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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.

Network28.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
28.0.0.0
Broadcast address
28.255.255.255
First usable
28.0.0.1
Last usable
28.255.255.254
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 1C000000 · Integer 469762048 to 486539263
Reverse DNS zone
28.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011100..00000000.00000000.0000000028.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00011100..00000000.00000000.0000000028.0.0.0
Broadcast00011100..11111111.11111111.1111111128.255.255.255
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)

28.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.0.0.0/1628.0.0.1 to 28.0.255.25428.0.255.25565,534
228.1.0.0/1628.1.0.1 to 28.1.255.25428.1.255.25565,534
328.2.0.0/1628.2.0.1 to 28.2.255.25428.2.255.25565,534
428.3.0.0/1628.3.0.1 to 28.3.255.25428.3.255.25565,534
528.4.0.0/1628.4.0.1 to 28.4.255.25428.4.255.25565,534
628.5.0.0/1628.5.0.1 to 28.5.255.25428.5.255.25565,534
728.6.0.0/1628.6.0.1 to 28.6.255.25428.6.255.25565,534
828.7.0.0/1628.7.0.1 to 28.7.255.25428.7.255.25565,534
928.8.0.0/1628.8.0.1 to 28.8.255.25428.8.255.25565,534
1028.9.0.0/1628.9.0.1 to 28.9.255.25428.9.255.25565,534
1128.10.0.0/1628.10.0.1 to 28.10.255.25428.10.255.25565,534
1228.11.0.0/1628.11.0.1 to 28.11.255.25428.11.255.25565,534
1328.12.0.0/1628.12.0.1 to 28.12.255.25428.12.255.25565,534
1428.13.0.0/1628.13.0.1 to 28.13.255.25428.13.255.25565,534
1528.14.0.0/1628.14.0.1 to 28.14.255.25428.14.255.25565,534
1628.15.0.0/1628.15.0.1 to 28.15.255.25428.15.255.25565,534
1728.16.0.0/1628.16.0.1 to 28.16.255.25428.16.255.25565,534
1828.17.0.0/1628.17.0.1 to 28.17.255.25428.17.255.25565,534
1928.18.0.0/1628.18.0.1 to 28.18.255.25428.18.255.25565,534
2028.19.0.0/1628.19.0.1 to 28.19.255.25428.19.255.25565,534
2128.20.0.0/1628.20.0.1 to 28.20.255.25428.20.255.25565,534
2228.21.0.0/1628.21.0.1 to 28.21.255.25428.21.255.25565,534
2328.22.0.0/1628.22.0.1 to 28.22.255.25428.22.255.25565,534
2428.23.0.0/1628.23.0.1 to 28.23.255.25428.23.255.25565,534
2528.24.0.0/1628.24.0.1 to 28.24.255.25428.24.255.25565,534
2628.25.0.0/1628.25.0.1 to 28.25.255.25428.25.255.25565,534
2728.26.0.0/1628.26.0.1 to 28.26.255.25428.26.255.25565,534
2828.27.0.0/1628.27.0.1 to 28.27.255.25428.27.255.25565,534
2928.28.0.0/1628.28.0.1 to 28.28.255.25428.28.255.25565,534
3028.29.0.0/1628.29.0.1 to 28.29.255.25428.29.255.25565,534
3128.30.0.0/1628.30.0.1 to 28.30.255.25428.30.255.25565,534
3228.31.0.0/1628.31.0.1 to 28.31.255.25428.31.255.25565,534
3328.32.0.0/1628.32.0.1 to 28.32.255.25428.32.255.25565,534
3428.33.0.0/1628.33.0.1 to 28.33.255.25428.33.255.25565,534
3528.34.0.0/1628.34.0.1 to 28.34.255.25428.34.255.25565,534
