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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.

Network28.210.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
28.210.0.0
Broadcast address
28.211.255.255
First usable
28.210.0.1
Last usable
28.211.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 1CD20000 · Integer 483524608 to 483655679
Reverse DNS zones
210.28.in-addr.arpa
211.28.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011100.11010010.00000000.0000000028.210.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00011100.11010010.00000000.0000000028.210.0.0
Broadcast00011100.11010011.11111111.1111111128.211.255.255
Split into smaller subnets/23
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

28.210.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.210.0.0/2328.210.0.1 to 28.210.1.25428.210.1.255510
228.210.2.0/2328.210.2.1 to 28.210.3.25428.210.3.255510
328.210.4.0/2328.210.4.1 to 28.210.5.25428.210.5.255510
428.210.6.0/2328.210.6.1 to 28.210.7.25428.210.7.255510
528.210.8.0/2328.210.8.1 to 28.210.9.25428.210.9.255510
628.210.10.0/2328.210.10.1 to 28.210.11.25428.210.11.255510
728.210.12.0/2328.210.12.1 to 28.210.13.25428.210.13.255510
828.210.14.0/2328.210.14.1 to 28.210.15.25428.210.15.255510
928.210.16.0/2328.210.16.1 to 28.210.17.25428.210.17.255510
1028.210.18.0/2328.210.18.1 to 28.210.19.25428.210.19.255510
1128.210.20.0/2328.210.20.1 to 28.210.21.25428.210.21.255510
1228.210.22.0/2328.210.22.1 to 28.210.23.25428.210.23.255510
1328.210.24.0/2328.210.24.1 to 28.210.25.25428.210.25.255510
1428.210.26.0/2328.210.26.1 to 28.210.27.25428.210.27.255510
1528.210.28.0/2328.210.28.1 to 28.210.29.25428.210.29.255510
1628.210.30.0/2328.210.30.1 to 28.210.31.25428.210.31.255510
1728.210.32.0/2328.210.32.1 to 28.210.33.25428.210.33.255510
1828.210.34.0/2328.210.34.1 to 28.210.35.25428.210.35.255510
1928.210.36.0/2328.210.36.1 to 28.210.37.25428.210.37.255510
2028.210.38.0/2328.210.38.1 to 28.210.39.25428.210.39.255510
2128.210.40.0/2328.210.40.1 to 28.210.41.25428.210.41.255510
2228.210.42.0/2328.210.42.1 to 28.210.43.25428.210.43.255510
2328.210.44.0/2328.210.44.1 to 28.210.45.25428.210.45.255510
2428.210.46.0/2328.210.46.1 to 28.210.47.25428.210.47.255510
2528.210.48.0/2328.210.48.1 to 28.210.49.25428.210.49.255510
2628.210.50.0/2328.210.50.1 to 28.210.51.25428.210.51.255510
2728.210.52.0/2328.210.52.1 to 28.210.53.25428.210.53.255510
2828.210.54.0/2328.210.54.1 to 28.210.55.25428.210.55.255510
2928.210.56.0/2328.210.56.1 to 28.210.57.25428.210.57.255510
3028.210.58.0/2328.210.58.1 to 28.210.59.25428.210.59.255510
3128.210.60.0/2328.210.60.1 to 28.210.61.25428.210.61.255510
3228.210.62.0/2328.210.62.1 to 28.210.63.25428.210.63.255510
3328.210.64.0/2328.210.64.1 to 28.210.65.25428.210.65.255510
3428.210.66.0/2328.210.66.1 to 28.210.67.25428.210.67.255510
