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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.

Network43.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
43.0.0.0
Broadcast address
43.255.255.255
First usable
43.0.0.1
Last usable
43.255.255.254
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 2B000000 · Integer 721420288 to 738197503
Reverse DNS zone
43.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101011..00000000.00000000.0000000043.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00101011..00000000.00000000.0000000043.0.0.0
Broadcast00101011..11111111.11111111.1111111143.255.255.255
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)

43.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
143.0.0.0/1643.0.0.1 to 43.0.255.25443.0.255.25565,534
243.1.0.0/1643.1.0.1 to 43.1.255.25443.1.255.25565,534
343.2.0.0/1643.2.0.1 to 43.2.255.25443.2.255.25565,534
443.3.0.0/1643.3.0.1 to 43.3.255.25443.3.255.25565,534
543.4.0.0/1643.4.0.1 to 43.4.255.25443.4.255.25565,534
643.5.0.0/1643.5.0.1 to 43.5.255.25443.5.255.25565,534
743.6.0.0/1643.6.0.1 to 43.6.255.25443.6.255.25565,534
843.7.0.0/1643.7.0.1 to 43.7.255.25443.7.255.25565,534
943.8.0.0/1643.8.0.1 to 43.8.255.25443.8.255.25565,534
1043.9.0.0/1643.9.0.1 to 43.9.255.25443.9.255.25565,534
1143.10.0.0/1643.10.0.1 to 43.10.255.25443.10.255.25565,534
1243.11.0.0/1643.11.0.1 to 43.11.255.25443.11.255.25565,534
1343.12.0.0/1643.12.0.1 to 43.12.255.25443.12.255.25565,534
1443.13.0.0/1643.13.0.1 to 43.13.255.25443.13.255.25565,534
1543.14.0.0/1643.14.0.1 to 43.14.255.25443.14.255.25565,534
1643.15.0.0/1643.15.0.1 to 43.15.255.25443.15.255.25565,534
1743.16.0.0/1643.16.0.1 to 43.16.255.25443.16.255.25565,534
1843.17.0.0/1643.17.0.1 to 43.17.255.25443.17.255.25565,534
1943.18.0.0/1643.18.0.1 to 43.18.255.25443.18.255.25565,534
2043.19.0.0/1643.19.0.1 to 43.19.255.25443.19.255.25565,534
2143.20.0.0/1643.20.0.1 to 43.20.255.25443.20.255.25565,534
2243.21.0.0/1643.21.0.1 to 43.21.255.25443.21.255.25565,534
2343.22.0.0/1643.22.0.1 to 43.22.255.25443.22.255.25565,534
2443.23.0.0/1643.23.0.1 to 43.23.255.25443.23.255.25565,534
2543.24.0.0/1643.24.0.1 to 43.24.255.25443.24.255.25565,534
2643.25.0.0/1643.25.0.1 to 43.25.255.25443.25.255.25565,534
2743.26.0.0/1643.26.0.1 to 43.26.255.25443.26.255.25565,534
2843.27.0.0/1643.27.0.1 to 43.27.255.25443.27.255.25565,534
2943.28.0.0/1643.28.0.1 to 43.28.255.25443.28.255.25565,534
3043.29.0.0/1643.29.0.1 to 43.29.255.25443.29.255.25565,534
3143.30.0.0/1643.30.0.1 to 43.30.255.25443.30.255.25565,534
3243.31.0.0/1643.31.0.1 to 43.31.255.25443.31.255.25565,534
3343.32.0.0/1643.32.0.1 to 43.32.255.25443.32.255.25565,534
3443.33.0.0/1643.33.0.1 to 43.33.255.25443.33.255.25565,534
3543.34.0.0/1643.34.0.1 to 43.34.255.25443.34.255.25565,534
