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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.

Network55.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
55.0.0.0
Broadcast address
55.127.255.255
First usable
55.0.0.1
Last usable
55.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 37000000 · Integer 922746880 to 931135487
Reverse DNS zones
0.55.in-addr.arpa
1.55.in-addr.arpa
2.55.in-addr.arpa
3.55.in-addr.arpa
4.55.in-addr.arpa
5.55.in-addr.arpa
6.55.in-addr.arpa
7.55.in-addr.arpa
8.55.in-addr.arpa
9.55.in-addr.arpa
10.55.in-addr.arpa
11.55.in-addr.arpa
12.55.in-addr.arpa
13.55.in-addr.arpa
14.55.in-addr.arpa
15.55.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110111.00000000.00000000.0000000055.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00110111.00000000.00000000.0000000055.0.0.0
Broadcast00110111.01111111.11111111.1111111155.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

55.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.0.0.0/2055.0.0.1 to 55.0.15.25455.0.15.2554,094
255.0.16.0/2055.0.16.1 to 55.0.31.25455.0.31.2554,094
355.0.32.0/2055.0.32.1 to 55.0.47.25455.0.47.2554,094
455.0.48.0/2055.0.48.1 to 55.0.63.25455.0.63.2554,094
555.0.64.0/2055.0.64.1 to 55.0.79.25455.0.79.2554,094
655.0.80.0/2055.0.80.1 to 55.0.95.25455.0.95.2554,094
755.0.96.0/2055.0.96.1 to 55.0.111.25455.0.111.2554,094
855.0.112.0/2055.0.112.1 to 55.0.127.25455.0.127.2554,094
955.0.128.0/2055.0.128.1 to 55.0.143.25455.0.143.2554,094
1055.0.144.0/2055.0.144.1 to 55.0.159.25455.0.159.2554,094
1155.0.160.0/2055.0.160.1 to 55.0.175.25455.0.175.2554,094
1255.0.176.0/2055.0.176.1 to 55.0.191.25455.0.191.2554,094
1355.0.192.0/2055.0.192.1 to 55.0.207.25455.0.207.2554,094
1455.0.208.0/2055.0.208.1 to 55.0.223.25455.0.223.2554,094
1555.0.224.0/2055.0.224.1 to 55.0.239.25455.0.239.2554,094
1655.0.240.0/2055.0.240.1 to 55.0.255.25455.0.255.2554,094
1755.1.0.0/2055.1.0.1 to 55.1.15.25455.1.15.2554,094
1855.1.16.0/2055.1.16.1 to 55.1.31.25455.1.31.2554,094
1955.1.32.0/2055.1.32.1 to 55.1.47.25455.1.47.2554,094
2055.1.48.0/2055.1.48.1 to 55.1.63.25455.1.63.2554,094
2155.1.64.0/2055.1.64.1 to 55.1.79.25455.1.79.2554,094
2255.1.80.0/2055.1.80.1 to 55.1.95.25455.1.95.2554,094
2355.1.96.0/2055.1.96.1 to 55.1.111.25455.1.111.2554,094
2455.1.112.0/2055.1.112.1 to 55.1.127.25455.1.127.2554,094
2555.1.128.0/2055.1.128.1 to 55.1.143.25455.1.143.2554,094
2655.1.144.0/2055.1.144.1 to 55.1.159.25455.1.159.2554,094
2755.1.160.0/2055.1.160.1 to 55.1.175.25455.1.175.2554,094
2855.1.176.0/2055.1.176.1 to 55.1.191.25455.1.191.2554,094
2955.1.192.0/2055.1.192.1 to 55.1.207.25455.1.207.2554,094
3055.1.208.0/2055.1.208.1 to 55.1.223.25455.1.223.2554,094
