/1738.207.128.1 to 38.207.255.25438.207.255.25532,766
16138.208.0.0/1738.208.0.1 to 38.208.127.25438.208.127.25532,766
16238.208.128.0/1738.208.128.1 to 38.208.255.25438.208.255.25532,766
16338.209.0.0/1738.209.0.1 to 38.209.127.25438.209.127.25532,766
16438.209.128.0/1738.209.128.1 to 38.209.255.25438.209.255.25532,766
16538.210.0.0/1738.210.0.1 to 38.210.127.25438.210.127.25532,766
16638.210.128.0/1738.210.128.1 to 38.210.255.25438.210.255.25532,766
16738.211.0.0/1738.211.0.1 to 38.211.127.25438.211.127.25532,766
16838.211.128.0/1738.211.128.1 to 38.211.255.25438.211.255.25532,766
16938.212.0.0/1738.212.0.1 to 38.212.127.25438.212.127.25532,766
17038.212.128.0/1738.212.128.1 to 38.212.255.25438.212.255.25532,766
17138.213.0.0/1738.213.0.1 to 38.213.127.25438.213.127.25532,766
17238.213.128.0/1738.213.128.1 to 38.213.255.25438.213.255.25532,766
17338.214.0.0/1738.214.0.1 to 38.214.127.25438.214.127.25532,766
17438.214.128.0/1738.214.128.1 to 38.214.255.25438.214.255.25532,766
17538.215.0.0/1738.215.0.1 to 38.215.127.25438.215.127.25532,766
17638.215.128.0/1738.215.128.1 to 38.215.255.25438.215.255.25532,766
17738.216.0.0/1738.216.0.1 to 38.216.127.25438.216.127.25532,766
17838.216.128.0/1738.216.128.1 to 38.216.255.25438.216.255.25532,766
17938.217.0.0/1738.217.0.1 to 38.217.127.25438.217.127.25532,766
18038.217.128.0/1738.217.128.1 to 38.217.255.25438.217.255.25532,766
18138.218.0.0/1738.218.0.1 to 38.218.127.25438.218.127.25532,766
18238.218.128.0/1738.218.128.1 to 38.218.255.25438.218.255.25532,766
18338.219.0.0/1738.219.0.1 to 38.219.127.25438.219.127.25532,766
18438.219.128.0/1738.219.128.1 to 38.219.255.25438.219.255.25532,766
18538.220.0.0/1738.220.0.1 to 38.220.127.25438.220.127.25532,766
18638.220.128.0/1738.220.128.1 to 38.220.255.25438.220.255.25532,766
18738.221.0.0/1738.221.0.1 to 38.221.127.25438.221.127.25532,766
18838.221.128.0/1738.221.128.1 to 38.221.255.25438.221.255.25532,766
18938.222.0.0/1738.222.0.1 to 38.222.127.25438.222.127.25532,766
19038.222.128.0/1738.222.128.1 to 38.222.255.25438.222.255.25532,766
19138.223.0.0/1738.223.0.1 to 38.223.127.25438.223.127.25532,766
19238.223.128.0/1738.223.128.1 to 38.223.255.25438.223.255.25532,766
19338.224.0.0/1738.224.0.1 to 38.224.127.25438.224.127.25532,766
19438.224.128.0/1738.224.128.1 to 38.224.255.25438.224.255.25532,766
19538.225.0.0/1738.225.0.1 to 38.225.127.25438.225.127.25532,766
19638.225.128.0/1738.225.128.1 to 38.225.255.25438.225.255.25532,766
19738.226.0.0/1738.226.0.1 to 38.226.127.25438.226.127.25532,766
19838.226.128.0/1738.226.128.1 to 38.226.255.25438.226.255.25532,766
19938.227.0.0/1738.227.0.1 to 38.227.127.25438.227.127.25532,766
20038.227.128.0/1738.227.128.1 to 38.227.255.25438.227.255.25532,766
20138.228.0.0/1738.228.0.1 to 38.228.127.25438.228.127.25532,766
20238.228.128.0/1738.228.128.1 to 38.228.255.25438.228.255.25532,766
20338.229.0.0/1738.229.0.1 to 38.229.127.25438.229.127.25532,766
20438.229.128.0/1738.229.128.1 to 38.229.255.25438.229.255.25532,766
20538.230.0.0/1738.230.0.1 to 38.230.127.25438.230.127.25532,766
20638.230.128.0/1738.230.128.1 to 38.230.255.25438.230.255.25532,766
20738.231.0.0/1738.231.0.1 to 38.231.127.25438.231.127.25532,766
20838.231.128.0/1738.231.128.1 to 38.231.255.25438.231.255.25532,766
