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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.

Network30.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
30.0.0.0
Broadcast address
31.255.255.255
First usable
30.0.0.1
Last usable
31.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 1E000000 · Integer 503316480 to 536870911
Reverse DNS zones
30.in-addr.arpa
31.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011110.00000000.00000000.0000000030.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00011110.00000000.00000000.0000000030.0.0.0
Broadcast00011111.11111111.11111111.1111111131.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

30.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
130.0.0.0/1930.0.0.1 to 30.0.31.25430.0.31.2558,190
230.0.32.0/1930.0.32.1 to 30.0.63.25430.0.63.2558,190
330.0.64.0/1930.0.64.1 to 30.0.95.25430.0.95.2558,190
430.0.96.0/1930.0.96.1 to 30.0.127.25430.0.127.2558,190
530.0.128.0/1930.0.128.1 to 30.0.159.25430.0.159.2558,190
630.0.160.0/1930.0.160.1 to 30.0.191.25430.0.191.2558,190
730.0.192.0/1930.0.192.1 to 30.0.223.25430.0.223.2558,190
830.0.224.0/1930.0.224.1 to 30.0.255.25430.0.255.2558,190
930.1.0.0/1930.1.0.1 to 30.1.31.25430.1.31.2558,190
1030.1.32.0/1930.1.32.1 to 30.1.63.25430.1.63.2558,190
1130.1.64.0/1930.1.64.1 to 30.1.95.25430.1.95.2558,190
1230.1.96.0/1930.1.96.1 to 30.1.127.25430.1.127.2558,190
1330.1.128.0/1930.1.128.1 to 30.1.159.25430.1.159.2558,190
1430.1.160.0/1930.1.160.1 to 30.1.191.25430.1.191.2558,190
1530.1.192.0/1930.1.192.1 to 30.1.223.25430.1.223.2558,190
1630.1.224.0/1930.1.224.1 to 30.1.255.25430.1.255.2558,190
1730.2.0.0/1930.2.0.1 to 30.2.31.25430.2.31.2558,190
1830.2.32.0/1930.2.32.1 to 30.2.63.25430.2.63.2558,190
1930.2.64.0/1930.2.64.1 to 30.2.95.25430.2.95.2558,190
2030.2.96.0/1930.2.96.1 to 30.2.127.25430.2.127.2558,190
2130.2.128.0/1930.2.128.1 to 30.2.159.25430.2.159.2558,190
2230.2.160.0/1930.2.160.1 to 30.2.191.25430.2.191.2558,190
2330.2.192.0/1930.2.192.1 to 30.2.223.25430.2.223.2558,190
2430.2.224.0/1930.2.224.1 to 30.2.255.25430.2.255.2558,190
2530.3.0.0/1930.3.0.1 to 30.3.31.25430.3.31.2558,190
2630.3.32.0/1930.3.32.1 to 30.3.63.25430.3.63.2558,190
2730.3.64.0/1930.3.64.1 to 30.3.95.25430.3.95.2558,190
2830.3.96.0/1930.3.96.1 to 30.3.127.25430.3.127.2558,190
2930.3.128.0/1930.3.128.1 to 30.3.159.25430.3.159.2558,190
3030.3.160.0/1930.3.160.1 to 30.3.191.25430.3.191.2558,190
3130.3.192.0/1930.3.192.1 to 30.3.223.25430.3.223.2558,190
3230.3.224.0/1930.3.224.1 to 30.3.255.25430.3.255.2558,190
3330.4.0.0/1930.4.0.1 to 30.4.31.25430.4.31.2558,190
3430.4.32.0/1930.4.32.1 to 30.4.63.25430.4.63.2558,190
3530.4.64.0/1930.4.64.1 to 30.4.95.25430.4.95.2558,190
