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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.

Network19.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
19.0.0.0
Broadcast address
19.31.255.255
First usable
19.0.0.1
Last usable
19.31.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 13000000 · Integer 318767104 to 320864255
Reverse DNS zones
0.19.in-addr.arpa
1.19.in-addr.arpa
2.19.in-addr.arpa
3.19.in-addr.arpa
4.19.in-addr.arpa
5.19.in-addr.arpa
6.19.in-addr.arpa
7.19.in-addr.arpa
8.19.in-addr.arpa
9.19.in-addr.arpa
10.19.in-addr.arpa
11.19.in-addr.arpa
12.19.in-addr.arpa
13.19.in-addr.arpa
14.19.in-addr.arpa
15.19.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010011.00000000.00000000.0000000019.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00010011.00000000.00000000.0000000019.0.0.0
Broadcast00010011.00011111.11111111.1111111119.31.255.255
Split into smaller subnets/19
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

19.0.0.0/11 makes 256 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
119.0.0.0/1919.0.0.1 to 19.0.31.25419.0.31.2558,190
219.0.32.0/1919.0.32.1 to 19.0.63.25419.0.63.2558,190
319.0.64.0/1919.0.64.1 to 19.0.95.25419.0.95.2558,190
419.0.96.0/1919.0.96.1 to 19.0.127.25419.0.127.2558,190
519.0.128.0/1919.0.128.1 to 19.0.159.25419.0.159.2558,190
619.0.160.0/1919.0.160.1 to 19.0.191.25419.0.191.2558,190
719.0.192.0/1919.0.192.1 to 19.0.223.25419.0.223.2558,190
819.0.224.0/1919.0.224.1 to 19.0.255.25419.0.255.2558,190
919.1.0.0/1919.1.0.1 to 19.1.31.25419.1.31.2558,190
1019.1.32.0/1919.1.32.1 to 19.1.63.25419.1.63.2558,190
1119.1.64.0/1919.1.64.1 to 19.1.95.25419.1.95.2558,190
1219.1.96.0/1919.1.96.1 to 19.1.127.25419.1.127.2558,190
1319.1.128.0/1919.1.128.1 to 19.1.159.25419.1.159.2558,190
1419.1.160.0/1919.1.160.1 to 19.1.191.25419.1.191.2558,190
1519.1.192.0/1919.1.192.1 to 19.1.223.25419.1.223.2558,190
1619.1.224.0/1919.1.224.1 to 19.1.255.25419.1.255.2558,190
1719.2.0.0/1919.2.0.1 to 19.2.31.25419.2.31.2558,190
1819.2.32.0/1919.2.32.1 to 19.2.63.25419.2.63.2558,190
1919.2.64.0/1919.2.64.1 to 19.2.95.25419.2.95.2558,190
2019.2.96.0/1919.2.96.1 to 19.2.127.25419.2.127.2558,190
2119.2.128.0/1919.2.128.1 to 19.2.159.25419.2.159.2558,190
2219.2.160.0/1919.2.160.1 to 19.2.191.25419.2.191.2558,190
2319.2.192.0/1919.2.192.1 to 19.2.223.25419.2.223.2558,190
2419.2.224.0/1919.2.224.1 to 19.2.255.25419.2.255.2558,190
2519.3.0.0/1919.3.0.1 to 19.3.31.25419.3.31.2558,190
2619.3.32.0/1919.3.32.1 to 19.3.63.25419.3.63.2558,190
2719.3.64.0/1919.3.64.1 to 19.3.95.25419.3.95.2558,190
2819.3.96.0/1919.3.96.1 to 19.3.127.25419.3.127.2558,190
2919.3.128.0/1919.3.128.1 to 19.3.159.25419.3.159.2558,190
3019.3.160.0/1919.3.160.1 to 19.3.191.25419.3.191.2558,190
