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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.

Network55.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
55.0.0.0
Broadcast address
55.255.255.255
First usable
55.0.0.1
Last usable
55.255.255.254
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 37000000 · Integer 922746880 to 939524095
Reverse DNS zone
55.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110111..00000000.00000000.0000000055.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00110111..00000000.00000000.0000000055.0.0.0
Broadcast00110111..11111111.11111111.1111111155.255.255.255
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)

55.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.0.0.0/1955.0.0.1 to 55.0.31.25455.0.31.2558,190
255.0.32.0/1955.0.32.1 to 55.0.63.25455.0.63.2558,190
355.0.64.0/1955.0.64.1 to 55.0.95.25455.0.95.2558,190
455.0.96.0/1955.0.96.1 to 55.0.127.25455.0.127.2558,190
555.0.128.0/1955.0.128.1 to 55.0.159.25455.0.159.2558,190
655.0.160.0/1955.0.160.1 to 55.0.191.25455.0.191.2558,190
755.0.192.0/1955.0.192.1 to 55.0.223.25455.0.223.2558,190
855.0.224.0/1955.0.224.1 to 55.0.255.25455.0.255.2558,190
955.1.0.0/1955.1.0.1 to 55.1.31.25455.1.31.2558,190
1055.1.32.0/1955.1.32.1 to 55.1.63.25455.1.63.2558,190
1155.1.64.0/1955.1.64.1 to 55.1.95.25455.1.95.2558,190
1255.1.96.0/1955.1.96.1 to 55.1.127.25455.1.127.2558,190
1355.1.128.0/1955.1.128.1 to 55.1.159.25455.1.159.2558,190
1455.1.160.0/1955.1.160.1 to 55.1.191.25455.1.191.2558,190
1555.1.192.0/1955.1.192.1 to 55.1.223.25455.1.223.2558,190
1655.1.224.0/1955.1.224.1 to 55.1.255.25455.1.255.2558,190
1755.2.0.0/1955.2.0.1 to 55.2.31.25455.2.31.2558,190
1855.2.32.0/1955.2.32.1 to 55.2.63.25455.2.63.2558,190
1955.2.64.0/1955.2.64.1 to 55.2.95.25455.2.95.2558,190
2055.2.96.0/1955.2.96.1 to 55.2.127.25455.2.127.2558,190
2155.2.128.0/1955.2.128.1 to 55.2.159.25455.2.159.2558,190
2255.2.160.0/1955.2.160.1 to 55.2.191.25455.2.191.2558,190
2355.2.192.0/1955.2.192.1 to 55.2.223.25455.2.223.2558,190
2455.2.224.0/1955.2.224.1 to 55.2.255.25455.2.255.2558,190
2555.3.0.0/1955.3.0.1 to 55.3.31.25455.3.31.2558,190
2655.3.32.0/1955.3.32.1 to 55.3.63.25455.3.63.2558,190
2755.3.64.0/1955.3.64.1 to 55.3.95.25455.3.95.2558,190
2855.3.96.0/1955.3.96.1 to 55.3.127.25455.3.127.2558,190
2955.3.128.0/1955.3.128.1 to 55.3.159.25455.3.159.2558,190
3055.3.160.0/1955.3.160.1 to 55.3.191.25455.3.191.2558,190
3155.3.192.0/1955.3.192.1 to 55.3.223.25455.3.223.2558,190
3255.3.224.0/1955.3.224.1 to 55.3.255.25455.3.255.2558,190
3355.4.0.0/1955.4.0.1 to 55.4.31.25455.4.31.2558,190
3455.4.32.0/1955.4.32.1 to 55.4.63.25455.4.63.2558,190
3555.4.64.0/1955.4.64.1 to 55.4.95.25455.4.95.2558,190