3643.35.0.0/1643.35.0.1 to 43.35.255.25443.35.255.25565,534
3743.36.0.0/1643.36.0.1 to 43.36.255.25443.36.255.25565,534
3843.37.0.0/1643.37.0.1 to 43.37.255.25443.37.255.25565,534
3943.38.0.0/1643.38.0.1 to 43.38.255.25443.38.255.25565,534
4043.39.0.0/1643.39.0.1 to 43.39.255.25443.39.255.25565,534
4143.40.0.0/1643.40.0.1 to 43.40.255.25443.40.255.25565,534
4243.41.0.0/1643.41.0.1 to 43.41.255.25443.41.255.25565,534
4343.42.0.0/1643.42.0.1 to 43.42.255.25443.42.255.25565,534
4443.43.0.0/1643.43.0.1 to 43.43.255.25443.43.255.25565,534
4543.44.0.0/1643.44.0.1 to 43.44.255.25443.44.255.25565,534
4643.45.0.0/1643.45.0.1 to 43.45.255.25443.45.255.25565,534
4743.46.0.0/1643.46.0.1 to 43.46.255.25443.46.255.25565,534
4843.47.0.0/1643.47.0.1 to 43.47.255.25443.47.255.25565,534
4943.48.0.0/1643.48.0.1 to 43.48.255.25443.48.255.25565,534
5043.49.0.0/1643.49.0.1 to 43.49.255.25443.49.255.25565,534
5143.50.0.0/1643.50.0.1 to 43.50.255.25443.50.255.25565,534
5243.51.0.0/1643.51.0.1 to 43.51.255.25443.51.255.25565,534
5343.52.0.0/1643.52.0.1 to 43.52.255.25443.52.255.25565,534
5443.53.0.0/1643.53.0.1 to 43.53.255.25443.53.255.25565,534
5543.54.0.0/1643.54.0.1 to 43.54.255.25443.54.255.25565,534
5643.55.0.0/1643.55.0.1 to 43.55.255.25443.55.255.25565,534
5743.56.0.0/1643.56.0.1 to 43.56.255.25443.56.255.25565,534
5843.57.0.0/1643.57.0.1 to 43.57.255.25443.57.255.25565,534
5943.58.0.0/1643.58.0.1 to 43.58.255.25443.58.255.25565,534
6043.59.0.0/1643.59.0.1 to 43.59.255.25443.59.255.25565,534
6143.60.0.0/1643.60.0.1 to 43.60.255.25443.60.255.25565,534
6243.61.0.0/1643.61.0.1 to 43.61.255.25443.61.255.25565,534
6343.62.0.0/1643.62.0.1 to 43.62.255.25443.62.255.25565,534
6443.63.0.0/1643.63.0.1 to 43.63.255.25443.63.255.25565,534
6543.64.0.0/1643.64.0.1 to 43.64.255.25443.64.255.25565,534
6643.65.0.0/1643.65.0.1 to 43.65.255.25443.65.255.25565,534
6743.66.0.0/1643.66.0.1 to 43.66.255.25443.66.255.25565,534
6843.67.0.0/1643.67.0.1 to 43.67.255.25443.67.255.25565,534
6943.68.0.0/1643.68.0.1 to 43.68.255.25443.68.255.25565,534
7043.69.0.0/1643.69.0.1 to 43.69.255.25443.69.255.25565,534
7143.70.0.0/1643.70.0.1 to 43.70.255.25443.70.255.25565,534
7243.71.0.0/1643.71.0.1 to 43.71.255.25443.71.255.25565,534
7343.72.0.0/1643.72.0.1 to 43.72.255.25443.72.255.25565,534
7443.73.0.0/1643.73.0.1 to 43.73.255.25443.73.255.25565,534
7543.74.0.0/1643.74.0.1 to 43.74.255.25443.74.255.25565,534
7643.75.0.0/1643.75.0.1 to 43.75.255.25443.75.255.25565,534
7743.76.0.0/1643.76.0.1 to 43.76.255.25443.76.255.25565,534
7843.77.0.0/1643.77.0.1 to 43.77.255.25443.77.255.25565,534
7943.78.0.0/1643.78.0.1 to 43.78.255.25443.78.255.25565,534
8043.79.0.0/1643.79.0.1 to 43.79.255.25443.79.255.25565,534
8143.80.0.0/1643.80.0.1 to 43.80.255.25443.80.255.25565,534
8243.81.0.0/1643.81.0.1 to 43.81.255.25443.81.255.25565,534
