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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.

Network99.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
99.0.0.0
Broadcast address
99.255.255.255
First usable
99.0.0.1
Last usable
99.255.255.254
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 63000000 · Integer 1660944384 to 1677721599
Reverse DNS zone
99.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100011..00000000.00000000.0000000099.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01100011..00000000.00000000.0000000099.0.0.0
Broadcast01100011..11111111.11111111.1111111199.255.255.255
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)

99.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
199.0.0.0/2099.0.0.1 to 99.0.15.25499.0.15.2554,094
299.0.16.0/2099.0.16.1 to 99.0.31.25499.0.31.2554,094
399.0.32.0/2099.0.32.1 to 99.0.47.25499.0.47.2554,094
499.0.48.0/2099.0.48.1 to 99.0.63.25499.0.63.2554,094
599.0.64.0/2099.0.64.1 to 99.0.79.25499.0.79.2554,094
699.0.80.0/2099.0.80.1 to 99.0.95.25499.0.95.2554,094
799.0.96.0/2099.0.96.1 to 99.0.111.25499.0.111.2554,094
899.0.112.0/2099.0.112.1 to 99.0.127.25499.0.127.2554,094
999.0.128.0/2099.0.128.1 to 99.0.143.25499.0.143.2554,094
1099.0.144.0/2099.0.144.1 to 99.0.159.25499.0.159.2554,094
1199.0.160.0/2099.0.160.1 to 99.0.175.25499.0.175.2554,094
1299.0.176.0/2099.0.176.1 to 99.0.191.25499.0.191.2554,094
1399.0.192.0/2099.0.192.1 to 99.0.207.25499.0.207.2554,094
1499.0.208.0/2099.0.208.1 to 99.0.223.25499.0.223.2554,094
1599.0.224.0/2099.0.224.1 to 99.0.239.25499.0.239.2554,094
1699.0.240.0/2099.0.240.1 to 99.0.255.25499.0.255.2554,094
1799.1.0.0/2099.1.0.1 to 99.1.15.25499.1.15.2554,094
1899.1.16.0/2099.1.16.1 to 99.1.31.25499.1.31.2554,094
1999.1.32.0/2099.1.32.1 to 99.1.47.25499.1.47.2554,094
2099.1.48.0/2099.1.48.1 to 99.1.63.25499.1.63.2554,094
2199.1.64.0/2099.1.64.1 to 99.1.79.25499.1.79.2554,094
2299.1.80.0/2099.1.80.1 to 99.1.95.25499.1.95.2554,094
2399.1.96.0/2099.1.96.1 to 99.1.111.25499.1.111.2554,094
2499.1.112.0/2099.1.112.1 to 99.1.127.25499.1.127.2554,094
2599.1.128.0/2099.1.128.1 to 99.1.143.25499.1.143.2554,094
2699.1.144.0/2099.1.144.1 to 99.1.159.25499.1.159.2554,094
2799.1.160.0/2099.1.160.1 to 99.1.175.25499.1.175.2554,094
2899.1.176.0/2099.1.176.1 to 99.1.191.25499.1.191.2554,094
2999.1.192.0/2099.1.192.1 to 99.1.207.25499.1.207.2554,094
3099.1.208.0/2099.1.208.1 to 99.1.223.25499.1.223.2554,094
3199.1.224.0/2099.1.224.1 to 99.1.239.25499.1.239.2554,094
3299.1.240.0/2099.1.240.1 to 99.1.255.25499.1.255.2554,094
3399.2.0.0/2099.2.0.1 to 99.2.15.25499.2.15.2554,094
3499.2.16.0/2099.2.16.1 to 99.2.31.25499.2.31.2554,094
