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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.

Network16.0.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
16.0.0.0
Broadcast address
16.15.255.255
First usable
16.0.0.1
Last usable
16.15.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 10000000 · Integer 268435456 to 269484031
Reverse DNS zones
0.16.in-addr.arpa
1.16.in-addr.arpa
2.16.in-addr.arpa
3.16.in-addr.arpa
4.16.in-addr.arpa
5.16.in-addr.arpa
6.16.in-addr.arpa
7.16.in-addr.arpa
8.16.in-addr.arpa
9.16.in-addr.arpa
10.16.in-addr.arpa
11.16.in-addr.arpa
12.16.in-addr.arpa
13.16.in-addr.arpa
14.16.in-addr.arpa
15.16.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010000.00000000.00000000.0000000016.0.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00010000.00000000.00000000.0000000016.0.0.0
Broadcast00010000.00001111.11111111.1111111116.15.255.255
Split into smaller subnets/22
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

16.0.0.0/12 makes 1,024 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.0.0.0/2216.0.0.1 to 16.0.3.25416.0.3.2551,022
216.0.4.0/2216.0.4.1 to 16.0.7.25416.0.7.2551,022
316.0.8.0/2216.0.8.1 to 16.0.11.25416.0.11.2551,022
416.0.12.0/2216.0.12.1 to 16.0.15.25416.0.15.2551,022
516.0.16.0/2216.0.16.1 to 16.0.19.25416.0.19.2551,022
616.0.20.0/2216.0.20.1 to 16.0.23.25416.0.23.2551,022
716.0.24.0/2216.0.24.1 to 16.0.27.25416.0.27.2551,022
816.0.28.0/2216.0.28.1 to 16.0.31.25416.0.31.2551,022
916.0.32.0/2216.0.32.1 to 16.0.35.25416.0.35.2551,022
1016.0.36.0/2216.0.36.1 to 16.0.39.25416.0.39.2551,022
1116.0.40.0/2216.0.40.1 to 16.0.43.25416.0.43.2551,022
1216.0.44.0/2216.0.44.1 to 16.0.47.25416.0.47.2551,022
1316.0.48.0/2216.0.48.1 to 16.0.51.25416.0.51.2551,022
1416.0.52.0/2216.0.52.1 to 16.0.55.25416.0.55.2551,022
1516.0.56.0/2216.0.56.1 to 16.0.59.25416.0.59.2551,022
1616.0.60.0/2216.0.60.1 to 16.0.63.25416.0.63.2551,022
1716.0.64.0/2216.0.64.1 to 16.0.67.25416.0.67.2551,022
1816.0.68.0/2216.0.68.1 to 16.0.71.25416.0.71.2551,022
1916.0.72.0/2216.0.72.1 to 16.0.75.25416.0.75.2551,022
2016.0.76.0/2216.0.76.1 to 16.0.79.25416.0.79.2551,022
2116.0.80.0/2216.0.80.1 to 16.0.83.25416.0.83.2551,022
2216.0.84.0/2216.0.84.1 to 16.0.87.25416.0.87.2551,022
2316.0.88.0/2216.0.88.1 to 16.0.91.25416.0.91.2551,022
2416.0.92.0/2216.0.92.1 to 16.0.95.25416.0.95.2551,022
2516.0.96.0/2216.0.96.1 to 16.0.99.25416.0.99.2551,022
2616.0.100.0/2216.0.100.1 to 16.0.103.25416.0.103.2551,022
2716.0.104.0/2216.0.104.1 to 16.0.107.25416.0.107.2551,022
2816.0.108.0/2216.0.108.1 to 16.0.111.25416.0.111.2551,022
2916.0.112.0/2216.0.112.1 to 16.0.115.25416.0.115.2551,022
