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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.

Network63.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
63.0.0.0
Broadcast address
63.63.255.255
First usable
63.0.0.1
Last usable
63.63.255.254
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 3F000000 · Integer 1056964608 to 1061158911
Reverse DNS zones
0.63.in-addr.arpa
1.63.in-addr.arpa
2.63.in-addr.arpa
3.63.in-addr.arpa
4.63.in-addr.arpa
5.63.in-addr.arpa
6.63.in-addr.arpa
7.63.in-addr.arpa
8.63.in-addr.arpa
9.63.in-addr.arpa
10.63.in-addr.arpa
11.63.in-addr.arpa
12.63.in-addr.arpa
13.63.in-addr.arpa
14.63.in-addr.arpa
15.63.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
Address00111111.00000000.00000000.0000000063.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00111111.00000000.00000000.0000000063.0.0.0
Broadcast00111111.00111111.11111111.1111111163.63.255.255
Split into smaller subnets/21
/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)

63.0.0.0/10 makes 2,048 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
163.0.0.0/2163.0.0.1 to 63.0.7.25463.0.7.2552,046
263.0.8.0/2163.0.8.1 to 63.0.15.25463.0.15.2552,046
363.0.16.0/2163.0.16.1 to 63.0.23.25463.0.23.2552,046
463.0.24.0/2163.0.24.1 to 63.0.31.25463.0.31.2552,046
563.0.32.0/2163.0.32.1 to 63.0.39.25463.0.39.2552,046
663.0.40.0/2163.0.40.1 to 63.0.47.25463.0.47.2552,046
763.0.48.0/2163.0.48.1 to 63.0.55.25463.0.55.2552,046
863.0.56.0/2163.0.56.1 to 63.0.63.25463.0.63.2552,046
963.0.64.0/2163.0.64.1 to 63.0.71.25463.0.71.2552,046
1063.0.72.0/2163.0.72.1 to 63.0.79.25463.0.79.2552,046
1163.0.80.0/2163.0.80.1 to 63.0.87.25463.0.87.2552,046
1263.0.88.0/2163.0.88.1 to 63.0.95.25463.0.95.2552,046
1363.0.96.0/2163.0.96.1 to 63.0.103.25463.0.103.2552,046
1463.0.104.0/2163.0.104.1 to 63.0.111.25463.0.111.2552,046
1563.0.112.0/2163.0.112.1 to 63.0.119.25463.0.119.2552,046
1663.0.120.0/2163.0.120.1 to 63.0.127.25463.0.127.2552,046
1763.0.128.0/2163.0.128.1 to 63.0.135.25463.0.135.2552,046
1863.0.136.0/2163.0.136.1 to 63.0.143.25463.0.143.2552,046
1963.0.144.0/2163.0.144.1 to 63.0.151.25463.0.151.2552,046
2063.0.152.0/2163.0.152.1 to 63.0.159.25463.0.159.2552,046
2163.0.160.0/2163.0.160.1 to 63.0.167.25463.0.167.2552,046
2263.0.168.0/2163.0.168.1 to 63.0.175.25463.0.175.2552,046
2363.0.176.0/2163.0.176.1 to 63.0.183.25463.0.183.2552,046
2463.0.184.0/2163.0.184.1 to 63.0.191.25463.0.191.2552,046
2563.0.192.0/2163.0.192.1 to 63.0.199.25463.0.199.2552,046
2663.0.200.0/2163.0.200.1 to 63.0.207.25463.0.207.2552,046
2763.0.208.0/2163.0.208.1 to 63.0.215.25463.0.215.2552,046
2863.0.216.0/2163.0.216.1 to 63.0.223.25463.0.223.2552,046
