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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.

Network23.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
23.0.0.0
Broadcast address
23.255.255.255
First usable
23.0.0.1
Last usable
23.255.255.254
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 17000000 · Integer 385875968 to 402653183
Reverse DNS zone
23.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010111..00000000.00000000.0000000023.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00010111..00000000.00000000.0000000023.0.0.0
Broadcast00010111..11111111.11111111.1111111123.255.255.255
Split into smaller subnets/20
/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)

23.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
123.0.0.0/2023.0.0.1 to 23.0.15.25423.0.15.2554,094
223.0.16.0/2023.0.16.1 to 23.0.31.25423.0.31.2554,094
323.0.32.0/2023.0.32.1 to 23.0.47.25423.0.47.2554,094
423.0.48.0/2023.0.48.1 to 23.0.63.25423.0.63.2554,094
523.0.64.0/2023.0.64.1 to 23.0.79.25423.0.79.2554,094
623.0.80.0/2023.0.80.1 to 23.0.95.25423.0.95.2554,094
723.0.96.0/2023.0.96.1 to 23.0.111.25423.0.111.2554,094
823.0.112.0/2023.0.112.1 to 23.0.127.25423.0.127.2554,094
923.0.128.0/2023.0.128.1 to 23.0.143.25423.0.143.2554,094
1023.0.144.0/2023.0.144.1 to 23.0.159.25423.0.159.2554,094
1123.0.160.0/2023.0.160.1 to 23.0.175.25423.0.175.2554,094
1223.0.176.0/2023.0.176.1 to 23.0.191.25423.0.191.2554,094
1323.0.192.0/2023.0.192.1 to 23.0.207.25423.0.207.2554,094
1423.0.208.0/2023.0.208.1 to 23.0.223.25423.0.223.2554,094
1523.0.224.0/2023.0.224.1 to 23.0.239.25423.0.239.2554,094
1623.0.240.0/2023.0.240.1 to 23.0.255.25423.0.255.2554,094
1723.1.0.0/2023.1.0.1 to 23.1.15.25423.1.15.2554,094
1823.1.16.0/2023.1.16.1 to 23.1.31.25423.1.31.2554,094
1923.1.32.0/2023.1.32.1 to 23.1.47.25423.1.47.2554,094
2023.1.48.0/2023.1.48.1 to 23.1.63.25423.1.63.2554,094
2123.1.64.0/2023.1.64.1 to 23.1.79.25423.1.79.2554,094
2223.1.80.0/2023.1.80.1 to 23.1.95.25423.1.95.2554,094
2323.1.96.0/2023.1.96.1 to 23.1.111.25423.1.111.2554,094
2423.1.112.0/2023.1.112.1 to 23.1.127.25423.1.127.2554,094
2523.1.128.0/2023.1.128.1 to 23.1.143.25423.1.143.2554,094
2623.1.144.0/2023.1.144.1 to 23.1.159.25423.1.159.2554,094
2723.1.160.0/2023.1.160.1 to 23.1.175.25423.1.175.2554,094
2823.1.176.0/2023.1.176.1 to 23.1.191.25423.1.191.2554,094
2923.1.192.0/2023.1.192.1 to 23.1.207.25423.1.207.2554,094
3023.1.208.0/2023.1.208.1 to 23.1.223.25423.1.223.2554,094
3123.1.224.0/2023.1.224.1 to 23.1.239.25423.1.239.2554,094
3223.1.240.0/2023.1.240.1 to 23.1.255.25423.1.255.2554,094
3323.2.0.0/2023.2.0.1 to 23.2.15.25423.2.15.2554,094