3630.4.96.0/1930.4.96.1 to 30.4.127.25430.4.127.2558,190
3730.4.128.0/1930.4.128.1 to 30.4.159.25430.4.159.2558,190
3830.4.160.0/1930.4.160.1 to 30.4.191.25430.4.191.2558,190
3930.4.192.0/1930.4.192.1 to 30.4.223.25430.4.223.2558,190
4030.4.224.0/1930.4.224.1 to 30.4.255.25430.4.255.2558,190
4130.5.0.0/1930.5.0.1 to 30.5.31.25430.5.31.2558,190
4230.5.32.0/1930.5.32.1 to 30.5.63.25430.5.63.2558,190
4330.5.64.0/1930.5.64.1 to 30.5.95.25430.5.95.2558,190
4430.5.96.0/1930.5.96.1 to 30.5.127.25430.5.127.2558,190
4530.5.128.0/1930.5.128.1 to 30.5.159.25430.5.159.2558,190
4630.5.160.0/1930.5.160.1 to 30.5.191.25430.5.191.2558,190
4730.5.192.0/1930.5.192.1 to 30.5.223.25430.5.223.2558,190
4830.5.224.0/1930.5.224.1 to 30.5.255.25430.5.255.2558,190
4930.6.0.0/1930.6.0.1 to 30.6.31.25430.6.31.2558,190
5030.6.32.0/1930.6.32.1 to 30.6.63.25430.6.63.2558,190
5130.6.64.0/1930.6.64.1 to 30.6.95.25430.6.95.2558,190
5230.6.96.0/1930.6.96.1 to 30.6.127.25430.6.127.2558,190
5330.6.128.0/1930.6.128.1 to 30.6.159.25430.6.159.2558,190
5430.6.160.0/1930.6.160.1 to 30.6.191.25430.6.191.2558,190
5530.6.192.0/1930.6.192.1 to 30.6.223.25430.6.223.2558,190
5630.6.224.0/1930.6.224.1 to 30.6.255.25430.6.255.2558,190
5730.7.0.0/1930.7.0.1 to 30.7.31.25430.7.31.2558,190
5830.7.32.0/1930.7.32.1 to 30.7.63.25430.7.63.2558,190
5930.7.64.0/1930.7.64.1 to 30.7.95.25430.7.95.2558,190
6030.7.96.0/1930.7.96.1 to 30.7.127.25430.7.127.2558,190
6130.7.128.0/1930.7.128.1 to 30.7.159.25430.7.159.2558,190
6230.7.160.0/1930.7.160.1 to 30.7.191.25430.7.191.2558,190
6330.7.192.0/1930.7.192.1 to 30.7.223.25430.7.223.2558,190
6430.7.224.0/1930.7.224.1 to 30.7.255.25430.7.255.2558,190
6530.8.0.0/1930.8.0.1 to 30.8.31.25430.8.31.2558,190
6630.8.32.0/1930.8.32.1 to 30.8.63.25430.8.63.2558,190
6730.8.64.0/1930.8.64.1 to 30.8.95.25430.8.95.2558,190
6830.8.96.0/1930.8.96.1 to 30.8.127.25430.8.127.2558,190
6930.8.128.0/1930.8.128.1 to 30.8.159.25430.8.159.2558,190
7030.8.160.0/1930.8.160.1 to 30.8.191.25430.8.191.2558,190
7130.8.192.0/1930.8.192.1 to 30.8.223.25430.8.223.2558,190
7230.8.224.0/1930.8.224.1 to 30.8.255.25430.8.255.2558,190
7330.9.0.0/1930.9.0.1 to 30.9.31.25430.9.31.2558,190
7430.9.32.0/1930.9.32.1 to 30.9.63.25430.9.63.2558,190
7530.9.64.0/1930.9.64.1 to 30.9.95.25430.9.95.2558,190
7630.9.96.0/1930.9.96.1 to 30.9.127.25430.9.127.2558,190
7730.9.128.0/1930.9.128.1 to 30.9.159.25430.9.159.2558,190
7830.9.160.0/1930.9.160.1 to 30.9.191.25430.9.191.2558,190
7930.9.192.0/1930.9.192.1 to 30.9.223.25430.9.223.2558,190
8030.9.224.0/1930.9.224.1 to 30.9.255.25430.9.255.2558,190
8130.10.0.0/1930.10.0.1 to 30.10.31.25430.10.31.2558,190
8230.10.32.0/1930.10.32.1 to 30.10.63.25430.10.63.2558,190
