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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.

Network34.80.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
34.80.0.0
Broadcast address
34.95.255.255
First usable
34.80.0.1
Last usable
34.95.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 22500000 · Integer 575668224 to 576716799
Reverse DNS zones
80.34.in-addr.arpa
81.34.in-addr.arpa
82.34.in-addr.arpa
83.34.in-addr.arpa
84.34.in-addr.arpa
85.34.in-addr.arpa
86.34.in-addr.arpa
87.34.in-addr.arpa
88.34.in-addr.arpa
89.34.in-addr.arpa
90.34.in-addr.arpa
91.34.in-addr.arpa
92.34.in-addr.arpa
93.34.in-addr.arpa
94.34.in-addr.arpa
95.34.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100010.01010000.00000000.0000000034.80.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00100010.01010000.00000000.0000000034.80.0.0
Broadcast00100010.01011111.11111111.1111111134.95.255.255
Split into smaller subnets/23
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

34.80.0.0/12 makes 2,048 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
134.80.0.0/2334.80.0.1 to 34.80.1.25434.80.1.255510
234.80.2.0/2334.80.2.1 to 34.80.3.25434.80.3.255510
334.80.4.0/2334.80.4.1 to 34.80.5.25434.80.5.255510
434.80.6.0/2334.80.6.1 to 34.80.7.25434.80.7.255510
534.80.8.0/2334.80.8.1 to 34.80.9.25434.80.9.255510
634.80.10.0/2334.80.10.1 to 34.80.11.25434.80.11.255510
734.80.12.0/2334.80.12.1 to 34.80.13.25434.80.13.255510
834.80.14.0/2334.80.14.1 to 34.80.15.25434.80.15.255510
934.80.16.0/2334.80.16.1 to 34.80.17.25434.80.17.255510
1034.80.18.0/2334.80.18.1 to 34.80.19.25434.80.19.255510
1134.80.20.0/2334.80.20.1 to 34.80.21.25434.80.21.255510
1234.80.22.0/2334.80.22.1 to 34.80.23.25434.80.23.255510
1334.80.24.0/2334.80.24.1 to 34.80.25.25434.80.25.255510
1434.80.26.0/2334.80.26.1 to 34.80.27.25434.80.27.255510
1534.80.28.0/2334.80.28.1 to 34.80.29.25434.80.29.255510
1634.80.30.0/2334.80.30.1 to 34.80.31.25434.80.31.255510
1734.80.32.0/2334.80.32.1 to 34.80.33.25434.80.33.255510
1834.80.34.0/2334.80.34.1 to 34.80.35.25434.80.35.255510
1934.80.36.0/2334.80.36.1 to 34.80.37.25434.80.37.255510
2034.80.38.0/2334.80.38.1 to 34.80.39.25434.80.39.255510
2134.80.40.0/2334.80.40.1 to 34.80.41.25434.80.41.255510
2234.80.42.0/2334.80.42.1 to 34.80.43.25434.80.43.255510
2334.80.44.0/2334.80.44.1 to 34.80.45.25434.80.45.255510
2434.80.46.0/2334.80.46.1 to 34.80.47.25434.80.47.255510
2534.80.48.0/2334.80.48.1 to 34.80.49.25434.80.49.255510
2634.80.50.0/2334.80.50.1 to 34.80.51.25434.80.51.255510
2734.80.52.0/2334.80.52.1 to 34.80.53.25434.80.53.255510
2834.80.54.0/2334.80.54.1 to 34.80.55.25434.80.55.255510
2934.80.56.0/2334.80.56.1 to 34.80.57.25434.80.57.255510
3034.80.58.0/2334.80.58.1 to 34.80.59.25434.80.59.255510
3134.80.60.0/2334.80.60.1 to 34.80.61.25434.80.61.255510
3234.80.62.0/2334.80.62.1 to 34.80.63.25434.80.63.255510
3334.80.64.0/2334.80.64.1 to 34.80.65.25434.80.65.255510
3434.80.66.0/2334.80.66.1 to 34.80.67.25434.80.67.255510
3534.80.68.0/2334.80.68.1 to 34.80.69.25434.80.69.255510