3155.1.224.0/2055.1.224.1 to 55.1.239.25455.1.239.2554,094
3255.1.240.0/2055.1.240.1 to 55.1.255.25455.1.255.2554,094
3355.2.0.0/2055.2.0.1 to 55.2.15.25455.2.15.2554,094
3455.2.16.0/2055.2.16.1 to 55.2.31.25455.2.31.2554,094
3555.2.32.0/2055.2.32.1 to 55.2.47.25455.2.47.2554,094
3655.2.48.0/2055.2.48.1 to 55.2.63.25455.2.63.2554,094
3755.2.64.0/2055.2.64.1 to 55.2.79.25455.2.79.2554,094
3855.2.80.0/2055.2.80.1 to 55.2.95.25455.2.95.2554,094
3955.2.96.0/2055.2.96.1 to 55.2.111.25455.2.111.2554,094
4055.2.112.0/2055.2.112.1 to 55.2.127.25455.2.127.2554,094
4155.2.128.0/2055.2.128.1 to 55.2.143.25455.2.143.2554,094
4255.2.144.0/2055.2.144.1 to 55.2.159.25455.2.159.2554,094
4355.2.160.0/2055.2.160.1 to 55.2.175.25455.2.175.2554,094
4455.2.176.0/2055.2.176.1 to 55.2.191.25455.2.191.2554,094
4555.2.192.0/2055.2.192.1 to 55.2.207.25455.2.207.2554,094
4655.2.208.0/2055.2.208.1 to 55.2.223.25455.2.223.2554,094
4755.2.224.0/2055.2.224.1 to 55.2.239.25455.2.239.2554,094
4855.2.240.0/2055.2.240.1 to 55.2.255.25455.2.255.2554,094
4955.3.0.0/2055.3.0.1 to 55.3.15.25455.3.15.2554,094
5055.3.16.0/2055.3.16.1 to 55.3.31.25455.3.31.2554,094
5155.3.32.0/2055.3.32.1 to 55.3.47.25455.3.47.2554,094
5255.3.48.0/2055.3.48.1 to 55.3.63.25455.3.63.2554,094
5355.3.64.0/2055.3.64.1 to 55.3.79.25455.3.79.2554,094
5455.3.80.0/2055.3.80.1 to 55.3.95.25455.3.95.2554,094
5555.3.96.0/2055.3.96.1 to 55.3.111.25455.3.111.2554,094
5655.3.112.0/2055.3.112.1 to 55.3.127.25455.3.127.2554,094
5755.3.128.0/2055.3.128.1 to 55.3.143.25455.3.143.2554,094
5855.3.144.0/2055.3.144.1 to 55.3.159.25455.3.159.2554,094
5955.3.160.0/2055.3.160.1 to 55.3.175.25455.3.175.2554,094
6055.3.176.0/2055.3.176.1 to 55.3.191.25455.3.191.2554,094
6155.3.192.0/2055.3.192.1 to 55.3.207.25455.3.207.2554,094
6255.3.208.0/2055.3.208.1 to 55.3.223.25455.3.223.2554,094
6355.3.224.0/2055.3.224.1 to 55.3.239.25455.3.239.2554,094
6455.3.240.0/2055.3.240.1 to 55.3.255.25455.3.255.2554,094
6555.4.0.0/2055.4.0.1 to 55.4.15.25455.4.15.2554,094
6655.4.16.0/2055.4.16.1 to 55.4.31.25455.4.31.2554,094
6755.4.32.0/2055.4.32.1 to 55.4.47.25455.4.47.2554,094
6855.4.48.0/2055.4.48.1 to 55.4.63.25455.4.63.2554,094
6955.4.64.0/2055.4.64.1 to 55.4.79.25455.4.79.2554,094
7055.4.80.0/2055.4.80.1 to 55.4.95.25455.4.95.2554,094
7155.4.96.0/2055.4.96.1 to 55.4.111.25455.4.111.2554,094
7255.4.112.0/2055.4.112.1 to 55.4.127.25455.4.127.2554,094
7355.4.128.0/2055.4.128.1 to 55.4.143.25455.4.143.2554,094
7455.4.144.0/2055.4.144.1 to 55.4.159.25455.4.159.2554,094
7555.4.160.0/2055.4.160.1 to 55.4.175.25455.4.175.2554,094
7655.4.176.0/2055.4.176.1 to 55.4.191.25455.4.191.2554,094
7755.4.192.0/2055.4.192.1 to 55.4.207.25455.4.207.2554,094
