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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.

Network16.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
16.0.0.0
Broadcast address
23.255.255.255
First usable
16.0.0.1
Last usable
23.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
A (default /8)
As numbers
Hex 10000000 · Integer 268435456 to 402653183
Reverse DNS zones
16.in-addr.arpa
17.in-addr.arpa
18.in-addr.arpa
19.in-addr.arpa
20.in-addr.arpa
21.in-addr.arpa
22.in-addr.arpa
23.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010000.00000000.00000000.0000000016.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network00010000.00000000.00000000.0000000016.0.0.0
Broadcast00010111.11111111.11111111.1111111123.255.255.255
Split into smaller subnets/15
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

16.0.0.0/5 makes 1,024 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.0.0.0/1516.0.0.1 to 16.1.255.25416.1.255.255131,070
216.2.0.0/1516.2.0.1 to 16.3.255.25416.3.255.255131,070
316.4.0.0/1516.4.0.1 to 16.5.255.25416.5.255.255131,070
416.6.0.0/1516.6.0.1 to 16.7.255.25416.7.255.255131,070
516.8.0.0/1516.8.0.1 to 16.9.255.25416.9.255.255131,070
616.10.0.0/1516.10.0.1 to 16.11.255.25416.11.255.255131,070
716.12.0.0/1516.12.0.1 to 16.13.255.25416.13.255.255131,070
816.14.0.0/1516.14.0.1 to 16.15.255.25416.15.255.255131,070
916.16.0.0/1516.16.0.1 to 16.17.255.25416.17.255.255131,070
1016.18.0.0/1516.18.0.1 to 16.19.255.25416.19.255.255131,070
1116.20.0.0/1516.20.0.1 to 16.21.255.25416.21.255.255131,070
1216.22.0.0/1516.22.0.1 to 16.23.255.25416.23.255.255131,070
1316.24.0.0/1516.24.0.1 to 16.25.255.25416.25.255.255131,070
1416.26.0.0/1516.26.0.1 to 16.27.255.25416.27.255.255131,070
1516.28.0.0/1516.28.0.1 to 16.29.255.25416.29.255.255131,070
1616.30.0.0/1516.30.0.1 to 16.31.255.25416.31.255.255131,070
1716.32.0.0/1516.32.0.1 to 16.33.255.25416.33.255.255131,070
1816.34.0.0/1516.34.0.1 to 16.35.255.25416.35.255.255131,070
1916.36.0.0/1516.36.0.1 to 16.37.255.25416.37.255.255131,070
2016.38.0.0/1516.38.0.1 to 16.39.255.25416.39.255.255131,070
2116.40.0.0/1516.40.0.1 to 16.41.255.25416.41.255.255131,070
2216.42.0.0/1516.42.0.1 to 16.43.255.25416.43.255.255131,070
2316.44.0.0/1516.44.0.1 to 16.45.255.25416.45.255.255131,070
2416.46.0.0/1516.46.0.1 to 16.47.255.25416.47.255.255131,070
2516.48.0.0/1516.48.0.1 to 16.49.255.25416.49.255.255131,070
2616.50.0.0/1516.50.0.1 to 16.51.255.25416.51.255.255131,070
2716.52.0.0/1516.52.0.1 to 16.53.255.25416.53.255.255131,070
2816.54.0.0/1516.54.0.1 to 16.55.255.25416.55.255.255131,070
2916.56.0.0/1516.56.0.1 to 16.57.255.25416.57.255.255131,070
3016.58.0.0/1516.58.0.1 to 16.59.255.25416.59.255.255131,070
3116.60.0.0/1516.60.0.1 to 16.61.255.25416.61.255.255131,070
3216.62.0.0/1516.62.0.1 to 16.63.255.25416.63.255.255131,070
3316.64.0.0/1516.64.0.1 to 16.65.255.25416.65.255.255131,070