3599.2.32.0/2099.2.32.1 to 99.2.47.25499.2.47.2554,094
3699.2.48.0/2099.2.48.1 to 99.2.63.25499.2.63.2554,094
3799.2.64.0/2099.2.64.1 to 99.2.79.25499.2.79.2554,094
3899.2.80.0/2099.2.80.1 to 99.2.95.25499.2.95.2554,094
3999.2.96.0/2099.2.96.1 to 99.2.111.25499.2.111.2554,094
4099.2.112.0/2099.2.112.1 to 99.2.127.25499.2.127.2554,094
4199.2.128.0/2099.2.128.1 to 99.2.143.25499.2.143.2554,094
4299.2.144.0/2099.2.144.1 to 99.2.159.25499.2.159.2554,094
4399.2.160.0/2099.2.160.1 to 99.2.175.25499.2.175.2554,094
4499.2.176.0/2099.2.176.1 to 99.2.191.25499.2.191.2554,094
4599.2.192.0/2099.2.192.1 to 99.2.207.25499.2.207.2554,094
4699.2.208.0/2099.2.208.1 to 99.2.223.25499.2.223.2554,094
4799.2.224.0/2099.2.224.1 to 99.2.239.25499.2.239.2554,094
4899.2.240.0/2099.2.240.1 to 99.2.255.25499.2.255.2554,094
4999.3.0.0/2099.3.0.1 to 99.3.15.25499.3.15.2554,094
5099.3.16.0/2099.3.16.1 to 99.3.31.25499.3.31.2554,094
5199.3.32.0/2099.3.32.1 to 99.3.47.25499.3.47.2554,094
5299.3.48.0/2099.3.48.1 to 99.3.63.25499.3.63.2554,094
5399.3.64.0/2099.3.64.1 to 99.3.79.25499.3.79.2554,094
5499.3.80.0/2099.3.80.1 to 99.3.95.25499.3.95.2554,094
5599.3.96.0/2099.3.96.1 to 99.3.111.25499.3.111.2554,094
5699.3.112.0/2099.3.112.1 to 99.3.127.25499.3.127.2554,094
5799.3.128.0/2099.3.128.1 to 99.3.143.25499.3.143.2554,094
5899.3.144.0/2099.3.144.1 to 99.3.159.25499.3.159.2554,094
5999.3.160.0/2099.3.160.1 to 99.3.175.25499.3.175.2554,094
6099.3.176.0/2099.3.176.1 to 99.3.191.25499.3.191.2554,094
6199.3.192.0/2099.3.192.1 to 99.3.207.25499.3.207.2554,094
6299.3.208.0/2099.3.208.1 to 99.3.223.25499.3.223.2554,094
6399.3.224.0/2099.3.224.1 to 99.3.239.25499.3.239.2554,094
6499.3.240.0/2099.3.240.1 to 99.3.255.25499.3.255.2554,094
6599.4.0.0/2099.4.0.1 to 99.4.15.25499.4.15.2554,094
6699.4.16.0/2099.4.16.1 to 99.4.31.25499.4.31.2554,094
6799.4.32.0/2099.4.32.1 to 99.4.47.25499.4.47.2554,094
6899.4.48.0/2099.4.48.1 to 99.4.63.25499.4.63.2554,094
6999.4.64.0/2099.4.64.1 to 99.4.79.25499.4.79.2554,094
7099.4.80.0/2099.4.80.1 to 99.4.95.25499.4.95.2554,094
7199.4.96.0/2099.4.96.1 to 99.4.111.25499.4.111.2554,094
7299.4.112.0/2099.4.112.1 to 99.4.127.25499.4.127.2554,094
7399.4.128.0/2099.4.128.1 to 99.4.143.25499.4.143.2554,094
7499.4.144.0/2099.4.144.1 to 99.4.159.25499.4.159.2554,094
7599.4.160.0/2099.4.160.1 to 99.4.175.25499.4.175.2554,094
7699.4.176.0/2099.4.176.1 to 99.4.191.25499.4.191.2554,094
7799.4.192.0/2099.4.192.1 to 99.4.207.25499.4.207.2554,094
7899.4.208.0/2099.4.208.1 to 99.4.223.25499.4.223.2554,094
7999.4.224.0/2099.4.224.1 to 99.4.239.25499.4.239.2554,094
8099.4.240.0/2099.4.240.1 to 99.4.255.25499.4.255.2554,094