3634.80.70.0/2334.80.70.1 to 34.80.71.25434.80.71.255510
3734.80.72.0/2334.80.72.1 to 34.80.73.25434.80.73.255510
3834.80.74.0/2334.80.74.1 to 34.80.75.25434.80.75.255510
3934.80.76.0/2334.80.76.1 to 34.80.77.25434.80.77.255510
4034.80.78.0/2334.80.78.1 to 34.80.79.25434.80.79.255510
4134.80.80.0/2334.80.80.1 to 34.80.81.25434.80.81.255510
4234.80.82.0/2334.80.82.1 to 34.80.83.25434.80.83.255510
4334.80.84.0/2334.80.84.1 to 34.80.85.25434.80.85.255510
4434.80.86.0/2334.80.86.1 to 34.80.87.25434.80.87.255510
4534.80.88.0/2334.80.88.1 to 34.80.89.25434.80.89.255510
4634.80.90.0/2334.80.90.1 to 34.80.91.25434.80.91.255510
4734.80.92.0/2334.80.92.1 to 34.80.93.25434.80.93.255510
4834.80.94.0/2334.80.94.1 to 34.80.95.25434.80.95.255510
4934.80.96.0/2334.80.96.1 to 34.80.97.25434.80.97.255510
5034.80.98.0/2334.80.98.1 to 34.80.99.25434.80.99.255510
5134.80.100.0/2334.80.100.1 to 34.80.101.25434.80.101.255510
5234.80.102.0/2334.80.102.1 to 34.80.103.25434.80.103.255510
5334.80.104.0/2334.80.104.1 to 34.80.105.25434.80.105.255510
5434.80.106.0/2334.80.106.1 to 34.80.107.25434.80.107.255510
5534.80.108.0/2334.80.108.1 to 34.80.109.25434.80.109.255510
5634.80.110.0/2334.80.110.1 to 34.80.111.25434.80.111.255510
5734.80.112.0/2334.80.112.1 to 34.80.113.25434.80.113.255510
5834.80.114.0/2334.80.114.1 to 34.80.115.25434.80.115.255510
5934.80.116.0/2334.80.116.1 to 34.80.117.25434.80.117.255510
6034.80.118.0/2334.80.118.1 to 34.80.119.25434.80.119.255510
6134.80.120.0/2334.80.120.1 to 34.80.121.25434.80.121.255510
6234.80.122.0/2334.80.122.1 to 34.80.123.25434.80.123.255510
6334.80.124.0/2334.80.124.1 to 34.80.125.25434.80.125.255510
6434.80.126.0/2334.80.126.1 to 34.80.127.25434.80.127.255510
6534.80.128.0/2334.80.128.1 to 34.80.129.25434.80.129.255510
6634.80.130.0/2334.80.130.1 to 34.80.131.25434.80.131.255510
6734.80.132.0/2334.80.132.1 to 34.80.133.25434.80.133.255510
6834.80.134.0/2334.80.134.1 to 34.80.135.25434.80.135.255510
6934.80.136.0/2334.80.136.1 to 34.80.137.25434.80.137.255510
7034.80.138.0/2334.80.138.1 to 34.80.139.25434.80.139.255510
7134.80.140.0/2334.80.140.1 to 34.80.141.25434.80.141.255510
7234.80.142.0/2334.80.142.1 to 34.80.143.25434.80.143.255510
7334.80.144.0/2334.80.144.1 to 34.80.145.25434.80.145.255510
7434.80.146.0/2334.80.146.1 to 34.80.147.25434.80.147.255510
7534.80.148.0/2334.80.148.1 to 34.80.149.25434.80.149.255510
7634.80.150.0/2334.80.150.1 to 34.80.151.25434.80.151.255510
7734.80.152.0/2334.80.152.1 to 34.80.153.25434.80.153.255510
7834.80.154.0/2334.80.154.1 to 34.80.155.25434.80.155.255510
7934.80.156.0/2334.80.156.1 to 34.80.157.25434.80.157.255510
8034.80.158.0/2334.80.158.1 to 34.80.159.25434.80.159.255510
8134.80.160.0/2334.80.160.1 to 34.80.161.25434.80.161.255510
8234.80.162.0/2334.80.162.1 to 34.80.163.25434.80.163.255510
8334.80.164.0/2334.80.164.1 to 34.80.165.25434.80.165.255510
8434.80.166.0/2334.80.166.1 to 34.80.167.25434.80.167.255510
8534.80.168.0/2334.80.168.1 to 34.80.169.25434.80.169.255510
8634.80.170.0/2334.80.170.1 to 34.80.171.25434.80.171.255510
