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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.

Network56.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
56.0.0.0
Broadcast address
56.127.255.255
First usable
56.0.0.1
Last usable
56.127.255.254
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 38000000 · Integer 939524096 to 947912703
Reverse DNS zones
0.56.in-addr.arpa
1.56.in-addr.arpa
2.56.in-addr.arpa
3.56.in-addr.arpa
4.56.in-addr.arpa
5.56.in-addr.arpa
6.56.in-addr.arpa
7.56.in-addr.arpa
8.56.in-addr.arpa
9.56.in-addr.arpa
10.56.in-addr.arpa
11.56.in-addr.arpa
12.56.in-addr.arpa
13.56.in-addr.arpa
14.56.in-addr.arpa
15.56.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
Address00111000.00000000.00000000.0000000056.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00111000.00000000.00000000.0000000056.0.0.0
Broadcast00111000.01111111.11111111.1111111156.127.255.255
Split into smaller subnets/19
/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)

56.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
156.0.0.0/1956.0.0.1 to 56.0.31.25456.0.31.2558,190
256.0.32.0/1956.0.32.1 to 56.0.63.25456.0.63.2558,190
356.0.64.0/1956.0.64.1 to 56.0.95.25456.0.95.2558,190
456.0.96.0/1956.0.96.1 to 56.0.127.25456.0.127.2558,190
556.0.128.0/1956.0.128.1 to 56.0.159.25456.0.159.2558,190
656.0.160.0/1956.0.160.1 to 56.0.191.25456.0.191.2558,190
756.0.192.0/1956.0.192.1 to 56.0.223.25456.0.223.2558,190
856.0.224.0/1956.0.224.1 to 56.0.255.25456.0.255.2558,190
956.1.0.0/1956.1.0.1 to 56.1.31.25456.1.31.2558,190
1056.1.32.0/1956.1.32.1 to 56.1.63.25456.1.63.2558,190
1156.1.64.0/1956.1.64.1 to 56.1.95.25456.1.95.2558,190
1256.1.96.0/1956.1.96.1 to 56.1.127.25456.1.127.2558,190
1356.1.128.0/1956.1.128.1 to 56.1.159.25456.1.159.2558,190
1456.1.160.0/1956.1.160.1 to 56.1.191.25456.1.191.2558,190
1556.1.192.0/1956.1.192.1 to 56.1.223.25456.1.223.2558,190
1656.1.224.0/1956.1.224.1 to 56.1.255.25456.1.255.2558,190
1756.2.0.0/1956.2.0.1 to 56.2.31.25456.2.31.2558,190
1856.2.32.0/1956.2.32.1 to 56.2.63.25456.2.63.2558,190
1956.2.64.0/1956.2.64.1 to 56.2.95.25456.2.95.2558,190
2056.2.96.0/1956.2.96.1 to 56.2.127.25456.2.127.2558,190
2156.2.128.0/1956.2.128.1 to 56.2.159.25456.2.159.2558,190
2256.2.160.0/1956.2.160.1 to 56.2.191.25456.2.191.2558,190
2356.2.192.0/1956.2.192.1 to 56.2.223.25456.2.223.2558,190
2456.2.224.0/1956.2.224.1 to 56.2.255.25456.2.255.2558,190
2556.3.0.0/1956.3.0.1 to 56.3.31.25456.3.31.2558,190
2656.3.32.0/1956.3.32.1 to 56.3.63.25456.3.63.2558,190
2756.3.64.0/1956.3.64.1 to 56.3.95.25456.3.95.2558,190
2856.3.96.0/1956.3.96.1 to 56.3.127.25456.3.127.2558,190
2956.3.128.0/1956.3.128.1 to 56.3.159.25456.3.159.2558,190
3056.3.160.0/1956.3.160.1 to 56.3.191.25456.3.191.2558,190