7855.4.208.0/2055.4.208.1 to 55.4.223.25455.4.223.2554,094
7955.4.224.0/2055.4.224.1 to 55.4.239.25455.4.239.2554,094
8055.4.240.0/2055.4.240.1 to 55.4.255.25455.4.255.2554,094
8155.5.0.0/2055.5.0.1 to 55.5.15.25455.5.15.2554,094
8255.5.16.0/2055.5.16.1 to 55.5.31.25455.5.31.2554,094
8355.5.32.0/2055.5.32.1 to 55.5.47.25455.5.47.2554,094
8455.5.48.0/2055.5.48.1 to 55.5.63.25455.5.63.2554,094
8555.5.64.0/2055.5.64.1 to 55.5.79.25455.5.79.2554,094
8655.5.80.0/2055.5.80.1 to 55.5.95.25455.5.95.2554,094
8755.5.96.0/2055.5.96.1 to 55.5.111.25455.5.111.2554,094
8855.5.112.0/2055.5.112.1 to 55.5.127.25455.5.127.2554,094
8955.5.128.0/2055.5.128.1 to 55.5.143.25455.5.143.2554,094
9055.5.144.0/2055.5.144.1 to 55.5.159.25455.5.159.2554,094
9155.5.160.0/2055.5.160.1 to 55.5.175.25455.5.175.2554,094
9255.5.176.0/2055.5.176.1 to 55.5.191.25455.5.191.2554,094
9355.5.192.0/2055.5.192.1 to 55.5.207.25455.5.207.2554,094
9455.5.208.0/2055.5.208.1 to 55.5.223.25455.5.223.2554,094
9555.5.224.0/2055.5.224.1 to 55.5.239.25455.5.239.2554,094
9655.5.240.0/2055.5.240.1 to 55.5.255.25455.5.255.2554,094
9755.6.0.0/2055.6.0.1 to 55.6.15.25455.6.15.2554,094
9855.6.16.0/2055.6.16.1 to 55.6.31.25455.6.31.2554,094
9955.6.32.0/2055.6.32.1 to 55.6.47.25455.6.47.2554,094
10055.6.48.0/2055.6.48.1 to 55.6.63.25455.6.63.2554,094
10155.6.64.0/2055.6.64.1 to 55.6.79.25455.6.79.2554,094
10255.6.80.0/2055.6.80.1 to 55.6.95.25455.6.95.2554,094
10355.6.96.0/2055.6.96.1 to 55.6.111.25455.6.111.2554,094
10455.6.112.0/2055.6.112.1 to 55.6.127.25455.6.127.2554,094
10555.6.128.0/2055.6.128.1 to 55.6.143.25455.6.143.2554,094
10655.6.144.0/2055.6.144.1 to 55.6.159.25455.6.159.2554,094
10755.6.160.0/2055.6.160.1 to 55.6.175.25455.6.175.2554,094
10855.6.176.0/2055.6.176.1 to 55.6.191.25455.6.191.2554,094
10955.6.192.0/2055.6.192.1 to 55.6.207.25455.6.207.2554,094
11055.6.208.0/2055.6.208.1 to 55.6.223.25455.6.223.2554,094
11155.6.224.0/2055.6.224.1 to 55.6.239.25455.6.239.2554,094
11255.6.240.0/2055.6.240.1 to 55.6.255.25455.6.255.2554,094
11355.7.0.0/2055.7.0.1 to 55.7.15.25455.7.15.2554,094
11455.7.16.0/2055.7.16.1 to 55.7.31.25455.7.31.2554,094
11555.7.32.0/2055.7.32.1 to 55.7.47.25455.7.47.2554,094
11655.7.48.0/2055.7.48.1 to 55.7.63.25455.7.63.2554,094
11755.7.64.0/2055.7.64.1 to 55.7.79.25455.7.79.2554,094
11855.7.80.0/2055.7.80.1 to 55.7.95.25455.7.95.2554,094
11955.7.96.0/2055.7.96.1 to 55.7.111.25455.7.111.2554,094
12055.7.112.0/2055.7.112.1 to 55.7.127.25455.7.127.2554,094
12155.7.128.0/2055.7.128.1 to 55.7.143.25455.7.143.2554,094
12255.7.144.0/2055.7.144.1 to 55.7.159.25455.7.159.2554,094
12355.7.160.0/2055.7.160.1 to 55.7.175.25455.7.175.2554,094
12455.7.176.0/2055.7.176.1 to 55.7.191.25455.7.191.2554,094