3628.35.0.0/1628.35.0.1 to 28.35.255.25428.35.255.25565,534
3728.36.0.0/1628.36.0.1 to 28.36.255.25428.36.255.25565,534
3828.37.0.0/1628.37.0.1 to 28.37.255.25428.37.255.25565,534
3928.38.0.0/1628.38.0.1 to 28.38.255.25428.38.255.25565,534
4028.39.0.0/1628.39.0.1 to 28.39.255.25428.39.255.25565,534
4128.40.0.0/1628.40.0.1 to 28.40.255.25428.40.255.25565,534
4228.41.0.0/1628.41.0.1 to 28.41.255.25428.41.255.25565,534
4328.42.0.0/1628.42.0.1 to 28.42.255.25428.42.255.25565,534
4428.43.0.0/1628.43.0.1 to 28.43.255.25428.43.255.25565,534
4528.44.0.0/1628.44.0.1 to 28.44.255.25428.44.255.25565,534
4628.45.0.0/1628.45.0.1 to 28.45.255.25428.45.255.25565,534
4728.46.0.0/1628.46.0.1 to 28.46.255.25428.46.255.25565,534
4828.47.0.0/1628.47.0.1 to 28.47.255.25428.47.255.25565,534
4928.48.0.0/1628.48.0.1 to 28.48.255.25428.48.255.25565,534
5028.49.0.0/1628.49.0.1 to 28.49.255.25428.49.255.25565,534
5128.50.0.0/1628.50.0.1 to 28.50.255.25428.50.255.25565,534
5228.51.0.0/1628.51.0.1 to 28.51.255.25428.51.255.25565,534
5328.52.0.0/1628.52.0.1 to 28.52.255.25428.52.255.25565,534
5428.53.0.0/1628.53.0.1 to 28.53.255.25428.53.255.25565,534
5528.54.0.0/1628.54.0.1 to 28.54.255.25428.54.255.25565,534
5628.55.0.0/1628.55.0.1 to 28.55.255.25428.55.255.25565,534
5728.56.0.0/1628.56.0.1 to 28.56.255.25428.56.255.25565,534
5828.57.0.0/1628.57.0.1 to 28.57.255.25428.57.255.25565,534
5928.58.0.0/1628.58.0.1 to 28.58.255.25428.58.255.25565,534
6028.59.0.0/1628.59.0.1 to 28.59.255.25428.59.255.25565,534
6128.60.0.0/1628.60.0.1 to 28.60.255.25428.60.255.25565,534
6228.61.0.0/1628.61.0.1 to 28.61.255.25428.61.255.25565,534
6328.62.0.0/1628.62.0.1 to 28.62.255.25428.62.255.25565,534
6428.63.0.0/1628.63.0.1 to 28.63.255.25428.63.255.25565,534
6528.64.0.0/1628.64.0.1 to 28.64.255.25428.64.255.25565,534
6628.65.0.0/1628.65.0.1 to 28.65.255.25428.65.255.25565,534
6728.66.0.0/1628.66.0.1 to 28.66.255.25428.66.255.25565,534
6828.67.0.0/1628.67.0.1 to 28.67.255.25428.67.255.25565,534
6928.68.0.0/1628.68.0.1 to 28.68.255.25428.68.255.25565,534
7028.69.0.0/1628.69.0.1 to 28.69.255.25428.69.255.25565,534
7128.70.0.0/1628.70.0.1 to 28.70.255.25428.70.255.25565,534
7228.71.0.0/1628.71.0.1 to 28.71.255.25428.71.255.25565,534
7328.72.0.0/1628.72.0.1 to 28.72.255.25428.72.255.25565,534
7428.73.0.0/1628.73.0.1 to 28.73.255.25428.73.255.25565,534
7528.74.0.0/1628.74.0.1 to 28.74.255.25428.74.255.25565,534
7628.75.0.0/1628.75.0.1 to 28.75.255.25428.75.255.25565,534
7728.76.0.0/1628.76.0.1 to 28.76.255.25428.76.255.25565,534
7828.77.0.0/1628.77.0.1 to 28.77.255.25428.77.255.25565,534
7928.78.0.0/1628.78.0.1 to 28.78.255.25428.78.255.25565,534
8028.79.0.0/1628.79.0.1 to 28.79.255.25428.79.255.25565,534
8128.80.0.0/1628.80.0.1 to 28.80.255.25428.80.255.25565,534
8228.81.0.0/1628.81.0.1 to 28.81.255.25428.81.255.25565,534