3423.2.16.0/2023.2.16.1 to 23.2.31.25423.2.31.2554,094
3523.2.32.0/2023.2.32.1 to 23.2.47.25423.2.47.2554,094
3623.2.48.0/2023.2.48.1 to 23.2.63.25423.2.63.2554,094
3723.2.64.0/2023.2.64.1 to 23.2.79.25423.2.79.2554,094
3823.2.80.0/2023.2.80.1 to 23.2.95.25423.2.95.2554,094
3923.2.96.0/2023.2.96.1 to 23.2.111.25423.2.111.2554,094
4023.2.112.0/2023.2.112.1 to 23.2.127.25423.2.127.2554,094
4123.2.128.0/2023.2.128.1 to 23.2.143.25423.2.143.2554,094
4223.2.144.0/2023.2.144.1 to 23.2.159.25423.2.159.2554,094
4323.2.160.0/2023.2.160.1 to 23.2.175.25423.2.175.2554,094
4423.2.176.0/2023.2.176.1 to 23.2.191.25423.2.191.2554,094
4523.2.192.0/2023.2.192.1 to 23.2.207.25423.2.207.2554,094
4623.2.208.0/2023.2.208.1 to 23.2.223.25423.2.223.2554,094
4723.2.224.0/2023.2.224.1 to 23.2.239.25423.2.239.2554,094
4823.2.240.0/2023.2.240.1 to 23.2.255.25423.2.255.2554,094
4923.3.0.0/2023.3.0.1 to 23.3.15.25423.3.15.2554,094
5023.3.16.0/2023.3.16.1 to 23.3.31.25423.3.31.2554,094
5123.3.32.0/2023.3.32.1 to 23.3.47.25423.3.47.2554,094
5223.3.48.0/2023.3.48.1 to 23.3.63.25423.3.63.2554,094
5323.3.64.0/2023.3.64.1 to 23.3.79.25423.3.79.2554,094
5423.3.80.0/2023.3.80.1 to 23.3.95.25423.3.95.2554,094
5523.3.96.0/2023.3.96.1 to 23.3.111.25423.3.111.2554,094
5623.3.112.0/2023.3.112.1 to 23.3.127.25423.3.127.2554,094
5723.3.128.0/2023.3.128.1 to 23.3.143.25423.3.143.2554,094
5823.3.144.0/2023.3.144.1 to 23.3.159.25423.3.159.2554,094
5923.3.160.0/2023.3.160.1 to 23.3.175.25423.3.175.2554,094
6023.3.176.0/2023.3.176.1 to 23.3.191.25423.3.191.2554,094
6123.3.192.0/2023.3.192.1 to 23.3.207.25423.3.207.2554,094
6223.3.208.0/2023.3.208.1 to 23.3.223.25423.3.223.2554,094
6323.3.224.0/2023.3.224.1 to 23.3.239.25423.3.239.2554,094
6423.3.240.0/2023.3.240.1 to 23.3.255.25423.3.255.2554,094
6523.4.0.0/2023.4.0.1 to 23.4.15.25423.4.15.2554,094
6623.4.16.0/2023.4.16.1 to 23.4.31.25423.4.31.2554,094
6723.4.32.0/2023.4.32.1 to 23.4.47.25423.4.47.2554,094
6823.4.48.0/2023.4.48.1 to 23.4.63.25423.4.63.2554,094
6923.4.64.0/2023.4.64.1 to 23.4.79.25423.4.79.2554,094
7023.4.80.0/2023.4.80.1 to 23.4.95.25423.4.95.2554,094
7123.4.96.0/2023.4.96.1 to 23.4.111.25423.4.111.2554,094
7223.4.112.0/2023.4.112.1 to 23.4.127.25423.4.127.2554,094
7323.4.128.0/2023.4.128.1 to 23.4.143.25423.4.143.2554,094
7423.4.144.0/2023.4.144.1 to 23.4.159.25423.4.159.2554,094
7523.4.160.0/2023.4.160.1 to 23.4.175.25423.4.175.2554,094
7623.4.176.0/2023.4.176.1 to 23.4.191.25423.4.191.2554,094
7723.4.192.0/2023.4.192.1 to 23.4.207.25423.4.207.2554,094
7823.4.208.0/2023.4.208.1 to 23.4.223.25423.4.223.2554,094
7923.4.224.0/2023.4.224.1 to 23.4.239.25423.4.239.2554,094
8023.4.240.0/2023.4.240.1 to 23.4.255.25423.4.255.2554,094