8330.10.64.0/1930.10.64.1 to 30.10.95.25430.10.95.2558,190
8430.10.96.0/1930.10.96.1 to 30.10.127.25430.10.127.2558,190
8530.10.128.0/1930.10.128.1 to 30.10.159.25430.10.159.2558,190
8630.10.160.0/1930.10.160.1 to 30.10.191.25430.10.191.2558,190
8730.10.192.0/1930.10.192.1 to 30.10.223.25430.10.223.2558,190
8830.10.224.0/1930.10.224.1 to 30.10.255.25430.10.255.2558,190
8930.11.0.0/1930.11.0.1 to 30.11.31.25430.11.31.2558,190
9030.11.32.0/1930.11.32.1 to 30.11.63.25430.11.63.2558,190
9130.11.64.0/1930.11.64.1 to 30.11.95.25430.11.95.2558,190
9230.11.96.0/1930.11.96.1 to 30.11.127.25430.11.127.2558,190
9330.11.128.0/1930.11.128.1 to 30.11.159.25430.11.159.2558,190
9430.11.160.0/1930.11.160.1 to 30.11.191.25430.11.191.2558,190
9530.11.192.0/1930.11.192.1 to 30.11.223.25430.11.223.2558,190
9630.11.224.0/1930.11.224.1 to 30.11.255.25430.11.255.2558,190
9730.12.0.0/1930.12.0.1 to 30.12.31.25430.12.31.2558,190
9830.12.32.0/1930.12.32.1 to 30.12.63.25430.12.63.2558,190
9930.12.64.0/1930.12.64.1 to 30.12.95.25430.12.95.2558,190
10030.12.96.0/1930.12.96.1 to 30.12.127.25430.12.127.2558,190
10130.12.128.0/1930.12.128.1 to 30.12.159.25430.12.159.2558,190
10230.12.160.0/1930.12.160.1 to 30.12.191.25430.12.191.2558,190
10330.12.192.0/1930.12.192.1 to 30.12.223.25430.12.223.2558,190
10430.12.224.0/1930.12.224.1 to 30.12.255.25430.12.255.2558,190
10530.13.0.0/1930.13.0.1 to 30.13.31.25430.13.31.2558,190
10630.13.32.0/1930.13.32.1 to 30.13.63.25430.13.63.2558,190
10730.13.64.0/1930.13.64.1 to 30.13.95.25430.13.95.2558,190
10830.13.96.0/1930.13.96.1 to 30.13.127.25430.13.127.2558,190
10930.13.128.0/1930.13.128.1 to 30.13.159.25430.13.159.2558,190
11030.13.160.0/1930.13.160.1 to 30.13.191.25430.13.191.2558,190
11130.13.192.0/1930.13.192.1 to 30.13.223.25430.13.223.2558,190
11230.13.224.0/1930.13.224.1 to 30.13.255.25430.13.255.2558,190
11330.14.0.0/1930.14.0.1 to 30.14.31.25430.14.31.2558,190
11430.14.32.0/1930.14.32.1 to 30.14.63.25430.14.63.2558,190
11530.14.64.0/1930.14.64.1 to 30.14.95.25430.14.95.2558,190
11630.14.96.0/1930.14.96.1 to 30.14.127.25430.14.127.2558,190
11730.14.128.0/1930.14.128.1 to 30.14.159.25430.14.159.2558,190
11830.14.160.0/1930.14.160.1 to 30.14.191.25430.14.191.2558,190
11930.14.192.0/1930.14.192.1 to 30.14.223.25430.14.223.2558,190
12030.14.224.0/1930.14.224.1 to 30.14.255.25430.14.255.2558,190
12130.15.0.0/1930.15.0.1 to 30.15.31.25430.15.31.2558,190
12230.15.32.0/1930.15.32.1 to 30.15.63.25430.15.63.2558,190
12330.15.64.0/1930.15.64.1 to 30.15.95.25430.15.95.2558,190
12430.15.96.0/1930.15.96.1 to 30.15.127.25430.15.127.2558,190
12530.15.128.0/1930.15.128.1 to 30.15.159.25430.15.159.2558,190
12630.15.160.0/1930.15.160.1 to 30.15.191.25430.15.191.2558,190