8199.5.0.0/2099.5.0.1 to 99.5.15.25499.5.15.2554,094
8299.5.16.0/2099.5.16.1 to 99.5.31.25499.5.31.2554,094
8399.5.32.0/2099.5.32.1 to 99.5.47.25499.5.47.2554,094
8499.5.48.0/2099.5.48.1 to 99.5.63.25499.5.63.2554,094
8599.5.64.0/2099.5.64.1 to 99.5.79.25499.5.79.2554,094
8699.5.80.0/2099.5.80.1 to 99.5.95.25499.5.95.2554,094
8799.5.96.0/2099.5.96.1 to 99.5.111.25499.5.111.2554,094
8899.5.112.0/2099.5.112.1 to 99.5.127.25499.5.127.2554,094
8999.5.128.0/2099.5.128.1 to 99.5.143.25499.5.143.2554,094
9099.5.144.0/2099.5.144.1 to 99.5.159.25499.5.159.2554,094
9199.5.160.0/2099.5.160.1 to 99.5.175.25499.5.175.2554,094
9299.5.176.0/2099.5.176.1 to 99.5.191.25499.5.191.2554,094
9399.5.192.0/2099.5.192.1 to 99.5.207.25499.5.207.2554,094
9499.5.208.0/2099.5.208.1 to 99.5.223.25499.5.223.2554,094
9599.5.224.0/2099.5.224.1 to 99.5.239.25499.5.239.2554,094
9699.5.240.0/2099.5.240.1 to 99.5.255.25499.5.255.2554,094
9799.6.0.0/2099.6.0.1 to 99.6.15.25499.6.15.2554,094
9899.6.16.0/2099.6.16.1 to 99.6.31.25499.6.31.2554,094
9999.6.32.0/2099.6.32.1 to 99.6.47.25499.6.47.2554,094
10099.6.48.0/2099.6.48.1 to 99.6.63.25499.6.63.2554,094
10199.6.64.0/2099.6.64.1 to 99.6.79.25499.6.79.2554,094
10299.6.80.0/2099.6.80.1 to 99.6.95.25499.6.95.2554,094
10399.6.96.0/2099.6.96.1 to 99.6.111.25499.6.111.2554,094
10499.6.112.0/2099.6.112.1 to 99.6.127.25499.6.127.2554,094
10599.6.128.0/2099.6.128.1 to 99.6.143.25499.6.143.2554,094
10699.6.144.0/2099.6.144.1 to 99.6.159.25499.6.159.2554,094
10799.6.160.0/2099.6.160.1 to 99.6.175.25499.6.175.2554,094
10899.6.176.0/2099.6.176.1 to 99.6.191.25499.6.191.2554,094
10999.6.192.0/2099.6.192.1 to 99.6.207.25499.6.207.2554,094
11099.6.208.0/2099.6.208.1 to 99.6.223.25499.6.223.2554,094
11199.6.224.0/2099.6.224.1 to 99.6.239.25499.6.239.2554,094
11299.6.240.0/2099.6.240.1 to 99.6.255.25499.6.255.2554,094
11399.7.0.0/2099.7.0.1 to 99.7.15.25499.7.15.2554,094
11499.7.16.0/2099.7.16.1 to 99.7.31.25499.7.31.2554,094
11599.7.32.0/2099.7.32.1 to 99.7.47.25499.7.47.2554,094
11699.7.48.0/2099.7.48.1 to 99.7.63.25499.7.63.2554,094
11799.7.64.0/2099.7.64.1 to 99.7.79.25499.7.79.2554,094
11899.7.80.0/2099.7.80.1 to 99.7.95.25499.7.95.2554,094
11999.7.96.0/2099.7.96.1 to 99.7.111.25499.7.111.2554,094
12099.7.112.0/2099.7.112.1 to 99.7.127.25499.7.127.2554,094
12199.7.128.0/2099.7.128.1 to 99.7.143.25499.7.143.2554,094
12299.7.144.0/2099.7.144.1 to 99.7.159.25499.7.159.2554,094
12399.7.160.0/2099.7.160.1 to 99.7.175.25499.7.175.2554,094
12499.7.176.0/2099.7.176.1 to 99.7.191.25499.7.191.2554,094
12599.7.192.0/2099.7.192.1 to 99.7.207.25499.7.207.2554,094
12699.7.208.0/2099.7.208.1 to 99.7.223.25499.7.223.2554,094