8123.5.0.0/2023.5.0.1 to 23.5.15.25423.5.15.2554,094
8223.5.16.0/2023.5.16.1 to 23.5.31.25423.5.31.2554,094
8323.5.32.0/2023.5.32.1 to 23.5.47.25423.5.47.2554,094
8423.5.48.0/2023.5.48.1 to 23.5.63.25423.5.63.2554,094
8523.5.64.0/2023.5.64.1 to 23.5.79.25423.5.79.2554,094
8623.5.80.0/2023.5.80.1 to 23.5.95.25423.5.95.2554,094
8723.5.96.0/2023.5.96.1 to 23.5.111.25423.5.111.2554,094
8823.5.112.0/2023.5.112.1 to 23.5.127.25423.5.127.2554,094
8923.5.128.0/2023.5.128.1 to 23.5.143.25423.5.143.2554,094
9023.5.144.0/2023.5.144.1 to 23.5.159.25423.5.159.2554,094
9123.5.160.0/2023.5.160.1 to 23.5.175.25423.5.175.2554,094
9223.5.176.0/2023.5.176.1 to 23.5.191.25423.5.191.2554,094
9323.5.192.0/2023.5.192.1 to 23.5.207.25423.5.207.2554,094
9423.5.208.0/2023.5.208.1 to 23.5.223.25423.5.223.2554,094
9523.5.224.0/2023.5.224.1 to 23.5.239.25423.5.239.2554,094
9623.5.240.0/2023.5.240.1 to 23.5.255.25423.5.255.2554,094
9723.6.0.0/2023.6.0.1 to 23.6.15.25423.6.15.2554,094
9823.6.16.0/2023.6.16.1 to 23.6.31.25423.6.31.2554,094
9923.6.32.0/2023.6.32.1 to 23.6.47.25423.6.47.2554,094
10023.6.48.0/2023.6.48.1 to 23.6.63.25423.6.63.2554,094
10123.6.64.0/2023.6.64.1 to 23.6.79.25423.6.79.2554,094
10223.6.80.0/2023.6.80.1 to 23.6.95.25423.6.95.2554,094
10323.6.96.0/2023.6.96.1 to 23.6.111.25423.6.111.2554,094
10423.6.112.0/2023.6.112.1 to 23.6.127.25423.6.127.2554,094
10523.6.128.0/2023.6.128.1 to 23.6.143.25423.6.143.2554,094
10623.6.144.0/2023.6.144.1 to 23.6.159.25423.6.159.2554,094
10723.6.160.0/2023.6.160.1 to 23.6.175.25423.6.175.2554,094
10823.6.176.0/2023.6.176.1 to 23.6.191.25423.6.191.2554,094
10923.6.192.0/2023.6.192.1 to 23.6.207.25423.6.207.2554,094
11023.6.208.0/2023.6.208.1 to 23.6.223.25423.6.223.2554,094
11123.6.224.0/2023.6.224.1 to 23.6.239.25423.6.239.2554,094
11223.6.240.0/2023.6.240.1 to 23.6.255.25423.6.255.2554,094
11323.7.0.0/2023.7.0.1 to 23.7.15.25423.7.15.2554,094
11423.7.16.0/2023.7.16.1 to 23.7.31.25423.7.31.2554,094
11523.7.32.0/2023.7.32.1 to 23.7.47.25423.7.47.2554,094
11623.7.48.0/2023.7.48.1 to 23.7.63.25423.7.63.2554,094
11723.7.64.0/2023.7.64.1 to 23.7.79.25423.7.79.2554,094
11823.7.80.0/2023.7.80.1 to 23.7.95.25423.7.95.2554,094
11923.7.96.0/2023.7.96.1 to 23.7.111.25423.7.111.2554,094
12023.7.112.0/2023.7.112.1 to 23.7.127.25423.7.127.2554,094
12123.7.128.0/2023.7.128.1 to 23.7.143.25423.7.143.2554,094
12223.7.144.0/2023.7.144.1 to 23.7.159.25423.7.159.2554,094
12323.7.160.0/2023.7.160.1 to 23.7.175.25423.7.175.2554,094
12423.7.176.0/2023.7.176.1 to 23.7.191.25423.7.191.2554,094
12523.7.192.0/2023.7.192.1 to 23.7.207.25423.7.207.2554,094
12623.7.208.0/2023.7.208.1 to 23.7.223.25423.7.223.2554,094