3119.3.192.0/1919.3.192.1 to 19.3.223.25419.3.223.2558,190
3219.3.224.0/1919.3.224.1 to 19.3.255.25419.3.255.2558,190
3319.4.0.0/1919.4.0.1 to 19.4.31.25419.4.31.2558,190
3419.4.32.0/1919.4.32.1 to 19.4.63.25419.4.63.2558,190
3519.4.64.0/1919.4.64.1 to 19.4.95.25419.4.95.2558,190
3619.4.96.0/1919.4.96.1 to 19.4.127.25419.4.127.2558,190
3719.4.128.0/1919.4.128.1 to 19.4.159.25419.4.159.2558,190
3819.4.160.0/1919.4.160.1 to 19.4.191.25419.4.191.2558,190
3919.4.192.0/1919.4.192.1 to 19.4.223.25419.4.223.2558,190
4019.4.224.0/1919.4.224.1 to 19.4.255.25419.4.255.2558,190
4119.5.0.0/1919.5.0.1 to 19.5.31.25419.5.31.2558,190
4219.5.32.0/1919.5.32.1 to 19.5.63.25419.5.63.2558,190
4319.5.64.0/1919.5.64.1 to 19.5.95.25419.5.95.2558,190
4419.5.96.0/1919.5.96.1 to 19.5.127.25419.5.127.2558,190
4519.5.128.0/1919.5.128.1 to 19.5.159.25419.5.159.2558,190
4619.5.160.0/1919.5.160.1 to 19.5.191.25419.5.191.2558,190
4719.5.192.0/1919.5.192.1 to 19.5.223.25419.5.223.2558,190
4819.5.224.0/1919.5.224.1 to 19.5.255.25419.5.255.2558,190
4919.6.0.0/1919.6.0.1 to 19.6.31.25419.6.31.2558,190
5019.6.32.0/1919.6.32.1 to 19.6.63.25419.6.63.2558,190
5119.6.64.0/1919.6.64.1 to 19.6.95.25419.6.95.2558,190
5219.6.96.0/1919.6.96.1 to 19.6.127.25419.6.127.2558,190
5319.6.128.0/1919.6.128.1 to 19.6.159.25419.6.159.2558,190
5419.6.160.0/1919.6.160.1 to 19.6.191.25419.6.191.2558,190
5519.6.192.0/1919.6.192.1 to 19.6.223.25419.6.223.2558,190
5619.6.224.0/1919.6.224.1 to 19.6.255.25419.6.255.2558,190
5719.7.0.0/1919.7.0.1 to 19.7.31.25419.7.31.2558,190
5819.7.32.0/1919.7.32.1 to 19.7.63.25419.7.63.2558,190
5919.7.64.0/1919.7.64.1 to 19.7.95.25419.7.95.2558,190
6019.7.96.0/1919.7.96.1 to 19.7.127.25419.7.127.2558,190
6119.7.128.0/1919.7.128.1 to 19.7.159.25419.7.159.2558,190
6219.7.160.0/1919.7.160.1 to 19.7.191.25419.7.191.2558,190
6319.7.192.0/1919.7.192.1 to 19.7.223.25419.7.223.2558,190
6419.7.224.0/1919.7.224.1 to 19.7.255.25419.7.255.2558,190
6519.8.0.0/1919.8.0.1 to 19.8.31.25419.8.31.2558,190
6619.8.32.0/1919.8.32.1 to 19.8.63.25419.8.63.2558,190
6719.8.64.0/1919.8.64.1 to 19.8.95.25419.8.95.2558,190
6819.8.96.0/1919.8.96.1 to 19.8.127.25419.8.127.2558,190
6919.8.128.0/1919.8.128.1 to 19.8.159.25419.8.159.2558,190
7019.8.160.0/1919.8.160.1 to 19.8.191.25419.8.191.2558,190
7119.8.192.0/1919.8.192.1 to 19.8.223.25419.8.223.2558,190
7219.8.224.0/1919.8.224.1 to 19.8.255.25419.8.255.2558,190
7319.9.0.0/1919.9.0.1 to 19.9.31.25419.9.31.2558,190
7419.9.32.0/1919.9.32.1 to 19.9.63.25419.9.63.2558,190
7519.9.64.0/1919.9.64.1 to 19.9.95.25419.9.95.2558,190
7619.9.96.0/1919.9.96.1 to 19.9.127.25419.9.127.2558,190
7719.9.128.0/1919.9.128.1 to 19.9.159.25419.9.159.2558,190
7819.9.160.0/1919.9.160.1 to 19.9.191.25419.9.191.2558,190
7919.9.192.0/1919.9.192.1 to 19.9.223.25419.9.223.2558,190