2963.0.224.0/2163.0.224.1 to 63.0.231.25463.0.231.2552,046
3063.0.232.0/2163.0.232.1 to 63.0.239.25463.0.239.2552,046
3163.0.240.0/2163.0.240.1 to 63.0.247.25463.0.247.2552,046
3263.0.248.0/2163.0.248.1 to 63.0.255.25463.0.255.2552,046
3363.1.0.0/2163.1.0.1 to 63.1.7.25463.1.7.2552,046
3463.1.8.0/2163.1.8.1 to 63.1.15.25463.1.15.2552,046
3563.1.16.0/2163.1.16.1 to 63.1.23.25463.1.23.2552,046
3663.1.24.0/2163.1.24.1 to 63.1.31.25463.1.31.2552,046
3763.1.32.0/2163.1.32.1 to 63.1.39.25463.1.39.2552,046
3863.1.40.0/2163.1.40.1 to 63.1.47.25463.1.47.2552,046
3963.1.48.0/2163.1.48.1 to 63.1.55.25463.1.55.2552,046
4063.1.56.0/2163.1.56.1 to 63.1.63.25463.1.63.2552,046
4163.1.64.0/2163.1.64.1 to 63.1.71.25463.1.71.2552,046
4263.1.72.0/2163.1.72.1 to 63.1.79.25463.1.79.2552,046
4363.1.80.0/2163.1.80.1 to 63.1.87.25463.1.87.2552,046
4463.1.88.0/2163.1.88.1 to 63.1.95.25463.1.95.2552,046
4563.1.96.0/2163.1.96.1 to 63.1.103.25463.1.103.2552,046
4663.1.104.0/2163.1.104.1 to 63.1.111.25463.1.111.2552,046
4763.1.112.0/2163.1.112.1 to 63.1.119.25463.1.119.2552,046
4863.1.120.0/2163.1.120.1 to 63.1.127.25463.1.127.2552,046
4963.1.128.0/2163.1.128.1 to 63.1.135.25463.1.135.2552,046
5063.1.136.0/2163.1.136.1 to 63.1.143.25463.1.143.2552,046
5163.1.144.0/2163.1.144.1 to 63.1.151.25463.1.151.2552,046
5263.1.152.0/2163.1.152.1 to 63.1.159.25463.1.159.2552,046
5363.1.160.0/2163.1.160.1 to 63.1.167.25463.1.167.2552,046
5463.1.168.0/2163.1.168.1 to 63.1.175.25463.1.175.2552,046
5563.1.176.0/2163.1.176.1 to 63.1.183.25463.1.183.2552,046
5663.1.184.0/2163.1.184.1 to 63.1.191.25463.1.191.2552,046
5763.1.192.0/2163.1.192.1 to 63.1.199.25463.1.199.2552,046
5863.1.200.0/2163.1.200.1 to 63.1.207.25463.1.207.2552,046
5963.1.208.0/2163.1.208.1 to 63.1.215.25463.1.215.2552,046
6063.1.216.0/2163.1.216.1 to 63.1.223.25463.1.223.2552,046
6163.1.224.0/2163.1.224.1 to 63.1.231.25463.1.231.2552,046
6263.1.232.0/2163.1.232.1 to 63.1.239.25463.1.239.2552,046
6363.1.240.0/2163.1.240.1 to 63.1.247.25463.1.247.2552,046
6463.1.248.0/2163.1.248.1 to 63.1.255.25463.1.255.2552,046
6563.2.0.0/2163.2.0.1 to 63.2.7.25463.2.7.2552,046
6663.2.8.0/2163.2.8.1 to 63.2.15.25463.2.15.2552,046
6763.2.16.0/2163.2.16.1 to 63.2.23.25463.2.23.2552,046
6863.2.24.0/2163.2.24.1 to 63.2.31.25463.2.31.2552,046
6963.2.32.0/2163.2.32.1 to 63.2.39.25463.2.39.2552,046
7063.2.40.0/2163.2.40.1 to 63.2.47.25463.2.47.2552,046
7163.2.48.0/2163.2.48.1 to 63.2.55.25463.2.55.2552,046
7263.2.56.0/2163.2.56.1 to 63.2.63.25463.2.63.2552,046
7363.2.64.0/2163.2.64.1 to 63.2.71.25463.2.71.2552,046
7463.2.72.0/2163.2.72.1 to 63.2.79.25463.2.79.2552,046
7563.2.80.0/2163.2.80.1 to 63.2.87.25463.2.87.2552,046