3655.4.96.0/1955.4.96.1 to 55.4.127.25455.4.127.2558,190
3755.4.128.0/1955.4.128.1 to 55.4.159.25455.4.159.2558,190
3855.4.160.0/1955.4.160.1 to 55.4.191.25455.4.191.2558,190
3955.4.192.0/1955.4.192.1 to 55.4.223.25455.4.223.2558,190
4055.4.224.0/1955.4.224.1 to 55.4.255.25455.4.255.2558,190
4155.5.0.0/1955.5.0.1 to 55.5.31.25455.5.31.2558,190
4255.5.32.0/1955.5.32.1 to 55.5.63.25455.5.63.2558,190
4355.5.64.0/1955.5.64.1 to 55.5.95.25455.5.95.2558,190
4455.5.96.0/1955.5.96.1 to 55.5.127.25455.5.127.2558,190
4555.5.128.0/1955.5.128.1 to 55.5.159.25455.5.159.2558,190
4655.5.160.0/1955.5.160.1 to 55.5.191.25455.5.191.2558,190
4755.5.192.0/1955.5.192.1 to 55.5.223.25455.5.223.2558,190
4855.5.224.0/1955.5.224.1 to 55.5.255.25455.5.255.2558,190
4955.6.0.0/1955.6.0.1 to 55.6.31.25455.6.31.2558,190
5055.6.32.0/1955.6.32.1 to 55.6.63.25455.6.63.2558,190
5155.6.64.0/1955.6.64.1 to 55.6.95.25455.6.95.2558,190
5255.6.96.0/1955.6.96.1 to 55.6.127.25455.6.127.2558,190
5355.6.128.0/1955.6.128.1 to 55.6.159.25455.6.159.2558,190
5455.6.160.0/1955.6.160.1 to 55.6.191.25455.6.191.2558,190
5555.6.192.0/1955.6.192.1 to 55.6.223.25455.6.223.2558,190
5655.6.224.0/1955.6.224.1 to 55.6.255.25455.6.255.2558,190
5755.7.0.0/1955.7.0.1 to 55.7.31.25455.7.31.2558,190
5855.7.32.0/1955.7.32.1 to 55.7.63.25455.7.63.2558,190
5955.7.64.0/1955.7.64.1 to 55.7.95.25455.7.95.2558,190
6055.7.96.0/1955.7.96.1 to 55.7.127.25455.7.127.2558,190
6155.7.128.0/1955.7.128.1 to 55.7.159.25455.7.159.2558,190
6255.7.160.0/1955.7.160.1 to 55.7.191.25455.7.191.2558,190
6355.7.192.0/1955.7.192.1 to 55.7.223.25455.7.223.2558,190
6455.7.224.0/1955.7.224.1 to 55.7.255.25455.7.255.2558,190
6555.8.0.0/1955.8.0.1 to 55.8.31.25455.8.31.2558,190
6655.8.32.0/1955.8.32.1 to 55.8.63.25455.8.63.2558,190
6755.8.64.0/1955.8.64.1 to 55.8.95.25455.8.95.2558,190
6855.8.96.0/1955.8.96.1 to 55.8.127.25455.8.127.2558,190
6955.8.128.0/1955.8.128.1 to 55.8.159.25455.8.159.2558,190
7055.8.160.0/1955.8.160.1 to 55.8.191.25455.8.191.2558,190
7155.8.192.0/1955.8.192.1 to 55.8.223.25455.8.223.2558,190
7255.8.224.0/1955.8.224.1 to 55.8.255.25455.8.255.2558,190
7355.9.0.0/1955.9.0.1 to 55.9.31.25455.9.31.2558,190
7455.9.32.0/1955.9.32.1 to 55.9.63.25455.9.63.2558,190
7555.9.64.0/1955.9.64.1 to 55.9.95.25455.9.95.2558,190
7655.9.96.0/1955.9.96.1 to 55.9.127.25455.9.127.2558,190
7755.9.128.0/1955.9.128.1 to 55.9.159.25455.9.159.2558,190
7855.9.160.0/1955.9.160.1 to 55.9.191.25455.9.191.2558,190
7955.9.192.0/1955.9.192.1 to 55.9.223.25455.9.223.2558,190
8055.9.224.0/1955.9.224.1 to 55.9.255.25455.9.255.2558,190
8155.10.0.0/1955.10.0.1 to 55.10.31.25455.10.31.2558,190
8255.10.32.0/1955.10.32.1 to 55.10.63.25455.10.63.2558,190