8734.80.172.0/2334.80.172.1 to 34.80.173.25434.80.173.255510
8834.80.174.0/2334.80.174.1 to 34.80.175.25434.80.175.255510
8934.80.176.0/2334.80.176.1 to 34.80.177.25434.80.177.255510
9034.80.178.0/2334.80.178.1 to 34.80.179.25434.80.179.255510
9134.80.180.0/2334.80.180.1 to 34.80.181.25434.80.181.255510
9234.80.182.0/2334.80.182.1 to 34.80.183.25434.80.183.255510
9334.80.184.0/2334.80.184.1 to 34.80.185.25434.80.185.255510
9434.80.186.0/2334.80.186.1 to 34.80.187.25434.80.187.255510
9534.80.188.0/2334.80.188.1 to 34.80.189.25434.80.189.255510
9634.80.190.0/2334.80.190.1 to 34.80.191.25434.80.191.255510
9734.80.192.0/2334.80.192.1 to 34.80.193.25434.80.193.255510
9834.80.194.0/2334.80.194.1 to 34.80.195.25434.80.195.255510
9934.80.196.0/2334.80.196.1 to 34.80.197.25434.80.197.255510
10034.80.198.0/2334.80.198.1 to 34.80.199.25434.80.199.255510
10134.80.200.0/2334.80.200.1 to 34.80.201.25434.80.201.255510
10234.80.202.0/2334.80.202.1 to 34.80.203.25434.80.203.255510
10334.80.204.0/2334.80.204.1 to 34.80.205.25434.80.205.255510
10434.80.206.0/2334.80.206.1 to 34.80.207.25434.80.207.255510
10534.80.208.0/2334.80.208.1 to 34.80.209.25434.80.209.255510
10634.80.210.0/2334.80.210.1 to 34.80.211.25434.80.211.255510
10734.80.212.0/2334.80.212.1 to 34.80.213.25434.80.213.255510
10834.80.214.0/2334.80.214.1 to 34.80.215.25434.80.215.255510
10934.80.216.0/2334.80.216.1 to 34.80.217.25434.80.217.255510
11034.80.218.0/2334.80.218.1 to 34.80.219.25434.80.219.255510
11134.80.220.0/2334.80.220.1 to 34.80.221.25434.80.221.255510
11234.80.222.0/2334.80.222.1 to 34.80.223.25434.80.223.255510
11334.80.224.0/2334.80.224.1 to 34.80.225.25434.80.225.255510
11434.80.226.0/2334.80.226.1 to 34.80.227.25434.80.227.255510
11534.80.228.0/2334.80.228.1 to 34.80.229.25434.80.229.255510
11634.80.230.0/2334.80.230.1 to 34.80.231.25434.80.231.255510
11734.80.232.0/2334.80.232.1 to 34.80.233.25434.80.233.255510
11834.80.234.0/2334.80.234.1 to 34.80.235.25434.80.235.255510
11934.80.236.0/2334.80.236.1 to 34.80.237.25434.80.237.255510
12034.80.238.0/2334.80.238.1 to 34.80.239.25434.80.239.255510
12134.80.240.0/2334.80.240.1 to 34.80.241.25434.80.241.255510
12234.80.242.0/2334.80.242.1 to 34.80.243.25434.80.243.255510
12334.80.244.0/2334.80.244.1 to 34.80.245.25434.80.245.255510
12434.80.246.0/2334.80.246.1 to 34.80.247.25434.80.247.255510
12534.80.248.0/2334.80.248.1 to 34.80.249.25434.80.249.255510
12634.80.250.0/2334.80.250.1 to 34.80.251.25434.80.251.255510
12734.80.252.0/2334.80.252.1 to 34.80.253.25434.80.253.255510
12834.80.254.0/2334.80.254.1 to 34.80.255.25434.80.255.255510
12934.81.0.0/2334.81.0.1 to 34.81.1.25434.81.1.255510
13034.81.2.0/2334.81.2.1 to 34.81.3.25434.81.3.255510
13134.81.4.0/2334.81.4.1 to 34.81.5.25434.81.5.255510
13234.81.6.0/2334.81.6.1 to 34.81.7.25434.81.7.255510
13334.81.8.0/2334.81.8.1 to 34.81.9.25434.81.9.255510
13434.81.10.0/2334.81.10.1 to 34.81.11.25434.81.11.255510
13534.81.12.0/2334.81.12.1 to 34.81.13.25434.81.13.255510
13634.81.14.0/2334.81.14.1 to 34.81.15.25434.81.15.255510