3016.0.116.0/2216.0.116.1 to 16.0.119.25416.0.119.2551,022
3116.0.120.0/2216.0.120.1 to 16.0.123.25416.0.123.2551,022
3216.0.124.0/2216.0.124.1 to 16.0.127.25416.0.127.2551,022
3316.0.128.0/2216.0.128.1 to 16.0.131.25416.0.131.2551,022
3416.0.132.0/2216.0.132.1 to 16.0.135.25416.0.135.2551,022
3516.0.136.0/2216.0.136.1 to 16.0.139.25416.0.139.2551,022
3616.0.140.0/2216.0.140.1 to 16.0.143.25416.0.143.2551,022
3716.0.144.0/2216.0.144.1 to 16.0.147.25416.0.147.2551,022
3816.0.148.0/2216.0.148.1 to 16.0.151.25416.0.151.2551,022
3916.0.152.0/2216.0.152.1 to 16.0.155.25416.0.155.2551,022
4016.0.156.0/2216.0.156.1 to 16.0.159.25416.0.159.2551,022
4116.0.160.0/2216.0.160.1 to 16.0.163.25416.0.163.2551,022
4216.0.164.0/2216.0.164.1 to 16.0.167.25416.0.167.2551,022
4316.0.168.0/2216.0.168.1 to 16.0.171.25416.0.171.2551,022
4416.0.172.0/2216.0.172.1 to 16.0.175.25416.0.175.2551,022
4516.0.176.0/2216.0.176.1 to 16.0.179.25416.0.179.2551,022
4616.0.180.0/2216.0.180.1 to 16.0.183.25416.0.183.2551,022
4716.0.184.0/2216.0.184.1 to 16.0.187.25416.0.187.2551,022
4816.0.188.0/2216.0.188.1 to 16.0.191.25416.0.191.2551,022
4916.0.192.0/2216.0.192.1 to 16.0.195.25416.0.195.2551,022
5016.0.196.0/2216.0.196.1 to 16.0.199.25416.0.199.2551,022
5116.0.200.0/2216.0.200.1 to 16.0.203.25416.0.203.2551,022
5216.0.204.0/2216.0.204.1 to 16.0.207.25416.0.207.2551,022
5316.0.208.0/2216.0.208.1 to 16.0.211.25416.0.211.2551,022
5416.0.212.0/2216.0.212.1 to 16.0.215.25416.0.215.2551,022
5516.0.216.0/2216.0.216.1 to 16.0.219.25416.0.219.2551,022
5616.0.220.0/2216.0.220.1 to 16.0.223.25416.0.223.2551,022
5716.0.224.0/2216.0.224.1 to 16.0.227.25416.0.227.2551,022
5816.0.228.0/2216.0.228.1 to 16.0.231.25416.0.231.2551,022
5916.0.232.0/2216.0.232.1 to 16.0.235.25416.0.235.2551,022
6016.0.236.0/2216.0.236.1 to 16.0.239.25416.0.239.2551,022
6116.0.240.0/2216.0.240.1 to 16.0.243.25416.0.243.2551,022
6216.0.244.0/2216.0.244.1 to 16.0.247.25416.0.247.2551,022
6316.0.248.0/2216.0.248.1 to 16.0.251.25416.0.251.2551,022
6416.0.252.0/2216.0.252.1 to 16.0.255.25416.0.255.2551,022
6516.1.0.0/2216.1.0.1 to 16.1.3.25416.1.3.2551,022
6616.1.4.0/2216.1.4.1 to 16.1.7.25416.1.7.2551,022
6716.1.8.0/2216.1.8.1 to 16.1.11.25416.1.11.2551,022
6816.1.12.0/2216.1.12.1 to 16.1.15.25416.1.15.2551,022
6916.1.16.0/2216.1.16.1 to 16.1.19.25416.1.19.2551,022
7016.1.20.0/2216.1.20.1 to 16.1.23.25416.1.23.2551,022
7116.1.24.0/2216.1.24.1 to 16.1.27.25416.1.27.2551,022
7216.1.28.0/2216.1.28.1 to 16.1.31.25416.1.31.2551,022
7316.1.32.0/2216.1.32.1 to 16.1.35.25416.1.35.2551,022
7416.1.36.0/2216.1.36.1 to 16.1.39.25416.1.39.2551,022
7516.1.40.0/2216.1.40.1 to 16.1.43.25416.1.43.2551,022