7663.2.88.0/2163.2.88.1 to 63.2.95.25463.2.95.2552,046
7763.2.96.0/2163.2.96.1 to 63.2.103.25463.2.103.2552,046
7863.2.104.0/2163.2.104.1 to 63.2.111.25463.2.111.2552,046
7963.2.112.0/2163.2.112.1 to 63.2.119.25463.2.119.2552,046
8063.2.120.0/2163.2.120.1 to 63.2.127.25463.2.127.2552,046
8163.2.128.0/2163.2.128.1 to 63.2.135.25463.2.135.2552,046
8263.2.136.0/2163.2.136.1 to 63.2.143.25463.2.143.2552,046
8363.2.144.0/2163.2.144.1 to 63.2.151.25463.2.151.2552,046
8463.2.152.0/2163.2.152.1 to 63.2.159.25463.2.159.2552,046
8563.2.160.0/2163.2.160.1 to 63.2.167.25463.2.167.2552,046
8663.2.168.0/2163.2.168.1 to 63.2.175.25463.2.175.2552,046
8763.2.176.0/2163.2.176.1 to 63.2.183.25463.2.183.2552,046
8863.2.184.0/2163.2.184.1 to 63.2.191.25463.2.191.2552,046
8963.2.192.0/2163.2.192.1 to 63.2.199.25463.2.199.2552,046
9063.2.200.0/2163.2.200.1 to 63.2.207.25463.2.207.2552,046
9163.2.208.0/2163.2.208.1 to 63.2.215.25463.2.215.2552,046
9263.2.216.0/2163.2.216.1 to 63.2.223.25463.2.223.2552,046
9363.2.224.0/2163.2.224.1 to 63.2.231.25463.2.231.2552,046
9463.2.232.0/2163.2.232.1 to 63.2.239.25463.2.239.2552,046
9563.2.240.0/2163.2.240.1 to 63.2.247.25463.2.247.2552,046
9663.2.248.0/2163.2.248.1 to 63.2.255.25463.2.255.2552,046
9763.3.0.0/2163.3.0.1 to 63.3.7.25463.3.7.2552,046
9863.3.8.0/2163.3.8.1 to 63.3.15.25463.3.15.2552,046
9963.3.16.0/2163.3.16.1 to 63.3.23.25463.3.23.2552,046
10063.3.24.0/2163.3.24.1 to 63.3.31.25463.3.31.2552,046
10163.3.32.0/2163.3.32.1 to 63.3.39.25463.3.39.2552,046
10263.3.40.0/2163.3.40.1 to 63.3.47.25463.3.47.2552,046
10363.3.48.0/2163.3.48.1 to 63.3.55.25463.3.55.2552,046
10463.3.56.0/2163.3.56.1 to 63.3.63.25463.3.63.2552,046
10563.3.64.0/2163.3.64.1 to 63.3.71.25463.3.71.2552,046
10663.3.72.0/2163.3.72.1 to 63.3.79.25463.3.79.2552,046
10763.3.80.0/2163.3.80.1 to 63.3.87.25463.3.87.2552,046
10863.3.88.0/2163.3.88.1 to 63.3.95.25463.3.95.2552,046
10963.3.96.0/2163.3.96.1 to 63.3.103.25463.3.103.2552,046
11063.3.104.0/2163.3.104.1 to 63.3.111.25463.3.111.2552,046
11163.3.112.0/2163.3.112.1 to 63.3.119.25463.3.119.2552,046
11263.3.120.0/2163.3.120.1 to 63.3.127.25463.3.127.2552,046
11363.3.128.0/2163.3.128.1 to 63.3.135.25463.3.135.2552,046
11463.3.136.0/2163.3.136.1 to 63.3.143.25463.3.143.2552,046
11563.3.144.0/2163.3.144.1 to 63.3.151.25463.3.151.2552,046
11663.3.152.0/2163.3.152.1 to 63.3.159.25463.3.159.2552,046
11763.3.160.0/2163.3.160.1 to 63.3.167.25463.3.167.2552,046
11863.3.168.0/2163.3.168.1 to 63.3.175.25463.3.175.2552,046
11963.3.176.0/2163.3.176.1 to 63.3.183.25463.3.183.2552,046
12063.3.184.0/2163.3.184.1 to 63.3.191.25463.3.191.2552,046
