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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.

Network63.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
63.0.0.0
Broadcast address
63.255.255.255
First usable
63.0.0.1
Last usable
63.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 3F000000 · Integer 1056964608 to 1073741823
Reverse DNS zone
63.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111111..00000000.00000000.0000000063.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00111111..00000000.00000000.0000000063.0.0.0
Broadcast00111111..11111111.11111111.1111111163.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

63.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
163.0.0.0/1963.0.0.1 to 63.0.31.25463.0.31.2558,190
263.0.32.0/1963.0.32.1 to 63.0.63.25463.0.63.2558,190
363.0.64.0/1963.0.64.1 to 63.0.95.25463.0.95.2558,190
463.0.96.0/1963.0.96.1 to 63.0.127.25463.0.127.2558,190
563.0.128.0/1963.0.128.1 to 63.0.159.25463.0.159.2558,190
663.0.160.0/1963.0.160.1 to 63.0.191.25463.0.191.2558,190
763.0.192.0/1963.0.192.1 to 63.0.223.25463.0.223.2558,190
863.0.224.0/1963.0.224.1 to 63.0.255.25463.0.255.2558,190
963.1.0.0/1963.1.0.1 to 63.1.31.25463.1.31.2558,190
1063.1.32.0/1963.1.32.1 to 63.1.63.25463.1.63.2558,190
1163.1.64.0/1963.1.64.1 to 63.1.95.25463.1.95.2558,190
1263.1.96.0/1963.1.96.1 to 63.1.127.25463.1.127.2558,190
1363.1.128.0/1963.1.128.1 to 63.1.159.25463.1.159.2558,190
1463.1.160.0/1963.1.160.1 to 63.1.191.25463.1.191.2558,190
1563.1.192.0/1963.1.192.1 to 63.1.223.25463.1.223.2558,190
1663.1.224.0/1963.1.224.1 to 63.1.255.25463.1.255.2558,190
1763.2.0.0/1963.2.0.1 to 63.2.31.25463.2.31.2558,190
1863.2.32.0/1963.2.32.1 to 63.2.63.25463.2.63.2558,190
1963.2.64.0/1963.2.64.1 to 63.2.95.25463.2.95.2558,190
2063.2.96.0/1963.2.96.1 to 63.2.127.25463.2.127.2558,190
2163.2.128.0/1963.2.128.1 to 63.2.159.25463.2.159.2558,190
2263.2.160.0/1963.2.160.1 to 63.2.191.25463.2.191.2558,190
2363.2.192.0/1963.2.192.1 to 63.2.223.25463.2.223.2558,190
2463.2.224.0/1963.2.224.1 to 63.2.255.25463.2.255.2558,190
2563.3.0.0/1963.3.0.1 to 63.3.31.25463.3.31.2558,190
2663.3.32.0/1963.3.32.1 to 63.3.63.25463.3.63.2558,190
2763.3.64.0/1963.3.64.1 to 63.3.95.25463.3.95.2558,190
2863.3.96.0/1963.3.96.1 to 63.3.127.25463.3.127.2558,190
2963.3.128.0/1963.3.128.1 to 63.3.159.25463.3.159.2558,190
3063.3.160.0/1963.3.160.1 to 63.3.191.25463.3.191.2558,190
3163.3.192.0/1963.3.192.1 to 63.3.223.25463.3.223.2558,190
3263.3.224.0/1963.3.224.1 to 63.3.255.25463.3.255.2558,190
3363.4.0.0/1963.4.0.1 to 63.4.31.25463.4.31.2558,190
3463.4.32.0/1963.4.32.1 to 63.4.63.25463.4.63.2558,190
3563.4.64.0/1963.4.64.1 to 63.4.95.25463.4.95.2558,190