3156.3.192.0/1956.3.192.1 to 56.3.223.25456.3.223.2558,190
3256.3.224.0/1956.3.224.1 to 56.3.255.25456.3.255.2558,190
3356.4.0.0/1956.4.0.1 to 56.4.31.25456.4.31.2558,190
3456.4.32.0/1956.4.32.1 to 56.4.63.25456.4.63.2558,190
3556.4.64.0/1956.4.64.1 to 56.4.95.25456.4.95.2558,190
3656.4.96.0/1956.4.96.1 to 56.4.127.25456.4.127.2558,190
3756.4.128.0/1956.4.128.1 to 56.4.159.25456.4.159.2558,190
3856.4.160.0/1956.4.160.1 to 56.4.191.25456.4.191.2558,190
3956.4.192.0/1956.4.192.1 to 56.4.223.25456.4.223.2558,190
4056.4.224.0/1956.4.224.1 to 56.4.255.25456.4.255.2558,190
4156.5.0.0/1956.5.0.1 to 56.5.31.25456.5.31.2558,190
4256.5.32.0/1956.5.32.1 to 56.5.63.25456.5.63.2558,190
4356.5.64.0/1956.5.64.1 to 56.5.95.25456.5.95.2558,190
4456.5.96.0/1956.5.96.1 to 56.5.127.25456.5.127.2558,190
4556.5.128.0/1956.5.128.1 to 56.5.159.25456.5.159.2558,190
4656.5.160.0/1956.5.160.1 to 56.5.191.25456.5.191.2558,190
4756.5.192.0/1956.5.192.1 to 56.5.223.25456.5.223.2558,190
4856.5.224.0/1956.5.224.1 to 56.5.255.25456.5.255.2558,190
4956.6.0.0/1956.6.0.1 to 56.6.31.25456.6.31.2558,190
5056.6.32.0/1956.6.32.1 to 56.6.63.25456.6.63.2558,190
5156.6.64.0/1956.6.64.1 to 56.6.95.25456.6.95.2558,190
5256.6.96.0/1956.6.96.1 to 56.6.127.25456.6.127.2558,190
5356.6.128.0/1956.6.128.1 to 56.6.159.25456.6.159.2558,190
5456.6.160.0/1956.6.160.1 to 56.6.191.25456.6.191.2558,190
5556.6.192.0/1956.6.192.1 to 56.6.223.25456.6.223.2558,190
5656.6.224.0/1956.6.224.1 to 56.6.255.25456.6.255.2558,190
5756.7.0.0/1956.7.0.1 to 56.7.31.25456.7.31.2558,190
5856.7.32.0/1956.7.32.1 to 56.7.63.25456.7.63.2558,190
5956.7.64.0/1956.7.64.1 to 56.7.95.25456.7.95.2558,190
6056.7.96.0/1956.7.96.1 to 56.7.127.25456.7.127.2558,190
6156.7.128.0/1956.7.128.1 to 56.7.159.25456.7.159.2558,190
6256.7.160.0/1956.7.160.1 to 56.7.191.25456.7.191.2558,190
6356.7.192.0/1956.7.192.1 to 56.7.223.25456.7.223.2558,190
6456.7.224.0/1956.7.224.1 to 56.7.255.25456.7.255.2558,190
6556.8.0.0/1956.8.0.1 to 56.8.31.25456.8.31.2558,190
6656.8.32.0/1956.8.32.1 to 56.8.63.25456.8.63.2558,190
6756.8.64.0/1956.8.64.1 to 56.8.95.25456.8.95.2558,190
6856.8.96.0/1956.8.96.1 to 56.8.127.25456.8.127.2558,190
6956.8.128.0/1956.8.128.1 to 56.8.159.25456.8.159.2558,190
7056.8.160.0/1956.8.160.1 to 56.8.191.25456.8.191.2558,190
7156.8.192.0/1956.8.192.1 to 56.8.223.25456.8.223.2558,190
7256.8.224.0/1956.8.224.1 to 56.8.255.25456.8.255.2558,190
7356.9.0.0/1956.9.0.1 to 56.9.31.25456.9.31.2558,190
7456.9.32.0/1956.9.32.1 to 56.9.63.25456.9.63.2558,190
7556.9.64.0/1956.9.64.1 to 56.9.95.25456.9.95.2558,190
7656.9.96.0/1956.9.96.1 to 56.9.127.25456.9.127.2558,190
7756.9.128.0/1956.9.128.1 to 56.9.159.25456.9.159.2558,190
7856.9.160.0/1956.9.160.1 to 56.9.191.25456.9.191.2558,190
