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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.

Network63.128.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
63.128.0.0
Broadcast address
63.191.255.255
First usable
63.128.0.1
Last usable
63.191.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 3F800000 · Integer 1065353216 to 1069547519
Reverse DNS zones
128.63.in-addr.arpa
129.63.in-addr.arpa
130.63.in-addr.arpa
131.63.in-addr.arpa
132.63.in-addr.arpa
133.63.in-addr.arpa
134.63.in-addr.arpa
135.63.in-addr.arpa
136.63.in-addr.arpa
137.63.in-addr.arpa
138.63.in-addr.arpa
139.63.in-addr.arpa
140.63.in-addr.arpa
141.63.in-addr.arpa
142.63.in-addr.arpa
143.63.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111111.10000000.00000000.0000000063.128.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00111111.10000000.00000000.0000000063.128.0.0
Broadcast00111111.10111111.11111111.1111111163.191.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

63.128.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
163.128.0.0/1863.128.0.1 to 63.128.63.25463.128.63.25516,382
263.128.64.0/1863.128.64.1 to 63.128.127.25463.128.127.25516,382
363.128.128.0/1863.128.128.1 to 63.128.191.25463.128.191.25516,382
463.128.192.0/1863.128.192.1 to 63.128.255.25463.128.255.25516,382
563.129.0.0/1863.129.0.1 to 63.129.63.25463.129.63.25516,382
663.129.64.0/1863.129.64.1 to 63.129.127.25463.129.127.25516,382
763.129.128.0/1863.129.128.1 to 63.129.191.25463.129.191.25516,382
863.129.192.0/1863.129.192.1 to 63.129.255.25463.129.255.25516,382
963.130.0.0/1863.130.0.1 to 63.130.63.25463.130.63.25516,382
1063.130.64.0/1863.130.64.1 to 63.130.127.25463.130.127.25516,382
1163.130.128.0/1863.130.128.1 to 63.130.191.25463.130.191.25516,382
1263.130.192.0/1863.130.192.1 to 63.130.255.25463.130.255.25516,382
1363.131.0.0/1863.131.0.1 to 63.131.63.25463.131.63.25516,382
1463.131.64.0/1863.131.64.1 to 63.131.127.25463.131.127.25516,382
1563.131.128.0/1863.131.128.1 to 63.131.191.25463.131.191.25516,382
1663.131.192.0/1863.131.192.1 to 63.131.255.25463.131.255.25516,382
1763.132.0.0/1863.132.0.1 to 63.132.63.25463.132.63.25516,382
1863.132.64.0/1863.132.64.1 to 63.132.127.25463.132.127.25516,382
1963.132.128.0/1863.132.128.1 to 63.132.191.25463.132.191.25516,382
2063.132.192.0/1863.132.192.1 to 63.132.255.25463.132.255.25516,382
2163.133.0.0/1863.133.0.1 to 63.133.63.25463.133.63.25516,382
2263.133.64.0/1863.133.64.1 to 63.133.127.25463.133.127.25516,382
2363.133.128.0/1863.133.128.1 to 63.133.191.25463.133.191.25516,382
2463.133.192.0/1863.133.192.1 to 63.133.255.25463.133.255.25516,382
2563.134.0.0/1863.134.0.1 to 63.134.63.25463.134.63.25516,382
2663.134.64.0/1863.134.64.1 to 63.134.127.25463.134.127.25516,382
2763.134.128.0/1863.134.128.1 to 63.134.191.25463.134.191.25516,382
2863.134.192.0/1863.134.192.1 to 63.134.255.25463.134.255.25516,382
2963.135.0.0/1863.135.0.1 to 63.135.63.25463.135.63.25516,382
3063.135.64.0/1863.135.64.1 to 63.135.127.25463.135.127.25516,382