12799.7.224.0/2099.7.224.1 to 99.7.239.25499.7.239.2554,094
12899.7.240.0/2099.7.240.1 to 99.7.255.25499.7.255.2554,094
12999.8.0.0/2099.8.0.1 to 99.8.15.25499.8.15.2554,094
13099.8.16.0/2099.8.16.1 to 99.8.31.25499.8.31.2554,094
13199.8.32.0/2099.8.32.1 to 99.8.47.25499.8.47.2554,094
13299.8.48.0/2099.8.48.1 to 99.8.63.25499.8.63.2554,094
13399.8.64.0/2099.8.64.1 to 99.8.79.25499.8.79.2554,094
13499.8.80.0/2099.8.80.1 to 99.8.95.25499.8.95.2554,094
13599.8.96.0/2099.8.96.1 to 99.8.111.25499.8.111.2554,094
13699.8.112.0/2099.8.112.1 to 99.8.127.25499.8.127.2554,094
13799.8.128.0/2099.8.128.1 to 99.8.143.25499.8.143.2554,094
13899.8.144.0/2099.8.144.1 to 99.8.159.25499.8.159.2554,094
13999.8.160.0/2099.8.160.1 to 99.8.175.25499.8.175.2554,094
14099.8.176.0/2099.8.176.1 to 99.8.191.25499.8.191.2554,094
14199.8.192.0/2099.8.192.1 to 99.8.207.25499.8.207.2554,094
14299.8.208.0/2099.8.208.1 to 99.8.223.25499.8.223.2554,094
14399.8.224.0/2099.8.224.1 to 99.8.239.25499.8.239.2554,094
14499.8.240.0/2099.8.240.1 to 99.8.255.25499.8.255.2554,094
14599.9.0.0/2099.9.0.1 to 99.9.15.25499.9.15.2554,094
14699.9.16.0/2099.9.16.1 to 99.9.31.25499.9.31.2554,094
14799.9.32.0/2099.9.32.1 to 99.9.47.25499.9.47.2554,094
14899.9.48.0/2099.9.48.1 to 99.9.63.25499.9.63.2554,094
14999.9.64.0/2099.9.64.1 to 99.9.79.25499.9.79.2554,094
15099.9.80.0/2099.9.80.1 to 99.9.95.25499.9.95.2554,094
15199.9.96.0/2099.9.96.1 to 99.9.111.25499.9.111.2554,094
15299.9.112.0/2099.9.112.1 to 99.9.127.25499.9.127.2554,094
15399.9.128.0/2099.9.128.1 to 99.9.143.25499.9.143.2554,094
15499.9.144.0/2099.9.144.1 to 99.9.159.25499.9.159.2554,094
15599.9.160.0/2099.9.160.1 to 99.9.175.25499.9.175.2554,094
15699.9.176.0/2099.9.176.1 to 99.9.191.25499.9.191.2554,094
15799.9.192.0/2099.9.192.1 to 99.9.207.25499.9.207.2554,094
15899.9.208.0/2099.9.208.1 to 99.9.223.25499.9.223.2554,094
15999.9.224.0/2099.9.224.1 to 99.9.239.25499.9.239.2554,094
16099.9.240.0/2099.9.240.1 to 99.9.255.25499.9.255.2554,094
16199.10.0.0/2099.10.0.1 to 99.10.15.25499.10.15.2554,094
16299.10.16.0/2099.10.16.1 to 99.10.31.25499.10.31.2554,094
16399.10.32.0/2099.10.32.1 to 99.10.47.25499.10.47.2554,094
16499.10.48.0/2099.10.48.1 to 99.10.63.25499.10.63.2554,094
16599.10.64.0/2099.10.64.1 to 99.10.79.25499.10.79.2554,094
16699.10.80.0/2099.10.80.1 to 99.10.95.25499.10.95.2554,094
16799.10.96.0/2099.10.96.1 to 99.10.111.25499.10.111.2554,094
16899.10.112.0/2099.10.112.1 to 99.10.127.25499.10.127.2554,094
16999.10.128.0/2099.10.128.1 to 99.10.143.25499.10.143.2554,094
17099.10.144.0/2099.10.144.1 to 99.10.159.25499.10.159.2554,094
17199.10.160.0/2099.10.160.1 to 99.10.175.25499.10.175.2554,094