12723.7.224.0/2023.7.224.1 to 23.7.239.25423.7.239.2554,094
12823.7.240.0/2023.7.240.1 to 23.7.255.25423.7.255.2554,094
12923.8.0.0/2023.8.0.1 to 23.8.15.25423.8.15.2554,094
13023.8.16.0/2023.8.16.1 to 23.8.31.25423.8.31.2554,094
13123.8.32.0/2023.8.32.1 to 23.8.47.25423.8.47.2554,094
13223.8.48.0/2023.8.48.1 to 23.8.63.25423.8.63.2554,094
13323.8.64.0/2023.8.64.1 to 23.8.79.25423.8.79.2554,094
13423.8.80.0/2023.8.80.1 to 23.8.95.25423.8.95.2554,094
13523.8.96.0/2023.8.96.1 to 23.8.111.25423.8.111.2554,094
13623.8.112.0/2023.8.112.1 to 23.8.127.25423.8.127.2554,094
13723.8.128.0/2023.8.128.1 to 23.8.143.25423.8.143.2554,094
13823.8.144.0/2023.8.144.1 to 23.8.159.25423.8.159.2554,094
13923.8.160.0/2023.8.160.1 to 23.8.175.25423.8.175.2554,094
14023.8.176.0/2023.8.176.1 to 23.8.191.25423.8.191.2554,094
14123.8.192.0/2023.8.192.1 to 23.8.207.25423.8.207.2554,094
14223.8.208.0/2023.8.208.1 to 23.8.223.25423.8.223.2554,094
14323.8.224.0/2023.8.224.1 to 23.8.239.25423.8.239.2554,094
14423.8.240.0/2023.8.240.1 to 23.8.255.25423.8.255.2554,094
14523.9.0.0/2023.9.0.1 to 23.9.15.25423.9.15.2554,094
14623.9.16.0/2023.9.16.1 to 23.9.31.25423.9.31.2554,094
14723.9.32.0/2023.9.32.1 to 23.9.47.25423.9.47.2554,094
14823.9.48.0/2023.9.48.1 to 23.9.63.25423.9.63.2554,094
14923.9.64.0/2023.9.64.1 to 23.9.79.25423.9.79.2554,094
15023.9.80.0/2023.9.80.1 to 23.9.95.25423.9.95.2554,094
15123.9.96.0/2023.9.96.1 to 23.9.111.25423.9.111.2554,094
15223.9.112.0/2023.9.112.1 to 23.9.127.25423.9.127.2554,094
15323.9.128.0/2023.9.128.1 to 23.9.143.25423.9.143.2554,094
15423.9.144.0/2023.9.144.1 to 23.9.159.25423.9.159.2554,094
15523.9.160.0/2023.9.160.1 to 23.9.175.25423.9.175.2554,094
15623.9.176.0/2023.9.176.1 to 23.9.191.25423.9.191.2554,094
15723.9.192.0/2023.9.192.1 to 23.9.207.25423.9.207.2554,094
15823.9.208.0/2023.9.208.1 to 23.9.223.25423.9.223.2554,094
15923.9.224.0/2023.9.224.1 to 23.9.239.25423.9.239.2554,094
16023.9.240.0/2023.9.240.1 to 23.9.255.25423.9.255.2554,094
16123.10.0.0/2023.10.0.1 to 23.10.15.25423.10.15.2554,094
16223.10.16.0/2023.10.16.1 to 23.10.31.25423.10.31.2554,094
16323.10.32.0/2023.10.32.1 to 23.10.47.25423.10.47.2554,094
16423.10.48.0/2023.10.48.1 to 23.10.63.25423.10.63.2554,094
16523.10.64.0/2023.10.64.1 to 23.10.79.25423.10.79.2554,094
16623.10.80.0/2023.10.80.1 to 23.10.95.25423.10.95.2554,094
16723.10.96.0/2023.10.96.1 to 23.10.111.25423.10.111.2554,094
16823.10.112.0/2023.10.112.1 to 23.10.127.25423.10.127.2554,094
16923.10.128.0/2023.10.128.1 to 23.10.143.25423.10.143.2554,094
17023.10.144.0/2023.10.144.1 to 23.10.159.25423.10.159.2554,094
17123.10.160.0/2023.10.160.1 to 23.10.175.25423.10.175.2554,094