12730.15.192.0/1930.15.192.1 to 30.15.223.25430.15.223.2558,190
12830.15.224.0/1930.15.224.1 to 30.15.255.25430.15.255.2558,190
12930.16.0.0/1930.16.0.1 to 30.16.31.25430.16.31.2558,190
13030.16.32.0/1930.16.32.1 to 30.16.63.25430.16.63.2558,190
13130.16.64.0/1930.16.64.1 to 30.16.95.25430.16.95.2558,190
13230.16.96.0/1930.16.96.1 to 30.16.127.25430.16.127.2558,190
13330.16.128.0/1930.16.128.1 to 30.16.159.25430.16.159.2558,190
13430.16.160.0/1930.16.160.1 to 30.16.191.25430.16.191.2558,190
13530.16.192.0/1930.16.192.1 to 30.16.223.25430.16.223.2558,190
13630.16.224.0/1930.16.224.1 to 30.16.255.25430.16.255.2558,190
13730.17.0.0/1930.17.0.1 to 30.17.31.25430.17.31.2558,190
13830.17.32.0/1930.17.32.1 to 30.17.63.25430.17.63.2558,190
13930.17.64.0/1930.17.64.1 to 30.17.95.25430.17.95.2558,190
14030.17.96.0/1930.17.96.1 to 30.17.127.25430.17.127.2558,190
14130.17.128.0/1930.17.128.1 to 30.17.159.25430.17.159.2558,190
14230.17.160.0/1930.17.160.1 to 30.17.191.25430.17.191.2558,190
14330.17.192.0/1930.17.192.1 to 30.17.223.25430.17.223.2558,190
14430.17.224.0/1930.17.224.1 to 30.17.255.25430.17.255.2558,190
14530.18.0.0/1930.18.0.1 to 30.18.31.25430.18.31.2558,190
14630.18.32.0/1930.18.32.1 to 30.18.63.25430.18.63.2558,190
14730.18.64.0/1930.18.64.1 to 30.18.95.25430.18.95.2558,190
14830.18.96.0/1930.18.96.1 to 30.18.127.25430.18.127.2558,190
14930.18.128.0/1930.18.128.1 to 30.18.159.25430.18.159.2558,190
15030.18.160.0/1930.18.160.1 to 30.18.191.25430.18.191.2558,190
15130.18.192.0/1930.18.192.1 to 30.18.223.25430.18.223.2558,190
15230.18.224.0/1930.18.224.1 to 30.18.255.25430.18.255.2558,190
15330.19.0.0/1930.19.0.1 to 30.19.31.25430.19.31.2558,190
15430.19.32.0/1930.19.32.1 to 30.19.63.25430.19.63.2558,190
15530.19.64.0/1930.19.64.1 to 30.19.95.25430.19.95.2558,190
15630.19.96.0/1930.19.96.1 to 30.19.127.25430.19.127.2558,190
15730.19.128.0/1930.19.128.1 to 30.19.159.25430.19.159.2558,190
15830.19.160.0/1930.19.160.1 to 30.19.191.25430.19.191.2558,190
15930.19.192.0/1930.19.192.1 to 30.19.223.25430.19.223.2558,190
16030.19.224.0/1930.19.224.1 to 30.19.255.25430.19.255.2558,190
16130.20.0.0/1930.20.0.1 to 30.20.31.25430.20.31.2558,190
16230.20.32.0/1930.20.32.1 to 30.20.63.25430.20.63.2558,190
16330.20.64.0/1930.20.64.1 to 30.20.95.25430.20.95.2558,190
16430.20.96.0/1930.20.96.1 to 30.20.127.25430.20.127.2558,190
16530.20.128.0/1930.20.128.1 to 30.20.159.25430.20.159.2558,190
16630.20.160.0/1930.20.160.1 to 30.20.191.25430.20.191.2558,190
16730.20.192.0/1930.20.192.1 to 30.20.223.25430.20.223.2558,190
16830.20.224.0/1930.20.224.1 to 30.20.255.25430.20.255.2558,190
16930.21.0.0/1930.21.0.1 to 30.21.31.25430.21.31.2558,190
17030.21.32.0/1930.21.32.1 to 30.21.63.25430.21.63.2558,190