8343.82.0.0/1643.82.0.1 to 43.82.255.25443.82.255.25565,534
8443.83.0.0/1643.83.0.1 to 43.83.255.25443.83.255.25565,534
8543.84.0.0/1643.84.0.1 to 43.84.255.25443.84.255.25565,534
8643.85.0.0/1643.85.0.1 to 43.85.255.25443.85.255.25565,534
8743.86.0.0/1643.86.0.1 to 43.86.255.25443.86.255.25565,534
8843.87.0.0/1643.87.0.1 to 43.87.255.25443.87.255.25565,534
8943.88.0.0/1643.88.0.1 to 43.88.255.25443.88.255.25565,534
9043.89.0.0/1643.89.0.1 to 43.89.255.25443.89.255.25565,534
9143.90.0.0/1643.90.0.1 to 43.90.255.25443.90.255.25565,534
9243.91.0.0/1643.91.0.1 to 43.91.255.25443.91.255.25565,534
9343.92.0.0/1643.92.0.1 to 43.92.255.25443.92.255.25565,534
9443.93.0.0/1643.93.0.1 to 43.93.255.25443.93.255.25565,534
9543.94.0.0/1643.94.0.1 to 43.94.255.25443.94.255.25565,534
9643.95.0.0/1643.95.0.1 to 43.95.255.25443.95.255.25565,534
9743.96.0.0/1643.96.0.1 to 43.96.255.25443.96.255.25565,534
9843.97.0.0/1643.97.0.1 to 43.97.255.25443.97.255.25565,534
9943.98.0.0/1643.98.0.1 to 43.98.255.25443.98.255.25565,534
10043.99.0.0/1643.99.0.1 to 43.99.255.25443.99.255.25565,534
10143.100.0.0/1643.100.0.1 to 43.100.255.25443.100.255.25565,534
10243.101.0.0/1643.101.0.1 to 43.101.255.25443.101.255.25565,534
10343.102.0.0/1643.102.0.1 to 43.102.255.25443.102.255.25565,534
10443.103.0.0/1643.103.0.1 to 43.103.255.25443.103.255.25565,534
10543.104.0.0/1643.104.0.1 to 43.104.255.25443.104.255.25565,534
10643.105.0.0/1643.105.0.1 to 43.105.255.25443.105.255.25565,534
10743.106.0.0/1643.106.0.1 to 43.106.255.25443.106.255.25565,534
10843.107.0.0/1643.107.0.1 to 43.107.255.25443.107.255.25565,534
10943.108.0.0/1643.108.0.1 to 43.108.255.25443.108.255.25565,534
11043.109.0.0/1643.109.0.1 to 43.109.255.25443.109.255.25565,534
11143.110.0.0/1643.110.0.1 to 43.110.255.25443.110.255.25565,534
11243.111.0.0/1643.111.0.1 to 43.111.255.25443.111.255.25565,534
11343.112.0.0/1643.112.0.1 to 43.112.255.25443.112.255.25565,534
11443.113.0.0/1643.113.0.1 to 43.113.255.25443.113.255.25565,534
11543.114.0.0/1643.114.0.1 to 43.114.255.25443.114.255.25565,534
11643.115.0.0/1643.115.0.1 to 43.115.255.25443.115.255.25565,534
11743.116.0.0/1643.116.0.1 to 43.116.255.25443.116.255.25565,534
11843.117.0.0/1643.117.0.1 to 43.117.255.25443.117.255.25565,534
11943.118.0.0/1643.118.0.1 to 43.118.255.25443.118.255.25565,534
12043.119.0.0/1643.119.0.1 to 43.119.255.25443.119.255.25565,534
12143.120.0.0/1643.120.0.1 to 43.120.255.25443.120.255.25565,534
12243.121.0.0/1643.121.0.1 to 43.121.255.25443.121.255.25565,534
12343.122.0.0/1643.122.0.1 to 43.122.255.25443.122.255.25565,534
12443.123.0.0/1643.123.0.1 to 43.123.255.25443.123.255.25565,534
12543.124.0.0/1643.124.0.1 to 43.124.255.25443.124.255.25565,534
12643.125.0.0/1643.125.0.1 to 43.125.255.25443.125.255.25565,534
12743.126.0.0/1643.126.0.1 to 43.126.255.25443.126.255.25565,534
