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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.

Network24.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
24.0.0.0
Broadcast address
31.255.255.255
First usable
24.0.0.1
Last usable
31.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
A (default /8)
As numbers
Hex 18000000 · Integer 402653184 to 536870911
Reverse DNS zones
24.in-addr.arpa
25.in-addr.arpa
26.in-addr.arpa
27.in-addr.arpa
28.in-addr.arpa
29.in-addr.arpa
30.in-addr.arpa
31.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011000.00000000.00000000.0000000024.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network00011000.00000000.00000000.0000000024.0.0.0
Broadcast00011111.11111111.11111111.1111111131.255.255.255
Split into smaller subnets/16
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

24.0.0.0/5 makes 2,048 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
124.0.0.0/1624.0.0.1 to 24.0.255.25424.0.255.25565,534
224.1.0.0/1624.1.0.1 to 24.1.255.25424.1.255.25565,534
324.2.0.0/1624.2.0.1 to 24.2.255.25424.2.255.25565,534
424.3.0.0/1624.3.0.1 to 24.3.255.25424.3.255.25565,534
524.4.0.0/1624.4.0.1 to 24.4.255.25424.4.255.25565,534
624.5.0.0/1624.5.0.1 to 24.5.255.25424.5.255.25565,534
724.6.0.0/1624.6.0.1 to 24.6.255.25424.6.255.25565,534
824.7.0.0/1624.7.0.1 to 24.7.255.25424.7.255.25565,534
924.8.0.0/1624.8.0.1 to 24.8.255.25424.8.255.25565,534
1024.9.0.0/1624.9.0.1 to 24.9.255.25424.9.255.25565,534
1124.10.0.0/1624.10.0.1 to 24.10.255.25424.10.255.25565,534
1224.11.0.0/1624.11.0.1 to 24.11.255.25424.11.255.25565,534
1324.12.0.0/1624.12.0.1 to 24.12.255.25424.12.255.25565,534
1424.13.0.0/1624.13.0.1 to 24.13.255.25424.13.255.25565,534
1524.14.0.0/1624.14.0.1 to 24.14.255.25424.14.255.25565,534
1624.15.0.0/1624.15.0.1 to 24.15.255.25424.15.255.25565,534
1724.16.0.0/1624.16.0.1 to 24.16.255.25424.16.255.25565,534
1824.17.0.0/1624.17.0.1 to 24.17.255.25424.17.255.25565,534
1924.18.0.0/1624.18.0.1 to 24.18.255.25424.18.255.25565,534
2024.19.0.0/1624.19.0.1 to 24.19.255.25424.19.255.25565,534
2124.20.0.0/1624.20.0.1 to 24.20.255.25424.20.255.25565,534
2224.21.0.0/1624.21.0.1 to 24.21.255.25424.21.255.25565,534
2324.22.0.0/1624.22.0.1 to 24.22.255.25424.22.255.25565,534
2424.23.0.0/1624.23.0.1 to 24.23.255.25424.23.255.25565,534
2524.24.0.0/1624.24.0.1 to 24.24.255.25424.24.255.25565,534
2624.25.0.0/1624.25.0.1 to 24.25.255.25424.25.255.25565,534
2724.26.0.0/1624.26.0.1 to 24.26.255.25424.26.255.25565,534
2824.27.0.0/1624.27.0.1 to 24.27.255.25424.27.255.25565,534
2924.28.0.0/1624.28.0.1 to 24.28.255.25424.28.255.25565,534
3024.29.0.0/1624.29.0.1 to 24.29.255.25424.29.255.25565,534
3124.30.0.0/1624.30.0.1 to 24.30.255.25424.30.255.25565,534
3224.31.0.0/1624.31.0.1 to 24.31.255.25424.31.255.25565,534
3324.32.0.0/1624.32.0.1 to 24.32.255.25424.32.255.25565,534