3528.210.68.0/2328.210.68.1 to 28.210.69.25428.210.69.255510
3628.210.70.0/2328.210.70.1 to 28.210.71.25428.210.71.255510
3728.210.72.0/2328.210.72.1 to 28.210.73.25428.210.73.255510
3828.210.74.0/2328.210.74.1 to 28.210.75.25428.210.75.255510
3928.210.76.0/2328.210.76.1 to 28.210.77.25428.210.77.255510
4028.210.78.0/2328.210.78.1 to 28.210.79.25428.210.79.255510
4128.210.80.0/2328.210.80.1 to 28.210.81.25428.210.81.255510
4228.210.82.0/2328.210.82.1 to 28.210.83.25428.210.83.255510
4328.210.84.0/2328.210.84.1 to 28.210.85.25428.210.85.255510
4428.210.86.0/2328.210.86.1 to 28.210.87.25428.210.87.255510
4528.210.88.0/2328.210.88.1 to 28.210.89.25428.210.89.255510
4628.210.90.0/2328.210.90.1 to 28.210.91.25428.210.91.255510
4728.210.92.0/2328.210.92.1 to 28.210.93.25428.210.93.255510
4828.210.94.0/2328.210.94.1 to 28.210.95.25428.210.95.255510
4928.210.96.0/2328.210.96.1 to 28.210.97.25428.210.97.255510
5028.210.98.0/2328.210.98.1 to 28.210.99.25428.210.99.255510
5128.210.100.0/2328.210.100.1 to 28.210.101.25428.210.101.255510
5228.210.102.0/2328.210.102.1 to 28.210.103.25428.210.103.255510
5328.210.104.0/2328.210.104.1 to 28.210.105.25428.210.105.255510
5428.210.106.0/2328.210.106.1 to 28.210.107.25428.210.107.255510
5528.210.108.0/2328.210.108.1 to 28.210.109.25428.210.109.255510
5628.210.110.0/2328.210.110.1 to 28.210.111.25428.210.111.255510
5728.210.112.0/2328.210.112.1 to 28.210.113.25428.210.113.255510
5828.210.114.0/2328.210.114.1 to 28.210.115.25428.210.115.255510
5928.210.116.0/2328.210.116.1 to 28.210.117.25428.210.117.255510
6028.210.118.0/2328.210.118.1 to 28.210.119.25428.210.119.255510
6128.210.120.0/2328.210.120.1 to 28.210.121.25428.210.121.255510
6228.210.122.0/2328.210.122.1 to 28.210.123.25428.210.123.255510
6328.210.124.0/2328.210.124.1 to 28.210.125.25428.210.125.255510
6428.210.126.0/2328.210.126.1 to 28.210.127.25428.210.127.255510
6528.210.128.0/2328.210.128.1 to 28.210.129.25428.210.129.255510
6628.210.130.0/2328.210.130.1 to 28.210.131.25428.210.131.255510
6728.210.132.0/2328.210.132.1 to 28.210.133.25428.210.133.255510
6828.210.134.0/2328.210.134.1 to 28.210.135.25428.210.135.255510
6928.210.136.0/2328.210.136.1 to 28.210.137.25428.210.137.255510
7028.210.138.0/2328.210.138.1 to 28.210.139.25428.210.139.255510
7128.210.140.0/2328.210.140.1 to 28.210.141.25428.210.141.255510
7228.210.142.0/2328.210.142.1 to 28.210.143.25428.210.143.255510
7328.210.144.0/2328.210.144.1 to 28.210.145.25428.210.145.255510
7428.210.146.0/2328.210.146.1 to 28.210.147.25428.210.147.255510
7528.210.148.0/2328.210.148.1 to 28.210.149.25428.210.149.255510
7628.210.150.0/2328.210.150.1 to 28.210.151.25428.210.151.255510
7728.210.152.0/2328.210.152.1 to 28.210.153.25428.210.153.255510
7828.210.154.0/2328.210.154.1 to 28.210.155.25428.210.155.255510
7928.210.156.0/2328.210.156.1 to 28.210.157.25428.210.157.255510