3163.135.128.0/1863.135.128.1 to 63.135.191.25463.135.191.25516,382
3263.135.192.0/1863.135.192.1 to 63.135.255.25463.135.255.25516,382
3363.136.0.0/1863.136.0.1 to 63.136.63.25463.136.63.25516,382
3463.136.64.0/1863.136.64.1 to 63.136.127.25463.136.127.25516,382
3563.136.128.0/1863.136.128.1 to 63.136.191.25463.136.191.25516,382
3663.136.192.0/1863.136.192.1 to 63.136.255.25463.136.255.25516,382
3763.137.0.0/1863.137.0.1 to 63.137.63.25463.137.63.25516,382
3863.137.64.0/1863.137.64.1 to 63.137.127.25463.137.127.25516,382
3963.137.128.0/1863.137.128.1 to 63.137.191.25463.137.191.25516,382
4063.137.192.0/1863.137.192.1 to 63.137.255.25463.137.255.25516,382
4163.138.0.0/1863.138.0.1 to 63.138.63.25463.138.63.25516,382
4263.138.64.0/1863.138.64.1 to 63.138.127.25463.138.127.25516,382
4363.138.128.0/1863.138.128.1 to 63.138.191.25463.138.191.25516,382
4463.138.192.0/1863.138.192.1 to 63.138.255.25463.138.255.25516,382
4563.139.0.0/1863.139.0.1 to 63.139.63.25463.139.63.25516,382
4663.139.64.0/1863.139.64.1 to 63.139.127.25463.139.127.25516,382
4763.139.128.0/1863.139.128.1 to 63.139.191.25463.139.191.25516,382
4863.139.192.0/1863.139.192.1 to 63.139.255.25463.139.255.25516,382
4963.140.0.0/1863.140.0.1 to 63.140.63.25463.140.63.25516,382
5063.140.64.0/1863.140.64.1 to 63.140.127.25463.140.127.25516,382
5163.140.128.0/1863.140.128.1 to 63.140.191.25463.140.191.25516,382
5263.140.192.0/1863.140.192.1 to 63.140.255.25463.140.255.25516,382
5363.141.0.0/1863.141.0.1 to 63.141.63.25463.141.63.25516,382
5463.141.64.0/1863.141.64.1 to 63.141.127.25463.141.127.25516,382
5563.141.128.0/1863.141.128.1 to 63.141.191.25463.141.191.25516,382
5663.141.192.0/1863.141.192.1 to 63.141.255.25463.141.255.25516,382
5763.142.0.0/1863.142.0.1 to 63.142.63.25463.142.63.25516,382
5863.142.64.0/1863.142.64.1 to 63.142.127.25463.142.127.25516,382
5963.142.128.0/1863.142.128.1 to 63.142.191.25463.142.191.25516,382
6063.142.192.0/1863.142.192.1 to 63.142.255.25463.142.255.25516,382
6163.143.0.0/1863.143.0.1 to 63.143.63.25463.143.63.25516,382
6263.143.64.0/1863.143.64.1 to 63.143.127.25463.143.127.25516,382
6363.143.128.0/1863.143.128.1 to 63.143.191.25463.143.191.25516,382
6463.143.192.0/1863.143.192.1 to 63.143.255.25463.143.255.25516,382
6563.144.0.0/1863.144.0.1 to 63.144.63.25463.144.63.25516,382
6663.144.64.0/1863.144.64.1 to 63.144.127.25463.144.127.25516,382
6763.144.128.0/1863.144.128.1 to 63.144.191.25463.144.191.25516,382
6863.144.192.0/1863.144.192.1 to 63.144.255.25463.144.255.25516,382
6963.145.0.0/1863.145.0.1 to 63.145.63.25463.145.63.25516,382
7063.145.64.0/1863.145.64.1 to 63.145.127.25463.145.127.25516,382
7163.145.128.0/1863.145.128.1 to 63.145.191.25463.145.191.25516,382
7263.145.192.0/1863.145.192.1 to 63.145.255.25463.145.255.25516,382
7363.146.0.0/1863.146.0.1 to 63.146.63.25463.146.63.25516,382
7463.146.64.0/1863.146.64.1 to 63.146.127.25463.146.127.25516,382
7563.146.128.0/1863.146.128.1 to 63.146.191.25463.146.191.25516,382
7663.146.192.0/1863.146.192.1 to 63.146.255.25463.146.255.25516,382
