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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.

Network63.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
63.0.0.0
Broadcast address
63.255.255.255
First usable
63.0.0.1
Last usable
63.255.255.254
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 3F000000 · Integer 1056964608 to 1073741823
Reverse DNS zone
63.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111111..00000000.00000000.0000000063.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00111111..00000000.00000000.0000000063.0.0.0
Broadcast00111111..11111111.11111111.1111111163.255.255.255
Split into smaller subnets/16
/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)

63.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
163.0.0.0/1663.0.0.1 to 63.0.255.25463.0.255.25565,534
263.1.0.0/1663.1.0.1 to 63.1.255.25463.1.255.25565,534
363.2.0.0/1663.2.0.1 to 63.2.255.25463.2.255.25565,534
463.3.0.0/1663.3.0.1 to 63.3.255.25463.3.255.25565,534
563.4.0.0/1663.4.0.1 to 63.4.255.25463.4.255.25565,534
663.5.0.0/1663.5.0.1 to 63.5.255.25463.5.255.25565,534
763.6.0.0/1663.6.0.1 to 63.6.255.25463.6.255.25565,534
863.7.0.0/1663.7.0.1 to 63.7.255.25463.7.255.25565,534
963.8.0.0/1663.8.0.1 to 63.8.255.25463.8.255.25565,534
1063.9.0.0/1663.9.0.1 to 63.9.255.25463.9.255.25565,534
1163.10.0.0/1663.10.0.1 to 63.10.255.25463.10.255.25565,534
1263.11.0.0/1663.11.0.1 to 63.11.255.25463.11.255.25565,534
1363.12.0.0/1663.12.0.1 to 63.12.255.25463.12.255.25565,534
1463.13.0.0/1663.13.0.1 to 63.13.255.25463.13.255.25565,534
1563.14.0.0/1663.14.0.1 to 63.14.255.25463.14.255.25565,534
1663.15.0.0/1663.15.0.1 to 63.15.255.25463.15.255.25565,534
1763.16.0.0/1663.16.0.1 to 63.16.255.25463.16.255.25565,534
1863.17.0.0/1663.17.0.1 to 63.17.255.25463.17.255.25565,534
1963.18.0.0/1663.18.0.1 to 63.18.255.25463.18.255.25565,534
2063.19.0.0/1663.19.0.1 to 63.19.255.25463.19.255.25565,534
2163.20.0.0/1663.20.0.1 to 63.20.255.25463.20.255.25565,534
2263.21.0.0/1663.21.0.1 to 63.21.255.25463.21.255.25565,534
2363.22.0.0/1663.22.0.1 to 63.22.255.25463.22.255.25565,534
2463.23.0.0/1663.23.0.1 to 63.23.255.25463.23.255.25565,534
2563.24.0.0/1663.24.0.1 to 63.24.255.25463.24.255.25565,534
2663.25.0.0/1663.25.0.1 to 63.25.255.25463.25.255.25565,534
2763.26.0.0/1663.26.0.1 to 63.26.255.25463.26.255.25565,534
2863.27.0.0/1663.27.0.1 to 63.27.255.25463.27.255.25565,534
2963.28.0.0/1663.28.0.1 to 63.28.255.25463.28.255.25565,534
3063.29.0.0/1663.29.0.1 to 63.29.255.25463.29.255.25565,534
3163.30.0.0/1663.30.0.1 to 63.30.255.25463.30.255.25565,534
3263.31.0.0/1663.31.0.1 to 63.31.255.25463.31.255.25565,534
3363.32.0.0/1663.32.0.1 to 63.32.255.25463.32.255.25565,534
3463.33.0.0/1663.33.0.1 to 63.33.255.25463.33.255.25565,534
3563.34.0.0/1663.34.0.1 to 63.34.255.25463.34.255.25565,534