8028.210.158.0/2328.210.158.1 to 28.210.159.25428.210.159.255510
8128.210.160.0/2328.210.160.1 to 28.210.161.25428.210.161.255510
8228.210.162.0/2328.210.162.1 to 28.210.163.25428.210.163.255510
8328.210.164.0/2328.210.164.1 to 28.210.165.25428.210.165.255510
8428.210.166.0/2328.210.166.1 to 28.210.167.25428.210.167.255510
8528.210.168.0/2328.210.168.1 to 28.210.169.25428.210.169.255510
8628.210.170.0/2328.210.170.1 to 28.210.171.25428.210.171.255510
8728.210.172.0/2328.210.172.1 to 28.210.173.25428.210.173.255510
8828.210.174.0/2328.210.174.1 to 28.210.175.25428.210.175.255510
8928.210.176.0/2328.210.176.1 to 28.210.177.25428.210.177.255510
9028.210.178.0/2328.210.178.1 to 28.210.179.25428.210.179.255510
9128.210.180.0/2328.210.180.1 to 28.210.181.25428.210.181.255510
9228.210.182.0/2328.210.182.1 to 28.210.183.25428.210.183.255510
9328.210.184.0/2328.210.184.1 to 28.210.185.25428.210.185.255510
9428.210.186.0/2328.210.186.1 to 28.210.187.25428.210.187.255510
9528.210.188.0/2328.210.188.1 to 28.210.189.25428.210.189.255510
9628.210.190.0/2328.210.190.1 to 28.210.191.25428.210.191.255510
9728.210.192.0/2328.210.192.1 to 28.210.193.25428.210.193.255510
9828.210.194.0/2328.210.194.1 to 28.210.195.25428.210.195.255510
9928.210.196.0/2328.210.196.1 to 28.210.197.25428.210.197.255510
10028.210.198.0/2328.210.198.1 to 28.210.199.25428.210.199.255510
10128.210.200.0/2328.210.200.1 to 28.210.201.25428.210.201.255510
10228.210.202.0/2328.210.202.1 to 28.210.203.25428.210.203.255510
10328.210.204.0/2328.210.204.1 to 28.210.205.25428.210.205.255510
10428.210.206.0/2328.210.206.1 to 28.210.207.25428.210.207.255510
10528.210.208.0/2328.210.208.1 to 28.210.209.25428.210.209.255510
10628.210.210.0/2328.210.210.1 to 28.210.211.25428.210.211.255510
10728.210.212.0/2328.210.212.1 to 28.210.213.25428.210.213.255510
10828.210.214.0/2328.210.214.1 to 28.210.215.25428.210.215.255510
10928.210.216.0/2328.210.216.1 to 28.210.217.25428.210.217.255510
11028.210.218.0/2328.210.218.1 to 28.210.219.25428.210.219.255510
11128.210.220.0/2328.210.220.1 to 28.210.221.25428.210.221.255510
11228.210.222.0/2328.210.222.1 to 28.210.223.25428.210.223.255510
11328.210.224.0/2328.210.224.1 to 28.210.225.25428.210.225.255510
11428.210.226.0/2328.210.226.1 to 28.210.227.25428.210.227.255510
11528.210.228.0/2328.210.228.1 to 28.210.229.25428.210.229.255510
11628.210.230.0/2328.210.230.1 to 28.210.231.25428.210.231.255510
11728.210.232.0/2328.210.232.1 to 28.210.233.25428.210.233.255510
11828.210.234.0/2328.210.234.1 to 28.210.235.25428.210.235.255510
11928.210.236.0/2328.210.236.1 to 28.210.237.25428.210.237.255510
12028.210.238.0/2328.210.238.1 to 28.210.239.25428.210.239.255510
12128.210.240.0/2328.210.240.1 to 28.210.241.25428.210.241.255510
12228.210.242.0/2328.210.242.1 to 28.210.243.25428.210.243.255510
12328.210.244.0/2328.210.244.1 to 28.210.245.25428.210.245.255510