7616.1.44.0/2216.1.44.1 to 16.1.47.25416.1.47.2551,022
7716.1.48.0/2216.1.48.1 to 16.1.51.25416.1.51.2551,022
7816.1.52.0/2216.1.52.1 to 16.1.55.25416.1.55.2551,022
7916.1.56.0/2216.1.56.1 to 16.1.59.25416.1.59.2551,022
8016.1.60.0/2216.1.60.1 to 16.1.63.25416.1.63.2551,022
8116.1.64.0/2216.1.64.1 to 16.1.67.25416.1.67.2551,022
8216.1.68.0/2216.1.68.1 to 16.1.71.25416.1.71.2551,022
8316.1.72.0/2216.1.72.1 to 16.1.75.25416.1.75.2551,022
8416.1.76.0/2216.1.76.1 to 16.1.79.25416.1.79.2551,022
8516.1.80.0/2216.1.80.1 to 16.1.83.25416.1.83.2551,022
8616.1.84.0/2216.1.84.1 to 16.1.87.25416.1.87.2551,022
8716.1.88.0/2216.1.88.1 to 16.1.91.25416.1.91.2551,022
8816.1.92.0/2216.1.92.1 to 16.1.95.25416.1.95.2551,022
8916.1.96.0/2216.1.96.1 to 16.1.99.25416.1.99.2551,022
9016.1.100.0/2216.1.100.1 to 16.1.103.25416.1.103.2551,022
9116.1.104.0/2216.1.104.1 to 16.1.107.25416.1.107.2551,022
9216.1.108.0/2216.1.108.1 to 16.1.111.25416.1.111.2551,022
9316.1.112.0/2216.1.112.1 to 16.1.115.25416.1.115.2551,022
9416.1.116.0/2216.1.116.1 to 16.1.119.25416.1.119.2551,022
9516.1.120.0/2216.1.120.1 to 16.1.123.25416.1.123.2551,022
9616.1.124.0/2216.1.124.1 to 16.1.127.25416.1.127.2551,022
9716.1.128.0/2216.1.128.1 to 16.1.131.25416.1.131.2551,022
9816.1.132.0/2216.1.132.1 to 16.1.135.25416.1.135.2551,022
9916.1.136.0/2216.1.136.1 to 16.1.139.25416.1.139.2551,022
10016.1.140.0/2216.1.140.1 to 16.1.143.25416.1.143.2551,022
10116.1.144.0/2216.1.144.1 to 16.1.147.25416.1.147.2551,022
10216.1.148.0/2216.1.148.1 to 16.1.151.25416.1.151.2551,022
10316.1.152.0/2216.1.152.1 to 16.1.155.25416.1.155.2551,022
10416.1.156.0/2216.1.156.1 to 16.1.159.25416.1.159.2551,022
10516.1.160.0/2216.1.160.1 to 16.1.163.25416.1.163.2551,022
10616.1.164.0/2216.1.164.1 to 16.1.167.25416.1.167.2551,022
10716.1.168.0/2216.1.168.1 to 16.1.171.25416.1.171.2551,022
10816.1.172.0/2216.1.172.1 to 16.1.175.25416.1.175.2551,022
10916.1.176.0/2216.1.176.1 to 16.1.179.25416.1.179.2551,022
11016.1.180.0/2216.1.180.1 to 16.1.183.25416.1.183.2551,022
11116.1.184.0/2216.1.184.1 to 16.1.187.25416.1.187.2551,022
11216.1.188.0/2216.1.188.1 to 16.1.191.25416.1.191.2551,022
11316.1.192.0/2216.1.192.1 to 16.1.195.25416.1.195.2551,022
11416.1.196.0/2216.1.196.1 to 16.1.199.25416.1.199.2551,022
11516.1.200.0/2216.1.200.1 to 16.1.203.25416.1.203.2551,022
11616.1.204.0/2216.1.204.1 to 16.1.207.25416.1.207.2551,022
11716.1.208.0/2216.1.208.1 to 16.1.211.25416.1.211.2551,022
11816.1.212.0/2216.1.212.1 to 16.1.215.25416.1.215.2551,022
11916.1.216.0/2216.1.216.1 to 16.1.219.25416.1.219.2551,022
12016.1.220.0/2216.1.220.1 to 16.1.223.25416.1.223.2551,022
12116.1.224.0/2216.1.224.1 to 16.1.227.25416.1.227.2551,022