8019.9.224.0/1919.9.224.1 to 19.9.255.25419.9.255.2558,190
8119.10.0.0/1919.10.0.1 to 19.10.31.25419.10.31.2558,190
8219.10.32.0/1919.10.32.1 to 19.10.63.25419.10.63.2558,190
8319.10.64.0/1919.10.64.1 to 19.10.95.25419.10.95.2558,190
8419.10.96.0/1919.10.96.1 to 19.10.127.25419.10.127.2558,190
8519.10.128.0/1919.10.128.1 to 19.10.159.25419.10.159.2558,190
8619.10.160.0/1919.10.160.1 to 19.10.191.25419.10.191.2558,190
8719.10.192.0/1919.10.192.1 to 19.10.223.25419.10.223.2558,190
8819.10.224.0/1919.10.224.1 to 19.10.255.25419.10.255.2558,190
8919.11.0.0/1919.11.0.1 to 19.11.31.25419.11.31.2558,190
9019.11.32.0/1919.11.32.1 to 19.11.63.25419.11.63.2558,190
9119.11.64.0/1919.11.64.1 to 19.11.95.25419.11.95.2558,190
9219.11.96.0/1919.11.96.1 to 19.11.127.25419.11.127.2558,190
9319.11.128.0/1919.11.128.1 to 19.11.159.25419.11.159.2558,190
9419.11.160.0/1919.11.160.1 to 19.11.191.25419.11.191.2558,190
9519.11.192.0/1919.11.192.1 to 19.11.223.25419.11.223.2558,190
9619.11.224.0/1919.11.224.1 to 19.11.255.25419.11.255.2558,190
9719.12.0.0/1919.12.0.1 to 19.12.31.25419.12.31.2558,190
9819.12.32.0/1919.12.32.1 to 19.12.63.25419.12.63.2558,190
9919.12.64.0/1919.12.64.1 to 19.12.95.25419.12.95.2558,190
10019.12.96.0/1919.12.96.1 to 19.12.127.25419.12.127.2558,190
10119.12.128.0/1919.12.128.1 to 19.12.159.25419.12.159.2558,190
10219.12.160.0/1919.12.160.1 to 19.12.191.25419.12.191.2558,190
10319.12.192.0/1919.12.192.1 to 19.12.223.25419.12.223.2558,190
10419.12.224.0/1919.12.224.1 to 19.12.255.25419.12.255.2558,190
10519.13.0.0/1919.13.0.1 to 19.13.31.25419.13.31.2558,190
10619.13.32.0/1919.13.32.1 to 19.13.63.25419.13.63.2558,190
10719.13.64.0/1919.13.64.1 to 19.13.95.25419.13.95.2558,190
10819.13.96.0/1919.13.96.1 to 19.13.127.25419.13.127.2558,190
10919.13.128.0/1919.13.128.1 to 19.13.159.25419.13.159.2558,190
11019.13.160.0/1919.13.160.1 to 19.13.191.25419.13.191.2558,190
11119.13.192.0/1919.13.192.1 to 19.13.223.25419.13.223.2558,190
11219.13.224.0/1919.13.224.1 to 19.13.255.25419.13.255.2558,190
11319.14.0.0/1919.14.0.1 to 19.14.31.25419.14.31.2558,190
11419.14.32.0/1919.14.32.1 to 19.14.63.25419.14.63.2558,190
11519.14.64.0/1919.14.64.1 to 19.14.95.25419.14.95.2558,190
11619.14.96.0/1919.14.96.1 to 19.14.127.25419.14.127.2558,190
11719.14.128.0/1919.14.128.1 to 19.14.159.25419.14.159.2558,190
11819.14.160.0/1919.14.160.1 to 19.14.191.25419.14.191.2558,190
11919.14.192.0/1919.14.192.1 to 19.14.223.25419.14.223.2558,190
12019.14.224.0/1919.14.224.1 to 19.14.255.25419.14.255.2558,190
12119.15.0.0/1919.15.0.1 to 19.15.31.25419.15.31.2558,190
12219.15.32.0/1919.15.32.1 to 19.15.63.25419.15.63.2558,190
12319.15.64.0/1919.15.64.1 to 19.15.95.25419.15.95.2558,190
12419.15.96.0/1919.15.96.1 to 19.15.127.25419.15.127.2558,190