12428.210.246.0/2328.210.246.1 to 28.210.247.25428.210.247.255510
12528.210.248.0/2328.210.248.1 to 28.210.249.25428.210.249.255510
12628.210.250.0/2328.210.250.1 to 28.210.251.25428.210.251.255510
12728.210.252.0/2328.210.252.1 to 28.210.253.25428.210.253.255510
12828.210.254.0/2328.210.254.1 to 28.210.255.25428.210.255.255510
12928.211.0.0/2328.211.0.1 to 28.211.1.25428.211.1.255510
13028.211.2.0/2328.211.2.1 to 28.211.3.25428.211.3.255510
13128.211.4.0/2328.211.4.1 to 28.211.5.25428.211.5.255510
13228.211.6.0/2328.211.6.1 to 28.211.7.25428.211.7.255510
13328.211.8.0/2328.211.8.1 to 28.211.9.25428.211.9.255510
13428.211.10.0/2328.211.10.1 to 28.211.11.25428.211.11.255510
13528.211.12.0/2328.211.12.1 to 28.211.13.25428.211.13.255510
13628.211.14.0/2328.211.14.1 to 28.211.15.25428.211.15.255510
13728.211.16.0/2328.211.16.1 to 28.211.17.25428.211.17.255510
13828.211.18.0/2328.211.18.1 to 28.211.19.25428.211.19.255510
13928.211.20.0/2328.211.20.1 to 28.211.21.25428.211.21.255510
14028.211.22.0/2328.211.22.1 to 28.211.23.25428.211.23.255510
14128.211.24.0/2328.211.24.1 to 28.211.25.25428.211.25.255510
14228.211.26.0/2328.211.26.1 to 28.211.27.25428.211.27.255510
14328.211.28.0/2328.211.28.1 to 28.211.29.25428.211.29.255510
14428.211.30.0/2328.211.30.1 to 28.211.31.25428.211.31.255510
14528.211.32.0/2328.211.32.1 to 28.211.33.25428.211.33.255510
14628.211.34.0/2328.211.34.1 to 28.211.35.25428.211.35.255510
14728.211.36.0/2328.211.36.1 to 28.211.37.25428.211.37.255510
14828.211.38.0/2328.211.38.1 to 28.211.39.25428.211.39.255510
14928.211.40.0/2328.211.40.1 to 28.211.41.25428.211.41.255510
15028.211.42.0/2328.211.42.1 to 28.211.43.25428.211.43.255510
15128.211.44.0/2328.211.44.1 to 28.211.45.25428.211.45.255510
15228.211.46.0/2328.211.46.1 to 28.211.47.25428.211.47.255510
15328.211.48.0/2328.211.48.1 to 28.211.49.25428.211.49.255510
15428.211.50.0/2328.211.50.1 to 28.211.51.25428.211.51.255510
15528.211.52.0/2328.211.52.1 to 28.211.53.25428.211.53.255510
15628.211.54.0/2328.211.54.1 to 28.211.55.25428.211.55.255510
15728.211.56.0/2328.211.56.1 to 28.211.57.25428.211.57.255510
15828.211.58.0/2328.211.58.1 to 28.211.59.25428.211.59.255510
15928.211.60.0/2328.211.60.1 to 28.211.61.25428.211.61.255510
16028.211.62.0/2328.211.62.1 to 28.211.63.25428.211.63.255510
16128.211.64.0/2328.211.64.1 to 28.211.65.25428.211.65.255510
16228.211.66.0/2328.211.66.1 to 28.211.67.25428.211.67.255510
16328.211.68.0/2328.211.68.1 to 28.211.69.25428.211.69.255510
16428.211.70.0/2328.211.70.1 to 28.211.71.25428.211.71.255510
16528.211.72.0/2328.211.72.1 to 28.211.73.25428.211.73.255510
16628.211.74.0/2328.211.74.1 to 28.211.75.25428.211.75.255510
16728.211.76.0/2328.211.76.1 to 28.211.77.25428.211.77.255510
16828.211.78.0/2328.211.78.1 to 28.211.79.25428.211.79.255510
16928.211.80.0/2328.211.80.1 to 28.211.81.25428.211.81.255510