7763.147.0.0/1863.147.0.1 to 63.147.63.25463.147.63.25516,382
7863.147.64.0/1863.147.64.1 to 63.147.127.25463.147.127.25516,382
7963.147.128.0/1863.147.128.1 to 63.147.191.25463.147.191.25516,382
8063.147.192.0/1863.147.192.1 to 63.147.255.25463.147.255.25516,382
8163.148.0.0/1863.148.0.1 to 63.148.63.25463.148.63.25516,382
8263.148.64.0/1863.148.64.1 to 63.148.127.25463.148.127.25516,382
8363.148.128.0/1863.148.128.1 to 63.148.191.25463.148.191.25516,382
8463.148.192.0/1863.148.192.1 to 63.148.255.25463.148.255.25516,382
8563.149.0.0/1863.149.0.1 to 63.149.63.25463.149.63.25516,382
8663.149.64.0/1863.149.64.1 to 63.149.127.25463.149.127.25516,382
8763.149.128.0/1863.149.128.1 to 63.149.191.25463.149.191.25516,382
8863.149.192.0/1863.149.192.1 to 63.149.255.25463.149.255.25516,382
8963.150.0.0/1863.150.0.1 to 63.150.63.25463.150.63.25516,382
9063.150.64.0/1863.150.64.1 to 63.150.127.25463.150.127.25516,382
9163.150.128.0/1863.150.128.1 to 63.150.191.25463.150.191.25516,382
9263.150.192.0/1863.150.192.1 to 63.150.255.25463.150.255.25516,382
9363.151.0.0/1863.151.0.1 to 63.151.63.25463.151.63.25516,382
9463.151.64.0/1863.151.64.1 to 63.151.127.25463.151.127.25516,382
9563.151.128.0/1863.151.128.1 to 63.151.191.25463.151.191.25516,382
9663.151.192.0/1863.151.192.1 to 63.151.255.25463.151.255.25516,382
9763.152.0.0/1863.152.0.1 to 63.152.63.25463.152.63.25516,382
9863.152.64.0/1863.152.64.1 to 63.152.127.25463.152.127.25516,382
9963.152.128.0/1863.152.128.1 to 63.152.191.25463.152.191.25516,382
10063.152.192.0/1863.152.192.1 to 63.152.255.25463.152.255.25516,382
10163.153.0.0/1863.153.0.1 to 63.153.63.25463.153.63.25516,382
10263.153.64.0/1863.153.64.1 to 63.153.127.25463.153.127.25516,382
10363.153.128.0/1863.153.128.1 to 63.153.191.25463.153.191.25516,382
10463.153.192.0/1863.153.192.1 to 63.153.255.25463.153.255.25516,382
10563.154.0.0/1863.154.0.1 to 63.154.63.25463.154.63.25516,382
10663.154.64.0/1863.154.64.1 to 63.154.127.25463.154.127.25516,382
10763.154.128.0/1863.154.128.1 to 63.154.191.25463.154.191.25516,382
10863.154.192.0/1863.154.192.1 to 63.154.255.25463.154.255.25516,382
10963.155.0.0/1863.155.0.1 to 63.155.63.25463.155.63.25516,382
11063.155.64.0/1863.155.64.1 to 63.155.127.25463.155.127.25516,382
11163.155.128.0/1863.155.128.1 to 63.155.191.25463.155.191.25516,382
11263.155.192.0/1863.155.192.1 to 63.155.255.25463.155.255.25516,382
11363.156.0.0/1863.156.0.1 to 63.156.63.25463.156.63.25516,382
11463.156.64.0/1863.156.64.1 to 63.156.127.25463.156.127.25516,382
11563.156.128.0/1863.156.128.1 to 63.156.191.25463.156.191.25516,382
11663.156.192.0/1863.156.192.1 to 63.156.255.25463.156.255.25516,382
11763.157.0.0/1863.157.0.1 to 63.157.63.25463.157.63.25516,382
11863.157.64.0/1863.157.64.1 to 63.157.127.25463.157.127.25516,382
11963.157.128.0/1863.157.128.1 to 63.157.191.25463.157.191.25516,382
12063.157.192.0/1863.157.192.1 to 63.157.255.25463.157.255.25516,382
12163.158.0.0/1863.158.0.1 to 63.158.63.25463.158.63.25516,382