12519.15.128.0/1919.15.128.1 to 19.15.159.25419.15.159.2558,190
12619.15.160.0/1919.15.160.1 to 19.15.191.25419.15.191.2558,190
12719.15.192.0/1919.15.192.1 to 19.15.223.25419.15.223.2558,190
12819.15.224.0/1919.15.224.1 to 19.15.255.25419.15.255.2558,190
12919.16.0.0/1919.16.0.1 to 19.16.31.25419.16.31.2558,190
13019.16.32.0/1919.16.32.1 to 19.16.63.25419.16.63.2558,190
13119.16.64.0/1919.16.64.1 to 19.16.95.25419.16.95.2558,190
13219.16.96.0/1919.16.96.1 to 19.16.127.25419.16.127.2558,190
13319.16.128.0/1919.16.128.1 to 19.16.159.25419.16.159.2558,190
13419.16.160.0/1919.16.160.1 to 19.16.191.25419.16.191.2558,190
13519.16.192.0/1919.16.192.1 to 19.16.223.25419.16.223.2558,190
13619.16.224.0/1919.16.224.1 to 19.16.255.25419.16.255.2558,190
13719.17.0.0/1919.17.0.1 to 19.17.31.25419.17.31.2558,190
13819.17.32.0/1919.17.32.1 to 19.17.63.25419.17.63.2558,190
13919.17.64.0/1919.17.64.1 to 19.17.95.25419.17.95.2558,190
14019.17.96.0/1919.17.96.1 to 19.17.127.25419.17.127.2558,190
14119.17.128.0/1919.17.128.1 to 19.17.159.25419.17.159.2558,190
14219.17.160.0/1919.17.160.1 to 19.17.191.25419.17.191.2558,190
14319.17.192.0/1919.17.192.1 to 19.17.223.25419.17.223.2558,190
14419.17.224.0/1919.17.224.1 to 19.17.255.25419.17.255.2558,190
14519.18.0.0/1919.18.0.1 to 19.18.31.25419.18.31.2558,190
14619.18.32.0/1919.18.32.1 to 19.18.63.25419.18.63.2558,190
14719.18.64.0/1919.18.64.1 to 19.18.95.25419.18.95.2558,190
14819.18.96.0/1919.18.96.1 to 19.18.127.25419.18.127.2558,190
14919.18.128.0/1919.18.128.1 to 19.18.159.25419.18.159.2558,190
15019.18.160.0/1919.18.160.1 to 19.18.191.25419.18.191.2558,190
15119.18.192.0/1919.18.192.1 to 19.18.223.25419.18.223.2558,190
15219.18.224.0/1919.18.224.1 to 19.18.255.25419.18.255.2558,190
15319.19.0.0/1919.19.0.1 to 19.19.31.25419.19.31.2558,190
15419.19.32.0/1919.19.32.1 to 19.19.63.25419.19.63.2558,190
15519.19.64.0/1919.19.64.1 to 19.19.95.25419.19.95.2558,190
15619.19.96.0/1919.19.96.1 to 19.19.127.25419.19.127.2558,190
15719.19.128.0/1919.19.128.1 to 19.19.159.25419.19.159.2558,190
15819.19.160.0/1919.19.160.1 to 19.19.191.25419.19.191.2558,190
15919.19.192.0/1919.19.192.1 to 19.19.223.25419.19.223.2558,190
16019.19.224.0/1919.19.224.1 to 19.19.255.25419.19.255.2558,190
16119.20.0.0/1919.20.0.1 to 19.20.31.25419.20.31.2558,190
16219.20.32.0/1919.20.32.1 to 19.20.63.25419.20.63.2558,190
16319.20.64.0/1919.20.64.1 to 19.20.95.25419.20.95.2558,190
16419.20.96.0/1919.20.96.1 to 19.20.127.25419.20.127.2558,190
16519.20.128.0/1919.20.128.1 to 19.20.159.25419.20.159.2558,190
16619.20.160.0/1919.20.160.1 to 19.20.191.25419.20.191.2558,190
16719.20.192.0/1919.20.192.1 to 19.20.223.25419.20.223.2558,190
16819.20.224.0/1919.20.224.1 to 19.20.255.25419.20.255.2558,190