17028.211.82.0/2328.211.82.1 to 28.211.83.25428.211.83.255510
17128.211.84.0/2328.211.84.1 to 28.211.85.25428.211.85.255510
17228.211.86.0/2328.211.86.1 to 28.211.87.25428.211.87.255510
17328.211.88.0/2328.211.88.1 to 28.211.89.25428.211.89.255510
17428.211.90.0/2328.211.90.1 to 28.211.91.25428.211.91.255510
17528.211.92.0/2328.211.92.1 to 28.211.93.25428.211.93.255510
17628.211.94.0/2328.211.94.1 to 28.211.95.25428.211.95.255510
17728.211.96.0/2328.211.96.1 to 28.211.97.25428.211.97.255510
17828.211.98.0/2328.211.98.1 to 28.211.99.25428.211.99.255510
17928.211.100.0/2328.211.100.1 to 28.211.101.25428.211.101.255510
18028.211.102.0/2328.211.102.1 to 28.211.103.25428.211.103.255510
18128.211.104.0/2328.211.104.1 to 28.211.105.25428.211.105.255510
18228.211.106.0/2328.211.106.1 to 28.211.107.25428.211.107.255510
18328.211.108.0/2328.211.108.1 to 28.211.109.25428.211.109.255510
18428.211.110.0/2328.211.110.1 to 28.211.111.25428.211.111.255510
18528.211.112.0/2328.211.112.1 to 28.211.113.25428.211.113.255510
18628.211.114.0/2328.211.114.1 to 28.211.115.25428.211.115.255510
18728.211.116.0/2328.211.116.1 to 28.211.117.25428.211.117.255510
18828.211.118.0/2328.211.118.1 to 28.211.119.25428.211.119.255510
18928.211.120.0/2328.211.120.1 to 28.211.121.25428.211.121.255510
19028.211.122.0/2328.211.122.1 to 28.211.123.25428.211.123.255510
19128.211.124.0/2328.211.124.1 to 28.211.125.25428.211.125.255510
19228.211.126.0/2328.211.126.1 to 28.211.127.25428.211.127.255510
19328.211.128.0/2328.211.128.1 to 28.211.129.25428.211.129.255510
19428.211.130.0/2328.211.130.1 to 28.211.131.25428.211.131.255510
19528.211.132.0/2328.211.132.1 to 28.211.133.25428.211.133.255510
19628.211.134.0/2328.211.134.1 to 28.211.135.25428.211.135.255510
19728.211.136.0/2328.211.136.1 to 28.211.137.25428.211.137.255510
19828.211.138.0/2328.211.138.1 to 28.211.139.25428.211.139.255510
19928.211.140.0/2328.211.140.1 to 28.211.141.25428.211.141.255510
20028.211.142.0/2328.211.142.1 to 28.211.143.25428.211.143.255510
20128.211.144.0/2328.211.144.1 to 28.211.145.25428.211.145.255510
20228.211.146.0/2328.211.146.1 to 28.211.147.25428.211.147.255510
20328.211.148.0/2328.211.148.1 to 28.211.149.25428.211.149.255510
20428.211.150.0/2328.211.150.1 to 28.211.151.25428.211.151.255510
20528.211.152.0/2328.211.152.1 to 28.211.153.25428.211.153.255510
20628.211.154.0/2328.211.154.1 to 28.211.155.25428.211.155.255510
20728.211.156.0/2328.211.156.1 to 28.211.157.25428.211.157.255510
20828.211.158.0/2328.211.158.1 to 28.211.159.25428.211.159.255510
20928.211.160.0/2328.211.160.1 to 28.211.161.25428.211.161.255510
21028.211.162.0/2328.211.162.1 to 28.211.163.25428.211.163.255510
21128.211.164.0/2328.211.164.1 to 28.211.165.25428.211.165.255510
21228.211.166.0/2328.211.166.1 to 28.211.167.25428.211.167.255510
21328.211.168.0/2328.211.168.1 to 28.211.169.25428.211.169.255510