3416.66.0.0/1516.66.0.1 to 16.67.255.25416.67.255.255131,070
3516.68.0.0/1516.68.0.1 to 16.69.255.25416.69.255.255131,070
3616.70.0.0/1516.70.0.1 to 16.71.255.25416.71.255.255131,070
3716.72.0.0/1516.72.0.1 to 16.73.255.25416.73.255.255131,070
3816.74.0.0/1516.74.0.1 to 16.75.255.25416.75.255.255131,070
3916.76.0.0/1516.76.0.1 to 16.77.255.25416.77.255.255131,070
4016.78.0.0/1516.78.0.1 to 16.79.255.25416.79.255.255131,070
4116.80.0.0/1516.80.0.1 to 16.81.255.25416.81.255.255131,070
4216.82.0.0/1516.82.0.1 to 16.83.255.25416.83.255.255131,070
4316.84.0.0/1516.84.0.1 to 16.85.255.25416.85.255.255131,070
4416.86.0.0/1516.86.0.1 to 16.87.255.25416.87.255.255131,070
4516.88.0.0/1516.88.0.1 to 16.89.255.25416.89.255.255131,070
4616.90.0.0/1516.90.0.1 to 16.91.255.25416.91.255.255131,070
4716.92.0.0/1516.92.0.1 to 16.93.255.25416.93.255.255131,070
4816.94.0.0/1516.94.0.1 to 16.95.255.25416.95.255.255131,070
4916.96.0.0/1516.96.0.1 to 16.97.255.25416.97.255.255131,070
5016.98.0.0/1516.98.0.1 to 16.99.255.25416.99.255.255131,070
5116.100.0.0/1516.100.0.1 to 16.101.255.25416.101.255.255131,070
5216.102.0.0/1516.102.0.1 to 16.103.255.25416.103.255.255131,070
5316.104.0.0/1516.104.0.1 to 16.105.255.25416.105.255.255131,070
5416.106.0.0/1516.106.0.1 to 16.107.255.25416.107.255.255131,070
5516.108.0.0/1516.108.0.1 to 16.109.255.25416.109.255.255131,070
5616.110.0.0/1516.110.0.1 to 16.111.255.25416.111.255.255131,070
5716.112.0.0/1516.112.0.1 to 16.113.255.25416.113.255.255131,070
5816.114.0.0/1516.114.0.1 to 16.115.255.25416.115.255.255131,070
5916.116.0.0/1516.116.0.1 to 16.117.255.25416.117.255.255131,070
6016.118.0.0/1516.118.0.1 to 16.119.255.25416.119.255.255131,070
6116.120.0.0/1516.120.0.1 to 16.121.255.25416.121.255.255131,070
6216.122.0.0/1516.122.0.1 to 16.123.255.25416.123.255.255131,070
6316.124.0.0/1516.124.0.1 to 16.125.255.25416.125.255.255131,070
6416.126.0.0/1516.126.0.1 to 16.127.255.25416.127.255.255131,070
6516.128.0.0/1516.128.0.1 to 16.129.255.25416.129.255.255131,070
6616.130.0.0/1516.130.0.1 to 16.131.255.25416.131.255.255131,070
6716.132.0.0/1516.132.0.1 to 16.133.255.25416.133.255.255131,070
6816.134.0.0/1516.134.0.1 to 16.135.255.25416.135.255.255131,070
6916.136.0.0/1516.136.0.1 to 16.137.255.25416.137.255.255131,070
7016.138.0.0/1516.138.0.1 to 16.139.255.25416.139.255.255131,070
7116.140.0.0/1516.140.0.1 to 16.141.255.25416.141.255.255131,070
7216.142.0.0/1516.142.0.1 to 16.143.255.25416.143.255.255131,070
7316.144.0.0/1516.144.0.1 to 16.145.255.25416.145.255.255131,070
7416.146.0.0/1516.146.0.1 to 16.147.255.25416.147.255.255131,070
7516.148.0.0/1516.148.0.1 to 16.149.255.25416.149.255.255131,070
7616.150.0.0/1516.150.0.1 to 16.151.255.25416.151.255.255131,070
7716.152.0.0/1516.152.0.1 to 16.153.255.25416.153.255.255131,070
7816.154.0.0/1516.154.0.1 to 16.155.255.25416.155.255.255131,070