12263.158.64.0/1863.158.64.1 to 63.158.127.25463.158.127.25516,382
12363.158.128.0/1863.158.128.1 to 63.158.191.25463.158.191.25516,382
12463.158.192.0/1863.158.192.1 to 63.158.255.25463.158.255.25516,382
12563.159.0.0/1863.159.0.1 to 63.159.63.25463.159.63.25516,382
12663.159.64.0/1863.159.64.1 to 63.159.127.25463.159.127.25516,382
12763.159.128.0/1863.159.128.1 to 63.159.191.25463.159.191.25516,382
12863.159.192.0/1863.159.192.1 to 63.159.255.25463.159.255.25516,382
12963.160.0.0/1863.160.0.1 to 63.160.63.25463.160.63.25516,382
13063.160.64.0/1863.160.64.1 to 63.160.127.25463.160.127.25516,382
13163.160.128.0/1863.160.128.1 to 63.160.191.25463.160.191.25516,382
13263.160.192.0/1863.160.192.1 to 63.160.255.25463.160.255.25516,382
13363.161.0.0/1863.161.0.1 to 63.161.63.25463.161.63.25516,382
13463.161.64.0/1863.161.64.1 to 63.161.127.25463.161.127.25516,382
13563.161.128.0/1863.161.128.1 to 63.161.191.25463.161.191.25516,382
13663.161.192.0/1863.161.192.1 to 63.161.255.25463.161.255.25516,382
13763.162.0.0/1863.162.0.1 to 63.162.63.25463.162.63.25516,382
13863.162.64.0/1863.162.64.1 to 63.162.127.25463.162.127.25516,382
13963.162.128.0/1863.162.128.1 to 63.162.191.25463.162.191.25516,382
14063.162.192.0/1863.162.192.1 to 63.162.255.25463.162.255.25516,382
14163.163.0.0/1863.163.0.1 to 63.163.63.25463.163.63.25516,382
14263.163.64.0/1863.163.64.1 to 63.163.127.25463.163.127.25516,382
14363.163.128.0/1863.163.128.1 to 63.163.191.25463.163.191.25516,382
14463.163.192.0/1863.163.192.1 to 63.163.255.25463.163.255.25516,382
14563.164.0.0/1863.164.0.1 to 63.164.63.25463.164.63.25516,382
14663.164.64.0/1863.164.64.1 to 63.164.127.25463.164.127.25516,382
14763.164.128.0/1863.164.128.1 to 63.164.191.25463.164.191.25516,382
14863.164.192.0/1863.164.192.1 to 63.164.255.25463.164.255.25516,382
14963.165.0.0/1863.165.0.1 to 63.165.63.25463.165.63.25516,382
15063.165.64.0/1863.165.64.1 to 63.165.127.25463.165.127.25516,382
15163.165.128.0/1863.165.128.1 to 63.165.191.25463.165.191.25516,382
15263.165.192.0/1863.165.192.1 to 63.165.255.25463.165.255.25516,382
15363.166.0.0/1863.166.0.1 to 63.166.63.25463.166.63.25516,382
15463.166.64.0/1863.166.64.1 to 63.166.127.25463.166.127.25516,382
15563.166.128.0/1863.166.128.1 to 63.166.191.25463.166.191.25516,382
15663.166.192.0/1863.166.192.1 to 63.166.255.25463.166.255.25516,382
15763.167.0.0/1863.167.0.1 to 63.167.63.25463.167.63.25516,382
15863.167.64.0/1863.167.64.1 to 63.167.127.25463.167.127.25516,382
15963.167.128.0/1863.167.128.1 to 63.167.191.25463.167.191.25516,382
16063.167.192.0/1863.167.192.1 to 63.167.255.25463.167.255.25516,382
16163.168.0.0/1863.168.0.1 to 63.168.63.25463.168.63.25516,382
16263.168.64.0/1863.168.64.1 to 63.168.127.25463.168.127.25516,382
16363.168.128.0/1863.168.128.1 to 63.168.191.25463.168.191.25516,382
16463.168.192.0/1863.168.192.1 to 63.168.255.25463.168.255.25516,382
16563.169.0.0/1863.169.0.1 to 63.169.63.25463.169.63.25516,382
16663.169.64.0/1863.169.64.1 to 63.169.127.25463.169.127.25516,382
16763.169.128.0/1863.169.128.1 to 63.169.191.25463.169.191.25516,382