17223.10.176.0/2023.10.176.1 to 23.10.191.25423.10.191.2554,094
17323.10.192.0/2023.10.192.1 to 23.10.207.25423.10.207.2554,094
17423.10.208.0/2023.10.208.1 to 23.10.223.25423.10.223.2554,094
17523.10.224.0/2023.10.224.1 to 23.10.239.25423.10.239.2554,094
17623.10.240.0/2023.10.240.1 to 23.10.255.25423.10.255.2554,094
17723.11.0.0/2023.11.0.1 to 23.11.15.25423.11.15.2554,094
17823.11.16.0/2023.11.16.1 to 23.11.31.25423.11.31.2554,094
17923.11.32.0/2023.11.32.1 to 23.11.47.25423.11.47.2554,094
18023.11.48.0/2023.11.48.1 to 23.11.63.25423.11.63.2554,094
18123.11.64.0/2023.11.64.1 to 23.11.79.25423.11.79.2554,094
18223.11.80.0/2023.11.80.1 to 23.11.95.25423.11.95.2554,094
18323.11.96.0/2023.11.96.1 to 23.11.111.25423.11.111.2554,094
18423.11.112.0/2023.11.112.1 to 23.11.127.25423.11.127.2554,094
18523.11.128.0/2023.11.128.1 to 23.11.143.25423.11.143.2554,094
18623.11.144.0/2023.11.144.1 to 23.11.159.25423.11.159.2554,094
18723.11.160.0/2023.11.160.1 to 23.11.175.25423.11.175.2554,094
18823.11.176.0/2023.11.176.1 to 23.11.191.25423.11.191.2554,094
18923.11.192.0/2023.11.192.1 to 23.11.207.25423.11.207.2554,094
19023.11.208.0/2023.11.208.1 to 23.11.223.25423.11.223.2554,094
19123.11.224.0/2023.11.224.1 to 23.11.239.25423.11.239.2554,094
19223.11.240.0/2023.11.240.1 to 23.11.255.25423.11.255.2554,094
19323.12.0.0/2023.12.0.1 to 23.12.15.25423.12.15.2554,094
19423.12.16.0/2023.12.16.1 to 23.12.31.25423.12.31.2554,094
19523.12.32.0/2023.12.32.1 to 23.12.47.25423.12.47.2554,094
19623.12.48.0/2023.12.48.1 to 23.12.63.25423.12.63.2554,094
19723.12.64.0/2023.12.64.1 to 23.12.79.25423.12.79.2554,094
19823.12.80.0/2023.12.80.1 to 23.12.95.25423.12.95.2554,094
19923.12.96.0/2023.12.96.1 to 23.12.111.25423.12.111.2554,094
20023.12.112.0/2023.12.112.1 to 23.12.127.25423.12.127.2554,094
20123.12.128.0/2023.12.128.1 to 23.12.143.25423.12.143.2554,094
20223.12.144.0/2023.12.144.1 to 23.12.159.25423.12.159.2554,094
20323.12.160.0/2023.12.160.1 to 23.12.175.25423.12.175.2554,094
20423.12.176.0/2023.12.176.1 to 23.12.191.25423.12.191.2554,094
20523.12.192.0/2023.12.192.1 to 23.12.207.25423.12.207.2554,094
20623.12.208.0/2023.12.208.1 to 23.12.223.25423.12.223.2554,094
20723.12.224.0/2023.12.224.1 to 23.12.239.25423.12.239.2554,094
20823.12.240.0/2023.12.240.1 to 23.12.255.25423.12.255.2554,094
20923.13.0.0/2023.13.0.1 to 23.13.15.25423.13.15.2554,094
21023.13.16.0/2023.13.16.1 to 23.13.31.25423.13.31.2554,094
21123.13.32.0/2023.13.32.1 to 23.13.47.25423.13.47.2554,094
21223.13.48.0/2023.13.48.1 to 23.13.63.25423.13.63.2554,094
21323.13.64.0/2023.13.64.1 to 23.13.79.25423.13.79.2554,094
21423.13.80.0/2023.13.80.1 to 23.13.95.25423.13.95.2554,094