7956.9.192.0/1956.9.192.1 to 56.9.223.25456.9.223.2558,190
8056.9.224.0/1956.9.224.1 to 56.9.255.25456.9.255.2558,190
8156.10.0.0/1956.10.0.1 to 56.10.31.25456.10.31.2558,190
8256.10.32.0/1956.10.32.1 to 56.10.63.25456.10.63.2558,190
8356.10.64.0/1956.10.64.1 to 56.10.95.25456.10.95.2558,190
8456.10.96.0/1956.10.96.1 to 56.10.127.25456.10.127.2558,190
8556.10.128.0/1956.10.128.1 to 56.10.159.25456.10.159.2558,190
8656.10.160.0/1956.10.160.1 to 56.10.191.25456.10.191.2558,190
8756.10.192.0/1956.10.192.1 to 56.10.223.25456.10.223.2558,190
8856.10.224.0/1956.10.224.1 to 56.10.255.25456.10.255.2558,190
8956.11.0.0/1956.11.0.1 to 56.11.31.25456.11.31.2558,190
9056.11.32.0/1956.11.32.1 to 56.11.63.25456.11.63.2558,190
9156.11.64.0/1956.11.64.1 to 56.11.95.25456.11.95.2558,190
9256.11.96.0/1956.11.96.1 to 56.11.127.25456.11.127.2558,190
9356.11.128.0/1956.11.128.1 to 56.11.159.25456.11.159.2558,190
9456.11.160.0/1956.11.160.1 to 56.11.191.25456.11.191.2558,190
9556.11.192.0/1956.11.192.1 to 56.11.223.25456.11.223.2558,190
9656.11.224.0/1956.11.224.1 to 56.11.255.25456.11.255.2558,190
9756.12.0.0/1956.12.0.1 to 56.12.31.25456.12.31.2558,190
9856.12.32.0/1956.12.32.1 to 56.12.63.25456.12.63.2558,190
9956.12.64.0/1956.12.64.1 to 56.12.95.25456.12.95.2558,190
10056.12.96.0/1956.12.96.1 to 56.12.127.25456.12.127.2558,190
10156.12.128.0/1956.12.128.1 to 56.12.159.25456.12.159.2558,190
10256.12.160.0/1956.12.160.1 to 56.12.191.25456.12.191.2558,190
10356.12.192.0/1956.12.192.1 to 56.12.223.25456.12.223.2558,190
10456.12.224.0/1956.12.224.1 to 56.12.255.25456.12.255.2558,190
10556.13.0.0/1956.13.0.1 to 56.13.31.25456.13.31.2558,190
10656.13.32.0/1956.13.32.1 to 56.13.63.25456.13.63.2558,190
10756.13.64.0/1956.13.64.1 to 56.13.95.25456.13.95.2558,190
10856.13.96.0/1956.13.96.1 to 56.13.127.25456.13.127.2558,190
10956.13.128.0/1956.13.128.1 to 56.13.159.25456.13.159.2558,190
11056.13.160.0/1956.13.160.1 to 56.13.191.25456.13.191.2558,190
11156.13.192.0/1956.13.192.1 to 56.13.223.25456.13.223.2558,190
11256.13.224.0/1956.13.224.1 to 56.13.255.25456.13.255.2558,190
11356.14.0.0/1956.14.0.1 to 56.14.31.25456.14.31.2558,190
11456.14.32.0/1956.14.32.1 to 56.14.63.25456.14.63.2558,190
11556.14.64.0/1956.14.64.1 to 56.14.95.25456.14.95.2558,190
11656.14.96.0/1956.14.96.1 to 56.14.127.25456.14.127.2558,190
11756.14.128.0/1956.14.128.1 to 56.14.159.25456.14.159.2558,190
11856.14.160.0/1956.14.160.1 to 56.14.191.25456.14.191.2558,190
11956.14.192.0/1956.14.192.1 to 56.14.223.25456.14.223.2558,190
12056.14.224.0/1956.14.224.1 to 56.14.255.25456.14.255.2558,190
12156.15.0.0/1956.15.0.1 to 56.15.31.25456.15.31.2558,190
12256.15.32.0/1956.15.32.1 to 56.15.63.25456.15.63.2558,190
12356.15.64.0/1956.15.64.1 to 56.15.95.25456.15.95.2558,190