3663.35.0.0/1663.35.0.1 to 63.35.255.25463.35.255.25565,534
3763.36.0.0/1663.36.0.1 to 63.36.255.25463.36.255.25565,534
3863.37.0.0/1663.37.0.1 to 63.37.255.25463.37.255.25565,534
3963.38.0.0/1663.38.0.1 to 63.38.255.25463.38.255.25565,534
4063.39.0.0/1663.39.0.1 to 63.39.255.25463.39.255.25565,534
4163.40.0.0/1663.40.0.1 to 63.40.255.25463.40.255.25565,534
4263.41.0.0/1663.41.0.1 to 63.41.255.25463.41.255.25565,534
4363.42.0.0/1663.42.0.1 to 63.42.255.25463.42.255.25565,534
4463.43.0.0/1663.43.0.1 to 63.43.255.25463.43.255.25565,534
4563.44.0.0/1663.44.0.1 to 63.44.255.25463.44.255.25565,534
4663.45.0.0/1663.45.0.1 to 63.45.255.25463.45.255.25565,534
4763.46.0.0/1663.46.0.1 to 63.46.255.25463.46.255.25565,534
4863.47.0.0/1663.47.0.1 to 63.47.255.25463.47.255.25565,534
4963.48.0.0/1663.48.0.1 to 63.48.255.25463.48.255.25565,534
5063.49.0.0/1663.49.0.1 to 63.49.255.25463.49.255.25565,534
5163.50.0.0/1663.50.0.1 to 63.50.255.25463.50.255.25565,534
5263.51.0.0/1663.51.0.1 to 63.51.255.25463.51.255.25565,534
5363.52.0.0/1663.52.0.1 to 63.52.255.25463.52.255.25565,534
5463.53.0.0/1663.53.0.1 to 63.53.255.25463.53.255.25565,534
5563.54.0.0/1663.54.0.1 to 63.54.255.25463.54.255.25565,534
5663.55.0.0/1663.55.0.1 to 63.55.255.25463.55.255.25565,534
5763.56.0.0/1663.56.0.1 to 63.56.255.25463.56.255.25565,534
5863.57.0.0/1663.57.0.1 to 63.57.255.25463.57.255.25565,534
5963.58.0.0/1663.58.0.1 to 63.58.255.25463.58.255.25565,534
6063.59.0.0/1663.59.0.1 to 63.59.255.25463.59.255.25565,534
6163.60.0.0/1663.60.0.1 to 63.60.255.25463.60.255.25565,534
6263.61.0.0/1663.61.0.1 to 63.61.255.25463.61.255.25565,534
6363.62.0.0/1663.62.0.1 to 63.62.255.25463.62.255.25565,534
6463.63.0.0/1663.63.0.1 to 63.63.255.25463.63.255.25565,534
6563.64.0.0/1663.64.0.1 to 63.64.255.25463.64.255.25565,534
6663.65.0.0/1663.65.0.1 to 63.65.255.25463.65.255.25565,534
6763.66.0.0/1663.66.0.1 to 63.66.255.25463.66.255.25565,534
6863.67.0.0/1663.67.0.1 to 63.67.255.25463.67.255.25565,534
6963.68.0.0/1663.68.0.1 to 63.68.255.25463.68.255.25565,534
7063.69.0.0/1663.69.0.1 to 63.69.255.25463.69.255.25565,534
7163.70.0.0/1663.70.0.1 to 63.70.255.25463.70.255.25565,534
7263.71.0.0/1663.71.0.1 to 63.71.255.25463.71.255.25565,534
7363.72.0.0/1663.72.0.1 to 63.72.255.25463.72.255.25565,534
7463.73.0.0/1663.73.0.1 to 63.73.255.25463.73.255.25565,534
7563.74.0.0/1663.74.0.1 to 63.74.255.25463.74.255.25565,534
7663.75.0.0/1663.75.0.1 to 63.75.255.25463.75.255.25565,534
7763.76.0.0/1663.76.0.1 to 63.76.255.25463.76.255.25565,534
7863.77.0.0/1663.77.0.1 to 63.77.255.25463.77.255.25565,534
7963.78.0.0/1663.78.0.1 to 63.78.255.25463.78.255.25565,534
8063.79.0.0/1663.79.0.1 to 63.79.255.25463.79.255.25565,534
8163.80.0.0/1663.80.0.1 to 63.80.255.25463.80.255.25565,534
8263.81.0.0/1663.81.0.1 to 63.81.255.25463.81.255.25565,534