7916.156.0.0/1516.156.0.1 to 16.157.255.25416.157.255.255131,070
8016.158.0.0/1516.158.0.1 to 16.159.255.25416.159.255.255131,070
8116.160.0.0/1516.160.0.1 to 16.161.255.25416.161.255.255131,070
8216.162.0.0/1516.162.0.1 to 16.163.255.25416.163.255.255131,070
8316.164.0.0/1516.164.0.1 to 16.165.255.25416.165.255.255131,070
8416.166.0.0/1516.166.0.1 to 16.167.255.25416.167.255.255131,070
8516.168.0.0/1516.168.0.1 to 16.169.255.25416.169.255.255131,070
8616.170.0.0/1516.170.0.1 to 16.171.255.25416.171.255.255131,070
8716.172.0.0/1516.172.0.1 to 16.173.255.25416.173.255.255131,070
8816.174.0.0/1516.174.0.1 to 16.175.255.25416.175.255.255131,070
8916.176.0.0/1516.176.0.1 to 16.177.255.25416.177.255.255131,070
9016.178.0.0/1516.178.0.1 to 16.179.255.25416.179.255.255131,070
9116.180.0.0/1516.180.0.1 to 16.181.255.25416.181.255.255131,070
9216.182.0.0/1516.182.0.1 to 16.183.255.25416.183.255.255131,070
9316.184.0.0/1516.184.0.1 to 16.185.255.25416.185.255.255131,070
9416.186.0.0/1516.186.0.1 to 16.187.255.25416.187.255.255131,070
9516.188.0.0/1516.188.0.1 to 16.189.255.25416.189.255.255131,070
9616.190.0.0/1516.190.0.1 to 16.191.255.25416.191.255.255131,070
9716.192.0.0/1516.192.0.1 to 16.193.255.25416.193.255.255131,070
9816.194.0.0/1516.194.0.1 to 16.195.255.25416.195.255.255131,070
9916.196.0.0/1516.196.0.1 to 16.197.255.25416.197.255.255131,070
10016.198.0.0/1516.198.0.1 to 16.199.255.25416.199.255.255131,070
10116.200.0.0/1516.200.0.1 to 16.201.255.25416.201.255.255131,070
10216.202.0.0/1516.202.0.1 to 16.203.255.25416.203.255.255131,070
10316.204.0.0/1516.204.0.1 to 16.205.255.25416.205.255.255131,070
10416.206.0.0/1516.206.0.1 to 16.207.255.25416.207.255.255131,070
10516.208.0.0/1516.208.0.1 to 16.209.255.25416.209.255.255131,070
10616.210.0.0/1516.210.0.1 to 16.211.255.25416.211.255.255131,070
10716.212.0.0/1516.212.0.1 to 16.213.255.25416.213.255.255131,070
10816.214.0.0/1516.214.0.1 to 16.215.255.25416.215.255.255131,070
10916.216.0.0/1516.216.0.1 to 16.217.255.25416.217.255.255131,070
11016.218.0.0/1516.218.0.1 to 16.219.255.25416.219.255.255131,070
11116.220.0.0/1516.220.0.1 to 16.221.255.25416.221.255.255131,070
11216.222.0.0/1516.222.0.1 to 16.223.255.25416.223.255.255131,070
11316.224.0.0/1516.224.0.1 to 16.225.255.25416.225.255.255131,070
11416.226.0.0/1516.226.0.1 to 16.227.255.25416.227.255.255131,070
11516.228.0.0/1516.228.0.1 to 16.229.255.25416.229.255.255131,070
11616.230.0.0/1516.230.0.1 to 16.231.255.25416.231.255.255131,070
11716.232.0.0/1516.232.0.1 to 16.233.255.25416.233.255.255131,070
11816.234.0.0/1516.234.0.1 to 16.235.255.25416.235.255.255131,070
11916.236.0.0/1516.236.0.1 to 16.237.255.25416.237.255.255131,070
12016.238.0.0/1516.238.0.1 to 16.239.255.25416.239.255.255131,070
12116.240.0.0/1516.240.0.1 to 16.241.255.25416.241.255.255131,070
12216.242.0.0/1516.242.0.1 to 16.243.255.25416.243.255.255131,070