8355.10.64.0/1955.10.64.1 to 55.10.95.25455.10.95.2558,190
8455.10.96.0/1955.10.96.1 to 55.10.127.25455.10.127.2558,190
8555.10.128.0/1955.10.128.1 to 55.10.159.25455.10.159.2558,190
8655.10.160.0/1955.10.160.1 to 55.10.191.25455.10.191.2558,190
8755.10.192.0/1955.10.192.1 to 55.10.223.25455.10.223.2558,190
8855.10.224.0/1955.10.224.1 to 55.10.255.25455.10.255.2558,190
8955.11.0.0/1955.11.0.1 to 55.11.31.25455.11.31.2558,190
9055.11.32.0/1955.11.32.1 to 55.11.63.25455.11.63.2558,190
9155.11.64.0/1955.11.64.1 to 55.11.95.25455.11.95.2558,190
9255.11.96.0/1955.11.96.1 to 55.11.127.25455.11.127.2558,190
9355.11.128.0/1955.11.128.1 to 55.11.159.25455.11.159.2558,190
9455.11.160.0/1955.11.160.1 to 55.11.191.25455.11.191.2558,190
9555.11.192.0/1955.11.192.1 to 55.11.223.25455.11.223.2558,190
9655.11.224.0/1955.11.224.1 to 55.11.255.25455.11.255.2558,190
9755.12.0.0/1955.12.0.1 to 55.12.31.25455.12.31.2558,190
9855.12.32.0/1955.12.32.1 to 55.12.63.25455.12.63.2558,190
9955.12.64.0/1955.12.64.1 to 55.12.95.25455.12.95.2558,190
10055.12.96.0/1955.12.96.1 to 55.12.127.25455.12.127.2558,190
10155.12.128.0/1955.12.128.1 to 55.12.159.25455.12.159.2558,190
10255.12.160.0/1955.12.160.1 to 55.12.191.25455.12.191.2558,190
10355.12.192.0/1955.12.192.1 to 55.12.223.25455.12.223.2558,190
10455.12.224.0/1955.12.224.1 to 55.12.255.25455.12.255.2558,190
10555.13.0.0/1955.13.0.1 to 55.13.31.25455.13.31.2558,190
10655.13.32.0/1955.13.32.1 to 55.13.63.25455.13.63.2558,190
10755.13.64.0/1955.13.64.1 to 55.13.95.25455.13.95.2558,190
10855.13.96.0/1955.13.96.1 to 55.13.127.25455.13.127.2558,190
10955.13.128.0/1955.13.128.1 to 55.13.159.25455.13.159.2558,190
11055.13.160.0/1955.13.160.1 to 55.13.191.25455.13.191.2558,190
11155.13.192.0/1955.13.192.1 to 55.13.223.25455.13.223.2558,190
11255.13.224.0/1955.13.224.1 to 55.13.255.25455.13.255.2558,190
11355.14.0.0/1955.14.0.1 to 55.14.31.25455.14.31.2558,190
11455.14.32.0/1955.14.32.1 to 55.14.63.25455.14.63.2558,190
11555.14.64.0/1955.14.64.1 to 55.14.95.25455.14.95.2558,190
11655.14.96.0/1955.14.96.1 to 55.14.127.25455.14.127.2558,190
11755.14.128.0/1955.14.128.1 to 55.14.159.25455.14.159.2558,190
11855.14.160.0/1955.14.160.1 to 55.14.191.25455.14.191.2558,190
11955.14.192.0/1955.14.192.1 to 55.14.223.25455.14.223.2558,190
12055.14.224.0/1955.14.224.1 to 55.14.255.25455.14.255.2558,190
12155.15.0.0/1955.15.0.1 to 55.15.31.25455.15.31.2558,190
12255.15.32.0/1955.15.32.1 to 55.15.63.25455.15.63.2558,190
12355.15.64.0/1955.15.64.1 to 55.15.95.25455.15.95.2558,190
12455.15.96.0/1955.15.96.1 to 55.15.127.25455.15.127.2558,190
12555.15.128.0/1955.15.128.1 to 55.15.159.25455.15.159.2558,190
12655.15.160.0/1955.15.160.1 to 55.15.191.25455.15.191.2558,190