12163.3.192.0/2163.3.192.1 to 63.3.199.25463.3.199.2552,046
12263.3.200.0/2163.3.200.1 to 63.3.207.25463.3.207.2552,046
12363.3.208.0/2163.3.208.1 to 63.3.215.25463.3.215.2552,046
12463.3.216.0/2163.3.216.1 to 63.3.223.25463.3.223.2552,046
12563.3.224.0/2163.3.224.1 to 63.3.231.25463.3.231.2552,046
12663.3.232.0/2163.3.232.1 to 63.3.239.25463.3.239.2552,046
12763.3.240.0/2163.3.240.1 to 63.3.247.25463.3.247.2552,046
12863.3.248.0/2163.3.248.1 to 63.3.255.25463.3.255.2552,046
12963.4.0.0/2163.4.0.1 to 63.4.7.25463.4.7.2552,046
13063.4.8.0/2163.4.8.1 to 63.4.15.25463.4.15.2552,046
13163.4.16.0/2163.4.16.1 to 63.4.23.25463.4.23.2552,046
13263.4.24.0/2163.4.24.1 to 63.4.31.25463.4.31.2552,046
13363.4.32.0/2163.4.32.1 to 63.4.39.25463.4.39.2552,046
13463.4.40.0/2163.4.40.1 to 63.4.47.25463.4.47.2552,046
13563.4.48.0/2163.4.48.1 to 63.4.55.25463.4.55.2552,046
13663.4.56.0/2163.4.56.1 to 63.4.63.25463.4.63.2552,046
13763.4.64.0/2163.4.64.1 to 63.4.71.25463.4.71.2552,046
13863.4.72.0/2163.4.72.1 to 63.4.79.25463.4.79.2552,046
13963.4.80.0/2163.4.80.1 to 63.4.87.25463.4.87.2552,046
14063.4.88.0/2163.4.88.1 to 63.4.95.25463.4.95.2552,046
14163.4.96.0/2163.4.96.1 to 63.4.103.25463.4.103.2552,046
14263.4.104.0/2163.4.104.1 to 63.4.111.25463.4.111.2552,046
14363.4.112.0/2163.4.112.1 to 63.4.119.25463.4.119.2552,046
14463.4.120.0/2163.4.120.1 to 63.4.127.25463.4.127.2552,046
14563.4.128.0/2163.4.128.1 to 63.4.135.25463.4.135.2552,046
14663.4.136.0/2163.4.136.1 to 63.4.143.25463.4.143.2552,046
14763.4.144.0/2163.4.144.1 to 63.4.151.25463.4.151.2552,046
14863.4.152.0/2163.4.152.1 to 63.4.159.25463.4.159.2552,046
14963.4.160.0/2163.4.160.1 to 63.4.167.25463.4.167.2552,046
15063.4.168.0/2163.4.168.1 to 63.4.175.25463.4.175.2552,046
15163.4.176.0/2163.4.176.1 to 63.4.183.25463.4.183.2552,046
15263.4.184.0/2163.4.184.1 to 63.4.191.25463.4.191.2552,046
15363.4.192.0/2163.4.192.1 to 63.4.199.25463.4.199.2552,046
15463.4.200.0/2163.4.200.1 to 63.4.207.25463.4.207.2552,046
15563.4.208.0/2163.4.208.1 to 63.4.215.25463.4.215.2552,046
15663.4.216.0/2163.4.216.1 to 63.4.223.25463.4.223.2552,046
15763.4.224.0/2163.4.224.1 to 63.4.231.25463.4.231.2552,046
15863.4.232.0/2163.4.232.1 to 63.4.239.25463.4.239.2552,046
15963.4.240.0/2163.4.240.1 to 63.4.247.25463.4.247.2552,046
16063.4.248.0/2163.4.248.1 to 63.4.255.25463.4.255.2552,046
16163.5.0.0/2163.5.0.1 to 63.5.7.25463.5.7.2552,046
16263.5.8.0/2163.5.8.1 to 63.5.15.25463.5.15.2552,046
16363.5.16.0/2163.5.16.1 to 63.5.23.25463.5.23.2552,046
16463.5.24.0/2163.5.24.1 to 63.5.31.25463.5.31.2552,046
16563.5.32.0/2163.5.32.1 to 63.5.39.25463.5.39.2552,046
16663.5.40.0/2163.5.40.1 to 63.5.47.25463.5.47.2552,046