12316.244.0.0/1516.244.0.1 to 16.245.255.25416.245.255.255131,070
12416.246.0.0/1516.246.0.1 to 16.247.255.25416.247.255.255131,070
12516.248.0.0/1516.248.0.1 to 16.249.255.25416.249.255.255131,070
12616.250.0.0/1516.250.0.1 to 16.251.255.25416.251.255.255131,070
12716.252.0.0/1516.252.0.1 to 16.253.255.25416.253.255.255131,070
12816.254.0.0/1516.254.0.1 to 16.255.255.25416.255.255.255131,070
12917.0.0.0/1517.0.0.1 to 17.1.255.25417.1.255.255131,070
13017.2.0.0/1517.2.0.1 to 17.3.255.25417.3.255.255131,070
13117.4.0.0/1517.4.0.1 to 17.5.255.25417.5.255.255131,070
13217.6.0.0/1517.6.0.1 to 17.7.255.25417.7.255.255131,070
13317.8.0.0/1517.8.0.1 to 17.9.255.25417.9.255.255131,070
13417.10.0.0/1517.10.0.1 to 17.11.255.25417.11.255.255131,070
13517.12.0.0/1517.12.0.1 to 17.13.255.25417.13.255.255131,070
13617.14.0.0/1517.14.0.1 to 17.15.255.25417.15.255.255131,070
13717.16.0.0/1517.16.0.1 to 17.17.255.25417.17.255.255131,070
13817.18.0.0/1517.18.0.1 to 17.19.255.25417.19.255.255131,070
13917.20.0.0/1517.20.0.1 to 17.21.255.25417.21.255.255131,070
14017.22.0.0/1517.22.0.1 to 17.23.255.25417.23.255.255131,070
14117.24.0.0/1517.24.0.1 to 17.25.255.25417.25.255.255131,070
14217.26.0.0/1517.26.0.1 to 17.27.255.25417.27.255.255131,070
14317.28.0.0/1517.28.0.1 to 17.29.255.25417.29.255.255131,070
14417.30.0.0/1517.30.0.1 to 17.31.255.25417.31.255.255131,070
14517.32.0.0/1517.32.0.1 to 17.33.255.25417.33.255.255131,070
14617.34.0.0/1517.34.0.1 to 17.35.255.25417.35.255.255131,070
14717.36.0.0/1517.36.0.1 to 17.37.255.25417.37.255.255131,070
14817.38.0.0/1517.38.0.1 to 17.39.255.25417.39.255.255131,070
14917.40.0.0/1517.40.0.1 to 17.41.255.25417.41.255.255131,070
15017.42.0.0/1517.42.0.1 to 17.43.255.25417.43.255.255131,070
15117.44.0.0/1517.44.0.1 to 17.45.255.25417.45.255.255131,070
15217.46.0.0/1517.46.0.1 to 17.47.255.25417.47.255.255131,070
15317.48.0.0/1517.48.0.1 to 17.49.255.25417.49.255.255131,070
15417.50.0.0/1517.50.0.1 to 17.51.255.25417.51.255.255131,070
15517.52.0.0/1517.52.0.1 to 17.53.255.25417.53.255.255131,070
15617.54.0.0/1517.54.0.1 to 17.55.255.25417.55.255.255131,070
15717.56.0.0/1517.56.0.1 to 17.57.255.25417.57.255.255131,070
15817.58.0.0/1517.58.0.1 to 17.59.255.25417.59.255.255131,070
15917.60.0.0/1517.60.0.1 to 17.61.255.25417.61.255.255131,070
16017.62.0.0/1517.62.0.1 to 17.63.255.25417.63.255.255131,070
16117.64.0.0/1517.64.0.1 to 17.65.255.25417.65.255.255131,070
16217.66.0.0/1517.66.0.1 to 17.67.255.25417.67.255.255131,070
16317.68.0.0/1517.68.0.1 to 17.69.255.25417.69.255.255131,070
16417.70.0.0/1517.70.0.1 to 17.71.255.25417.71.255.255131,070
16517.72.0.0/1517.72.0.1 to 17.73.255.25417.73.255.255131,070
16617.74.0.0/1517.74.0.1 to 17.75.255.25417.75.255.255131,070
16717.76.0.0/1517.76.0.1 to 17.77.255.25417.77.255.255131,070
16817.78.0.0/1517.78.0.1 to 17.79.255.25417.79.255.255131,070
16917.80.0.0/1517.80.0.1 to 17.81.255.25417.81.255.255131,070