3663.4.96.0/1963.4.96.1 to 63.4.127.25463.4.127.2558,190
3763.4.128.0/1963.4.128.1 to 63.4.159.25463.4.159.2558,190
3863.4.160.0/1963.4.160.1 to 63.4.191.25463.4.191.2558,190
3963.4.192.0/1963.4.192.1 to 63.4.223.25463.4.223.2558,190
4063.4.224.0/1963.4.224.1 to 63.4.255.25463.4.255.2558,190
4163.5.0.0/1963.5.0.1 to 63.5.31.25463.5.31.2558,190
4263.5.32.0/1963.5.32.1 to 63.5.63.25463.5.63.2558,190
4363.5.64.0/1963.5.64.1 to 63.5.95.25463.5.95.2558,190
4463.5.96.0/1963.5.96.1 to 63.5.127.25463.5.127.2558,190
4563.5.128.0/1963.5.128.1 to 63.5.159.25463.5.159.2558,190
4663.5.160.0/1963.5.160.1 to 63.5.191.25463.5.191.2558,190
4763.5.192.0/1963.5.192.1 to 63.5.223.25463.5.223.2558,190
4863.5.224.0/1963.5.224.1 to 63.5.255.25463.5.255.2558,190
4963.6.0.0/1963.6.0.1 to 63.6.31.25463.6.31.2558,190
5063.6.32.0/1963.6.32.1 to 63.6.63.25463.6.63.2558,190
5163.6.64.0/1963.6.64.1 to 63.6.95.25463.6.95.2558,190
5263.6.96.0/1963.6.96.1 to 63.6.127.25463.6.127.2558,190
5363.6.128.0/1963.6.128.1 to 63.6.159.25463.6.159.2558,190
5463.6.160.0/1963.6.160.1 to 63.6.191.25463.6.191.2558,190
5563.6.192.0/1963.6.192.1 to 63.6.223.25463.6.223.2558,190
5663.6.224.0/1963.6.224.1 to 63.6.255.25463.6.255.2558,190
5763.7.0.0/1963.7.0.1 to 63.7.31.25463.7.31.2558,190
5863.7.32.0/1963.7.32.1 to 63.7.63.25463.7.63.2558,190
5963.7.64.0/1963.7.64.1 to 63.7.95.25463.7.95.2558,190
6063.7.96.0/1963.7.96.1 to 63.7.127.25463.7.127.2558,190
6163.7.128.0/1963.7.128.1 to 63.7.159.25463.7.159.2558,190
6263.7.160.0/1963.7.160.1 to 63.7.191.25463.7.191.2558,190
6363.7.192.0/1963.7.192.1 to 63.7.223.25463.7.223.2558,190
6463.7.224.0/1963.7.224.1 to 63.7.255.25463.7.255.2558,190
6563.8.0.0/1963.8.0.1 to 63.8.31.25463.8.31.2558,190
6663.8.32.0/1963.8.32.1 to 63.8.63.25463.8.63.2558,190
6763.8.64.0/1963.8.64.1 to 63.8.95.25463.8.95.2558,190
6863.8.96.0/1963.8.96.1 to 63.8.127.25463.8.127.2558,190
6963.8.128.0/1963.8.128.1 to 63.8.159.25463.8.159.2558,190
7063.8.160.0/1963.8.160.1 to 63.8.191.25463.8.191.2558,190
7163.8.192.0/1963.8.192.1 to 63.8.223.25463.8.223.2558,190
7263.8.224.0/1963.8.224.1 to 63.8.255.25463.8.255.2558,190
7363.9.0.0/1963.9.0.1 to 63.9.31.25463.9.31.2558,190
7463.9.32.0/1963.9.32.1 to 63.9.63.25463.9.63.2558,190
7563.9.64.0/1963.9.64.1 to 63.9.95.25463.9.95.2558,190
7663.9.96.0/1963.9.96.1 to 63.9.127.25463.9.127.2558,190
7763.9.128.0/1963.9.128.1 to 63.9.159.25463.9.159.2558,190
7863.9.160.0/1963.9.160.1 to 63.9.191.25463.9.191.2558,190
7963.9.192.0/1963.9.192.1 to 63.9.223.25463.9.223.2558,190
8063.9.224.0/1963.9.224.1 to 63.9.255.25463.9.255.2558,190
8163.10.0.0/1963.10.0.1 to 63.10.31.25463.10.31.2558,190
8263.10.32.0/1963.10.32.1 to 63.10.63.25463.10.63.2558,190