12555.7.192.0/2055.7.192.1 to 55.7.207.25455.7.207.2554,094
12655.7.208.0/2055.7.208.1 to 55.7.223.25455.7.223.2554,094
12755.7.224.0/2055.7.224.1 to 55.7.239.25455.7.239.2554,094
12855.7.240.0/2055.7.240.1 to 55.7.255.25455.7.255.2554,094
12955.8.0.0/2055.8.0.1 to 55.8.15.25455.8.15.2554,094
13055.8.16.0/2055.8.16.1 to 55.8.31.25455.8.31.2554,094
13155.8.32.0/2055.8.32.1 to 55.8.47.25455.8.47.2554,094
13255.8.48.0/2055.8.48.1 to 55.8.63.25455.8.63.2554,094
13355.8.64.0/2055.8.64.1 to 55.8.79.25455.8.79.2554,094
13455.8.80.0/2055.8.80.1 to 55.8.95.25455.8.95.2554,094
13555.8.96.0/2055.8.96.1 to 55.8.111.25455.8.111.2554,094
13655.8.112.0/2055.8.112.1 to 55.8.127.25455.8.127.2554,094
13755.8.128.0/2055.8.128.1 to 55.8.143.25455.8.143.2554,094
13855.8.144.0/2055.8.144.1 to 55.8.159.25455.8.159.2554,094
13955.8.160.0/2055.8.160.1 to 55.8.175.25455.8.175.2554,094
14055.8.176.0/2055.8.176.1 to 55.8.191.25455.8.191.2554,094
14155.8.192.0/2055.8.192.1 to 55.8.207.25455.8.207.2554,094
14255.8.208.0/2055.8.208.1 to 55.8.223.25455.8.223.2554,094
14355.8.224.0/2055.8.224.1 to 55.8.239.25455.8.239.2554,094
14455.8.240.0/2055.8.240.1 to 55.8.255.25455.8.255.2554,094
14555.9.0.0/2055.9.0.1 to 55.9.15.25455.9.15.2554,094
14655.9.16.0/2055.9.16.1 to 55.9.31.25455.9.31.2554,094
14755.9.32.0/2055.9.32.1 to 55.9.47.25455.9.47.2554,094
14855.9.48.0/2055.9.48.1 to 55.9.63.25455.9.63.2554,094
14955.9.64.0/2055.9.64.1 to 55.9.79.25455.9.79.2554,094
15055.9.80.0/2055.9.80.1 to 55.9.95.25455.9.95.2554,094
15155.9.96.0/2055.9.96.1 to 55.9.111.25455.9.111.2554,094
15255.9.112.0/2055.9.112.1 to 55.9.127.25455.9.127.2554,094
15355.9.128.0/2055.9.128.1 to 55.9.143.25455.9.143.2554,094
15455.9.144.0/2055.9.144.1 to 55.9.159.25455.9.159.2554,094
15555.9.160.0/2055.9.160.1 to 55.9.175.25455.9.175.2554,094
15655.9.176.0/2055.9.176.1 to 55.9.191.25455.9.191.2554,094
15755.9.192.0/2055.9.192.1 to 55.9.207.25455.9.207.2554,094
15855.9.208.0/2055.9.208.1 to 55.9.223.25455.9.223.2554,094
15955.9.224.0/2055.9.224.1 to 55.9.239.25455.9.239.2554,094
16055.9.240.0/2055.9.240.1 to 55.9.255.25455.9.255.2554,094
16155.10.0.0/2055.10.0.1 to 55.10.15.25455.10.15.2554,094
16255.10.16.0/2055.10.16.1 to 55.10.31.25455.10.31.2554,094
16355.10.32.0/2055.10.32.1 to 55.10.47.25455.10.47.2554,094
16455.10.48.0/2055.10.48.1 to 55.10.63.25455.10.63.2554,094
16555.10.64.0/2055.10.64.1 to 55.10.79.25455.10.79.2554,094
16655.10.80.0/2055.10.80.1 to 55.10.95.25455.10.95.2554,094
16755.10.96.0/2055.10.96.1 to 55.10.111.25455.10.111.2554,094
16855.10.112.0/2055.10.112.1 to 55.10.127.25455.10.127.2554,094
16955.10.128.0/2055.10.128.1 to 55.10.143.25455.10.143.2554,094
17055.10.144.0/2055.10.144.1 to 55.10.159.25455.10.159.2554,094