3424.33.0.0/1624.33.0.1 to 24.33.255.25424.33.255.25565,534
3524.34.0.0/1624.34.0.1 to 24.34.255.25424.34.255.25565,534
3624.35.0.0/1624.35.0.1 to 24.35.255.25424.35.255.25565,534
3724.36.0.0/1624.36.0.1 to 24.36.255.25424.36.255.25565,534
3824.37.0.0/1624.37.0.1 to 24.37.255.25424.37.255.25565,534
3924.38.0.0/1624.38.0.1 to 24.38.255.25424.38.255.25565,534
4024.39.0.0/1624.39.0.1 to 24.39.255.25424.39.255.25565,534
4124.40.0.0/1624.40.0.1 to 24.40.255.25424.40.255.25565,534
4224.41.0.0/1624.41.0.1 to 24.41.255.25424.41.255.25565,534
4324.42.0.0/1624.42.0.1 to 24.42.255.25424.42.255.25565,534
4424.43.0.0/1624.43.0.1 to 24.43.255.25424.43.255.25565,534
4524.44.0.0/1624.44.0.1 to 24.44.255.25424.44.255.25565,534
4624.45.0.0/1624.45.0.1 to 24.45.255.25424.45.255.25565,534
4724.46.0.0/1624.46.0.1 to 24.46.255.25424.46.255.25565,534
4824.47.0.0/1624.47.0.1 to 24.47.255.25424.47.255.25565,534
4924.48.0.0/1624.48.0.1 to 24.48.255.25424.48.255.25565,534
5024.49.0.0/1624.49.0.1 to 24.49.255.25424.49.255.25565,534
5124.50.0.0/1624.50.0.1 to 24.50.255.25424.50.255.25565,534
5224.51.0.0/1624.51.0.1 to 24.51.255.25424.51.255.25565,534
5324.52.0.0/1624.52.0.1 to 24.52.255.25424.52.255.25565,534
5424.53.0.0/1624.53.0.1 to 24.53.255.25424.53.255.25565,534
5524.54.0.0/1624.54.0.1 to 24.54.255.25424.54.255.25565,534
5624.55.0.0/1624.55.0.1 to 24.55.255.25424.55.255.25565,534
5724.56.0.0/1624.56.0.1 to 24.56.255.25424.56.255.25565,534
5824.57.0.0/1624.57.0.1 to 24.57.255.25424.57.255.25565,534
5924.58.0.0/1624.58.0.1 to 24.58.255.25424.58.255.25565,534
6024.59.0.0/1624.59.0.1 to 24.59.255.25424.59.255.25565,534
6124.60.0.0/1624.60.0.1 to 24.60.255.25424.60.255.25565,534
6224.61.0.0/1624.61.0.1 to 24.61.255.25424.61.255.25565,534
6324.62.0.0/1624.62.0.1 to 24.62.255.25424.62.255.25565,534
6424.63.0.0/1624.63.0.1 to 24.63.255.25424.63.255.25565,534
6524.64.0.0/1624.64.0.1 to 24.64.255.25424.64.255.25565,534
6624.65.0.0/1624.65.0.1 to 24.65.255.25424.65.255.25565,534
6724.66.0.0/1624.66.0.1 to 24.66.255.25424.66.255.25565,534
6824.67.0.0/1624.67.0.1 to 24.67.255.25424.67.255.25565,534
6924.68.0.0/1624.68.0.1 to 24.68.255.25424.68.255.25565,534
7024.69.0.0/1624.69.0.1 to 24.69.255.25424.69.255.25565,534
7124.70.0.0/1624.70.0.1 to 24.70.255.25424.70.255.25565,534
7224.71.0.0/1624.71.0.1 to 24.71.255.25424.71.255.25565,534
7324.72.0.0/1624.72.0.1 to 24.72.255.25424.72.255.25565,534
7424.73.0.0/1624.73.0.1 to 24.73.255.25424.73.255.25565,534
7524.74.0.0/1624.74.0.1 to 24.74.255.25424.74.255.25565,534
7624.75.0.0/1624.75.0.1 to 24.75.255.25424.75.255.25565,534
7724.76.0.0/1624.76.0.1 to 24.76.255.25424.76.255.25565,534
7824.77.0.0/1624.77.0.1 to 24.77.255.25424.77.255.25565,534
7924.78.0.0/1624.78.0.1 to 24.78.255.25424.78.255.25565,534
8024.79.0.0/1624.79.0.1 to 24.79.255.25424.79.255.25565,534