21428.211.170.0/2328.211.170.1 to 28.211.171.25428.211.171.255510
21528.211.172.0/2328.211.172.1 to 28.211.173.25428.211.173.255510
21628.211.174.0/2328.211.174.1 to 28.211.175.25428.211.175.255510
21728.211.176.0/2328.211.176.1 to 28.211.177.25428.211.177.255510
21828.211.178.0/2328.211.178.1 to 28.211.179.25428.211.179.255510
21928.211.180.0/2328.211.180.1 to 28.211.181.25428.211.181.255510
22028.211.182.0/2328.211.182.1 to 28.211.183.25428.211.183.255510
22128.211.184.0/2328.211.184.1 to 28.211.185.25428.211.185.255510
22228.211.186.0/2328.211.186.1 to 28.211.187.25428.211.187.255510
22328.211.188.0/2328.211.188.1 to 28.211.189.25428.211.189.255510
22428.211.190.0/2328.211.190.1 to 28.211.191.25428.211.191.255510
22528.211.192.0/2328.211.192.1 to 28.211.193.25428.211.193.255510
22628.211.194.0/2328.211.194.1 to 28.211.195.25428.211.195.255510
22728.211.196.0/2328.211.196.1 to 28.211.197.25428.211.197.255510
22828.211.198.0/2328.211.198.1 to 28.211.199.25428.211.199.255510
22928.211.200.0/2328.211.200.1 to 28.211.201.25428.211.201.255510
23028.211.202.0/2328.211.202.1 to 28.211.203.25428.211.203.255510
23128.211.204.0/2328.211.204.1 to 28.211.205.25428.211.205.255510
23228.211.206.0/2328.211.206.1 to 28.211.207.25428.211.207.255510
23328.211.208.0/2328.211.208.1 to 28.211.209.25428.211.209.255510
23428.211.210.0/2328.211.210.1 to 28.211.211.25428.211.211.255510
23528.211.212.0/2328.211.212.1 to 28.211.213.25428.211.213.255510
23628.211.214.0/2328.211.214.1 to 28.211.215.25428.211.215.255510
23728.211.216.0/2328.211.216.1 to 28.211.217.25428.211.217.255510
23828.211.218.0/2328.211.218.1 to 28.211.219.25428.211.219.255510
23928.211.220.0/2328.211.220.1 to 28.211.221.25428.211.221.255510
24028.211.222.0/2328.211.222.1 to 28.211.223.25428.211.223.255510
24128.211.224.0/2328.211.224.1 to 28.211.225.25428.211.225.255510
24228.211.226.0/2328.211.226.1 to 28.211.227.25428.211.227.255510
24328.211.228.0/2328.211.228.1 to 28.211.229.25428.211.229.255510
24428.211.230.0/2328.211.230.1 to 28.211.231.25428.211.231.255510
24528.211.232.0/2328.211.232.1 to 28.211.233.25428.211.233.255510
24628.211.234.0/2328.211.234.1 to 28.211.235.25428.211.235.255510
24728.211.236.0/2328.211.236.1 to 28.211.237.25428.211.237.255510
24828.211.238.0/2328.211.238.1 to 28.211.239.25428.211.239.255510
24928.211.240.0/2328.211.240.1 to 28.211.241.25428.211.241.255510
25028.211.242.0/2328.211.242.1 to 28.211.243.25428.211.243.255510
25128.211.244.0/2328.211.244.1 to 28.211.245.25428.211.245.255510
25228.211.246.0/2328.211.246.1 to 28.211.247.25428.211.247.255510
25328.211.248.0/2328.211.248.1 to 28.211.249.25428.211.249.255510
25428.211.250.0/2328.211.250.1 to 28.211.251.25428.211.251.255510
25528.211.252.0/2328.211.252.1 to 28.211.253.25428.211.253.255510
25628.211.254.0/2328.211.254.1 to 28.211.255.25428.211.255.255510

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.