16863.169.192.0/1863.169.192.1 to 63.169.255.25463.169.255.25516,382
16963.170.0.0/1863.170.0.1 to 63.170.63.25463.170.63.25516,382
17063.170.64.0/1863.170.64.1 to 63.170.127.25463.170.127.25516,382
17163.170.128.0/1863.170.128.1 to 63.170.191.25463.170.191.25516,382
17263.170.192.0/1863.170.192.1 to 63.170.255.25463.170.255.25516,382
17363.171.0.0/1863.171.0.1 to 63.171.63.25463.171.63.25516,382
17463.171.64.0/1863.171.64.1 to 63.171.127.25463.171.127.25516,382
17563.171.128.0/1863.171.128.1 to 63.171.191.25463.171.191.25516,382
17663.171.192.0/1863.171.192.1 to 63.171.255.25463.171.255.25516,382
17763.172.0.0/1863.172.0.1 to 63.172.63.25463.172.63.25516,382
17863.172.64.0/1863.172.64.1 to 63.172.127.25463.172.127.25516,382
17963.172.128.0/1863.172.128.1 to 63.172.191.25463.172.191.25516,382
18063.172.192.0/1863.172.192.1 to 63.172.255.25463.172.255.25516,382
18163.173.0.0/1863.173.0.1 to 63.173.63.25463.173.63.25516,382
18263.173.64.0/1863.173.64.1 to 63.173.127.25463.173.127.25516,382
18363.173.128.0/1863.173.128.1 to 63.173.191.25463.173.191.25516,382
18463.173.192.0/1863.173.192.1 to 63.173.255.25463.173.255.25516,382
18563.174.0.0/1863.174.0.1 to 63.174.63.25463.174.63.25516,382
18663.174.64.0/1863.174.64.1 to 63.174.127.25463.174.127.25516,382
18763.174.128.0/1863.174.128.1 to 63.174.191.25463.174.191.25516,382
18863.174.192.0/1863.174.192.1 to 63.174.255.25463.174.255.25516,382
18963.175.0.0/1863.175.0.1 to 63.175.63.25463.175.63.25516,382
19063.175.64.0/1863.175.64.1 to 63.175.127.25463.175.127.25516,382
19163.175.128.0/1863.175.128.1 to 63.175.191.25463.175.191.25516,382
19263.175.192.0/1863.175.192.1 to 63.175.255.25463.175.255.25516,382
19363.176.0.0/1863.176.0.1 to 63.176.63.25463.176.63.25516,382
19463.176.64.0/1863.176.64.1 to 63.176.127.25463.176.127.25516,382
19563.176.128.0/1863.176.128.1 to 63.176.191.25463.176.191.25516,382
19663.176.192.0/1863.176.192.1 to 63.176.255.25463.176.255.25516,382
19763.177.0.0/1863.177.0.1 to 63.177.63.25463.177.63.25516,382
19863.177.64.0/1863.177.64.1 to 63.177.127.25463.177.127.25516,382
19963.177.128.0/1863.177.128.1 to 63.177.191.25463.177.191.25516,382
20063.177.192.0/1863.177.192.1 to 63.177.255.25463.177.255.25516,382
20163.178.0.0/1863.178.0.1 to 63.178.63.25463.178.63.25516,382
20263.178.64.0/1863.178.64.1 to 63.178.127.25463.178.127.25516,382
20363.178.128.0/1863.178.128.1 to 63.178.191.25463.178.191.25516,382
20463.178.192.0/1863.178.192.1 to 63.178.255.25463.178.255.25516,382
20563.179.0.0/1863.179.0.1 to 63.179.63.25463.179.63.25516,382
20663.179.64.0/1863.179.64.1 to 63.179.127.25463.179.127.25516,382
20763.179.128.0/1863.179.128.1 to 63.179.191.25463.179.191.25516,382
20863.179.192.0/1863.179.192.1 to 63.179.255.25463.179.255.25516,382
20963.180.0.0/1863.180.0.1 to 63.180.63.25463.180.63.25516,382
21063.180.64.0/1863.180.64.1 to 63.180.127.25463.180.127.25516,382
21163.180.128.0/1863.180.128.1 to 63.180.191.25463.180.191.25516,382
21263.180.192.0/1863.180.192.1 to 63.180.255.25463.180.255.25516,382