8363.10.64.0/1963.10.64.1 to 63.10.95.25463.10.95.2558,190
8463.10.96.0/1963.10.96.1 to 63.10.127.25463.10.127.2558,190
8563.10.128.0/1963.10.128.1 to 63.10.159.25463.10.159.2558,190
8663.10.160.0/1963.10.160.1 to 63.10.191.25463.10.191.2558,190
8763.10.192.0/1963.10.192.1 to 63.10.223.25463.10.223.2558,190
8863.10.224.0/1963.10.224.1 to 63.10.255.25463.10.255.2558,190
8963.11.0.0/1963.11.0.1 to 63.11.31.25463.11.31.2558,190
9063.11.32.0/1963.11.32.1 to 63.11.63.25463.11.63.2558,190
9163.11.64.0/1963.11.64.1 to 63.11.95.25463.11.95.2558,190
9263.11.96.0/1963.11.96.1 to 63.11.127.25463.11.127.2558,190
9363.11.128.0/1963.11.128.1 to 63.11.159.25463.11.159.2558,190
9463.11.160.0/1963.11.160.1 to 63.11.191.25463.11.191.2558,190
9563.11.192.0/1963.11.192.1 to 63.11.223.25463.11.223.2558,190
9663.11.224.0/1963.11.224.1 to 63.11.255.25463.11.255.2558,190
9763.12.0.0/1963.12.0.1 to 63.12.31.25463.12.31.2558,190
9863.12.32.0/1963.12.32.1 to 63.12.63.25463.12.63.2558,190
9963.12.64.0/1963.12.64.1 to 63.12.95.25463.12.95.2558,190
10063.12.96.0/1963.12.96.1 to 63.12.127.25463.12.127.2558,190
10163.12.128.0/1963.12.128.1 to 63.12.159.25463.12.159.2558,190
10263.12.160.0/1963.12.160.1 to 63.12.191.25463.12.191.2558,190
10363.12.192.0/1963.12.192.1 to 63.12.223.25463.12.223.2558,190
10463.12.224.0/1963.12.224.1 to 63.12.255.25463.12.255.2558,190
10563.13.0.0/1963.13.0.1 to 63.13.31.25463.13.31.2558,190
10663.13.32.0/1963.13.32.1 to 63.13.63.25463.13.63.2558,190
10763.13.64.0/1963.13.64.1 to 63.13.95.25463.13.95.2558,190
10863.13.96.0/1963.13.96.1 to 63.13.127.25463.13.127.2558,190
10963.13.128.0/1963.13.128.1 to 63.13.159.25463.13.159.2558,190
11063.13.160.0/1963.13.160.1 to 63.13.191.25463.13.191.2558,190
11163.13.192.0/1963.13.192.1 to 63.13.223.25463.13.223.2558,190
11263.13.224.0/1963.13.224.1 to 63.13.255.25463.13.255.2558,190
11363.14.0.0/1963.14.0.1 to 63.14.31.25463.14.31.2558,190
11463.14.32.0/1963.14.32.1 to 63.14.63.25463.14.63.2558,190
11563.14.64.0/1963.14.64.1 to 63.14.95.25463.14.95.2558,190
11663.14.96.0/1963.14.96.1 to 63.14.127.25463.14.127.2558,190
11763.14.128.0/1963.14.128.1 to 63.14.159.25463.14.159.2558,190
11863.14.160.0/1963.14.160.1 to 63.14.191.25463.14.191.2558,190
11963.14.192.0/1963.14.192.1 to 63.14.223.25463.14.223.2558,190
12063.14.224.0/1963.14.224.1 to 63.14.255.25463.14.255.2558,190
12163.15.0.0/1963.15.0.1 to 63.15.31.25463.15.31.2558,190
12263.15.32.0/1963.15.32.1 to 63.15.63.25463.15.63.2558,190
12363.15.64.0/1963.15.64.1 to 63.15.95.25463.15.95.2558,190
12463.15.96.0/1963.15.96.1 to 63.15.127.25463.15.127.2558,190
12563.15.128.0/1963.15.128.1 to 63.15.159.25463.15.159.2558,190
12663.15.160.0/1963.15.160.1 to 63.15.191.25463.15.191.2558,190