8363.82.0.0/1663.82.0.1 to 63.82.255.25463.82.255.25565,534
8463.83.0.0/1663.83.0.1 to 63.83.255.25463.83.255.25565,534
8563.84.0.0/1663.84.0.1 to 63.84.255.25463.84.255.25565,534
8663.85.0.0/1663.85.0.1 to 63.85.255.25463.85.255.25565,534
8763.86.0.0/1663.86.0.1 to 63.86.255.25463.86.255.25565,534
8863.87.0.0/1663.87.0.1 to 63.87.255.25463.87.255.25565,534
8963.88.0.0/1663.88.0.1 to 63.88.255.25463.88.255.25565,534
9063.89.0.0/1663.89.0.1 to 63.89.255.25463.89.255.25565,534
9163.90.0.0/1663.90.0.1 to 63.90.255.25463.90.255.25565,534
9263.91.0.0/1663.91.0.1 to 63.91.255.25463.91.255.25565,534
9363.92.0.0/1663.92.0.1 to 63.92.255.25463.92.255.25565,534
9463.93.0.0/1663.93.0.1 to 63.93.255.25463.93.255.25565,534
9563.94.0.0/1663.94.0.1 to 63.94.255.25463.94.255.25565,534
9663.95.0.0/1663.95.0.1 to 63.95.255.25463.95.255.25565,534
9763.96.0.0/1663.96.0.1 to 63.96.255.25463.96.255.25565,534
9863.97.0.0/1663.97.0.1 to 63.97.255.25463.97.255.25565,534
9963.98.0.0/1663.98.0.1 to 63.98.255.25463.98.255.25565,534
10063.99.0.0/1663.99.0.1 to 63.99.255.25463.99.255.25565,534
10163.100.0.0/1663.100.0.1 to 63.100.255.25463.100.255.25565,534
10263.101.0.0/1663.101.0.1 to 63.101.255.25463.101.255.25565,534
10363.102.0.0/1663.102.0.1 to 63.102.255.25463.102.255.25565,534
10463.103.0.0/1663.103.0.1 to 63.103.255.25463.103.255.25565,534
10563.104.0.0/1663.104.0.1 to 63.104.255.25463.104.255.25565,534
10663.105.0.0/1663.105.0.1 to 63.105.255.25463.105.255.25565,534
10763.106.0.0/1663.106.0.1 to 63.106.255.25463.106.255.25565,534
10863.107.0.0/1663.107.0.1 to 63.107.255.25463.107.255.25565,534
10963.108.0.0/1663.108.0.1 to 63.108.255.25463.108.255.25565,534
11063.109.0.0/1663.109.0.1 to 63.109.255.25463.109.255.25565,534
11163.110.0.0/1663.110.0.1 to 63.110.255.25463.110.255.25565,534
11263.111.0.0/1663.111.0.1 to 63.111.255.25463.111.255.25565,534
11363.112.0.0/1663.112.0.1 to 63.112.255.25463.112.255.25565,534
11463.113.0.0/1663.113.0.1 to 63.113.255.25463.113.255.25565,534
11563.114.0.0/1663.114.0.1 to 63.114.255.25463.114.255.25565,534
11663.115.0.0/1663.115.0.1 to 63.115.255.25463.115.255.25565,534
11763.116.0.0/1663.116.0.1 to 63.116.255.25463.116.255.25565,534
11863.117.0.0/1663.117.0.1 to 63.117.255.25463.117.255.25565,534
11963.118.0.0/1663.118.0.1 to 63.118.255.25463.118.255.25565,534
12063.119.0.0/1663.119.0.1 to 63.119.255.25463.119.255.25565,534
12163.120.0.0/1663.120.0.1 to 63.120.255.25463.120.255.25565,534
12263.121.0.0/1663.121.0.1 to 63.121.255.25463.121.255.25565,534
12363.122.0.0/1663.122.0.1 to 63.122.255.25463.122.255.25565,534
12463.123.0.0/1663.123.0.1 to 63.123.255.25463.123.255.25565,534
12563.124.0.0/1663.124.0.1 to 63.124.255.25463.124.255.25565,534
12663.125.0.0/1663.125.0.1 to 63.125.255.25463.125.255.25565,534
12763.126.0.0/1663.126.0.1 to 63.126.255.25463.126.255.25565,534