21363.181.0.0/1863.181.0.1 to 63.181.63.25463.181.63.25516,382
21463.181.64.0/1863.181.64.1 to 63.181.127.25463.181.127.25516,382
21563.181.128.0/1863.181.128.1 to 63.181.191.25463.181.191.25516,382
21663.181.192.0/1863.181.192.1 to 63.181.255.25463.181.255.25516,382
21763.182.0.0/1863.182.0.1 to 63.182.63.25463.182.63.25516,382
21863.182.64.0/1863.182.64.1 to 63.182.127.25463.182.127.25516,382
21963.182.128.0/1863.182.128.1 to 63.182.191.25463.182.191.25516,382
22063.182.192.0/1863.182.192.1 to 63.182.255.25463.182.255.25516,382
22163.183.0.0/1863.183.0.1 to 63.183.63.25463.183.63.25516,382
22263.183.64.0/1863.183.64.1 to 63.183.127.25463.183.127.25516,382
22363.183.128.0/1863.183.128.1 to 63.183.191.25463.183.191.25516,382
22463.183.192.0/1863.183.192.1 to 63.183.255.25463.183.255.25516,382
22563.184.0.0/1863.184.0.1 to 63.184.63.25463.184.63.25516,382
22663.184.64.0/1863.184.64.1 to 63.184.127.25463.184.127.25516,382
22763.184.128.0/1863.184.128.1 to 63.184.191.25463.184.191.25516,382
22863.184.192.0/1863.184.192.1 to 63.184.255.25463.184.255.25516,382
22963.185.0.0/1863.185.0.1 to 63.185.63.25463.185.63.25516,382
23063.185.64.0/1863.185.64.1 to 63.185.127.25463.185.127.25516,382
23163.185.128.0/1863.185.128.1 to 63.185.191.25463.185.191.25516,382
23263.185.192.0/1863.185.192.1 to 63.185.255.25463.185.255.25516,382
23363.186.0.0/1863.186.0.1 to 63.186.63.25463.186.63.25516,382
23463.186.64.0/1863.186.64.1 to 63.186.127.25463.186.127.25516,382
23563.186.128.0/1863.186.128.1 to 63.186.191.25463.186.191.25516,382
23663.186.192.0/1863.186.192.1 to 63.186.255.25463.186.255.25516,382
23763.187.0.0/1863.187.0.1 to 63.187.63.25463.187.63.25516,382
23863.187.64.0/1863.187.64.1 to 63.187.127.25463.187.127.25516,382
23963.187.128.0/1863.187.128.1 to 63.187.191.25463.187.191.25516,382
24063.187.192.0/1863.187.192.1 to 63.187.255.25463.187.255.25516,382
24163.188.0.0/1863.188.0.1 to 63.188.63.25463.188.63.25516,382
24263.188.64.0/1863.188.64.1 to 63.188.127.25463.188.127.25516,382
24363.188.128.0/1863.188.128.1 to 63.188.191.25463.188.191.25516,382
24463.188.192.0/1863.188.192.1 to 63.188.255.25463.188.255.25516,382
24563.189.0.0/1863.189.0.1 to 63.189.63.25463.189.63.25516,382
24663.189.64.0/1863.189.64.1 to 63.189.127.25463.189.127.25516,382
24763.189.128.0/1863.189.128.1 to 63.189.191.25463.189.191.25516,382
24863.189.192.0/1863.189.192.1 to 63.189.255.25463.189.255.25516,382
24963.190.0.0/1863.190.0.1 to 63.190.63.25463.190.63.25516,382
25063.190.64.0/1863.190.64.1 to 63.190.127.25463.190.127.25516,382
25163.190.128.0/1863.190.128.1 to 63.190.191.25463.190.191.25516,382
25263.190.192.0/1863.190.192.1 to 63.190.255.25463.190.255.25516,382
25363.191.0.0/1863.191.0.1 to 63.191.63.25463.191.63.25516,382
25463.191.64.0/1863.191.64.1 to 63.191.127.25463.191.127.25516,382
25563.191.128.0/1863.191.128.1 to 63.191.191.25463.191.191.25516,382
25663.191.192.0/1863.191.192.1 to 63.191.255.25463.191.255.25516,382

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.