17155.10.160.0/2055.10.160.1 to 55.10.175.25455.10.175.2554,094
17255.10.176.0/2055.10.176.1 to 55.10.191.25455.10.191.2554,094
17355.10.192.0/2055.10.192.1 to 55.10.207.25455.10.207.2554,094
17455.10.208.0/2055.10.208.1 to 55.10.223.25455.10.223.2554,094
17555.10.224.0/2055.10.224.1 to 55.10.239.25455.10.239.2554,094
17655.10.240.0/2055.10.240.1 to 55.10.255.25455.10.255.2554,094
17755.11.0.0/2055.11.0.1 to 55.11.15.25455.11.15.2554,094
17855.11.16.0/2055.11.16.1 to 55.11.31.25455.11.31.2554,094
17955.11.32.0/2055.11.32.1 to 55.11.47.25455.11.47.2554,094
18055.11.48.0/2055.11.48.1 to 55.11.63.25455.11.63.2554,094
18155.11.64.0/2055.11.64.1 to 55.11.79.25455.11.79.2554,094
18255.11.80.0/2055.11.80.1 to 55.11.95.25455.11.95.2554,094
18355.11.96.0/2055.11.96.1 to 55.11.111.25455.11.111.2554,094
18455.11.112.0/2055.11.112.1 to 55.11.127.25455.11.127.2554,094
18555.11.128.0/2055.11.128.1 to 55.11.143.25455.11.143.2554,094
18655.11.144.0/2055.11.144.1 to 55.11.159.25455.11.159.2554,094
18755.11.160.0/2055.11.160.1 to 55.11.175.25455.11.175.2554,094
18855.11.176.0/2055.11.176.1 to 55.11.191.25455.11.191.2554,094
18955.11.192.0/2055.11.192.1 to 55.11.207.25455.11.207.2554,094
19055.11.208.0/2055.11.208.1 to 55.11.223.25455.11.223.2554,094
19155.11.224.0/2055.11.224.1 to 55.11.239.25455.11.239.2554,094
19255.11.240.0/2055.11.240.1 to 55.11.255.25455.11.255.2554,094
19355.12.0.0/2055.12.0.1 to 55.12.15.25455.12.15.2554,094
19455.12.16.0/2055.12.16.1 to 55.12.31.25455.12.31.2554,094
19555.12.32.0/2055.12.32.1 to 55.12.47.25455.12.47.2554,094
19655.12.48.0/2055.12.48.1 to 55.12.63.25455.12.63.2554,094
19755.12.64.0/2055.12.64.1 to 55.12.79.25455.12.79.2554,094
19855.12.80.0/2055.12.80.1 to 55.12.95.25455.12.95.2554,094
19955.12.96.0/2055.12.96.1 to 55.12.111.25455.12.111.2554,094
20055.12.112.0/2055.12.112.1 to 55.12.127.25455.12.127.2554,094
20155.12.128.0/2055.12.128.1 to 55.12.143.25455.12.143.2554,094
20255.12.144.0/2055.12.144.1 to 55.12.159.25455.12.159.2554,094
20355.12.160.0/2055.12.160.1 to 55.12.175.25455.12.175.2554,094
20455.12.176.0/2055.12.176.1 to 55.12.191.25455.12.191.2554,094
20555.12.192.0/2055.12.192.1 to 55.12.207.25455.12.207.2554,094
20655.12.208.0/2055.12.208.1 to 55.12.223.25455.12.223.2554,094
20755.12.224.0/2055.12.224.1 to 55.12.239.25455.12.239.2554,094
20855.12.240.0/2055.12.240.1 to 55.12.255.25455.12.255.2554,094
20955.13.0.0/2055.13.0.1 to 55.13.15.25455.13.15.2554,094
21055.13.16.0/2055.13.16.1 to 55.13.31.25455.13.31.2554,094
21155.13.32.0/2055.13.32.1 to 55.13.47.25455.13.47.2554,094
21255.13.48.0/2055.13.48.1 to 55.13.63.25455.13.63.2554,094
21355.13.64.0/2055.13.64.1 to 55.13.79.25455.13.79.2554,094
21455.13.80.0/2055.13.80.1 to 55.13.95.25455.13.95.2554,094