16919.21.0.0/1919.21.0.1 to 19.21.31.25419.21.31.2558,190
17019.21.32.0/1919.21.32.1 to 19.21.63.25419.21.63.2558,190
17119.21.64.0/1919.21.64.1 to 19.21.95.25419.21.95.2558,190
17219.21.96.0/1919.21.96.1 to 19.21.127.25419.21.127.2558,190
17319.21.128.0/1919.21.128.1 to 19.21.159.25419.21.159.2558,190
17419.21.160.0/1919.21.160.1 to 19.21.191.25419.21.191.2558,190
17519.21.192.0/1919.21.192.1 to 19.21.223.25419.21.223.2558,190
17619.21.224.0/1919.21.224.1 to 19.21.255.25419.21.255.2558,190
17719.22.0.0/1919.22.0.1 to 19.22.31.25419.22.31.2558,190
17819.22.32.0/1919.22.32.1 to 19.22.63.25419.22.63.2558,190
17919.22.64.0/1919.22.64.1 to 19.22.95.25419.22.95.2558,190
18019.22.96.0/1919.22.96.1 to 19.22.127.25419.22.127.2558,190
18119.22.128.0/1919.22.128.1 to 19.22.159.25419.22.159.2558,190
18219.22.160.0/1919.22.160.1 to 19.22.191.25419.22.191.2558,190
18319.22.192.0/1919.22.192.1 to 19.22.223.25419.22.223.2558,190
18419.22.224.0/1919.22.224.1 to 19.22.255.25419.22.255.2558,190
18519.23.0.0/1919.23.0.1 to 19.23.31.25419.23.31.2558,190
18619.23.32.0/1919.23.32.1 to 19.23.63.25419.23.63.2558,190
18719.23.64.0/1919.23.64.1 to 19.23.95.25419.23.95.2558,190
18819.23.96.0/1919.23.96.1 to 19.23.127.25419.23.127.2558,190
18919.23.128.0/1919.23.128.1 to 19.23.159.25419.23.159.2558,190
19019.23.160.0/1919.23.160.1 to 19.23.191.25419.23.191.2558,190
19119.23.192.0/1919.23.192.1 to 19.23.223.25419.23.223.2558,190
19219.23.224.0/1919.23.224.1 to 19.23.255.25419.23.255.2558,190
19319.24.0.0/1919.24.0.1 to 19.24.31.25419.24.31.2558,190
19419.24.32.0/1919.24.32.1 to 19.24.63.25419.24.63.2558,190
19519.24.64.0/1919.24.64.1 to 19.24.95.25419.24.95.2558,190
19619.24.96.0/1919.24.96.1 to 19.24.127.25419.24.127.2558,190
19719.24.128.0/1919.24.128.1 to 19.24.159.25419.24.159.2558,190
19819.24.160.0/1919.24.160.1 to 19.24.191.25419.24.191.2558,190
19919.24.192.0/1919.24.192.1 to 19.24.223.25419.24.223.2558,190
20019.24.224.0/1919.24.224.1 to 19.24.255.25419.24.255.2558,190
20119.25.0.0/1919.25.0.1 to 19.25.31.25419.25.31.2558,190
20219.25.32.0/1919.25.32.1 to 19.25.63.25419.25.63.2558,190
20319.25.64.0/1919.25.64.1 to 19.25.95.25419.25.95.2558,190
20419.25.96.0/1919.25.96.1 to 19.25.127.25419.25.127.2558,190
20519.25.128.0/1919.25.128.1 to 19.25.159.25419.25.159.2558,190
20619.25.160.0/1919.25.160.1 to 19.25.191.25419.25.191.2558,190
20719.25.192.0/1919.25.192.1 to 19.25.223.25419.25.223.2558,190
20819.25.224.0/1919.25.224.1 to 19.25.255.25419.25.255.2558,190
20919.26.0.0/1919.26.0.1 to 19.26.31.25419.26.31.2558,190
21019.26.32.0/1919.26.32.1 to 19.26.63.25419.26.63.2558,190
21119.26.64.0/1919.26.64.1 to 19.26.95.25419.26.95.2558,190
21219.26.96.0/1919.26.96.1 to 19.26.127.25419.26.127.2558,190
21319.26.128.0/1919.26.128.1 to 19.26.159.25419.26.159.2558,190