17299.10.176.0/2099.10.176.1 to 99.10.191.25499.10.191.2554,094
17399.10.192.0/2099.10.192.1 to 99.10.207.25499.10.207.2554,094
17499.10.208.0/2099.10.208.1 to 99.10.223.25499.10.223.2554,094
17599.10.224.0/2099.10.224.1 to 99.10.239.25499.10.239.2554,094
17699.10.240.0/2099.10.240.1 to 99.10.255.25499.10.255.2554,094
17799.11.0.0/2099.11.0.1 to 99.11.15.25499.11.15.2554,094
17899.11.16.0/2099.11.16.1 to 99.11.31.25499.11.31.2554,094
17999.11.32.0/2099.11.32.1 to 99.11.47.25499.11.47.2554,094
18099.11.48.0/2099.11.48.1 to 99.11.63.25499.11.63.2554,094
18199.11.64.0/2099.11.64.1 to 99.11.79.25499.11.79.2554,094
18299.11.80.0/2099.11.80.1 to 99.11.95.25499.11.95.2554,094
18399.11.96.0/2099.11.96.1 to 99.11.111.25499.11.111.2554,094
18499.11.112.0/2099.11.112.1 to 99.11.127.25499.11.127.2554,094
18599.11.128.0/2099.11.128.1 to 99.11.143.25499.11.143.2554,094
18699.11.144.0/2099.11.144.1 to 99.11.159.25499.11.159.2554,094
18799.11.160.0/2099.11.160.1 to 99.11.175.25499.11.175.2554,094
18899.11.176.0/2099.11.176.1 to 99.11.191.25499.11.191.2554,094
18999.11.192.0/2099.11.192.1 to 99.11.207.25499.11.207.2554,094
19099.11.208.0/2099.11.208.1 to 99.11.223.25499.11.223.2554,094
19199.11.224.0/2099.11.224.1 to 99.11.239.25499.11.239.2554,094
19299.11.240.0/2099.11.240.1 to 99.11.255.25499.11.255.2554,094
19399.12.0.0/2099.12.0.1 to 99.12.15.25499.12.15.2554,094
19499.12.16.0/2099.12.16.1 to 99.12.31.25499.12.31.2554,094
19599.12.32.0/2099.12.32.1 to 99.12.47.25499.12.47.2554,094
19699.12.48.0/2099.12.48.1 to 99.12.63.25499.12.63.2554,094
19799.12.64.0/2099.12.64.1 to 99.12.79.25499.12.79.2554,094
19899.12.80.0/2099.12.80.1 to 99.12.95.25499.12.95.2554,094
19999.12.96.0/2099.12.96.1 to 99.12.111.25499.12.111.2554,094
20099.12.112.0/2099.12.112.1 to 99.12.127.25499.12.127.2554,094
20199.12.128.0/2099.12.128.1 to 99.12.143.25499.12.143.2554,094
20299.12.144.0/2099.12.144.1 to 99.12.159.25499.12.159.2554,094
20399.12.160.0/2099.12.160.1 to 99.12.175.25499.12.175.2554,094
20499.12.176.0/2099.12.176.1 to 99.12.191.25499.12.191.2554,094
20599.12.192.0/2099.12.192.1 to 99.12.207.25499.12.207.2554,094
20699.12.208.0/2099.12.208.1 to 99.12.223.25499.12.223.2554,094
20799.12.224.0/2099.12.224.1 to 99.12.239.25499.12.239.2554,094
20899.12.240.0/2099.12.240.1 to 99.12.255.25499.12.255.2554,094
20999.13.0.0/2099.13.0.1 to 99.13.15.25499.13.15.2554,094
21099.13.16.0/2099.13.16.1 to 99.13.31.25499.13.31.2554,094
21199.13.32.0/2099.13.32.1 to 99.13.47.25499.13.47.2554,094
21299.13.48.0/2099.13.48.1 to 99.13.63.25499.13.63.2554,094
21399.13.64.0/2099.13.64.1 to 99.13.79.25499.13.79.2554,094
21499.13.80.0/2099.13.80.1 to 99.13.95.25499.13.95.2554,094