8328.82.0.0/1628.82.0.1 to 28.82.255.25428.82.255.25565,534
8428.83.0.0/1628.83.0.1 to 28.83.255.25428.83.255.25565,534
8528.84.0.0/1628.84.0.1 to 28.84.255.25428.84.255.25565,534
8628.85.0.0/1628.85.0.1 to 28.85.255.25428.85.255.25565,534
8728.86.0.0/1628.86.0.1 to 28.86.255.25428.86.255.25565,534
8828.87.0.0/1628.87.0.1 to 28.87.255.25428.87.255.25565,534
8928.88.0.0/1628.88.0.1 to 28.88.255.25428.88.255.25565,534
9028.89.0.0/1628.89.0.1 to 28.89.255.25428.89.255.25565,534
9128.90.0.0/1628.90.0.1 to 28.90.255.25428.90.255.25565,534
9228.91.0.0/1628.91.0.1 to 28.91.255.25428.91.255.25565,534
9328.92.0.0/1628.92.0.1 to 28.92.255.25428.92.255.25565,534
9428.93.0.0/1628.93.0.1 to 28.93.255.25428.93.255.25565,534
9528.94.0.0/1628.94.0.1 to 28.94.255.25428.94.255.25565,534
9628.95.0.0/1628.95.0.1 to 28.95.255.25428.95.255.25565,534
9728.96.0.0/1628.96.0.1 to 28.96.255.25428.96.255.25565,534
9828.97.0.0/1628.97.0.1 to 28.97.255.25428.97.255.25565,534
9928.98.0.0/1628.98.0.1 to 28.98.255.25428.98.255.25565,534
10028.99.0.0/1628.99.0.1 to 28.99.255.25428.99.255.25565,534
10128.100.0.0/1628.100.0.1 to 28.100.255.25428.100.255.25565,534
10228.101.0.0/1628.101.0.1 to 28.101.255.25428.101.255.25565,534
10328.102.0.0/1628.102.0.1 to 28.102.255.25428.102.255.25565,534
10428.103.0.0/1628.103.0.1 to 28.103.255.25428.103.255.25565,534
10528.104.0.0/1628.104.0.1 to 28.104.255.25428.104.255.25565,534
10628.105.0.0/1628.105.0.1 to 28.105.255.25428.105.255.25565,534
10728.106.0.0/1628.106.0.1 to 28.106.255.25428.106.255.25565,534
10828.107.0.0/1628.107.0.1 to 28.107.255.25428.107.255.25565,534
10928.108.0.0/1628.108.0.1 to 28.108.255.25428.108.255.25565,534
11028.109.0.0/1628.109.0.1 to 28.109.255.25428.109.255.25565,534
11128.110.0.0/1628.110.0.1 to 28.110.255.25428.110.255.25565,534
11228.111.0.0/1628.111.0.1 to 28.111.255.25428.111.255.25565,534
11328.112.0.0/1628.112.0.1 to 28.112.255.25428.112.255.25565,534
11428.113.0.0/1628.113.0.1 to 28.113.255.25428.113.255.25565,534
11528.114.0.0/1628.114.0.1 to 28.114.255.25428.114.255.25565,534
11628.115.0.0/1628.115.0.1 to 28.115.255.25428.115.255.25565,534
11728.116.0.0/1628.116.0.1 to 28.116.255.25428.116.255.25565,534
11828.117.0.0/1628.117.0.1 to 28.117.255.25428.117.255.25565,534
11928.118.0.0/1628.118.0.1 to 28.118.255.25428.118.255.25565,534
12028.119.0.0/1628.119.0.1 to 28.119.255.25428.119.255.25565,534
12128.120.0.0/1628.120.0.1 to 28.120.255.25428.120.255.25565,534
12228.121.0.0/1628.121.0.1 to 28.121.255.25428.121.255.25565,534
12328.122.0.0/1628.122.0.1 to 28.122.255.25428.122.255.25565,534
12428.123.0.0/1628.123.0.1 to 28.123.255.25428.123.255.25565,534
12528.124.0.0/1628.124.0.1 to 28.124.255.25428.124.255.25565,534
12628.125.0.0/1628.125.0.1 to 28.125.255.25428.125.255.25565,534
12728.126.0.0/1628.126.0.1 to 28.126.255.25428.126.255.25565,534