12863.127.0.0/1663.127.0.1 to 63.127.255.25463.127.255.25565,534
12963.128.0.0/1663.128.0.1 to 63.128.255.25463.128.255.25565,534
13063.129.0.0/1663.129.0.1 to 63.129.255.25463.129.255.25565,534
13163.130.0.0/1663.130.0.1 to 63.130.255.25463.130.255.25565,534
13263.131.0.0/1663.131.0.1 to 63.131.255.25463.131.255.25565,534
13363.132.0.0/1663.132.0.1 to 63.132.255.25463.132.255.25565,534
13463.133.0.0/1663.133.0.1 to 63.133.255.25463.133.255.25565,534
13563.134.0.0/1663.134.0.1 to 63.134.255.25463.134.255.25565,534
13663.135.0.0/1663.135.0.1 to 63.135.255.25463.135.255.25565,534
13763.136.0.0/1663.136.0.1 to 63.136.255.25463.136.255.25565,534
13863.137.0.0/1663.137.0.1 to 63.137.255.25463.137.255.25565,534
13963.138.0.0/1663.138.0.1 to 63.138.255.25463.138.255.25565,534
14063.139.0.0/1663.139.0.1 to 63.139.255.25463.139.255.25565,534
14163.140.0.0/1663.140.0.1 to 63.140.255.25463.140.255.25565,534
14263.141.0.0/1663.141.0.1 to 63.141.255.25463.141.255.25565,534
14363.142.0.0/1663.142.0.1 to 63.142.255.25463.142.255.25565,534
14463.143.0.0/1663.143.0.1 to 63.143.255.25463.143.255.25565,534
14563.144.0.0/1663.144.0.1 to 63.144.255.25463.144.255.25565,534
14663.145.0.0/1663.145.0.1 to 63.145.255.25463.145.255.25565,534
14763.146.0.0/1663.146.0.1 to 63.146.255.25463.146.255.25565,534
14863.147.0.0/1663.147.0.1 to 63.147.255.25463.147.255.25565,534
14963.148.0.0/1663.148.0.1 to 63.148.255.25463.148.255.25565,534
15063.149.0.0/1663.149.0.1 to 63.149.255.25463.149.255.25565,534
15163.150.0.0/1663.150.0.1 to 63.150.255.25463.150.255.25565,534
15263.151.0.0/1663.151.0.1 to 63.151.255.25463.151.255.25565,534
15363.152.0.0/1663.152.0.1 to 63.152.255.25463.152.255.25565,534
15463.153.0.0/1663.153.0.1 to 63.153.255.25463.153.255.25565,534
15563.154.0.0/1663.154.0.1 to 63.154.255.25463.154.255.25565,534
15663.155.0.0/1663.155.0.1 to 63.155.255.25463.155.255.25565,534
15763.156.0.0/1663.156.0.1 to 63.156.255.25463.156.255.25565,534
15863.157.0.0/1663.157.0.1 to 63.157.255.25463.157.255.25565,534
15963.158.0.0/1663.158.0.1 to 63.158.255.25463.158.255.25565,534
16063.159.0.0/1663.159.0.1 to 63.159.255.25463.159.255.25565,534
16163.160.0.0/1663.160.0.1 to 63.160.255.25463.160.255.25565,534
16263.161.0.0/1663.161.0.1 to 63.161.255.25463.161.255.25565,534
16363.162.0.0/1663.162.0.1 to 63.162.255.25463.162.255.25565,534
16463.163.0.0/1663.163.0.1 to 63.163.255.25463.163.255.25565,534
16563.164.0.0/1663.164.0.1 to 63.164.255.25463.164.255.25565,534
16663.165.0.0/1663.165.0.1 to 63.165.255.25463.165.255.25565,534
16763.166.0.0/1663.166.0.1 to 63.166.255.25463.166.255.25565,534
16863.167.0.0/1663.167.0.1 to 63.167.255.25463.167.255.25565,534
16963.168.0.0/1663.168.0.1 to 63.168.255.25463.168.255.25565,534
17063.169.0.0/1663.169.0.1 to 63.169.255.25463.169.255.25565,534