12843.127.0.0/1643.127.0.1 to 43.127.255.25443.127.255.25565,534
12943.128.0.0/1643.128.0.1 to 43.128.255.25443.128.255.25565,534
13043.129.0.0/1643.129.0.1 to 43.129.255.25443.129.255.25565,534
13143.130.0.0/1643.130.0.1 to 43.130.255.25443.130.255.25565,534
13243.131.0.0/1643.131.0.1 to 43.131.255.25443.131.255.25565,534
13343.132.0.0/1643.132.0.1 to 43.132.255.25443.132.255.25565,534
13443.133.0.0/1643.133.0.1 to 43.133.255.25443.133.255.25565,534
13543.134.0.0/1643.134.0.1 to 43.134.255.25443.134.255.25565,534
13643.135.0.0/1643.135.0.1 to 43.135.255.25443.135.255.25565,534
13743.136.0.0/1643.136.0.1 to 43.136.255.25443.136.255.25565,534
13843.137.0.0/1643.137.0.1 to 43.137.255.25443.137.255.25565,534
13943.138.0.0/1643.138.0.1 to 43.138.255.25443.138.255.25565,534
14043.139.0.0/1643.139.0.1 to 43.139.255.25443.139.255.25565,534
14143.140.0.0/1643.140.0.1 to 43.140.255.25443.140.255.25565,534
14243.141.0.0/1643.141.0.1 to 43.141.255.25443.141.255.25565,534
14343.142.0.0/1643.142.0.1 to 43.142.255.25443.142.255.25565,534
14443.143.0.0/1643.143.0.1 to 43.143.255.25443.143.255.25565,534
14543.144.0.0/1643.144.0.1 to 43.144.255.25443.144.255.25565,534
14643.145.0.0/1643.145.0.1 to 43.145.255.25443.145.255.25565,534
14743.146.0.0/1643.146.0.1 to 43.146.255.25443.146.255.25565,534
14843.147.0.0/1643.147.0.1 to 43.147.255.25443.147.255.25565,534
14943.148.0.0/1643.148.0.1 to 43.148.255.25443.148.255.25565,534
15043.149.0.0/1643.149.0.1 to 43.149.255.25443.149.255.25565,534
15143.150.0.0/1643.150.0.1 to 43.150.255.25443.150.255.25565,534
15243.151.0.0/1643.151.0.1 to 43.151.255.25443.151.255.25565,534
15343.152.0.0/1643.152.0.1 to 43.152.255.25443.152.255.25565,534
15443.153.0.0/1643.153.0.1 to 43.153.255.25443.153.255.25565,534
15543.154.0.0/1643.154.0.1 to 43.154.255.25443.154.255.25565,534
15643.155.0.0/1643.155.0.1 to 43.155.255.25443.155.255.25565,534
15743.156.0.0/1643.156.0.1 to 43.156.255.25443.156.255.25565,534
15843.157.0.0/1643.157.0.1 to 43.157.255.25443.157.255.25565,534
15943.158.0.0/1643.158.0.1 to 43.158.255.25443.158.255.25565,534
16043.159.0.0/1643.159.0.1 to 43.159.255.25443.159.255.25565,534
16143.160.0.0/1643.160.0.1 to 43.160.255.25443.160.255.25565,534
16243.161.0.0/1643.161.0.1 to 43.161.255.25443.161.255.25565,534
16343.162.0.0/1643.162.0.1 to 43.162.255.25443.162.255.25565,534
16443.163.0.0/1643.163.0.1 to 43.163.255.25443.163.255.25565,534
16543.164.0.0/1643.164.0.1 to 43.164.255.25443.164.255.25565,534
16643.165.0.0/1643.165.0.1 to 43.165.255.25443.165.255.25565,534
16743.166.0.0/1643.166.0.1 to 43.166.255.25443.166.255.25565,534
16843.167.0.0/1643.167.0.1 to 43.167.255.25443.167.255.25565,534
16943.168.0.0/1643.168.0.1 to 43.168.255.25443.168.255.25565,534
17043.169.0.0/1643.169.0.1 to 43.169.255.25443.169.255.25565,534