16763.5.48.0/2163.5.48.1 to 63.5.55.25463.5.55.2552,046
16863.5.56.0/2163.5.56.1 to 63.5.63.25463.5.63.2552,046
16963.5.64.0/2163.5.64.1 to 63.5.71.25463.5.71.2552,046
17063.5.72.0/2163.5.72.1 to 63.5.79.25463.5.79.2552,046
17163.5.80.0/2163.5.80.1 to 63.5.87.25463.5.87.2552,046
17263.5.88.0/2163.5.88.1 to 63.5.95.25463.5.95.2552,046
17363.5.96.0/2163.5.96.1 to 63.5.103.25463.5.103.2552,046
17463.5.104.0/2163.5.104.1 to 63.5.111.25463.5.111.2552,046
17563.5.112.0/2163.5.112.1 to 63.5.119.25463.5.119.2552,046
17663.5.120.0/2163.5.120.1 to 63.5.127.25463.5.127.2552,046
17763.5.128.0/2163.5.128.1 to 63.5.135.25463.5.135.2552,046
17863.5.136.0/2163.5.136.1 to 63.5.143.25463.5.143.2552,046
17963.5.144.0/2163.5.144.1 to 63.5.151.25463.5.151.2552,046
18063.5.152.0/2163.5.152.1 to 63.5.159.25463.5.159.2552,046
18163.5.160.0/2163.5.160.1 to 63.5.167.25463.5.167.2552,046
18263.5.168.0/2163.5.168.1 to 63.5.175.25463.5.175.2552,046
18363.5.176.0/2163.5.176.1 to 63.5.183.25463.5.183.2552,046
18463.5.184.0/2163.5.184.1 to 63.5.191.25463.5.191.2552,046
18563.5.192.0/2163.5.192.1 to 63.5.199.25463.5.199.2552,046
18663.5.200.0/2163.5.200.1 to 63.5.207.25463.5.207.2552,046
18763.5.208.0/2163.5.208.1 to 63.5.215.25463.5.215.2552,046
18863.5.216.0/2163.5.216.1 to 63.5.223.25463.5.223.2552,046
18963.5.224.0/2163.5.224.1 to 63.5.231.25463.5.231.2552,046
19063.5.232.0/2163.5.232.1 to 63.5.239.25463.5.239.2552,046
19163.5.240.0/2163.5.240.1 to 63.5.247.25463.5.247.2552,046
19263.5.248.0/2163.5.248.1 to 63.5.255.25463.5.255.2552,046
19363.6.0.0/2163.6.0.1 to 63.6.7.25463.6.7.2552,046
19463.6.8.0/2163.6.8.1 to 63.6.15.25463.6.15.2552,046
19563.6.16.0/2163.6.16.1 to 63.6.23.25463.6.23.2552,046
19663.6.24.0/2163.6.24.1 to 63.6.31.25463.6.31.2552,046
19763.6.32.0/2163.6.32.1 to 63.6.39.25463.6.39.2552,046
19863.6.40.0/2163.6.40.1 to 63.6.47.25463.6.47.2552,046
19963.6.48.0/2163.6.48.1 to 63.6.55.25463.6.55.2552,046
20063.6.56.0/2163.6.56.1 to 63.6.63.25463.6.63.2552,046
20163.6.64.0/2163.6.64.1 to 63.6.71.25463.6.71.2552,046
20263.6.72.0/2163.6.72.1 to 63.6.79.25463.6.79.2552,046
20363.6.80.0/2163.6.80.1 to 63.6.87.25463.6.87.2552,046
20463.6.88.0/2163.6.88.1 to 63.6.95.25463.6.95.2552,046
20563.6.96.0/2163.6.96.1 to 63.6.103.25463.6.103.2552,046
20663.6.104.0/2163.6.104.1 to 63.6.111.25463.6.111.2552,046
20763.6.112.0/2163.6.112.1 to 63.6.119.25463.6.119.2552,046
20863.6.120.0/2163.6.120.1 to 63.6.127.25463.6.127.2552,046
20963.6.128.0/2163.6.128.1 to 63.6.135.25463.6.135.2552,046
21063.6.136.0/2163.6.136.1 to 63.6.143.25463.6.143.2552,046
21163.6.144.0/2163.6.144.1 to 63.6.151.25463.6.151.2552,046
21263.6.152.0/2163.6.152.1 to 63.6.159.25463.6.159.2552,046