17163.170.0.0/1663.170.0.1 to 63.170.255.25463.170.255.25565,534
17263.171.0.0/1663.171.0.1 to 63.171.255.25463.171.255.25565,534
17363.172.0.0/1663.172.0.1 to 63.172.255.25463.172.255.25565,534
17463.173.0.0/1663.173.0.1 to 63.173.255.25463.173.255.25565,534
17563.174.0.0/1663.174.0.1 to 63.174.255.25463.174.255.25565,534
17663.175.0.0/1663.175.0.1 to 63.175.255.25463.175.255.25565,534
17763.176.0.0/1663.176.0.1 to 63.176.255.25463.176.255.25565,534
17863.177.0.0/1663.177.0.1 to 63.177.255.25463.177.255.25565,534
17963.178.0.0/1663.178.0.1 to 63.178.255.25463.178.255.25565,534
18063.179.0.0/1663.179.0.1 to 63.179.255.25463.179.255.25565,534
18163.180.0.0/1663.180.0.1 to 63.180.255.25463.180.255.25565,534
18263.181.0.0/1663.181.0.1 to 63.181.255.25463.181.255.25565,534
18363.182.0.0/1663.182.0.1 to 63.182.255.25463.182.255.25565,534
18463.183.0.0/1663.183.0.1 to 63.183.255.25463.183.255.25565,534
18563.184.0.0/1663.184.0.1 to 63.184.255.25463.184.255.25565,534
18663.185.0.0/1663.185.0.1 to 63.185.255.25463.185.255.25565,534
18763.186.0.0/1663.186.0.1 to 63.186.255.25463.186.255.25565,534
18863.187.0.0/1663.187.0.1 to 63.187.255.25463.187.255.25565,534
18963.188.0.0/1663.188.0.1 to 63.188.255.25463.188.255.25565,534
19063.189.0.0/1663.189.0.1 to 63.189.255.25463.189.255.25565,534
19163.190.0.0/1663.190.0.1 to 63.190.255.25463.190.255.25565,534
19263.191.0.0/1663.191.0.1 to 63.191.255.25463.191.255.25565,534
19363.192.0.0/1663.192.0.1 to 63.192.255.25463.192.255.25565,534
19463.193.0.0/1663.193.0.1 to 63.193.255.25463.193.255.25565,534
19563.194.0.0/1663.194.0.1 to 63.194.255.25463.194.255.25565,534
19663.195.0.0/1663.195.0.1 to 63.195.255.25463.195.255.25565,534
19763.196.0.0/1663.196.0.1 to 63.196.255.25463.196.255.25565,534
19863.197.0.0/1663.197.0.1 to 63.197.255.25463.197.255.25565,534
19963.198.0.0/1663.198.0.1 to 63.198.255.25463.198.255.25565,534
20063.199.0.0/1663.199.0.1 to 63.199.255.25463.199.255.25565,534
20163.200.0.0/1663.200.0.1 to 63.200.255.25463.200.255.25565,534
20263.201.0.0/1663.201.0.1 to 63.201.255.25463.201.255.25565,534
20363.202.0.0/1663.202.0.1 to 63.202.255.25463.202.255.25565,534
20463.203.0.0/1663.203.0.1 to 63.203.255.25463.203.255.25565,534
20563.204.0.0/1663.204.0.1 to 63.204.255.25463.204.255.25565,534
20663.205.0.0/1663.205.0.1 to 63.205.255.25463.205.255.25565,534
20763.206.0.0/1663.206.0.1 to 63.206.255.25463.206.255.25565,534
20863.207.0.0/1663.207.0.1 to 63.207.255.25463.207.255.25565,534
20963.208.0.0/1663.208.0.1 to 63.208.255.25463.208.255.25565,534
21063.209.0.0/1663.209.0.1 to 63.209.255.25463.209.255.25565,534
21163.210.0.0/1663.210.0.1 to 63.210.255.25463.210.255.25565,534
21263.211.0.0/1663.211.0.1 to 63.211.255.25463.211.255.25565,534
21363.212.0.0/1663.212.0.1 to 63.212.255.25463.212.255.25565,534