17017.82.0.0/1517.82.0.1 to 17.83.255.25417.83.255.255131,070
17117.84.0.0/1517.84.0.1 to 17.85.255.25417.85.255.255131,070
17217.86.0.0/1517.86.0.1 to 17.87.255.25417.87.255.255131,070
17317.88.0.0/1517.88.0.1 to 17.89.255.25417.89.255.255131,070
17417.90.0.0/1517.90.0.1 to 17.91.255.25417.91.255.255131,070
17517.92.0.0/1517.92.0.1 to 17.93.255.25417.93.255.255131,070
17617.94.0.0/1517.94.0.1 to 17.95.255.25417.95.255.255131,070
17717.96.0.0/1517.96.0.1 to 17.97.255.25417.97.255.255131,070
17817.98.0.0/1517.98.0.1 to 17.99.255.25417.99.255.255131,070
17917.100.0.0/1517.100.0.1 to 17.101.255.25417.101.255.255131,070
18017.102.0.0/1517.102.0.1 to 17.103.255.25417.103.255.255131,070
18117.104.0.0/1517.104.0.1 to 17.105.255.25417.105.255.255131,070
18217.106.0.0/1517.106.0.1 to 17.107.255.25417.107.255.255131,070
18317.108.0.0/1517.108.0.1 to 17.109.255.25417.109.255.255131,070
18417.110.0.0/1517.110.0.1 to 17.111.255.25417.111.255.255131,070
18517.112.0.0/1517.112.0.1 to 17.113.255.25417.113.255.255131,070
18617.114.0.0/1517.114.0.1 to 17.115.255.25417.115.255.255131,070
18717.116.0.0/1517.116.0.1 to 17.117.255.25417.117.255.255131,070
18817.118.0.0/1517.118.0.1 to 17.119.255.25417.119.255.255131,070
18917.120.0.0/1517.120.0.1 to 17.121.255.25417.121.255.255131,070
19017.122.0.0/1517.122.0.1 to 17.123.255.25417.123.255.255131,070
19117.124.0.0/1517.124.0.1 to 17.125.255.25417.125.255.255131,070
19217.126.0.0/1517.126.0.1 to 17.127.255.25417.127.255.255131,070
19317.128.0.0/1517.128.0.1 to 17.129.255.25417.129.255.255131,070
19417.130.0.0/1517.130.0.1 to 17.131.255.25417.131.255.255131,070
19517.132.0.0/1517.132.0.1 to 17.133.255.25417.133.255.255131,070
19617.134.0.0/1517.134.0.1 to 17.135.255.25417.135.255.255131,070
19717.136.0.0/1517.136.0.1 to 17.137.255.25417.137.255.255131,070
19817.138.0.0/1517.138.0.1 to 17.139.255.25417.139.255.255131,070
19917.140.0.0/1517.140.0.1 to 17.141.255.25417.141.255.255131,070
20017.142.0.0/1517.142.0.1 to 17.143.255.25417.143.255.255131,070
20117.144.0.0/1517.144.0.1 to 17.145.255.25417.145.255.255131,070
20217.146.0.0/1517.146.0.1 to 17.147.255.25417.147.255.255131,070
20317.148.0.0/1517.148.0.1 to 17.149.255.25417.149.255.255131,070
20417.150.0.0/1517.150.0.1 to 17.151.255.25417.151.255.255131,070
20517.152.0.0/1517.152.0.1 to 17.153.255.25417.153.255.255131,070
20617.154.0.0/1517.154.0.1 to 17.155.255.25417.155.255.255131,070
20717.156.0.0/1517.156.0.1 to 17.157.255.25417.157.255.255131,070
20817.158.0.0/1517.158.0.1 to 17.159.255.25417.159.255.255131,070
20917.160.0.0/1517.160.0.1 to 17.161.255.25417.161.255.255131,070
21017.162.0.0/1517.162.0.1 to 17.163.255.25417.163.255.255131,070
21117.164.0.0/1517.164.0.1 to 17.165.255.25417.165.255.255131,070
21217.166.0.0/1517.166.0.1 to 17.167.255.25417.167.255.255131,070
21317.168.0.0/1517.168.0.1 to 17.169.255.25417.169.255.255131,070