12763.15.192.0/1963.15.192.1 to 63.15.223.25463.15.223.2558,190
12863.15.224.0/1963.15.224.1 to 63.15.255.25463.15.255.2558,190
12963.16.0.0/1963.16.0.1 to 63.16.31.25463.16.31.2558,190
13063.16.32.0/1963.16.32.1 to 63.16.63.25463.16.63.2558,190
13163.16.64.0/1963.16.64.1 to 63.16.95.25463.16.95.2558,190
13263.16.96.0/1963.16.96.1 to 63.16.127.25463.16.127.2558,190
13363.16.128.0/1963.16.128.1 to 63.16.159.25463.16.159.2558,190
13463.16.160.0/1963.16.160.1 to 63.16.191.25463.16.191.2558,190
13563.16.192.0/1963.16.192.1 to 63.16.223.25463.16.223.2558,190
13663.16.224.0/1963.16.224.1 to 63.16.255.25463.16.255.2558,190
13763.17.0.0/1963.17.0.1 to 63.17.31.25463.17.31.2558,190
13863.17.32.0/1963.17.32.1 to 63.17.63.25463.17.63.2558,190
13963.17.64.0/1963.17.64.1 to 63.17.95.25463.17.95.2558,190
14063.17.96.0/1963.17.96.1 to 63.17.127.25463.17.127.2558,190
14163.17.128.0/1963.17.128.1 to 63.17.159.25463.17.159.2558,190
14263.17.160.0/1963.17.160.1 to 63.17.191.25463.17.191.2558,190
14363.17.192.0/1963.17.192.1 to 63.17.223.25463.17.223.2558,190
14463.17.224.0/1963.17.224.1 to 63.17.255.25463.17.255.2558,190
14563.18.0.0/1963.18.0.1 to 63.18.31.25463.18.31.2558,190
14663.18.32.0/1963.18.32.1 to 63.18.63.25463.18.63.2558,190
14763.18.64.0/1963.18.64.1 to 63.18.95.25463.18.95.2558,190
14863.18.96.0/1963.18.96.1 to 63.18.127.25463.18.127.2558,190
14963.18.128.0/1963.18.128.1 to 63.18.159.25463.18.159.2558,190
15063.18.160.0/1963.18.160.1 to 63.18.191.25463.18.191.2558,190
15163.18.192.0/1963.18.192.1 to 63.18.223.25463.18.223.2558,190
15263.18.224.0/1963.18.224.1 to 63.18.255.25463.18.255.2558,190
15363.19.0.0/1963.19.0.1 to 63.19.31.25463.19.31.2558,190
15463.19.32.0/1963.19.32.1 to 63.19.63.25463.19.63.2558,190
15563.19.64.0/1963.19.64.1 to 63.19.95.25463.19.95.2558,190
15663.19.96.0/1963.19.96.1 to 63.19.127.25463.19.127.2558,190
15763.19.128.0/1963.19.128.1 to 63.19.159.25463.19.159.2558,190
15863.19.160.0/1963.19.160.1 to 63.19.191.25463.19.191.2558,190
15963.19.192.0/1963.19.192.1 to 63.19.223.25463.19.223.2558,190
16063.19.224.0/1963.19.224.1 to 63.19.255.25463.19.255.2558,190
16163.20.0.0/1963.20.0.1 to 63.20.31.25463.20.31.2558,190
16263.20.32.0/1963.20.32.1 to 63.20.63.25463.20.63.2558,190
16363.20.64.0/1963.20.64.1 to 63.20.95.25463.20.95.2558,190
16463.20.96.0/1963.20.96.1 to 63.20.127.25463.20.127.2558,190
16563.20.128.0/1963.20.128.1 to 63.20.159.25463.20.159.2558,190
16663.20.160.0/1963.20.160.1 to 63.20.191.25463.20.191.2558,190
16763.20.192.0/1963.20.192.1 to 63.20.223.25463.20.223.2558,190
16863.20.224.0/1963.20.224.1 to 63.20.255.25463.20.255.2558,190
16963.21.0.0/1963.21.0.1 to 63.21.31.25463.21.31.2558,190
17063.21.32.0/1963.21.32.1 to 63.21.63.25463.21.63.2558,190