12456.15.96.0/1956.15.96.1 to 56.15.127.25456.15.127.2558,190
12556.15.128.0/1956.15.128.1 to 56.15.159.25456.15.159.2558,190
12656.15.160.0/1956.15.160.1 to 56.15.191.25456.15.191.2558,190
12756.15.192.0/1956.15.192.1 to 56.15.223.25456.15.223.2558,190
12856.15.224.0/1956.15.224.1 to 56.15.255.25456.15.255.2558,190
12956.16.0.0/1956.16.0.1 to 56.16.31.25456.16.31.2558,190
13056.16.32.0/1956.16.32.1 to 56.16.63.25456.16.63.2558,190
13156.16.64.0/1956.16.64.1 to 56.16.95.25456.16.95.2558,190
13256.16.96.0/1956.16.96.1 to 56.16.127.25456.16.127.2558,190
13356.16.128.0/1956.16.128.1 to 56.16.159.25456.16.159.2558,190
13456.16.160.0/1956.16.160.1 to 56.16.191.25456.16.191.2558,190
13556.16.192.0/1956.16.192.1 to 56.16.223.25456.16.223.2558,190
13656.16.224.0/1956.16.224.1 to 56.16.255.25456.16.255.2558,190
13756.17.0.0/1956.17.0.1 to 56.17.31.25456.17.31.2558,190
13856.17.32.0/1956.17.32.1 to 56.17.63.25456.17.63.2558,190
13956.17.64.0/1956.17.64.1 to 56.17.95.25456.17.95.2558,190
14056.17.96.0/1956.17.96.1 to 56.17.127.25456.17.127.2558,190
14156.17.128.0/1956.17.128.1 to 56.17.159.25456.17.159.2558,190
14256.17.160.0/1956.17.160.1 to 56.17.191.25456.17.191.2558,190
14356.17.192.0/1956.17.192.1 to 56.17.223.25456.17.223.2558,190
14456.17.224.0/1956.17.224.1 to 56.17.255.25456.17.255.2558,190
14556.18.0.0/1956.18.0.1 to 56.18.31.25456.18.31.2558,190
14656.18.32.0/1956.18.32.1 to 56.18.63.25456.18.63.2558,190
14756.18.64.0/1956.18.64.1 to 56.18.95.25456.18.95.2558,190
14856.18.96.0/1956.18.96.1 to 56.18.127.25456.18.127.2558,190
14956.18.128.0/1956.18.128.1 to 56.18.159.25456.18.159.2558,190
15056.18.160.0/1956.18.160.1 to 56.18.191.25456.18.191.2558,190
15156.18.192.0/1956.18.192.1 to 56.18.223.25456.18.223.2558,190
15256.18.224.0/1956.18.224.1 to 56.18.255.25456.18.255.2558,190
15356.19.0.0/1956.19.0.1 to 56.19.31.25456.19.31.2558,190
15456.19.32.0/1956.19.32.1 to 56.19.63.25456.19.63.2558,190
15556.19.64.0/1956.19.64.1 to 56.19.95.25456.19.95.2558,190
15656.19.96.0/1956.19.96.1 to 56.19.127.25456.19.127.2558,190
15756.19.128.0/1956.19.128.1 to 56.19.159.25456.19.159.2558,190
15856.19.160.0/1956.19.160.1 to 56.19.191.25456.19.191.2558,190
15956.19.192.0/1956.19.192.1 to 56.19.223.25456.19.223.2558,190
16056.19.224.0/1956.19.224.1 to 56.19.255.25456.19.255.2558,190
16156.20.0.0/1956.20.0.1 to 56.20.31.25456.20.31.2558,190
16256.20.32.0/1956.20.32.1 to 56.20.63.25456.20.63.2558,190
16356.20.64.0/1956.20.64.1 to 56.20.95.25456.20.95.2558,190
16456.20.96.0/1956.20.96.1 to 56.20.127.25456.20.127.2558,190
16556.20.128.0/1956.20.128.1 to 56.20.159.25456.20.159.2558,190
16656.20.160.0/1956.20.160.1 to 56.20.191.25456.20.191.2558,190
16756.20.192.0/1956.20.192.1 to 56.20.223.25456.20.223.2558,190
16856.20.224.0/1956.20.224.1 to 56.20.255.25456.20.255.2558,190