12755.15.192.0/1955.15.192.1 to 55.15.223.25455.15.223.2558,190
12855.15.224.0/1955.15.224.1 to 55.15.255.25455.15.255.2558,190
12955.16.0.0/1955.16.0.1 to 55.16.31.25455.16.31.2558,190
13055.16.32.0/1955.16.32.1 to 55.16.63.25455.16.63.2558,190
13155.16.64.0/1955.16.64.1 to 55.16.95.25455.16.95.2558,190
13255.16.96.0/1955.16.96.1 to 55.16.127.25455.16.127.2558,190
13355.16.128.0/1955.16.128.1 to 55.16.159.25455.16.159.2558,190
13455.16.160.0/1955.16.160.1 to 55.16.191.25455.16.191.2558,190
13555.16.192.0/1955.16.192.1 to 55.16.223.25455.16.223.2558,190
13655.16.224.0/1955.16.224.1 to 55.16.255.25455.16.255.2558,190
13755.17.0.0/1955.17.0.1 to 55.17.31.25455.17.31.2558,190
13855.17.32.0/1955.17.32.1 to 55.17.63.25455.17.63.2558,190
13955.17.64.0/1955.17.64.1 to 55.17.95.25455.17.95.2558,190
14055.17.96.0/1955.17.96.1 to 55.17.127.25455.17.127.2558,190
14155.17.128.0/1955.17.128.1 to 55.17.159.25455.17.159.2558,190
14255.17.160.0/1955.17.160.1 to 55.17.191.25455.17.191.2558,190
14355.17.192.0/1955.17.192.1 to 55.17.223.25455.17.223.2558,190
14455.17.224.0/1955.17.224.1 to 55.17.255.25455.17.255.2558,190
14555.18.0.0/1955.18.0.1 to 55.18.31.25455.18.31.2558,190
14655.18.32.0/1955.18.32.1 to 55.18.63.25455.18.63.2558,190
14755.18.64.0/1955.18.64.1 to 55.18.95.25455.18.95.2558,190
14855.18.96.0/1955.18.96.1 to 55.18.127.25455.18.127.2558,190
14955.18.128.0/1955.18.128.1 to 55.18.159.25455.18.159.2558,190
15055.18.160.0/1955.18.160.1 to 55.18.191.25455.18.191.2558,190
15155.18.192.0/1955.18.192.1 to 55.18.223.25455.18.223.2558,190
15255.18.224.0/1955.18.224.1 to 55.18.255.25455.18.255.2558,190
15355.19.0.0/1955.19.0.1 to 55.19.31.25455.19.31.2558,190
15455.19.32.0/1955.19.32.1 to 55.19.63.25455.19.63.2558,190
15555.19.64.0/1955.19.64.1 to 55.19.95.25455.19.95.2558,190
15655.19.96.0/1955.19.96.1 to 55.19.127.25455.19.127.2558,190
15755.19.128.0/1955.19.128.1 to 55.19.159.25455.19.159.2558,190
15855.19.160.0/1955.19.160.1 to 55.19.191.25455.19.191.2558,190
15955.19.192.0/1955.19.192.1 to 55.19.223.25455.19.223.2558,190
16055.19.224.0/1955.19.224.1 to 55.19.255.25455.19.255.2558,190
16155.20.0.0/1955.20.0.1 to 55.20.31.25455.20.31.2558,190
16255.20.32.0/1955.20.32.1 to 55.20.63.25455.20.63.2558,190
16355.20.64.0/1955.20.64.1 to 55.20.95.25455.20.95.2558,190
16455.20.96.0/1955.20.96.1 to 55.20.127.25455.20.127.2558,190
16555.20.128.0/1955.20.128.1 to 55.20.159.25455.20.159.2558,190
16655.20.160.0/1955.20.160.1 to 55.20.191.25455.20.191.2558,190
16755.20.192.0/1955.20.192.1 to 55.20.223.25455.20.223.2558,190
16855.20.224.0/1955.20.224.1 to 55.20.255.25455.20.255.2558,190
16955.21.0.0/1955.21.0.1 to 55.21.31.25455.21.31.2558,190
17055.21.32.0/1955.21.32.1 to 55.21.63.25455.21.63.2558,190