17163.21.64.0/1963.21.64.1 to 63.21.95.25463.21.95.2558,190
17263.21.96.0/1963.21.96.1 to 63.21.127.25463.21.127.2558,190
17363.21.128.0/1963.21.128.1 to 63.21.159.25463.21.159.2558,190
17463.21.160.0/1963.21.160.1 to 63.21.191.25463.21.191.2558,190
17563.21.192.0/1963.21.192.1 to 63.21.223.25463.21.223.2558,190
17663.21.224.0/1963.21.224.1 to 63.21.255.25463.21.255.2558,190
17763.22.0.0/1963.22.0.1 to 63.22.31.25463.22.31.2558,190
17863.22.32.0/1963.22.32.1 to 63.22.63.25463.22.63.2558,190
17963.22.64.0/1963.22.64.1 to 63.22.95.25463.22.95.2558,190
18063.22.96.0/1963.22.96.1 to 63.22.127.25463.22.127.2558,190
18163.22.128.0/1963.22.128.1 to 63.22.159.25463.22.159.2558,190
18263.22.160.0/1963.22.160.1 to 63.22.191.25463.22.191.2558,190
18363.22.192.0/1963.22.192.1 to 63.22.223.25463.22.223.2558,190
18463.22.224.0/1963.22.224.1 to 63.22.255.25463.22.255.2558,190
18563.23.0.0/1963.23.0.1 to 63.23.31.25463.23.31.2558,190
18663.23.32.0/1963.23.32.1 to 63.23.63.25463.23.63.2558,190
18763.23.64.0/1963.23.64.1 to 63.23.95.25463.23.95.2558,190
18863.23.96.0/1963.23.96.1 to 63.23.127.25463.23.127.2558,190
18963.23.128.0/1963.23.128.1 to 63.23.159.25463.23.159.2558,190
19063.23.160.0/1963.23.160.1 to 63.23.191.25463.23.191.2558,190
19163.23.192.0/1963.23.192.1 to 63.23.223.25463.23.223.2558,190
19263.23.224.0/1963.23.224.1 to 63.23.255.25463.23.255.2558,190
19363.24.0.0/1963.24.0.1 to 63.24.31.25463.24.31.2558,190
19463.24.32.0/1963.24.32.1 to 63.24.63.25463.24.63.2558,190
19563.24.64.0/1963.24.64.1 to 63.24.95.25463.24.95.2558,190
19663.24.96.0/1963.24.96.1 to 63.24.127.25463.24.127.2558,190
19763.24.128.0/1963.24.128.1 to 63.24.159.25463.24.159.2558,190
19863.24.160.0/1963.24.160.1 to 63.24.191.25463.24.191.2558,190
19963.24.192.0/1963.24.192.1 to 63.24.223.25463.24.223.2558,190
20063.24.224.0/1963.24.224.1 to 63.24.255.25463.24.255.2558,190
20163.25.0.0/1963.25.0.1 to 63.25.31.25463.25.31.2558,190
20263.25.32.0/1963.25.32.1 to 63.25.63.25463.25.63.2558,190
20363.25.64.0/1963.25.64.1 to 63.25.95.25463.25.95.2558,190
20463.25.96.0/1963.25.96.1 to 63.25.127.25463.25.127.2558,190
20563.25.128.0/1963.25.128.1 to 63.25.159.25463.25.159.2558,190
20663.25.160.0/1963.25.160.1 to 63.25.191.25463.25.191.2558,190
20763.25.192.0/1963.25.192.1 to 63.25.223.25463.25.223.2558,190
20863.25.224.0/1963.25.224.1 to 63.25.255.25463.25.255.2558,190
20963.26.0.0/1963.26.0.1 to 63.26.31.25463.26.31.2558,190
21063.26.32.0/1963.26.32.1 to 63.26.63.25463.26.63.2558,190
21163.26.64.0/1963.26.64.1 to 63.26.95.25463.26.95.2558,190
21263.26.96.0/1963.26.96.1 to 63.26.127.25463.26.127.2558,190
21363.26.128.0/1963.26.128.1 to 63.26.159.25463.26.159.2558,190