8124.80.0.0/1624.80.0.1 to 24.80.255.25424.80.255.25565,534
8224.81.0.0/1624.81.0.1 to 24.81.255.25424.81.255.25565,534
8324.82.0.0/1624.82.0.1 to 24.82.255.25424.82.255.25565,534
8424.83.0.0/1624.83.0.1 to 24.83.255.25424.83.255.25565,534
8524.84.0.0/1624.84.0.1 to 24.84.255.25424.84.255.25565,534
8624.85.0.0/1624.85.0.1 to 24.85.255.25424.85.255.25565,534
8724.86.0.0/1624.86.0.1 to 24.86.255.25424.86.255.25565,534
8824.87.0.0/1624.87.0.1 to 24.87.255.25424.87.255.25565,534
8924.88.0.0/1624.88.0.1 to 24.88.255.25424.88.255.25565,534
9024.89.0.0/1624.89.0.1 to 24.89.255.25424.89.255.25565,534
9124.90.0.0/1624.90.0.1 to 24.90.255.25424.90.255.25565,534
9224.91.0.0/1624.91.0.1 to 24.91.255.25424.91.255.25565,534
9324.92.0.0/1624.92.0.1 to 24.92.255.25424.92.255.25565,534
9424.93.0.0/1624.93.0.1 to 24.93.255.25424.93.255.25565,534
9524.94.0.0/1624.94.0.1 to 24.94.255.25424.94.255.25565,534
9624.95.0.0/1624.95.0.1 to 24.95.255.25424.95.255.25565,534
9724.96.0.0/1624.96.0.1 to 24.96.255.25424.96.255.25565,534
9824.97.0.0/1624.97.0.1 to 24.97.255.25424.97.255.25565,534
9924.98.0.0/1624.98.0.1 to 24.98.255.25424.98.255.25565,534
10024.99.0.0/1624.99.0.1 to 24.99.255.25424.99.255.25565,534
10124.100.0.0/1624.100.0.1 to 24.100.255.25424.100.255.25565,534
10224.101.0.0/1624.101.0.1 to 24.101.255.25424.101.255.25565,534
10324.102.0.0/1624.102.0.1 to 24.102.255.25424.102.255.25565,534
10424.103.0.0/1624.103.0.1 to 24.103.255.25424.103.255.25565,534
10524.104.0.0/1624.104.0.1 to 24.104.255.25424.104.255.25565,534
10624.105.0.0/1624.105.0.1 to 24.105.255.25424.105.255.25565,534
10724.106.0.0/1624.106.0.1 to 24.106.255.25424.106.255.25565,534
10824.107.0.0/1624.107.0.1 to 24.107.255.25424.107.255.25565,534
10924.108.0.0/1624.108.0.1 to 24.108.255.25424.108.255.25565,534
11024.109.0.0/1624.109.0.1 to 24.109.255.25424.109.255.25565,534
11124.110.0.0/1624.110.0.1 to 24.110.255.25424.110.255.25565,534
11224.111.0.0/1624.111.0.1 to 24.111.255.25424.111.255.25565,534
11324.112.0.0/1624.112.0.1 to 24.112.255.25424.112.255.25565,534
11424.113.0.0/1624.113.0.1 to 24.113.255.25424.113.255.25565,534
11524.114.0.0/1624.114.0.1 to 24.114.255.25424.114.255.25565,534
11624.115.0.0/1624.115.0.1 to 24.115.255.25424.115.255.25565,534
11724.116.0.0/1624.116.0.1 to 24.116.255.25424.116.255.25565,534
11824.117.0.0/1624.117.0.1 to 24.117.255.25424.117.255.25565,534
11924.118.0.0/1624.118.0.1 to 24.118.255.25424.118.255.25565,534
12024.119.0.0/1624.119.0.1 to 24.119.255.25424.119.255.25565,534
12124.120.0.0/1624.120.0.1 to 24.120.255.25424.120.255.25565,534
12224.121.0.0/1624.121.0.1 to 24.121.255.25424.121.255.25565,534
12324.122.0.0/1624.122.0.1 to 24.122.255.25424.122.255.25565,534
12424.123.0.0/1624.123.0.1 to 24.123.255.25424.123.255.25565,534
12524.124.0.0/1624.124.0.1 to 24.124.255.25424.124.255.25565,534
12624.125.0.0/1624.125.0.1 to 24.125.255.25424.125.255.25565,534