21523.13.96.0/2023.13.96.1 to 23.13.111.25423.13.111.2554,094
21623.13.112.0/2023.13.112.1 to 23.13.127.25423.13.127.2554,094
21723.13.128.0/2023.13.128.1 to 23.13.143.25423.13.143.2554,094
21823.13.144.0/2023.13.144.1 to 23.13.159.25423.13.159.2554,094
21923.13.160.0/2023.13.160.1 to 23.13.175.25423.13.175.2554,094
22023.13.176.0/2023.13.176.1 to 23.13.191.25423.13.191.2554,094
22123.13.192.0/2023.13.192.1 to 23.13.207.25423.13.207.2554,094
22223.13.208.0/2023.13.208.1 to 23.13.223.25423.13.223.2554,094
22323.13.224.0/2023.13.224.1 to 23.13.239.25423.13.239.2554,094
22423.13.240.0/2023.13.240.1 to 23.13.255.25423.13.255.2554,094
22523.14.0.0/2023.14.0.1 to 23.14.15.25423.14.15.2554,094
22623.14.16.0/2023.14.16.1 to 23.14.31.25423.14.31.2554,094
22723.14.32.0/2023.14.32.1 to 23.14.47.25423.14.47.2554,094
22823.14.48.0/2023.14.48.1 to 23.14.63.25423.14.63.2554,094
22923.14.64.0/2023.14.64.1 to 23.14.79.25423.14.79.2554,094
23023.14.80.0/2023.14.80.1 to 23.14.95.25423.14.95.2554,094
23123.14.96.0/2023.14.96.1 to 23.14.111.25423.14.111.2554,094
23223.14.112.0/2023.14.112.1 to 23.14.127.25423.14.127.2554,094
23323.14.128.0/2023.14.128.1 to 23.14.143.25423.14.143.2554,094
23423.14.144.0/2023.14.144.1 to 23.14.159.25423.14.159.2554,094
23523.14.160.0/2023.14.160.1 to 23.14.175.25423.14.175.2554,094
23623.14.176.0/2023.14.176.1 to 23.14.191.25423.14.191.2554,094
23723.14.192.0/2023.14.192.1 to 23.14.207.25423.14.207.2554,094
23823.14.208.0/2023.14.208.1 to 23.14.223.25423.14.223.2554,094
23923.14.224.0/2023.14.224.1 to 23.14.239.25423.14.239.2554,094
24023.14.240.0/2023.14.240.1 to 23.14.255.25423.14.255.2554,094
24123.15.0.0/2023.15.0.1 to 23.15.15.25423.15.15.2554,094
24223.15.16.0/2023.15.16.1 to 23.15.31.25423.15.31.2554,094
24323.15.32.0/2023.15.32.1 to 23.15.47.25423.15.47.2554,094
24423.15.48.0/2023.15.48.1 to 23.15.63.25423.15.63.2554,094
24523.15.64.0/2023.15.64.1 to 23.15.79.25423.15.79.2554,094
24623.15.80.0/2023.15.80.1 to 23.15.95.25423.15.95.2554,094
24723.15.96.0/2023.15.96.1 to 23.15.111.25423.15.111.2554,094
24823.15.112.0/2023.15.112.1 to 23.15.127.25423.15.127.2554,094
24923.15.128.0/2023.15.128.1 to 23.15.143.25423.15.143.2554,094
25023.15.144.0/2023.15.144.1 to 23.15.159.25423.15.159.2554,094
25123.15.160.0/2023.15.160.1 to 23.15.175.25423.15.175.2554,094
25223.15.176.0/2023.15.176.1 to 23.15.191.25423.15.191.2554,094
25323.15.192.0/2023.15.192.1 to 23.15.207.25423.15.207.2554,094
25423.15.208.0/2023.15.208.1 to 23.15.223.25423.15.223.2554,094
25523.15.224.0/2023.15.224.1 to 23.15.239.25423.15.239.2554,094
25623.15.240.0/2023.15.240.1 to 23.15.255.25423.15.255.2554,094

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.