21599.13.96.0/2099.13.96.1 to 99.13.111.25499.13.111.2554,094
21699.13.112.0/2099.13.112.1 to 99.13.127.25499.13.127.2554,094
21799.13.128.0/2099.13.128.1 to 99.13.143.25499.13.143.2554,094
21899.13.144.0/2099.13.144.1 to 99.13.159.25499.13.159.2554,094
21999.13.160.0/2099.13.160.1 to 99.13.175.25499.13.175.2554,094
22099.13.176.0/2099.13.176.1 to 99.13.191.25499.13.191.2554,094
22199.13.192.0/2099.13.192.1 to 99.13.207.25499.13.207.2554,094
22299.13.208.0/2099.13.208.1 to 99.13.223.25499.13.223.2554,094
22399.13.224.0/2099.13.224.1 to 99.13.239.25499.13.239.2554,094
22499.13.240.0/2099.13.240.1 to 99.13.255.25499.13.255.2554,094
22599.14.0.0/2099.14.0.1 to 99.14.15.25499.14.15.2554,094
22699.14.16.0/2099.14.16.1 to 99.14.31.25499.14.31.2554,094
22799.14.32.0/2099.14.32.1 to 99.14.47.25499.14.47.2554,094
22899.14.48.0/2099.14.48.1 to 99.14.63.25499.14.63.2554,094
22999.14.64.0/2099.14.64.1 to 99.14.79.25499.14.79.2554,094
23099.14.80.0/2099.14.80.1 to 99.14.95.25499.14.95.2554,094
23199.14.96.0/2099.14.96.1 to 99.14.111.25499.14.111.2554,094
23299.14.112.0/2099.14.112.1 to 99.14.127.25499.14.127.2554,094
23399.14.128.0/2099.14.128.1 to 99.14.143.25499.14.143.2554,094
23499.14.144.0/2099.14.144.1 to 99.14.159.25499.14.159.2554,094
23599.14.160.0/2099.14.160.1 to 99.14.175.25499.14.175.2554,094
23699.14.176.0/2099.14.176.1 to 99.14.191.25499.14.191.2554,094
23799.14.192.0/2099.14.192.1 to 99.14.207.25499.14.207.2554,094
23899.14.208.0/2099.14.208.1 to 99.14.223.25499.14.223.2554,094
23999.14.224.0/2099.14.224.1 to 99.14.239.25499.14.239.2554,094
24099.14.240.0/2099.14.240.1 to 99.14.255.25499.14.255.2554,094
24199.15.0.0/2099.15.0.1 to 99.15.15.25499.15.15.2554,094
24299.15.16.0/2099.15.16.1 to 99.15.31.25499.15.31.2554,094
24399.15.32.0/2099.15.32.1 to 99.15.47.25499.15.47.2554,094
24499.15.48.0/2099.15.48.1 to 99.15.63.25499.15.63.2554,094
24599.15.64.0/2099.15.64.1 to 99.15.79.25499.15.79.2554,094
24699.15.80.0/2099.15.80.1 to 99.15.95.25499.15.95.2554,094
24799.15.96.0/2099.15.96.1 to 99.15.111.25499.15.111.2554,094
24899.15.112.0/2099.15.112.1 to 99.15.127.25499.15.127.2554,094
24999.15.128.0/2099.15.128.1 to 99.15.143.25499.15.143.2554,094
25099.15.144.0/2099.15.144.1 to 99.15.159.25499.15.159.2554,094
25199.15.160.0/2099.15.160.1 to 99.15.175.25499.15.175.2554,094
25299.15.176.0/2099.15.176.1 to 99.15.191.25499.15.191.2554,094
25399.15.192.0/2099.15.192.1 to 99.15.207.25499.15.207.2554,094
25499.15.208.0/2099.15.208.1 to 99.15.223.25499.15.223.2554,094
25599.15.224.0/2099.15.224.1 to 99.15.239.25499.15.239.2554,094
25699.15.240.0/2099.15.240.1 to 99.15.255.25499.15.255.2554,094

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.