12828.127.0.0/1628.127.0.1 to 28.127.255.25428.127.255.25565,534
12928.128.0.0/1628.128.0.1 to 28.128.255.25428.128.255.25565,534
13028.129.0.0/1628.129.0.1 to 28.129.255.25428.129.255.25565,534
13128.130.0.0/1628.130.0.1 to 28.130.255.25428.130.255.25565,534
13228.131.0.0/1628.131.0.1 to 28.131.255.25428.131.255.25565,534
13328.132.0.0/1628.132.0.1 to 28.132.255.25428.132.255.25565,534
13428.133.0.0/1628.133.0.1 to 28.133.255.25428.133.255.25565,534
13528.134.0.0/1628.134.0.1 to 28.134.255.25428.134.255.25565,534
13628.135.0.0/1628.135.0.1 to 28.135.255.25428.135.255.25565,534
13728.136.0.0/1628.136.0.1 to 28.136.255.25428.136.255.25565,534
13828.137.0.0/1628.137.0.1 to 28.137.255.25428.137.255.25565,534
13928.138.0.0/1628.138.0.1 to 28.138.255.25428.138.255.25565,534
14028.139.0.0/1628.139.0.1 to 28.139.255.25428.139.255.25565,534
14128.140.0.0/1628.140.0.1 to 28.140.255.25428.140.255.25565,534
14228.141.0.0/1628.141.0.1 to 28.141.255.25428.141.255.25565,534
14328.142.0.0/1628.142.0.1 to 28.142.255.25428.142.255.25565,534
14428.143.0.0/1628.143.0.1 to 28.143.255.25428.143.255.25565,534
14528.144.0.0/1628.144.0.1 to 28.144.255.25428.144.255.25565,534
14628.145.0.0/1628.145.0.1 to 28.145.255.25428.145.255.25565,534
14728.146.0.0/1628.146.0.1 to 28.146.255.25428.146.255.25565,534
14828.147.0.0/1628.147.0.1 to 28.147.255.25428.147.255.25565,534
14928.148.0.0/1628.148.0.1 to 28.148.255.25428.148.255.25565,534
15028.149.0.0/1628.149.0.1 to 28.149.255.25428.149.255.25565,534
15128.150.0.0/1628.150.0.1 to 28.150.255.25428.150.255.25565,534
15228.151.0.0/1628.151.0.1 to 28.151.255.25428.151.255.25565,534
15328.152.0.0/1628.152.0.1 to 28.152.255.25428.152.255.25565,534
15428.153.0.0/1628.153.0.1 to 28.153.255.25428.153.255.25565,534
15528.154.0.0/1628.154.0.1 to 28.154.255.25428.154.255.25565,534
15628.155.0.0/1628.155.0.1 to 28.155.255.25428.155.255.25565,534
15728.156.0.0/1628.156.0.1 to 28.156.255.25428.156.255.25565,534
15828.157.0.0/1628.157.0.1 to 28.157.255.25428.157.255.25565,534
15928.158.0.0/1628.158.0.1 to 28.158.255.25428.158.255.25565,534
16028.159.0.0/1628.159.0.1 to 28.159.255.25428.159.255.25565,534
16128.160.0.0/1628.160.0.1 to 28.160.255.25428.160.255.25565,534
16228.161.0.0/1628.161.0.1 to 28.161.255.25428.161.255.25565,534
16328.162.0.0/1628.162.0.1 to 28.162.255.25428.162.255.25565,534
16428.163.0.0/1628.163.0.1 to 28.163.255.25428.163.255.25565,534
16528.164.0.0/1628.164.0.1 to 28.164.255.25428.164.255.25565,534
16628.165.0.0/1628.165.0.1 to 28.165.255.25428.165.255.25565,534
16728.166.0.0/1628.166.0.1 to 28.166.255.25428.166.255.25565,534
16828.167.0.0/1628.167.0.1 to 28.167.255.25428.167.255.25565,534
16928.168.0.0/1628.168.0.1 to 28.168.255.25428.168.255.25565,534
17028.169.0.0/1628.169.0.1 to 28.169.255.25428.169.255.25565,534