17155.21.64.0/1955.21.64.1 to 55.21.95.25455.21.95.2558,190
17255.21.96.0/1955.21.96.1 to 55.21.127.25455.21.127.2558,190
17355.21.128.0/1955.21.128.1 to 55.21.159.25455.21.159.2558,190
17455.21.160.0/1955.21.160.1 to 55.21.191.25455.21.191.2558,190
17555.21.192.0/1955.21.192.1 to 55.21.223.25455.21.223.2558,190
17655.21.224.0/1955.21.224.1 to 55.21.255.25455.21.255.2558,190
17755.22.0.0/1955.22.0.1 to 55.22.31.25455.22.31.2558,190
17855.22.32.0/1955.22.32.1 to 55.22.63.25455.22.63.2558,190
17955.22.64.0/1955.22.64.1 to 55.22.95.25455.22.95.2558,190
18055.22.96.0/1955.22.96.1 to 55.22.127.25455.22.127.2558,190
18155.22.128.0/1955.22.128.1 to 55.22.159.25455.22.159.2558,190
18255.22.160.0/1955.22.160.1 to 55.22.191.25455.22.191.2558,190
18355.22.192.0/1955.22.192.1 to 55.22.223.25455.22.223.2558,190
18455.22.224.0/1955.22.224.1 to 55.22.255.25455.22.255.2558,190
18555.23.0.0/1955.23.0.1 to 55.23.31.25455.23.31.2558,190
18655.23.32.0/1955.23.32.1 to 55.23.63.25455.23.63.2558,190
18755.23.64.0/1955.23.64.1 to 55.23.95.25455.23.95.2558,190
18855.23.96.0/1955.23.96.1 to 55.23.127.25455.23.127.2558,190
18955.23.128.0/1955.23.128.1 to 55.23.159.25455.23.159.2558,190
19055.23.160.0/1955.23.160.1 to 55.23.191.25455.23.191.2558,190
19155.23.192.0/1955.23.192.1 to 55.23.223.25455.23.223.2558,190
19255.23.224.0/1955.23.224.1 to 55.23.255.25455.23.255.2558,190
19355.24.0.0/1955.24.0.1 to 55.24.31.25455.24.31.2558,190
19455.24.32.0/1955.24.32.1 to 55.24.63.25455.24.63.2558,190
19555.24.64.0/1955.24.64.1 to 55.24.95.25455.24.95.2558,190
19655.24.96.0/1955.24.96.1 to 55.24.127.25455.24.127.2558,190
19755.24.128.0/1955.24.128.1 to 55.24.159.25455.24.159.2558,190
19855.24.160.0/1955.24.160.1 to 55.24.191.25455.24.191.2558,190
19955.24.192.0/1955.24.192.1 to 55.24.223.25455.24.223.2558,190
20055.24.224.0/1955.24.224.1 to 55.24.255.25455.24.255.2558,190
20155.25.0.0/1955.25.0.1 to 55.25.31.25455.25.31.2558,190
20255.25.32.0/1955.25.32.1 to 55.25.63.25455.25.63.2558,190
20355.25.64.0/1955.25.64.1 to 55.25.95.25455.25.95.2558,190
20455.25.96.0/1955.25.96.1 to 55.25.127.25455.25.127.2558,190
20555.25.128.0/1955.25.128.1 to 55.25.159.25455.25.159.2558,190
20655.25.160.0/1955.25.160.1 to 55.25.191.25455.25.191.2558,190
20755.25.192.0/1955.25.192.1 to 55.25.223.25455.25.223.2558,190
20855.25.224.0/1955.25.224.1 to 55.25.255.25455.25.255.2558,190
20955.26.0.0/1955.26.0.1 to 55.26.31.25455.26.31.2558,190
21055.26.32.0/1955.26.32.1 to 55.26.63.25455.26.63.2558,190
21155.26.64.0/1955.26.64.1 to 55.26.95.25455.26.95.2558,190
21255.26.96.0/1955.26.96.1 to 55.26.127.25455.26.127.2558,190
21355.26.128.0/1955.26.128.1 to 55.26.159.25455.26.159.2558,190