21417.170.0.0/1517.170.0.1 to 17.171.255.25417.171.255.255131,070
21517.172.0.0/1517.172.0.1 to 17.173.255.25417.173.255.255131,070
21617.174.0.0/1517.174.0.1 to 17.175.255.25417.175.255.255131,070
21717.176.0.0/1517.176.0.1 to 17.177.255.25417.177.255.255131,070
21817.178.0.0/1517.178.0.1 to 17.179.255.25417.179.255.255131,070
21917.180.0.0/1517.180.0.1 to 17.181.255.25417.181.255.255131,070
22017.182.0.0/1517.182.0.1 to 17.183.255.25417.183.255.255131,070
22117.184.0.0/1517.184.0.1 to 17.185.255.25417.185.255.255131,070
22217.186.0.0/1517.186.0.1 to 17.187.255.25417.187.255.255131,070
22317.188.0.0/1517.188.0.1 to 17.189.255.25417.189.255.255131,070
22417.190.0.0/1517.190.0.1 to 17.191.255.25417.191.255.255131,070
22517.192.0.0/1517.192.0.1 to 17.193.255.25417.193.255.255131,070
22617.194.0.0/1517.194.0.1 to 17.195.255.25417.195.255.255131,070
22717.196.0.0/1517.196.0.1 to 17.197.255.25417.197.255.255131,070
22817.198.0.0/1517.198.0.1 to 17.199.255.25417.199.255.255131,070
22917.200.0.0/1517.200.0.1 to 17.201.255.25417.201.255.255131,070
23017.202.0.0/1517.202.0.1 to 17.203.255.25417.203.255.255131,070
23117.204.0.0/1517.204.0.1 to 17.205.255.25417.205.255.255131,070
23217.206.0.0/1517.206.0.1 to 17.207.255.25417.207.255.255131,070
23317.208.0.0/1517.208.0.1 to 17.209.255.25417.209.255.255131,070
23417.210.0.0/1517.210.0.1 to 17.211.255.25417.211.255.255131,070
23517.212.0.0/1517.212.0.1 to 17.213.255.25417.213.255.255131,070
23617.214.0.0/1517.214.0.1 to 17.215.255.25417.215.255.255131,070
23717.216.0.0/1517.216.0.1 to 17.217.255.25417.217.255.255131,070
23817.218.0.0/1517.218.0.1 to 17.219.255.25417.219.255.255131,070
23917.220.0.0/1517.220.0.1 to 17.221.255.25417.221.255.255131,070
24017.222.0.0/1517.222.0.1 to 17.223.255.25417.223.255.255131,070
24117.224.0.0/1517.224.0.1 to 17.225.255.25417.225.255.255131,070
24217.226.0.0/1517.226.0.1 to 17.227.255.25417.227.255.255131,070
24317.228.0.0/1517.228.0.1 to 17.229.255.25417.229.255.255131,070
24417.230.0.0/1517.230.0.1 to 17.231.255.25417.231.255.255131,070
24517.232.0.0/1517.232.0.1 to 17.233.255.25417.233.255.255131,070
24617.234.0.0/1517.234.0.1 to 17.235.255.25417.235.255.255131,070
24717.236.0.0/1517.236.0.1 to 17.237.255.25417.237.255.255131,070
24817.238.0.0/1517.238.0.1 to 17.239.255.25417.239.255.255131,070
24917.240.0.0/1517.240.0.1 to 17.241.255.25417.241.255.255131,070
25017.242.0.0/1517.242.0.1 to 17.243.255.25417.243.255.255131,070
25117.244.0.0/1517.244.0.1 to 17.245.255.25417.245.255.255131,070
25217.246.0.0/1517.246.0.1 to 17.247.255.25417.247.255.255131,070
25317.248.0.0/1517.248.0.1 to 17.249.255.25417.249.255.255131,070
25417.250.0.0/1517.250.0.1 to 17.251.255.25417.251.255.255131,070
25517.252.0.0/1517.252.0.1 to 17.253.255.25417.253.255.255131,070
25617.254.0.0/1517.254.0.1 to 17.255.255.25417.255.255.255131,070

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.