21463.26.160.0/1963.26.160.1 to 63.26.191.25463.26.191.2558,190
21563.26.192.0/1963.26.192.1 to 63.26.223.25463.26.223.2558,190
21663.26.224.0/1963.26.224.1 to 63.26.255.25463.26.255.2558,190
21763.27.0.0/1963.27.0.1 to 63.27.31.25463.27.31.2558,190
21863.27.32.0/1963.27.32.1 to 63.27.63.25463.27.63.2558,190
21963.27.64.0/1963.27.64.1 to 63.27.95.25463.27.95.2558,190
22063.27.96.0/1963.27.96.1 to 63.27.127.25463.27.127.2558,190
22163.27.128.0/1963.27.128.1 to 63.27.159.25463.27.159.2558,190
22263.27.160.0/1963.27.160.1 to 63.27.191.25463.27.191.2558,190
22363.27.192.0/1963.27.192.1 to 63.27.223.25463.27.223.2558,190
22463.27.224.0/1963.27.224.1 to 63.27.255.25463.27.255.2558,190
22563.28.0.0/1963.28.0.1 to 63.28.31.25463.28.31.2558,190
22663.28.32.0/1963.28.32.1 to 63.28.63.25463.28.63.2558,190
22763.28.64.0/1963.28.64.1 to 63.28.95.25463.28.95.2558,190
22863.28.96.0/1963.28.96.1 to 63.28.127.25463.28.127.2558,190
22963.28.128.0/1963.28.128.1 to 63.28.159.25463.28.159.2558,190
23063.28.160.0/1963.28.160.1 to 63.28.191.25463.28.191.2558,190
23163.28.192.0/1963.28.192.1 to 63.28.223.25463.28.223.2558,190
23263.28.224.0/1963.28.224.1 to 63.28.255.25463.28.255.2558,190
23363.29.0.0/1963.29.0.1 to 63.29.31.25463.29.31.2558,190
23463.29.32.0/1963.29.32.1 to 63.29.63.25463.29.63.2558,190
23563.29.64.0/1963.29.64.1 to 63.29.95.25463.29.95.2558,190
23663.29.96.0/1963.29.96.1 to 63.29.127.25463.29.127.2558,190
23763.29.128.0/1963.29.128.1 to 63.29.159.25463.29.159.2558,190
23863.29.160.0/1963.29.160.1 to 63.29.191.25463.29.191.2558,190
23963.29.192.0/1963.29.192.1 to 63.29.223.25463.29.223.2558,190
24063.29.224.0/1963.29.224.1 to 63.29.255.25463.29.255.2558,190
24163.30.0.0/1963.30.0.1 to 63.30.31.25463.30.31.2558,190
24263.30.32.0/1963.30.32.1 to 63.30.63.25463.30.63.2558,190
24363.30.64.0/1963.30.64.1 to 63.30.95.25463.30.95.2558,190
24463.30.96.0/1963.30.96.1 to 63.30.127.25463.30.127.2558,190
24563.30.128.0/1963.30.128.1 to 63.30.159.25463.30.159.2558,190
24663.30.160.0/1963.30.160.1 to 63.30.191.25463.30.191.2558,190
24763.30.192.0/1963.30.192.1 to 63.30.223.25463.30.223.2558,190
24863.30.224.0/1963.30.224.1 to 63.30.255.25463.30.255.2558,190
24963.31.0.0/1963.31.0.1 to 63.31.31.25463.31.31.2558,190
25063.31.32.0/1963.31.32.1 to 63.31.63.25463.31.63.2558,190
25163.31.64.0/1963.31.64.1 to 63.31.95.25463.31.95.2558,190
25263.31.96.0/1963.31.96.1 to 63.31.127.25463.31.127.2558,190
25363.31.128.0/1963.31.128.1 to 63.31.159.25463.31.159.2558,190
25463.31.160.0/1963.31.160.1 to 63.31.191.25463.31.191.2558,190
25563.31.192.0/1963.31.192.1 to 63.31.223.25463.31.223.2558,190
25663.31.224.0/1963.31.224.1 to 63.31.255.25463.31.255.2558,190

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.