17130.21.64.0/1930.21.64.1 to 30.21.95.25430.21.95.2558,190
17230.21.96.0/1930.21.96.1 to 30.21.127.25430.21.127.2558,190
17330.21.128.0/1930.21.128.1 to 30.21.159.25430.21.159.2558,190
17430.21.160.0/1930.21.160.1 to 30.21.191.25430.21.191.2558,190
17530.21.192.0/1930.21.192.1 to 30.21.223.25430.21.223.2558,190
17630.21.224.0/1930.21.224.1 to 30.21.255.25430.21.255.2558,190
17730.22.0.0/1930.22.0.1 to 30.22.31.25430.22.31.2558,190
17830.22.32.0/1930.22.32.1 to 30.22.63.25430.22.63.2558,190
17930.22.64.0/1930.22.64.1 to 30.22.95.25430.22.95.2558,190
18030.22.96.0/1930.22.96.1 to 30.22.127.25430.22.127.2558,190
18130.22.128.0/1930.22.128.1 to 30.22.159.25430.22.159.2558,190
18230.22.160.0/1930.22.160.1 to 30.22.191.25430.22.191.2558,190
18330.22.192.0/1930.22.192.1 to 30.22.223.25430.22.223.2558,190
18430.22.224.0/1930.22.224.1 to 30.22.255.25430.22.255.2558,190
18530.23.0.0/1930.23.0.1 to 30.23.31.25430.23.31.2558,190
18630.23.32.0/1930.23.32.1 to 30.23.63.25430.23.63.2558,190
18730.23.64.0/1930.23.64.1 to 30.23.95.25430.23.95.2558,190
18830.23.96.0/1930.23.96.1 to 30.23.127.25430.23.127.2558,190
18930.23.128.0/1930.23.128.1 to 30.23.159.25430.23.159.2558,190
19030.23.160.0/1930.23.160.1 to 30.23.191.25430.23.191.2558,190
19130.23.192.0/1930.23.192.1 to 30.23.223.25430.23.223.2558,190
19230.23.224.0/1930.23.224.1 to 30.23.255.25430.23.255.2558,190
19330.24.0.0/1930.24.0.1 to 30.24.31.25430.24.31.2558,190
19430.24.32.0/1930.24.32.1 to 30.24.63.25430.24.63.2558,190
19530.24.64.0/1930.24.64.1 to 30.24.95.25430.24.95.2558,190
19630.24.96.0/1930.24.96.1 to 30.24.127.25430.24.127.2558,190
19730.24.128.0/1930.24.128.1 to 30.24.159.25430.24.159.2558,190
19830.24.160.0/1930.24.160.1 to 30.24.191.25430.24.191.2558,190
19930.24.192.0/1930.24.192.1 to 30.24.223.25430.24.223.2558,190
20030.24.224.0/1930.24.224.1 to 30.24.255.25430.24.255.2558,190
20130.25.0.0/1930.25.0.1 to 30.25.31.25430.25.31.2558,190
20230.25.32.0/1930.25.32.1 to 30.25.63.25430.25.63.2558,190
20330.25.64.0/1930.25.64.1 to 30.25.95.25430.25.95.2558,190
20430.25.96.0/1930.25.96.1 to 30.25.127.25430.25.127.2558,190
20530.25.128.0/1930.25.128.1 to 30.25.159.25430.25.159.2558,190
20630.25.160.0/1930.25.160.1 to 30.25.191.25430.25.191.2558,190
20730.25.192.0/1930.25.192.1 to 30.25.223.25430.25.223.2558,190
20830.25.224.0/1930.25.224.1 to 30.25.255.25430.25.255.2558,190
20930.26.0.0/1930.26.0.1 to 30.26.31.25430.26.31.2558,190
21030.26.32.0/1930.26.32.1 to 30.26.63.25430.26.63.2558,190
21130.26.64.0/1930.26.64.1 to 30.26.95.25430.26.95.2558,190
21230.26.96.0/1930.26.96.1 to 30.26.127.25430.26.127.2558,190
21330.26.128.0/1930.26.128.1 to 30.26.159.25430.26.159.2558,190