21463.213.0.0/1663.213.0.1 to 63.213.255.25463.213.255.25565,534
21563.214.0.0/1663.214.0.1 to 63.214.255.25463.214.255.25565,534
21663.215.0.0/1663.215.0.1 to 63.215.255.25463.215.255.25565,534
21763.216.0.0/1663.216.0.1 to 63.216.255.25463.216.255.25565,534
21863.217.0.0/1663.217.0.1 to 63.217.255.25463.217.255.25565,534
21963.218.0.0/1663.218.0.1 to 63.218.255.25463.218.255.25565,534
22063.219.0.0/1663.219.0.1 to 63.219.255.25463.219.255.25565,534
22163.220.0.0/1663.220.0.1 to 63.220.255.25463.220.255.25565,534
22263.221.0.0/1663.221.0.1 to 63.221.255.25463.221.255.25565,534
22363.222.0.0/1663.222.0.1 to 63.222.255.25463.222.255.25565,534
22463.223.0.0/1663.223.0.1 to 63.223.255.25463.223.255.25565,534
22563.224.0.0/1663.224.0.1 to 63.224.255.25463.224.255.25565,534
22663.225.0.0/1663.225.0.1 to 63.225.255.25463.225.255.25565,534
22763.226.0.0/1663.226.0.1 to 63.226.255.25463.226.255.25565,534
22863.227.0.0/1663.227.0.1 to 63.227.255.25463.227.255.25565,534
22963.228.0.0/1663.228.0.1 to 63.228.255.25463.228.255.25565,534
23063.229.0.0/1663.229.0.1 to 63.229.255.25463.229.255.25565,534
23163.230.0.0/1663.230.0.1 to 63.230.255.25463.230.255.25565,534
23263.231.0.0/1663.231.0.1 to 63.231.255.25463.231.255.25565,534
23363.232.0.0/1663.232.0.1 to 63.232.255.25463.232.255.25565,534
23463.233.0.0/1663.233.0.1 to 63.233.255.25463.233.255.25565,534
23563.234.0.0/1663.234.0.1 to 63.234.255.25463.234.255.25565,534
23663.235.0.0/1663.235.0.1 to 63.235.255.25463.235.255.25565,534
23763.236.0.0/1663.236.0.1 to 63.236.255.25463.236.255.25565,534
23863.237.0.0/1663.237.0.1 to 63.237.255.25463.237.255.25565,534
23963.238.0.0/1663.238.0.1 to 63.238.255.25463.238.255.25565,534
24063.239.0.0/1663.239.0.1 to 63.239.255.25463.239.255.25565,534
24163.240.0.0/1663.240.0.1 to 63.240.255.25463.240.255.25565,534
24263.241.0.0/1663.241.0.1 to 63.241.255.25463.241.255.25565,534
24363.242.0.0/1663.242.0.1 to 63.242.255.25463.242.255.25565,534
24463.243.0.0/1663.243.0.1 to 63.243.255.25463.243.255.25565,534
24563.244.0.0/1663.244.0.1 to 63.244.255.25463.244.255.25565,534
24663.245.0.0/1663.245.0.1 to 63.245.255.25463.245.255.25565,534
24763.246.0.0/1663.246.0.1 to 63.246.255.25463.246.255.25565,534
24863.247.0.0/1663.247.0.1 to 63.247.255.25463.247.255.25565,534
24963.248.0.0/1663.248.0.1 to 63.248.255.25463.248.255.25565,534
25063.249.0.0/1663.249.0.1 to 63.249.255.25463.249.255.25565,534
25163.250.0.0/1663.250.0.1 to 63.250.255.25463.250.255.25565,534
25263.251.0.0/1663.251.0.1 to 63.251.255.25463.251.255.25565,534
25363.252.0.0/1663.252.0.1 to 63.252.255.25463.252.255.25565,534
25463.253.0.0/1663.253.0.1 to 63.253.255.25463.253.255.25565,534
25563.254.0.0/1663.254.0.1 to 63.254.255.25463.254.255.25565,534
25663.255.0.0/1663.255.0.1 to 63.255.255.25463.255.255.25565,534

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.