12216.1.228.0/2216.1.228.1 to 16.1.231.25416.1.231.2551,022
12316.1.232.0/2216.1.232.1 to 16.1.235.25416.1.235.2551,022
12416.1.236.0/2216.1.236.1 to 16.1.239.25416.1.239.2551,022
12516.1.240.0/2216.1.240.1 to 16.1.243.25416.1.243.2551,022
12616.1.244.0/2216.1.244.1 to 16.1.247.25416.1.247.2551,022
12716.1.248.0/2216.1.248.1 to 16.1.251.25416.1.251.2551,022
12816.1.252.0/2216.1.252.1 to 16.1.255.25416.1.255.2551,022
12916.2.0.0/2216.2.0.1 to 16.2.3.25416.2.3.2551,022
13016.2.4.0/2216.2.4.1 to 16.2.7.25416.2.7.2551,022
13116.2.8.0/2216.2.8.1 to 16.2.11.25416.2.11.2551,022
13216.2.12.0/2216.2.12.1 to 16.2.15.25416.2.15.2551,022
13316.2.16.0/2216.2.16.1 to 16.2.19.25416.2.19.2551,022
13416.2.20.0/2216.2.20.1 to 16.2.23.25416.2.23.2551,022
13516.2.24.0/2216.2.24.1 to 16.2.27.25416.2.27.2551,022
13616.2.28.0/2216.2.28.1 to 16.2.31.25416.2.31.2551,022
13716.2.32.0/2216.2.32.1 to 16.2.35.25416.2.35.2551,022
13816.2.36.0/2216.2.36.1 to 16.2.39.25416.2.39.2551,022
13916.2.40.0/2216.2.40.1 to 16.2.43.25416.2.43.2551,022
14016.2.44.0/2216.2.44.1 to 16.2.47.25416.2.47.2551,022
14116.2.48.0/2216.2.48.1 to 16.2.51.25416.2.51.2551,022
14216.2.52.0/2216.2.52.1 to 16.2.55.25416.2.55.2551,022
14316.2.56.0/2216.2.56.1 to 16.2.59.25416.2.59.2551,022
14416.2.60.0/2216.2.60.1 to 16.2.63.25416.2.63.2551,022
14516.2.64.0/2216.2.64.1 to 16.2.67.25416.2.67.2551,022
14616.2.68.0/2216.2.68.1 to 16.2.71.25416.2.71.2551,022
14716.2.72.0/2216.2.72.1 to 16.2.75.25416.2.75.2551,022
14816.2.76.0/2216.2.76.1 to 16.2.79.25416.2.79.2551,022
14916.2.80.0/2216.2.80.1 to 16.2.83.25416.2.83.2551,022
15016.2.84.0/2216.2.84.1 to 16.2.87.25416.2.87.2551,022
15116.2.88.0/2216.2.88.1 to 16.2.91.25416.2.91.2551,022
15216.2.92.0/2216.2.92.1 to 16.2.95.25416.2.95.2551,022
15316.2.96.0/2216.2.96.1 to 16.2.99.25416.2.99.2551,022
15416.2.100.0/2216.2.100.1 to 16.2.103.25416.2.103.2551,022
15516.2.104.0/2216.2.104.1 to 16.2.107.25416.2.107.2551,022
15616.2.108.0/2216.2.108.1 to 16.2.111.25416.2.111.2551,022
15716.2.112.0/2216.2.112.1 to 16.2.115.25416.2.115.2551,022
15816.2.116.0/2216.2.116.1 to 16.2.119.25416.2.119.2551,022
15916.2.120.0/2216.2.120.1 to 16.2.123.25416.2.123.2551,022
16016.2.124.0/2216.2.124.1 to 16.2.127.25416.2.127.2551,022
16116.2.128.0/2216.2.128.1 to 16.2.131.25416.2.131.2551,022
16216.2.132.0/2216.2.132.1 to 16.2.135.25416.2.135.2551,022
16316.2.136.0/2216.2.136.1 to 16.2.139.25416.2.139.2551,022
16416.2.140.0/2216.2.140.1 to 16.2.143.25416.2.143.2551,022
16516.2.144.0/2216.2.144.1 to 16.2.147.25416.2.147.2551,022
16616.2.148.0/2216.2.148.1 to 16.2.151.25416.2.151.2551,022
16716.2.152.0/2216.2.152.1 to 16.2.155.25416.2.155.2551,022