16956.21.0.0/1956.21.0.1 to 56.21.31.25456.21.31.2558,190
17056.21.32.0/1956.21.32.1 to 56.21.63.25456.21.63.2558,190
17156.21.64.0/1956.21.64.1 to 56.21.95.25456.21.95.2558,190
17256.21.96.0/1956.21.96.1 to 56.21.127.25456.21.127.2558,190
17356.21.128.0/1956.21.128.1 to 56.21.159.25456.21.159.2558,190
17456.21.160.0/1956.21.160.1 to 56.21.191.25456.21.191.2558,190
17556.21.192.0/1956.21.192.1 to 56.21.223.25456.21.223.2558,190
17656.21.224.0/1956.21.224.1 to 56.21.255.25456.21.255.2558,190
17756.22.0.0/1956.22.0.1 to 56.22.31.25456.22.31.2558,190
17856.22.32.0/1956.22.32.1 to 56.22.63.25456.22.63.2558,190
17956.22.64.0/1956.22.64.1 to 56.22.95.25456.22.95.2558,190
18056.22.96.0/1956.22.96.1 to 56.22.127.25456.22.127.2558,190
18156.22.128.0/1956.22.128.1 to 56.22.159.25456.22.159.2558,190
18256.22.160.0/1956.22.160.1 to 56.22.191.25456.22.191.2558,190
18356.22.192.0/1956.22.192.1 to 56.22.223.25456.22.223.2558,190
18456.22.224.0/1956.22.224.1 to 56.22.255.25456.22.255.2558,190
18556.23.0.0/1956.23.0.1 to 56.23.31.25456.23.31.2558,190
18656.23.32.0/1956.23.32.1 to 56.23.63.25456.23.63.2558,190
18756.23.64.0/1956.23.64.1 to 56.23.95.25456.23.95.2558,190
18856.23.96.0/1956.23.96.1 to 56.23.127.25456.23.127.2558,190
18956.23.128.0/1956.23.128.1 to 56.23.159.25456.23.159.2558,190
19056.23.160.0/1956.23.160.1 to 56.23.191.25456.23.191.2558,190
19156.23.192.0/1956.23.192.1 to 56.23.223.25456.23.223.2558,190
19256.23.224.0/1956.23.224.1 to 56.23.255.25456.23.255.2558,190
19356.24.0.0/1956.24.0.1 to 56.24.31.25456.24.31.2558,190
19456.24.32.0/1956.24.32.1 to 56.24.63.25456.24.63.2558,190
19556.24.64.0/1956.24.64.1 to 56.24.95.25456.24.95.2558,190
19656.24.96.0/1956.24.96.1 to 56.24.127.25456.24.127.2558,190
19756.24.128.0/1956.24.128.1 to 56.24.159.25456.24.159.2558,190
19856.24.160.0/1956.24.160.1 to 56.24.191.25456.24.191.2558,190
19956.24.192.0/1956.24.192.1 to 56.24.223.25456.24.223.2558,190
20056.24.224.0/1956.24.224.1 to 56.24.255.25456.24.255.2558,190
20156.25.0.0/1956.25.0.1 to 56.25.31.25456.25.31.2558,190
20256.25.32.0/1956.25.32.1 to 56.25.63.25456.25.63.2558,190
20356.25.64.0/1956.25.64.1 to 56.25.95.25456.25.95.2558,190
20456.25.96.0/1956.25.96.1 to 56.25.127.25456.25.127.2558,190
20556.25.128.0/1956.25.128.1 to 56.25.159.25456.25.159.2558,190
20656.25.160.0/1956.25.160.1 to 56.25.191.25456.25.191.2558,190
20756.25.192.0/1956.25.192.1 to 56.25.223.25456.25.223.2558,190
20856.25.224.0/1956.25.224.1 to 56.25.255.25456.25.255.2558,190
20956.26.0.0/1956.26.0.1 to 56.26.31.25456.26.31.2558,190
21056.26.32.0/1956.26.32.1 to 56.26.63.25456.26.63.2558,190
21156.26.64.0/1956.26.64.1 to 56.26.95.25456.26.95.2558,190
21256.26.96.0/1956.26.96.1 to 56.26.127.25456.26.127.2558,190