12724.126.0.0/1624.126.0.1 to 24.126.255.25424.126.255.25565,534
12824.127.0.0/1624.127.0.1 to 24.127.255.25424.127.255.25565,534
12924.128.0.0/1624.128.0.1 to 24.128.255.25424.128.255.25565,534
13024.129.0.0/1624.129.0.1 to 24.129.255.25424.129.255.25565,534
13124.130.0.0/1624.130.0.1 to 24.130.255.25424.130.255.25565,534
13224.131.0.0/1624.131.0.1 to 24.131.255.25424.131.255.25565,534
13324.132.0.0/1624.132.0.1 to 24.132.255.25424.132.255.25565,534
13424.133.0.0/1624.133.0.1 to 24.133.255.25424.133.255.25565,534
13524.134.0.0/1624.134.0.1 to 24.134.255.25424.134.255.25565,534
13624.135.0.0/1624.135.0.1 to 24.135.255.25424.135.255.25565,534
13724.136.0.0/1624.136.0.1 to 24.136.255.25424.136.255.25565,534
13824.137.0.0/1624.137.0.1 to 24.137.255.25424.137.255.25565,534
13924.138.0.0/1624.138.0.1 to 24.138.255.25424.138.255.25565,534
14024.139.0.0/1624.139.0.1 to 24.139.255.25424.139.255.25565,534
14124.140.0.0/1624.140.0.1 to 24.140.255.25424.140.255.25565,534
14224.141.0.0/1624.141.0.1 to 24.141.255.25424.141.255.25565,534
14324.142.0.0/1624.142.0.1 to 24.142.255.25424.142.255.25565,534
14424.143.0.0/1624.143.0.1 to 24.143.255.25424.143.255.25565,534
14524.144.0.0/1624.144.0.1 to 24.144.255.25424.144.255.25565,534
14624.145.0.0/1624.145.0.1 to 24.145.255.25424.145.255.25565,534
14724.146.0.0/1624.146.0.1 to 24.146.255.25424.146.255.25565,534
14824.147.0.0/1624.147.0.1 to 24.147.255.25424.147.255.25565,534
14924.148.0.0/1624.148.0.1 to 24.148.255.25424.148.255.25565,534
15024.149.0.0/1624.149.0.1 to 24.149.255.25424.149.255.25565,534
15124.150.0.0/1624.150.0.1 to 24.150.255.25424.150.255.25565,534
15224.151.0.0/1624.151.0.1 to 24.151.255.25424.151.255.25565,534
15324.152.0.0/1624.152.0.1 to 24.152.255.25424.152.255.25565,534
15424.153.0.0/1624.153.0.1 to 24.153.255.25424.153.255.25565,534
15524.154.0.0/1624.154.0.1 to 24.154.255.25424.154.255.25565,534
15624.155.0.0/1624.155.0.1 to 24.155.255.25424.155.255.25565,534
15724.156.0.0/1624.156.0.1 to 24.156.255.25424.156.255.25565,534
15824.157.0.0/1624.157.0.1 to 24.157.255.25424.157.255.25565,534
15924.158.0.0/1624.158.0.1 to 24.158.255.25424.158.255.25565,534
16024.159.0.0/1624.159.0.1 to 24.159.255.25424.159.255.25565,534
16124.160.0.0/1624.160.0.1 to 24.160.255.25424.160.255.25565,534
16224.161.0.0/1624.161.0.1 to 24.161.255.25424.161.255.25565,534
16324.162.0.0/1624.162.0.1 to 24.162.255.25424.162.255.25565,534
16424.163.0.0/1624.163.0.1 to 24.163.255.25424.163.255.25565,534
16524.164.0.0/1624.164.0.1 to 24.164.255.25424.164.255.25565,534
16624.165.0.0/1624.165.0.1 to 24.165.255.25424.165.255.25565,534
16724.166.0.0/1624.166.0.1 to 24.166.255.25424.166.255.25565,534
16824.167.0.0/1624.167.0.1 to 24.167.255.25424.167.255.25565,534
16924.168.0.0/1624.168.0.1 to 24.168.255.25424.168.255.25565,534