21430.26.160.0/1930.26.160.1 to 30.26.191.25430.26.191.2558,190
21530.26.192.0/1930.26.192.1 to 30.26.223.25430.26.223.2558,190
21630.26.224.0/1930.26.224.1 to 30.26.255.25430.26.255.2558,190
21730.27.0.0/1930.27.0.1 to 30.27.31.25430.27.31.2558,190
21830.27.32.0/1930.27.32.1 to 30.27.63.25430.27.63.2558,190
21930.27.64.0/1930.27.64.1 to 30.27.95.25430.27.95.2558,190
22030.27.96.0/1930.27.96.1 to 30.27.127.25430.27.127.2558,190
22130.27.128.0/1930.27.128.1 to 30.27.159.25430.27.159.2558,190
22230.27.160.0/1930.27.160.1 to 30.27.191.25430.27.191.2558,190
22330.27.192.0/1930.27.192.1 to 30.27.223.25430.27.223.2558,190
22430.27.224.0/1930.27.224.1 to 30.27.255.25430.27.255.2558,190
22530.28.0.0/1930.28.0.1 to 30.28.31.25430.28.31.2558,190
22630.28.32.0/1930.28.32.1 to 30.28.63.25430.28.63.2558,190
22730.28.64.0/1930.28.64.1 to 30.28.95.25430.28.95.2558,190
22830.28.96.0/1930.28.96.1 to 30.28.127.25430.28.127.2558,190
22930.28.128.0/1930.28.128.1 to 30.28.159.25430.28.159.2558,190
23030.28.160.0/1930.28.160.1 to 30.28.191.25430.28.191.2558,190
23130.28.192.0/1930.28.192.1 to 30.28.223.25430.28.223.2558,190
23230.28.224.0/1930.28.224.1 to 30.28.255.25430.28.255.2558,190
23330.29.0.0/1930.29.0.1 to 30.29.31.25430.29.31.2558,190
23430.29.32.0/1930.29.32.1 to 30.29.63.25430.29.63.2558,190
23530.29.64.0/1930.29.64.1 to 30.29.95.25430.29.95.2558,190
23630.29.96.0/1930.29.96.1 to 30.29.127.25430.29.127.2558,190
23730.29.128.0/1930.29.128.1 to 30.29.159.25430.29.159.2558,190
23830.29.160.0/1930.29.160.1 to 30.29.191.25430.29.191.2558,190
23930.29.192.0/1930.29.192.1 to 30.29.223.25430.29.223.2558,190
24030.29.224.0/1930.29.224.1 to 30.29.255.25430.29.255.2558,190
24130.30.0.0/1930.30.0.1 to 30.30.31.25430.30.31.2558,190
24230.30.32.0/1930.30.32.1 to 30.30.63.25430.30.63.2558,190
24330.30.64.0/1930.30.64.1 to 30.30.95.25430.30.95.2558,190
24430.30.96.0/1930.30.96.1 to 30.30.127.25430.30.127.2558,190
24530.30.128.0/1930.30.128.1 to 30.30.159.25430.30.159.2558,190
24630.30.160.0/1930.30.160.1 to 30.30.191.25430.30.191.2558,190
24730.30.192.0/1930.30.192.1 to 30.30.223.25430.30.223.2558,190
24830.30.224.0/1930.30.224.1 to 30.30.255.25430.30.255.2558,190
24930.31.0.0/1930.31.0.1 to 30.31.31.25430.31.31.2558,190
25030.31.32.0/1930.31.32.1 to 30.31.63.25430.31.63.2558,190
25130.31.64.0/1930.31.64.1 to 30.31.95.25430.31.95.2558,190
25230.31.96.0/1930.31.96.1 to 30.31.127.25430.31.127.2558,190
25330.31.128.0/1930.31.128.1 to 30.31.159.25430.31.159.2558,190
25430.31.160.0/1930.31.160.1 to 30.31.191.25430.31.191.2558,190
25530.31.192.0/1930.31.192.1 to 30.31.223.25430.31.223.2558,190
25630.31.224.0/1930.31.224.1 to 30.31.255.25430.31.255.2558,190

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.