21419.26.160.0/1919.26.160.1 to 19.26.191.25419.26.191.2558,190
21519.26.192.0/1919.26.192.1 to 19.26.223.25419.26.223.2558,190
21619.26.224.0/1919.26.224.1 to 19.26.255.25419.26.255.2558,190
21719.27.0.0/1919.27.0.1 to 19.27.31.25419.27.31.2558,190
21819.27.32.0/1919.27.32.1 to 19.27.63.25419.27.63.2558,190
21919.27.64.0/1919.27.64.1 to 19.27.95.25419.27.95.2558,190
22019.27.96.0/1919.27.96.1 to 19.27.127.25419.27.127.2558,190
22119.27.128.0/1919.27.128.1 to 19.27.159.25419.27.159.2558,190
22219.27.160.0/1919.27.160.1 to 19.27.191.25419.27.191.2558,190
22319.27.192.0/1919.27.192.1 to 19.27.223.25419.27.223.2558,190
22419.27.224.0/1919.27.224.1 to 19.27.255.25419.27.255.2558,190
22519.28.0.0/1919.28.0.1 to 19.28.31.25419.28.31.2558,190
22619.28.32.0/1919.28.32.1 to 19.28.63.25419.28.63.2558,190
22719.28.64.0/1919.28.64.1 to 19.28.95.25419.28.95.2558,190
22819.28.96.0/1919.28.96.1 to 19.28.127.25419.28.127.2558,190
22919.28.128.0/1919.28.128.1 to 19.28.159.25419.28.159.2558,190
23019.28.160.0/1919.28.160.1 to 19.28.191.25419.28.191.2558,190
23119.28.192.0/1919.28.192.1 to 19.28.223.25419.28.223.2558,190
23219.28.224.0/1919.28.224.1 to 19.28.255.25419.28.255.2558,190
23319.29.0.0/1919.29.0.1 to 19.29.31.25419.29.31.2558,190
23419.29.32.0/1919.29.32.1 to 19.29.63.25419.29.63.2558,190
23519.29.64.0/1919.29.64.1 to 19.29.95.25419.29.95.2558,190
23619.29.96.0/1919.29.96.1 to 19.29.127.25419.29.127.2558,190
23719.29.128.0/1919.29.128.1 to 19.29.159.25419.29.159.2558,190
23819.29.160.0/1919.29.160.1 to 19.29.191.25419.29.191.2558,190
23919.29.192.0/1919.29.192.1 to 19.29.223.25419.29.223.2558,190
24019.29.224.0/1919.29.224.1 to 19.29.255.25419.29.255.2558,190
24119.30.0.0/1919.30.0.1 to 19.30.31.25419.30.31.2558,190
24219.30.32.0/1919.30.32.1 to 19.30.63.25419.30.63.2558,190
24319.30.64.0/1919.30.64.1 to 19.30.95.25419.30.95.2558,190
24419.30.96.0/1919.30.96.1 to 19.30.127.25419.30.127.2558,190
24519.30.128.0/1919.30.128.1 to 19.30.159.25419.30.159.2558,190
24619.30.160.0/1919.30.160.1 to 19.30.191.25419.30.191.2558,190
24719.30.192.0/1919.30.192.1 to 19.30.223.25419.30.223.2558,190
24819.30.224.0/1919.30.224.1 to 19.30.255.25419.30.255.2558,190
24919.31.0.0/1919.31.0.1 to 19.31.31.25419.31.31.2558,190
25019.31.32.0/1919.31.32.1 to 19.31.63.25419.31.63.2558,190
25119.31.64.0/1919.31.64.1 to 19.31.95.25419.31.95.2558,190
25219.31.96.0/1919.31.96.1 to 19.31.127.25419.31.127.2558,190
25319.31.128.0/1919.31.128.1 to 19.31.159.25419.31.159.2558,190
25419.31.160.0/1919.31.160.1 to 19.31.191.25419.31.191.2558,190
25519.31.192.0/1919.31.192.1 to 19.31.223.25419.31.223.2558,190
25619.31.224.0/1919.31.224.1 to 19.31.255.25419.31.255.2558,190

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.