21363.6.160.0/2163.6.160.1 to 63.6.167.25463.6.167.2552,046
21463.6.168.0/2163.6.168.1 to 63.6.175.25463.6.175.2552,046
21563.6.176.0/2163.6.176.1 to 63.6.183.25463.6.183.2552,046
21663.6.184.0/2163.6.184.1 to 63.6.191.25463.6.191.2552,046
21763.6.192.0/2163.6.192.1 to 63.6.199.25463.6.199.2552,046
21863.6.200.0/2163.6.200.1 to 63.6.207.25463.6.207.2552,046
21963.6.208.0/2163.6.208.1 to 63.6.215.25463.6.215.2552,046
22063.6.216.0/2163.6.216.1 to 63.6.223.25463.6.223.2552,046
22163.6.224.0/2163.6.224.1 to 63.6.231.25463.6.231.2552,046
22263.6.232.0/2163.6.232.1 to 63.6.239.25463.6.239.2552,046
22363.6.240.0/2163.6.240.1 to 63.6.247.25463.6.247.2552,046
22463.6.248.0/2163.6.248.1 to 63.6.255.25463.6.255.2552,046
22563.7.0.0/2163.7.0.1 to 63.7.7.25463.7.7.2552,046
22663.7.8.0/2163.7.8.1 to 63.7.15.25463.7.15.2552,046
22763.7.16.0/2163.7.16.1 to 63.7.23.25463.7.23.2552,046
22863.7.24.0/2163.7.24.1 to 63.7.31.25463.7.31.2552,046
22963.7.32.0/2163.7.32.1 to 63.7.39.25463.7.39.2552,046
23063.7.40.0/2163.7.40.1 to 63.7.47.25463.7.47.2552,046
23163.7.48.0/2163.7.48.1 to 63.7.55.25463.7.55.2552,046
23263.7.56.0/2163.7.56.1 to 63.7.63.25463.7.63.2552,046
23363.7.64.0/2163.7.64.1 to 63.7.71.25463.7.71.2552,046
23463.7.72.0/2163.7.72.1 to 63.7.79.25463.7.79.2552,046
23563.7.80.0/2163.7.80.1 to 63.7.87.25463.7.87.2552,046
23663.7.88.0/2163.7.88.1 to 63.7.95.25463.7.95.2552,046
23763.7.96.0/2163.7.96.1 to 63.7.103.25463.7.103.2552,046
23863.7.104.0/2163.7.104.1 to 63.7.111.25463.7.111.2552,046
23963.7.112.0/2163.7.112.1 to 63.7.119.25463.7.119.2552,046
24063.7.120.0/2163.7.120.1 to 63.7.127.25463.7.127.2552,046
24163.7.128.0/2163.7.128.1 to 63.7.135.25463.7.135.2552,046
24263.7.136.0/2163.7.136.1 to 63.7.143.25463.7.143.2552,046
24363.7.144.0/2163.7.144.1 to 63.7.151.25463.7.151.2552,046
24463.7.152.0/2163.7.152.1 to 63.7.159.25463.7.159.2552,046
24563.7.160.0/2163.7.160.1 to 63.7.167.25463.7.167.2552,046
24663.7.168.0/2163.7.168.1 to 63.7.175.25463.7.175.2552,046
24763.7.176.0/2163.7.176.1 to 63.7.183.25463.7.183.2552,046
24863.7.184.0/2163.7.184.1 to 63.7.191.25463.7.191.2552,046
24963.7.192.0/2163.7.192.1 to 63.7.199.25463.7.199.2552,046
25063.7.200.0/2163.7.200.1 to 63.7.207.25463.7.207.2552,046
25163.7.208.0/2163.7.208.1 to 63.7.215.25463.7.215.2552,046
25263.7.216.0/2163.7.216.1 to 63.7.223.25463.7.223.2552,046
25363.7.224.0/2163.7.224.1 to 63.7.231.25463.7.231.2552,046
25463.7.232.0/2163.7.232.1 to 63.7.239.25463.7.239.2552,046
25563.7.240.0/2163.7.240.1 to 63.7.247.25463.7.247.2552,046
25663.7.248.0/2163.7.248.1 to 63.7.255.25463.7.255.2552,046

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.