16816.2.156.0/2216.2.156.1 to 16.2.159.25416.2.159.2551,022
16916.2.160.0/2216.2.160.1 to 16.2.163.25416.2.163.2551,022
17016.2.164.0/2216.2.164.1 to 16.2.167.25416.2.167.2551,022
17116.2.168.0/2216.2.168.1 to 16.2.171.25416.2.171.2551,022
17216.2.172.0/2216.2.172.1 to 16.2.175.25416.2.175.2551,022
17316.2.176.0/2216.2.176.1 to 16.2.179.25416.2.179.2551,022
17416.2.180.0/2216.2.180.1 to 16.2.183.25416.2.183.2551,022
17516.2.184.0/2216.2.184.1 to 16.2.187.25416.2.187.2551,022
17616.2.188.0/2216.2.188.1 to 16.2.191.25416.2.191.2551,022
17716.2.192.0/2216.2.192.1 to 16.2.195.25416.2.195.2551,022
17816.2.196.0/2216.2.196.1 to 16.2.199.25416.2.199.2551,022
17916.2.200.0/2216.2.200.1 to 16.2.203.25416.2.203.2551,022
18016.2.204.0/2216.2.204.1 to 16.2.207.25416.2.207.2551,022
18116.2.208.0/2216.2.208.1 to 16.2.211.25416.2.211.2551,022
18216.2.212.0/2216.2.212.1 to 16.2.215.25416.2.215.2551,022
18316.2.216.0/2216.2.216.1 to 16.2.219.25416.2.219.2551,022
18416.2.220.0/2216.2.220.1 to 16.2.223.25416.2.223.2551,022
18516.2.224.0/2216.2.224.1 to 16.2.227.25416.2.227.2551,022
18616.2.228.0/2216.2.228.1 to 16.2.231.25416.2.231.2551,022
18716.2.232.0/2216.2.232.1 to 16.2.235.25416.2.235.2551,022
18816.2.236.0/2216.2.236.1 to 16.2.239.25416.2.239.2551,022
18916.2.240.0/2216.2.240.1 to 16.2.243.25416.2.243.2551,022
19016.2.244.0/2216.2.244.1 to 16.2.247.25416.2.247.2551,022
19116.2.248.0/2216.2.248.1 to 16.2.251.25416.2.251.2551,022
19216.2.252.0/2216.2.252.1 to 16.2.255.25416.2.255.2551,022
19316.3.0.0/2216.3.0.1 to 16.3.3.25416.3.3.2551,022
19416.3.4.0/2216.3.4.1 to 16.3.7.25416.3.7.2551,022
19516.3.8.0/2216.3.8.1 to 16.3.11.25416.3.11.2551,022
19616.3.12.0/2216.3.12.1 to 16.3.15.25416.3.15.2551,022
19716.3.16.0/2216.3.16.1 to 16.3.19.25416.3.19.2551,022
19816.3.20.0/2216.3.20.1 to 16.3.23.25416.3.23.2551,022
19916.3.24.0/2216.3.24.1 to 16.3.27.25416.3.27.2551,022
20016.3.28.0/2216.3.28.1 to 16.3.31.25416.3.31.2551,022
20116.3.32.0/2216.3.32.1 to 16.3.35.25416.3.35.2551,022
20216.3.36.0/2216.3.36.1 to 16.3.39.25416.3.39.2551,022
20316.3.40.0/2216.3.40.1 to 16.3.43.25416.3.43.2551,022
20416.3.44.0/2216.3.44.1 to 16.3.47.25416.3.47.2551,022
20516.3.48.0/2216.3.48.1 to 16.3.51.25416.3.51.2551,022
20616.3.52.0/2216.3.52.1 to 16.3.55.25416.3.55.2551,022
20716.3.56.0/2216.3.56.1 to 16.3.59.25416.3.59.2551,022
20816.3.60.0/2216.3.60.1 to 16.3.63.25416.3.63.2551,022
20916.3.64.0/2216.3.64.1 to 16.3.67.25416.3.67.2551,022
21016.3.68.0/2216.3.68.1 to 16.3.71.25416.3.71.2551,022
21116.3.72.0/2216.3.72.1 to 16.3.75.25416.3.75.2551,022
21216.3.76.0/2216.3.76.1 to 16.3.79.25416.3.79.2551,022