21455.26.160.0/1955.26.160.1 to 55.26.191.25455.26.191.2558,190
21555.26.192.0/1955.26.192.1 to 55.26.223.25455.26.223.2558,190
21655.26.224.0/1955.26.224.1 to 55.26.255.25455.26.255.2558,190
21755.27.0.0/1955.27.0.1 to 55.27.31.25455.27.31.2558,190
21855.27.32.0/1955.27.32.1 to 55.27.63.25455.27.63.2558,190
21955.27.64.0/1955.27.64.1 to 55.27.95.25455.27.95.2558,190
22055.27.96.0/1955.27.96.1 to 55.27.127.25455.27.127.2558,190
22155.27.128.0/1955.27.128.1 to 55.27.159.25455.27.159.2558,190
22255.27.160.0/1955.27.160.1 to 55.27.191.25455.27.191.2558,190
22355.27.192.0/1955.27.192.1 to 55.27.223.25455.27.223.2558,190
22455.27.224.0/1955.27.224.1 to 55.27.255.25455.27.255.2558,190
22555.28.0.0/1955.28.0.1 to 55.28.31.25455.28.31.2558,190
22655.28.32.0/1955.28.32.1 to 55.28.63.25455.28.63.2558,190
22755.28.64.0/1955.28.64.1 to 55.28.95.25455.28.95.2558,190
22855.28.96.0/1955.28.96.1 to 55.28.127.25455.28.127.2558,190
22955.28.128.0/1955.28.128.1 to 55.28.159.25455.28.159.2558,190
23055.28.160.0/1955.28.160.1 to 55.28.191.25455.28.191.2558,190
23155.28.192.0/1955.28.192.1 to 55.28.223.25455.28.223.2558,190
23255.28.224.0/1955.28.224.1 to 55.28.255.25455.28.255.2558,190
23355.29.0.0/1955.29.0.1 to 55.29.31.25455.29.31.2558,190
23455.29.32.0/1955.29.32.1 to 55.29.63.25455.29.63.2558,190
23555.29.64.0/1955.29.64.1 to 55.29.95.25455.29.95.2558,190
23655.29.96.0/1955.29.96.1 to 55.29.127.25455.29.127.2558,190
23755.29.128.0/1955.29.128.1 to 55.29.159.25455.29.159.2558,190
23855.29.160.0/1955.29.160.1 to 55.29.191.25455.29.191.2558,190
23955.29.192.0/1955.29.192.1 to 55.29.223.25455.29.223.2558,190
24055.29.224.0/1955.29.224.1 to 55.29.255.25455.29.255.2558,190
24155.30.0.0/1955.30.0.1 to 55.30.31.25455.30.31.2558,190
24255.30.32.0/1955.30.32.1 to 55.30.63.25455.30.63.2558,190
24355.30.64.0/1955.30.64.1 to 55.30.95.25455.30.95.2558,190
24455.30.96.0/1955.30.96.1 to 55.30.127.25455.30.127.2558,190
24555.30.128.0/1955.30.128.1 to 55.30.159.25455.30.159.2558,190
24655.30.160.0/1955.30.160.1 to 55.30.191.25455.30.191.2558,190
24755.30.192.0/1955.30.192.1 to 55.30.223.25455.30.223.2558,190
24855.30.224.0/1955.30.224.1 to 55.30.255.25455.30.255.2558,190
24955.31.0.0/1955.31.0.1 to 55.31.31.25455.31.31.2558,190
25055.31.32.0/1955.31.32.1 to 55.31.63.25455.31.63.2558,190
25155.31.64.0/1955.31.64.1 to 55.31.95.25455.31.95.2558,190
25255.31.96.0/1955.31.96.1 to 55.31.127.25455.31.127.2558,190
25355.31.128.0/1955.31.128.1 to 55.31.159.25455.31.159.2558,190
25455.31.160.0/1955.31.160.1 to 55.31.191.25455.31.191.2558,190
25555.31.192.0/1955.31.192.1 to 55.31.223.25455.31.223.2558,190
25655.31.224.0/1955.31.224.1 to 55.31.255.25455.31.255.2558,190

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.