17143.170.0.0/1643.170.0.1 to 43.170.255.25443.170.255.25565,534
17243.171.0.0/1643.171.0.1 to 43.171.255.25443.171.255.25565,534
17343.172.0.0/1643.172.0.1 to 43.172.255.25443.172.255.25565,534
17443.173.0.0/1643.173.0.1 to 43.173.255.25443.173.255.25565,534
17543.174.0.0/1643.174.0.1 to 43.174.255.25443.174.255.25565,534
17643.175.0.0/1643.175.0.1 to 43.175.255.25443.175.255.25565,534
17743.176.0.0/1643.176.0.1 to 43.176.255.25443.176.255.25565,534
17843.177.0.0/1643.177.0.1 to 43.177.255.25443.177.255.25565,534
17943.178.0.0/1643.178.0.1 to 43.178.255.25443.178.255.25565,534
18043.179.0.0/1643.179.0.1 to 43.179.255.25443.179.255.25565,534
18143.180.0.0/1643.180.0.1 to 43.180.255.25443.180.255.25565,534
18243.181.0.0/1643.181.0.1 to 43.181.255.25443.181.255.25565,534
18343.182.0.0/1643.182.0.1 to 43.182.255.25443.182.255.25565,534
18443.183.0.0/1643.183.0.1 to 43.183.255.25443.183.255.25565,534
18543.184.0.0/1643.184.0.1 to 43.184.255.25443.184.255.25565,534
18643.185.0.0/1643.185.0.1 to 43.185.255.25443.185.255.25565,534
18743.186.0.0/1643.186.0.1 to 43.186.255.25443.186.255.25565,534
18843.187.0.0/1643.187.0.1 to 43.187.255.25443.187.255.25565,534
18943.188.0.0/1643.188.0.1 to 43.188.255.25443.188.255.25565,534
19043.189.0.0/1643.189.0.1 to 43.189.255.25443.189.255.25565,534
19143.190.0.0/1643.190.0.1 to 43.190.255.25443.190.255.25565,534
19243.191.0.0/1643.191.0.1 to 43.191.255.25443.191.255.25565,534
19343.192.0.0/1643.192.0.1 to 43.192.255.25443.192.255.25565,534
19443.193.0.0/1643.193.0.1 to 43.193.255.25443.193.255.25565,534
19543.194.0.0/1643.194.0.1 to 43.194.255.25443.194.255.25565,534
19643.195.0.0/1643.195.0.1 to 43.195.255.25443.195.255.25565,534
19743.196.0.0/1643.196.0.1 to 43.196.255.25443.196.255.25565,534
19843.197.0.0/1643.197.0.1 to 43.197.255.25443.197.255.25565,534
19943.198.0.0/1643.198.0.1 to 43.198.255.25443.198.255.25565,534
20043.199.0.0/1643.199.0.1 to 43.199.255.25443.199.255.25565,534
20143.200.0.0/1643.200.0.1 to 43.200.255.25443.200.255.25565,534
20243.201.0.0/1643.201.0.1 to 43.201.255.25443.201.255.25565,534
20343.202.0.0/1643.202.0.1 to 43.202.255.25443.202.255.25565,534
20443.203.0.0/1643.203.0.1 to 43.203.255.25443.203.255.25565,534
20543.204.0.0/1643.204.0.1 to 43.204.255.25443.204.255.25565,534
20643.205.0.0/1643.205.0.1 to 43.205.255.25443.205.255.25565,534
20743.206.0.0/1643.206.0.1 to 43.206.255.25443.206.255.25565,534
20843.207.0.0/1643.207.0.1 to 43.207.255.25443.207.255.25565,534
20943.208.0.0/1643.208.0.1 to 43.208.255.25443.208.255.25565,534
21043.209.0.0/1643.209.0.1 to 43.209.255.25443.209.255.25565,534
21143.210.0.0/1643.210.0.1 to 43.210.255.25443.210.255.25565,534
21243.211.0.0/1643.211.0.1 to 43.211.255.25443.211.255.25565,534
21343.212.0.0/1643.212.0.1 to 43.212.255.25443.212.255.25565,534
21443.213.0.0/1643.213.0.1 to 43.213.255.25443.213.255.25565,534