21316.3.80.0/2216.3.80.1 to 16.3.83.25416.3.83.2551,022
21416.3.84.0/2216.3.84.1 to 16.3.87.25416.3.87.2551,022
21516.3.88.0/2216.3.88.1 to 16.3.91.25416.3.91.2551,022
21616.3.92.0/2216.3.92.1 to 16.3.95.25416.3.95.2551,022
21716.3.96.0/2216.3.96.1 to 16.3.99.25416.3.99.2551,022
21816.3.100.0/2216.3.100.1 to 16.3.103.25416.3.103.2551,022
21916.3.104.0/2216.3.104.1 to 16.3.107.25416.3.107.2551,022
22016.3.108.0/2216.3.108.1 to 16.3.111.25416.3.111.2551,022
22116.3.112.0/2216.3.112.1 to 16.3.115.25416.3.115.2551,022
22216.3.116.0/2216.3.116.1 to 16.3.119.25416.3.119.2551,022
22316.3.120.0/2216.3.120.1 to 16.3.123.25416.3.123.2551,022
22416.3.124.0/2216.3.124.1 to 16.3.127.25416.3.127.2551,022
22516.3.128.0/2216.3.128.1 to 16.3.131.25416.3.131.2551,022
22616.3.132.0/2216.3.132.1 to 16.3.135.25416.3.135.2551,022
22716.3.136.0/2216.3.136.1 to 16.3.139.25416.3.139.2551,022
22816.3.140.0/2216.3.140.1 to 16.3.143.25416.3.143.2551,022
22916.3.144.0/2216.3.144.1 to 16.3.147.25416.3.147.2551,022
23016.3.148.0/2216.3.148.1 to 16.3.151.25416.3.151.2551,022
23116.3.152.0/2216.3.152.1 to 16.3.155.25416.3.155.2551,022
23216.3.156.0/2216.3.156.1 to 16.3.159.25416.3.159.2551,022
23316.3.160.0/2216.3.160.1 to 16.3.163.25416.3.163.2551,022
23416.3.164.0/2216.3.164.1 to 16.3.167.25416.3.167.2551,022
23516.3.168.0/2216.3.168.1 to 16.3.171.25416.3.171.2551,022
23616.3.172.0/2216.3.172.1 to 16.3.175.25416.3.175.2551,022
23716.3.176.0/2216.3.176.1 to 16.3.179.25416.3.179.2551,022
23816.3.180.0/2216.3.180.1 to 16.3.183.25416.3.183.2551,022
23916.3.184.0/2216.3.184.1 to 16.3.187.25416.3.187.2551,022
24016.3.188.0/2216.3.188.1 to 16.3.191.25416.3.191.2551,022
24116.3.192.0/2216.3.192.1 to 16.3.195.25416.3.195.2551,022
24216.3.196.0/2216.3.196.1 to 16.3.199.25416.3.199.2551,022
24316.3.200.0/2216.3.200.1 to 16.3.203.25416.3.203.2551,022
24416.3.204.0/2216.3.204.1 to 16.3.207.25416.3.207.2551,022
24516.3.208.0/2216.3.208.1 to 16.3.211.25416.3.211.2551,022
24616.3.212.0/2216.3.212.1 to 16.3.215.25416.3.215.2551,022
24716.3.216.0/2216.3.216.1 to 16.3.219.25416.3.219.2551,022
24816.3.220.0/2216.3.220.1 to 16.3.223.25416.3.223.2551,022
24916.3.224.0/2216.3.224.1 to 16.3.227.25416.3.227.2551,022
25016.3.228.0/2216.3.228.1 to 16.3.231.25416.3.231.2551,022
25116.3.232.0/2216.3.232.1 to 16.3.235.25416.3.235.2551,022
25216.3.236.0/2216.3.236.1 to 16.3.239.25416.3.239.2551,022
25316.3.240.0/2216.3.240.1 to 16.3.243.25416.3.243.2551,022
25416.3.244.0/2216.3.244.1 to 16.3.247.25416.3.247.2551,022
25516.3.248.0/2216.3.248.1 to 16.3.251.25416.3.251.2551,022
25616.3.252.0/2216.3.252.1 to 16.3.255.25416.3.255.2551,022

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.