17024.169.0.0/1624.169.0.1 to 24.169.255.25424.169.255.25565,534
17124.170.0.0/1624.170.0.1 to 24.170.255.25424.170.255.25565,534
17224.171.0.0/1624.171.0.1 to 24.171.255.25424.171.255.25565,534
17324.172.0.0/1624.172.0.1 to 24.172.255.25424.172.255.25565,534
17424.173.0.0/1624.173.0.1 to 24.173.255.25424.173.255.25565,534
17524.174.0.0/1624.174.0.1 to 24.174.255.25424.174.255.25565,534
17624.175.0.0/1624.175.0.1 to 24.175.255.25424.175.255.25565,534
17724.176.0.0/1624.176.0.1 to 24.176.255.25424.176.255.25565,534
17824.177.0.0/1624.177.0.1 to 24.177.255.25424.177.255.25565,534
17924.178.0.0/1624.178.0.1 to 24.178.255.25424.178.255.25565,534
18024.179.0.0/1624.179.0.1 to 24.179.255.25424.179.255.25565,534
18124.180.0.0/1624.180.0.1 to 24.180.255.25424.180.255.25565,534
18224.181.0.0/1624.181.0.1 to 24.181.255.25424.181.255.25565,534
18324.182.0.0/1624.182.0.1 to 24.182.255.25424.182.255.25565,534
18424.183.0.0/1624.183.0.1 to 24.183.255.25424.183.255.25565,534
18524.184.0.0/1624.184.0.1 to 24.184.255.25424.184.255.25565,534
18624.185.0.0/1624.185.0.1 to 24.185.255.25424.185.255.25565,534
18724.186.0.0/1624.186.0.1 to 24.186.255.25424.186.255.25565,534
18824.187.0.0/1624.187.0.1 to 24.187.255.25424.187.255.25565,534
18924.188.0.0/1624.188.0.1 to 24.188.255.25424.188.255.25565,534
19024.189.0.0/1624.189.0.1 to 24.189.255.25424.189.255.25565,534
19124.190.0.0/1624.190.0.1 to 24.190.255.25424.190.255.25565,534
19224.191.0.0/1624.191.0.1 to 24.191.255.25424.191.255.25565,534
19324.192.0.0/1624.192.0.1 to 24.192.255.25424.192.255.25565,534
19424.193.0.0/1624.193.0.1 to 24.193.255.25424.193.255.25565,534
19524.194.0.0/1624.194.0.1 to 24.194.255.25424.194.255.25565,534
19624.195.0.0/1624.195.0.1 to 24.195.255.25424.195.255.25565,534
19724.196.0.0/1624.196.0.1 to 24.196.255.25424.196.255.25565,534
19824.197.0.0/1624.197.0.1 to 24.197.255.25424.197.255.25565,534
19924.198.0.0/1624.198.0.1 to 24.198.255.25424.198.255.25565,534
20024.199.0.0/1624.199.0.1 to 24.199.255.25424.199.255.25565,534
20124.200.0.0/1624.200.0.1 to 24.200.255.25424.200.255.25565,534
20224.201.0.0/1624.201.0.1 to 24.201.255.25424.201.255.25565,534
20324.202.0.0/1624.202.0.1 to 24.202.255.25424.202.255.25565,534
20424.203.0.0/1624.203.0.1 to 24.203.255.25424.203.255.25565,534
20524.204.0.0/1624.204.0.1 to 24.204.255.25424.204.255.25565,534
20624.205.0.0/1624.205.0.1 to 24.205.255.25424.205.255.25565,534
20724.206.0.0/1624.206.0.1 to 24.206.255.25424.206.255.25565,534
20824.207.0.0/1624.207.0.1 to 24.207.255.25424.207.255.25565,534
20924.208.0.0/1624.208.0.1 to 24.208.255.25424.208.255.25565,534
21024.209.0.0/1624.209.0.1 to 24.209.255.25424.209.255.25565,534
21124.210.0.0/1624.210.0.1 to 24.210.255.25424.210.255.25565,534
21224.211.0.0/1624.211.0.1 to 24.211.255.25424.211.255.25565,534
21324.212.0.0/1624.212.0.1 to 24.212.255.25424.212.255.25565,534