21555.13.96.0/2055.13.96.1 to 55.13.111.25455.13.111.2554,094
21655.13.112.0/2055.13.112.1 to 55.13.127.25455.13.127.2554,094
21755.13.128.0/2055.13.128.1 to 55.13.143.25455.13.143.2554,094
21855.13.144.0/2055.13.144.1 to 55.13.159.25455.13.159.2554,094
21955.13.160.0/2055.13.160.1 to 55.13.175.25455.13.175.2554,094
22055.13.176.0/2055.13.176.1 to 55.13.191.25455.13.191.2554,094
22155.13.192.0/2055.13.192.1 to 55.13.207.25455.13.207.2554,094
22255.13.208.0/2055.13.208.1 to 55.13.223.25455.13.223.2554,094
22355.13.224.0/2055.13.224.1 to 55.13.239.25455.13.239.2554,094
22455.13.240.0/2055.13.240.1 to 55.13.255.25455.13.255.2554,094
22555.14.0.0/2055.14.0.1 to 55.14.15.25455.14.15.2554,094
22655.14.16.0/2055.14.16.1 to 55.14.31.25455.14.31.2554,094
22755.14.32.0/2055.14.32.1 to 55.14.47.25455.14.47.2554,094
22855.14.48.0/2055.14.48.1 to 55.14.63.25455.14.63.2554,094
22955.14.64.0/2055.14.64.1 to 55.14.79.25455.14.79.2554,094
23055.14.80.0/2055.14.80.1 to 55.14.95.25455.14.95.2554,094
23155.14.96.0/2055.14.96.1 to 55.14.111.25455.14.111.2554,094
23255.14.112.0/2055.14.112.1 to 55.14.127.25455.14.127.2554,094
23355.14.128.0/2055.14.128.1 to 55.14.143.25455.14.143.2554,094
23455.14.144.0/2055.14.144.1 to 55.14.159.25455.14.159.2554,094
23555.14.160.0/2055.14.160.1 to 55.14.175.25455.14.175.2554,094
23655.14.176.0/2055.14.176.1 to 55.14.191.25455.14.191.2554,094
23755.14.192.0/2055.14.192.1 to 55.14.207.25455.14.207.2554,094
23855.14.208.0/2055.14.208.1 to 55.14.223.25455.14.223.2554,094
23955.14.224.0/2055.14.224.1 to 55.14.239.25455.14.239.2554,094
24055.14.240.0/2055.14.240.1 to 55.14.255.25455.14.255.2554,094
24155.15.0.0/2055.15.0.1 to 55.15.15.25455.15.15.2554,094
24255.15.16.0/2055.15.16.1 to 55.15.31.25455.15.31.2554,094
24355.15.32.0/2055.15.32.1 to 55.15.47.25455.15.47.2554,094
24455.15.48.0/2055.15.48.1 to 55.15.63.25455.15.63.2554,094
24555.15.64.0/2055.15.64.1 to 55.15.79.25455.15.79.2554,094
24655.15.80.0/2055.15.80.1 to 55.15.95.25455.15.95.2554,094
24755.15.96.0/2055.15.96.1 to 55.15.111.25455.15.111.2554,094
24855.15.112.0/2055.15.112.1 to 55.15.127.25455.15.127.2554,094
24955.15.128.0/2055.15.128.1 to 55.15.143.25455.15.143.2554,094
25055.15.144.0/2055.15.144.1 to 55.15.159.25455.15.159.2554,094
25155.15.160.0/2055.15.160.1 to 55.15.175.25455.15.175.2554,094
25255.15.176.0/2055.15.176.1 to 55.15.191.25455.15.191.2554,094
25355.15.192.0/2055.15.192.1 to 55.15.207.25455.15.207.2554,094
25455.15.208.0/2055.15.208.1 to 55.15.223.25455.15.223.2554,094
25555.15.224.0/2055.15.224.1 to 55.15.239.25455.15.239.2554,094
25655.15.240.0/2055.15.240.1 to 55.15.255.25455.15.255.2554,094

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.