17128.170.0.0/1628.170.0.1 to 28.170.255.25428.170.255.25565,534
17228.171.0.0/1628.171.0.1 to 28.171.255.25428.171.255.25565,534
17328.172.0.0/1628.172.0.1 to 28.172.255.25428.172.255.25565,534
17428.173.0.0/1628.173.0.1 to 28.173.255.25428.173.255.25565,534
17528.174.0.0/1628.174.0.1 to 28.174.255.25428.174.255.25565,534
17628.175.0.0/1628.175.0.1 to 28.175.255.25428.175.255.25565,534
17728.176.0.0/1628.176.0.1 to 28.176.255.25428.176.255.25565,534
17828.177.0.0/1628.177.0.1 to 28.177.255.25428.177.255.25565,534
17928.178.0.0/1628.178.0.1 to 28.178.255.25428.178.255.25565,534
18028.179.0.0/1628.179.0.1 to 28.179.255.25428.179.255.25565,534
18128.180.0.0/1628.180.0.1 to 28.180.255.25428.180.255.25565,534
18228.181.0.0/1628.181.0.1 to 28.181.255.25428.181.255.25565,534
18328.182.0.0/1628.182.0.1 to 28.182.255.25428.182.255.25565,534
18428.183.0.0/1628.183.0.1 to 28.183.255.25428.183.255.25565,534
18528.184.0.0/1628.184.0.1 to 28.184.255.25428.184.255.25565,534
18628.185.0.0/1628.185.0.1 to 28.185.255.25428.185.255.25565,534
18728.186.0.0/1628.186.0.1 to 28.186.255.25428.186.255.25565,534
18828.187.0.0/1628.187.0.1 to 28.187.255.25428.187.255.25565,534
18928.188.0.0/1628.188.0.1 to 28.188.255.25428.188.255.25565,534
19028.189.0.0/1628.189.0.1 to 28.189.255.25428.189.255.25565,534
19128.190.0.0/1628.190.0.1 to 28.190.255.25428.190.255.25565,534
19228.191.0.0/1628.191.0.1 to 28.191.255.25428.191.255.25565,534
19328.192.0.0/1628.192.0.1 to 28.192.255.25428.192.255.25565,534
19428.193.0.0/1628.193.0.1 to 28.193.255.25428.193.255.25565,534
19528.194.0.0/1628.194.0.1 to 28.194.255.25428.194.255.25565,534
19628.195.0.0/1628.195.0.1 to 28.195.255.25428.195.255.25565,534
19728.196.0.0/1628.196.0.1 to 28.196.255.25428.196.255.25565,534
19828.197.0.0/1628.197.0.1 to 28.197.255.25428.197.255.25565,534
19928.198.0.0/1628.198.0.1 to 28.198.255.25428.198.255.25565,534
20028.199.0.0/1628.199.0.1 to 28.199.255.25428.199.255.25565,534
20128.200.0.0/1628.200.0.1 to 28.200.255.25428.200.255.25565,534
20228.201.0.0/1628.201.0.1 to 28.201.255.25428.201.255.25565,534
20328.202.0.0/1628.202.0.1 to 28.202.255.25428.202.255.25565,534
20428.203.0.0/1628.203.0.1 to 28.203.255.25428.203.255.25565,534
20528.204.0.0/1628.204.0.1 to 28.204.255.25428.204.255.25565,534
20628.205.0.0/1628.205.0.1 to 28.205.255.25428.205.255.25565,534
20728.206.0.0/1628.206.0.1 to 28.206.255.25428.206.255.25565,534
20828.207.0.0/1628.207.0.1 to 28.207.255.25428.207.255.25565,534
20928.208.0.0/1628.208.0.1 to 28.208.255.25428.208.255.25565,534
21028.209.0.0/1628.209.0.1 to 28.209.255.25428.209.255.25565,534
21128.210.0.0/1628.210.0.1 to 28.210.255.25428.210.255.25565,534
21228.211.0.0/1628.211.0.1 to 28.211.255.25428.211.255.25565,534
21328.212.0.0/1628.212.0.1 to 28.212.255.25428.212.255.25565,534
21428.213.0.0/1628.213.0.1 to 28.213.255.25428.213.255.25565,534