21424.213.0.0/1624.213.0.1 to 24.213.255.25424.213.255.25565,534
21524.214.0.0/1624.214.0.1 to 24.214.255.25424.214.255.25565,534
21624.215.0.0/1624.215.0.1 to 24.215.255.25424.215.255.25565,534
21724.216.0.0/1624.216.0.1 to 24.216.255.25424.216.255.25565,534
21824.217.0.0/1624.217.0.1 to 24.217.255.25424.217.255.25565,534
21924.218.0.0/1624.218.0.1 to 24.218.255.25424.218.255.25565,534
22024.219.0.0/1624.219.0.1 to 24.219.255.25424.219.255.25565,534
22124.220.0.0/1624.220.0.1 to 24.220.255.25424.220.255.25565,534
22224.221.0.0/1624.221.0.1 to 24.221.255.25424.221.255.25565,534
22324.222.0.0/1624.222.0.1 to 24.222.255.25424.222.255.25565,534
22424.223.0.0/1624.223.0.1 to 24.223.255.25424.223.255.25565,534
22524.224.0.0/1624.224.0.1 to 24.224.255.25424.224.255.25565,534
22624.225.0.0/1624.225.0.1 to 24.225.255.25424.225.255.25565,534
22724.226.0.0/1624.226.0.1 to 24.226.255.25424.226.255.25565,534
22824.227.0.0/1624.227.0.1 to 24.227.255.25424.227.255.25565,534
22924.228.0.0/1624.228.0.1 to 24.228.255.25424.228.255.25565,534
23024.229.0.0/1624.229.0.1 to 24.229.255.25424.229.255.25565,534
23124.230.0.0/1624.230.0.1 to 24.230.255.25424.230.255.25565,534
23224.231.0.0/1624.231.0.1 to 24.231.255.25424.231.255.25565,534
23324.232.0.0/1624.232.0.1 to 24.232.255.25424.232.255.25565,534
23424.233.0.0/1624.233.0.1 to 24.233.255.25424.233.255.25565,534
23524.234.0.0/1624.234.0.1 to 24.234.255.25424.234.255.25565,534
23624.235.0.0/1624.235.0.1 to 24.235.255.25424.235.255.25565,534
23724.236.0.0/1624.236.0.1 to 24.236.255.25424.236.255.25565,534
23824.237.0.0/1624.237.0.1 to 24.237.255.25424.237.255.25565,534
23924.238.0.0/1624.238.0.1 to 24.238.255.25424.238.255.25565,534
24024.239.0.0/1624.239.0.1 to 24.239.255.25424.239.255.25565,534
24124.240.0.0/1624.240.0.1 to 24.240.255.25424.240.255.25565,534
24224.241.0.0/1624.241.0.1 to 24.241.255.25424.241.255.25565,534
24324.242.0.0/1624.242.0.1 to 24.242.255.25424.242.255.25565,534
24424.243.0.0/1624.243.0.1 to 24.243.255.25424.243.255.25565,534
24524.244.0.0/1624.244.0.1 to 24.244.255.25424.244.255.25565,534
24624.245.0.0/1624.245.0.1 to 24.245.255.25424.245.255.25565,534
24724.246.0.0/1624.246.0.1 to 24.246.255.25424.246.255.25565,534
24824.247.0.0/1624.247.0.1 to 24.247.255.25424.247.255.25565,534
24924.248.0.0/1624.248.0.1 to 24.248.255.25424.248.255.25565,534
25024.249.0.0/1624.249.0.1 to 24.249.255.25424.249.255.25565,534
25124.250.0.0/1624.250.0.1 to 24.250.255.25424.250.255.25565,534
25224.251.0.0/1624.251.0.1 to 24.251.255.25424.251.255.25565,534
25324.252.0.0/1624.252.0.1 to 24.252.255.25424.252.255.25565,534
25424.253.0.0/1624.253.0.1 to 24.253.255.25424.253.255.25565,534
25524.254.0.0/1624.254.0.1 to 24.254.255.25424.254.255.25565,534
25624.255.0.0/1624.255.0.1 to 24.255.255.25424.255.255.25565,534

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.