21356.26.128.0/1956.26.128.1 to 56.26.159.25456.26.159.2558,190
21456.26.160.0/1956.26.160.1 to 56.26.191.25456.26.191.2558,190
21556.26.192.0/1956.26.192.1 to 56.26.223.25456.26.223.2558,190
21656.26.224.0/1956.26.224.1 to 56.26.255.25456.26.255.2558,190
21756.27.0.0/1956.27.0.1 to 56.27.31.25456.27.31.2558,190
21856.27.32.0/1956.27.32.1 to 56.27.63.25456.27.63.2558,190
21956.27.64.0/1956.27.64.1 to 56.27.95.25456.27.95.2558,190
22056.27.96.0/1956.27.96.1 to 56.27.127.25456.27.127.2558,190
22156.27.128.0/1956.27.128.1 to 56.27.159.25456.27.159.2558,190
22256.27.160.0/1956.27.160.1 to 56.27.191.25456.27.191.2558,190
22356.27.192.0/1956.27.192.1 to 56.27.223.25456.27.223.2558,190
22456.27.224.0/1956.27.224.1 to 56.27.255.25456.27.255.2558,190
22556.28.0.0/1956.28.0.1 to 56.28.31.25456.28.31.2558,190
22656.28.32.0/1956.28.32.1 to 56.28.63.25456.28.63.2558,190
22756.28.64.0/1956.28.64.1 to 56.28.95.25456.28.95.2558,190
22856.28.96.0/1956.28.96.1 to 56.28.127.25456.28.127.2558,190
22956.28.128.0/1956.28.128.1 to 56.28.159.25456.28.159.2558,190
23056.28.160.0/1956.28.160.1 to 56.28.191.25456.28.191.2558,190
23156.28.192.0/1956.28.192.1 to 56.28.223.25456.28.223.2558,190
23256.28.224.0/1956.28.224.1 to 56.28.255.25456.28.255.2558,190
23356.29.0.0/1956.29.0.1 to 56.29.31.25456.29.31.2558,190
23456.29.32.0/1956.29.32.1 to 56.29.63.25456.29.63.2558,190
23556.29.64.0/1956.29.64.1 to 56.29.95.25456.29.95.2558,190
23656.29.96.0/1956.29.96.1 to 56.29.127.25456.29.127.2558,190
23756.29.128.0/1956.29.128.1 to 56.29.159.25456.29.159.2558,190
23856.29.160.0/1956.29.160.1 to 56.29.191.25456.29.191.2558,190
23956.29.192.0/1956.29.192.1 to 56.29.223.25456.29.223.2558,190
24056.29.224.0/1956.29.224.1 to 56.29.255.25456.29.255.2558,190
24156.30.0.0/1956.30.0.1 to 56.30.31.25456.30.31.2558,190
24256.30.32.0/1956.30.32.1 to 56.30.63.25456.30.63.2558,190
24356.30.64.0/1956.30.64.1 to 56.30.95.25456.30.95.2558,190
24456.30.96.0/1956.30.96.1 to 56.30.127.25456.30.127.2558,190
24556.30.128.0/1956.30.128.1 to 56.30.159.25456.30.159.2558,190
24656.30.160.0/1956.30.160.1 to 56.30.191.25456.30.191.2558,190
24756.30.192.0/1956.30.192.1 to 56.30.223.25456.30.223.2558,190
24856.30.224.0/1956.30.224.1 to 56.30.255.25456.30.255.2558,190
24956.31.0.0/1956.31.0.1 to 56.31.31.25456.31.31.2558,190
25056.31.32.0/1956.31.32.1 to 56.31.63.25456.31.63.2558,190
25156.31.64.0/1956.31.64.1 to 56.31.95.25456.31.95.2558,190
25256.31.96.0/1956.31.96.1 to 56.31.127.25456.31.127.2558,190
25356.31.128.0/1956.31.128.1 to 56.31.159.25456.31.159.2558,190
25456.31.160.0/1956.31.160.1 to 56.31.191.25456.31.191.2558,190
25556.31.192.0/1956.31.192.1 to 56.31.223.25456.31.223.2558,190
25656.31.224.0/1956.31.224.1 to 56.31.255.25456.31.255.2558,190

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.