21543.214.0.0/1643.214.0.1 to 43.214.255.25443.214.255.25565,534
21643.215.0.0/1643.215.0.1 to 43.215.255.25443.215.255.25565,534
21743.216.0.0/1643.216.0.1 to 43.216.255.25443.216.255.25565,534
21843.217.0.0/1643.217.0.1 to 43.217.255.25443.217.255.25565,534
21943.218.0.0/1643.218.0.1 to 43.218.255.25443.218.255.25565,534
22043.219.0.0/1643.219.0.1 to 43.219.255.25443.219.255.25565,534
22143.220.0.0/1643.220.0.1 to 43.220.255.25443.220.255.25565,534
22243.221.0.0/1643.221.0.1 to 43.221.255.25443.221.255.25565,534
22343.222.0.0/1643.222.0.1 to 43.222.255.25443.222.255.25565,534
22443.223.0.0/1643.223.0.1 to 43.223.255.25443.223.255.25565,534
22543.224.0.0/1643.224.0.1 to 43.224.255.25443.224.255.25565,534
22643.225.0.0/1643.225.0.1 to 43.225.255.25443.225.255.25565,534
22743.226.0.0/1643.226.0.1 to 43.226.255.25443.226.255.25565,534
22843.227.0.0/1643.227.0.1 to 43.227.255.25443.227.255.25565,534
22943.228.0.0/1643.228.0.1 to 43.228.255.25443.228.255.25565,534
23043.229.0.0/1643.229.0.1 to 43.229.255.25443.229.255.25565,534
23143.230.0.0/1643.230.0.1 to 43.230.255.25443.230.255.25565,534
23243.231.0.0/1643.231.0.1 to 43.231.255.25443.231.255.25565,534
23343.232.0.0/1643.232.0.1 to 43.232.255.25443.232.255.25565,534
23443.233.0.0/1643.233.0.1 to 43.233.255.25443.233.255.25565,534
23543.234.0.0/1643.234.0.1 to 43.234.255.25443.234.255.25565,534
23643.235.0.0/1643.235.0.1 to 43.235.255.25443.235.255.25565,534
23743.236.0.0/1643.236.0.1 to 43.236.255.25443.236.255.25565,534
23843.237.0.0/1643.237.0.1 to 43.237.255.25443.237.255.25565,534
23943.238.0.0/1643.238.0.1 to 43.238.255.25443.238.255.25565,534
24043.239.0.0/1643.239.0.1 to 43.239.255.25443.239.255.25565,534
24143.240.0.0/1643.240.0.1 to 43.240.255.25443.240.255.25565,534
24243.241.0.0/1643.241.0.1 to 43.241.255.25443.241.255.25565,534
24343.242.0.0/1643.242.0.1 to 43.242.255.25443.242.255.25565,534
24443.243.0.0/1643.243.0.1 to 43.243.255.25443.243.255.25565,534
24543.244.0.0/1643.244.0.1 to 43.244.255.25443.244.255.25565,534
24643.245.0.0/1643.245.0.1 to 43.245.255.25443.245.255.25565,534
24743.246.0.0/1643.246.0.1 to 43.246.255.25443.246.255.25565,534
24843.247.0.0/1643.247.0.1 to 43.247.255.25443.247.255.25565,534
24943.248.0.0/1643.248.0.1 to 43.248.255.25443.248.255.25565,534
25043.249.0.0/1643.249.0.1 to 43.249.255.25443.249.255.25565,534
25143.250.0.0/1643.250.0.1 to 43.250.255.25443.250.255.25565,534
25243.251.0.0/1643.251.0.1 to 43.251.255.25443.251.255.25565,534
25343.252.0.0/1643.252.0.1 to 43.252.255.25443.252.255.25565,534
25443.253.0.0/1643.253.0.1 to 43.253.255.25443.253.255.25565,534
25543.254.0.0/1643.254.0.1 to 43.254.255.25443.254.255.25565,534
25643.255.0.0/1643.255.0.1 to 43.255.255.25443.255.255.25565,534

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.