21528.214.0.0/1628.214.0.1 to 28.214.255.25428.214.255.25565,534
21628.215.0.0/1628.215.0.1 to 28.215.255.25428.215.255.25565,534
21728.216.0.0/1628.216.0.1 to 28.216.255.25428.216.255.25565,534
21828.217.0.0/1628.217.0.1 to 28.217.255.25428.217.255.25565,534
21928.218.0.0/1628.218.0.1 to 28.218.255.25428.218.255.25565,534
22028.219.0.0/1628.219.0.1 to 28.219.255.25428.219.255.25565,534
22128.220.0.0/1628.220.0.1 to 28.220.255.25428.220.255.25565,534
22228.221.0.0/1628.221.0.1 to 28.221.255.25428.221.255.25565,534
22328.222.0.0/1628.222.0.1 to 28.222.255.25428.222.255.25565,534
22428.223.0.0/1628.223.0.1 to 28.223.255.25428.223.255.25565,534
22528.224.0.0/1628.224.0.1 to 28.224.255.25428.224.255.25565,534
22628.225.0.0/1628.225.0.1 to 28.225.255.25428.225.255.25565,534
22728.226.0.0/1628.226.0.1 to 28.226.255.25428.226.255.25565,534
22828.227.0.0/1628.227.0.1 to 28.227.255.25428.227.255.25565,534
22928.228.0.0/1628.228.0.1 to 28.228.255.25428.228.255.25565,534
23028.229.0.0/1628.229.0.1 to 28.229.255.25428.229.255.25565,534
23128.230.0.0/1628.230.0.1 to 28.230.255.25428.230.255.25565,534
23228.231.0.0/1628.231.0.1 to 28.231.255.25428.231.255.25565,534
23328.232.0.0/1628.232.0.1 to 28.232.255.25428.232.255.25565,534
23428.233.0.0/1628.233.0.1 to 28.233.255.25428.233.255.25565,534
23528.234.0.0/1628.234.0.1 to 28.234.255.25428.234.255.25565,534
23628.235.0.0/1628.235.0.1 to 28.235.255.25428.235.255.25565,534
23728.236.0.0/1628.236.0.1 to 28.236.255.25428.236.255.25565,534
23828.237.0.0/1628.237.0.1 to 28.237.255.25428.237.255.25565,534
23928.238.0.0/1628.238.0.1 to 28.238.255.25428.238.255.25565,534
24028.239.0.0/1628.239.0.1 to 28.239.255.25428.239.255.25565,534
24128.240.0.0/1628.240.0.1 to 28.240.255.25428.240.255.25565,534
24228.241.0.0/1628.241.0.1 to 28.241.255.25428.241.255.25565,534
24328.242.0.0/1628.242.0.1 to 28.242.255.25428.242.255.25565,534
24428.243.0.0/1628.243.0.1 to 28.243.255.25428.243.255.25565,534
24528.244.0.0/1628.244.0.1 to 28.244.255.25428.244.255.25565,534
24628.245.0.0/1628.245.0.1 to 28.245.255.25428.245.255.25565,534
24728.246.0.0/1628.246.0.1 to 28.246.255.25428.246.255.25565,534
24828.247.0.0/1628.247.0.1 to 28.247.255.25428.247.255.25565,534
24928.248.0.0/1628.248.0.1 to 28.248.255.25428.248.255.25565,534
25028.249.0.0/1628.249.0.1 to 28.249.255.25428.249.255.25565,534
25128.250.0.0/1628.250.0.1 to 28.250.255.25428.250.255.25565,534
25228.251.0.0/1628.251.0.1 to 28.251.255.25428.251.255.25565,534
25328.252.0.0/1628.252.0.1 to 28.252.255.25428.252.255.25565,534
25428.253.0.0/1628.253.0.1 to 28.253.255.25428.253.255.25565,534
25528.254.0.0/1628.254.0.1 to 28.254.255.25428.254.255.25565,534
25628.255.0.0/1628.255.0.1 to 28.255.255.25428.255.255.25565,534

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.