20938.232.0.0/1738.232.0.1 to 38.232.127.25438.232.127.25532,766
21038.232.128.0/1738.232.128.1 to 38.232.255.25438.232.255.25532,766
21138.233.0.0/1738.233.0.1 to 38.233.127.25438.233.127.25532,766
21238.233.128.0/1738.233.128.1 to 38.233.255.25438.233.255.25532,766
21338.234.0.0/1738.234.0.1 to 38.234.127.25438.234.127.25532,766
21438.234.128.0/1738.234.128.1 to 38.234.255.25438.234.255.25532,766
21538.235.0.0/1738.235.0.1 to 38.235.127.25438.235.127.25532,766
21638.235.128.0/1738.235.128.1 to 38.235.255.25438.235.255.25532,766
21738.236.0.0/1738.236.0.1 to 38.236.127.25438.236.127.25532,766
21838.236.128.0/1738.236.128.1 to 38.236.255.25438.236.255.25532,766
21938.237.0.0/1738.237.0.1 to 38.237.127.25438.237.127.25532,766
22038.237.128.0/1738.237.128.1 to 38.237.255.25438.237.255.25532,766
22138.238.0.0/1738.238.0.1 to 38.238.127.25438.238.127.25532,766
22238.238.128.0/1738.238.128.1 to 38.238.255.25438.238.255.25532,766
22338.239.0.0/1738.239.0.1 to 38.239.127.25438.239.127.25532,766
22438.239.128.0/1738.239.128.1 to 38.239.255.25438.239.255.25532,766
22538.240.0.0/1738.240.0.1 to 38.240.127.25438.240.127.25532,766
22638.240.128.0/1738.240.128.1 to 38.240.255.25438.240.255.25532,766
22738.241.0.0/1738.241.0.1 to 38.241.127.25438.241.127.25532,766
22838.241.128.0/1738.241.128.1 to 38.241.255.25438.241.255.25532,766
22938.242.0.0/1738.242.0.1 to 38.242.127.25438.242.127.25532,766
23038.242.128.0/1738.242.128.1 to 38.242.255.25438.242.255.25532,766
23138.243.0.0/1738.243.0.1 to 38.243.127.25438.243.127.25532,766
23238.243.128.0/1738.243.128.1 to 38.243.255.25438.243.255.25532,766
23338.244.0.0/1738.244.0.1 to 38.244.127.25438.244.127.25532,766
23438.244.128.0/1738.244.128.1 to 38.244.255.25438.244.255.25532,766
23538.245.0.0/1738.245.0.1 to 38.245.127.25438.245.127.25532,766
23638.245.128.0/1738.245.128.1 to 38.245.255.25438.245.255.25532,766
23738.246.0.0/1738.246.0.1 to 38.246.127.25438.246.127.25532,766
23838.246.128.0/1738.246.128.1 to 38.246.255.25438.246.255.25532,766
23938.247.0.0/1738.247.0.1 to 38.247.127.25438.247.127.25532,766
24038.247.128.0/1738.247.128.1 to 38.247.255.25438.247.255.25532,766
24138.248.0.0/1738.248.0.1 to 38.248.127.25438.248.127.25532,766
24238.248.128.0/1738.248.128.1 to 38.248.255.25438.248.255.25532,766
24338.249.0.0/1738.249.0.1 to 38.249.127.25438.249.127.25532,766
24438.249.128.0/1738.249.128.1 to 38.249.255.25438.249.255.25532,766
24538.250.0.0/1738.250.0.1 to 38.250.127.25438.250.127.25532,766
24638.250.128.0/1738.250.128.1 to 38.250.255.25438.250.255.25532,766
24738.251.0.0/1738.251.0.1 to 38.251.127.25438.251.127.25532,766
24838.251.128.0/1738.251.128.1 to 38.251.255.25438.251.255.25532,766
24938.252.0.0/1738.252.0.1 to 38.252.127.25438.252.127.25532,766
25038.252.128.0/1738.252.128.1 to 38.252.255.25438.252.255.25532,766
25138.253.0.0/1738.253.0.1 to 38.253.127.25438.253.127.25532,766
25238.253.128.0/1738.253.128.1 to 38.253.255.25438.253.255.25532,766
25338.254.0.0/1738.254.0.1 to 38.254.127.25438.254.127.25532,766
25438.254.128.0/1738.254.128.1 to 38.254.255.25438.254.255.25532,766
25538.255.0.0/1738.255.0.1 to 38.255.127.25438.255.127.25532,766
25638.255.128.0/1738.255.128.1 to 38.255.255.25438.255.255.25532,766

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.