13734.81.16.0/2334.81.16.1 to 34.81.17.25434.81.17.255510
13834.81.18.0/2334.81.18.1 to 34.81.19.25434.81.19.255510
13934.81.20.0/2334.81.20.1 to 34.81.21.25434.81.21.255510
14034.81.22.0/2334.81.22.1 to 34.81.23.25434.81.23.255510
14134.81.24.0/2334.81.24.1 to 34.81.25.25434.81.25.255510
14234.81.26.0/2334.81.26.1 to 34.81.27.25434.81.27.255510
14334.81.28.0/2334.81.28.1 to 34.81.29.25434.81.29.255510
14434.81.30.0/2334.81.30.1 to 34.81.31.25434.81.31.255510
14534.81.32.0/2334.81.32.1 to 34.81.33.25434.81.33.255510
14634.81.34.0/2334.81.34.1 to 34.81.35.25434.81.35.255510
14734.81.36.0/2334.81.36.1 to 34.81.37.25434.81.37.255510
14834.81.38.0/2334.81.38.1 to 34.81.39.25434.81.39.255510
14934.81.40.0/2334.81.40.1 to 34.81.41.25434.81.41.255510
15034.81.42.0/2334.81.42.1 to 34.81.43.25434.81.43.255510
15134.81.44.0/2334.81.44.1 to 34.81.45.25434.81.45.255510
15234.81.46.0/2334.81.46.1 to 34.81.47.25434.81.47.255510
15334.81.48.0/2334.81.48.1 to 34.81.49.25434.81.49.255510
15434.81.50.0/2334.81.50.1 to 34.81.51.25434.81.51.255510
15534.81.52.0/2334.81.52.1 to 34.81.53.25434.81.53.255510
15634.81.54.0/2334.81.54.1 to 34.81.55.25434.81.55.255510
15734.81.56.0/2334.81.56.1 to 34.81.57.25434.81.57.255510
15834.81.58.0/2334.81.58.1 to 34.81.59.25434.81.59.255510
15934.81.60.0/2334.81.60.1 to 34.81.61.25434.81.61.255510
16034.81.62.0/2334.81.62.1 to 34.81.63.25434.81.63.255510
16134.81.64.0/2334.81.64.1 to 34.81.65.25434.81.65.255510
16234.81.66.0/2334.81.66.1 to 34.81.67.25434.81.67.255510
16334.81.68.0/2334.81.68.1 to 34.81.69.25434.81.69.255510
16434.81.70.0/2334.81.70.1 to 34.81.71.25434.81.71.255510
16534.81.72.0/2334.81.72.1 to 34.81.73.25434.81.73.255510
16634.81.74.0/2334.81.74.1 to 34.81.75.25434.81.75.255510
16734.81.76.0/2334.81.76.1 to 34.81.77.25434.81.77.255510
16834.81.78.0/2334.81.78.1 to 34.81.79.25434.81.79.255510
16934.81.80.0/2334.81.80.1 to 34.81.81.25434.81.81.255510
17034.81.82.0/2334.81.82.1 to 34.81.83.25434.81.83.255510
17134.81.84.0/2334.81.84.1 to 34.81.85.25434.81.85.255510
17234.81.86.0/2334.81.86.1 to 34.81.87.25434.81.87.255510
17334.81.88.0/2334.81.88.1 to 34.81.89.25434.81.89.255510
17434.81.90.0/2334.81.90.1 to 34.81.91.25434.81.91.255510
17534.81.92.0/2334.81.92.1 to 34.81.93.25434.81.93.255510
17634.81.94.0/2334.81.94.1 to 34.81.95.25434.81.95.255510
17734.81.96.0/2334.81.96.1 to 34.81.97.25434.81.97.255510
17834.81.98.0/2334.81.98.1 to 34.81.99.25434.81.99.255510
17934.81.100.0/2334.81.100.1 to 34.81.101.25434.81.101.255510
18034.81.102.0/2334.81.102.1 to 34.81.103.25434.81.103.255510
18134.81.104.0/2334.81.104.1 to 34.81.105.25434.81.105.255510
18234.81.106.0/2334.81.106.1 to 34.81.107.25434.81.107.255510
18334.81.108.0/2334.81.108.1 to 34.81.109.25434.81.109.255510
18434.81.110.0/2334.81.110.1 to 34.81.111.25434.81.111.255510
18534.81.112.0/2334.81.112.1 to 34.81.113.25434.81.113.255510
18634.81.114.0/2334.81.114.1 to 34.81.115.25434.81.115.255510
18734.81.116.0/2334.81.116.1 to 34.81.117.25434.81.117.255510
18834.81.118.0/2334.81.118.1 to 34.81.119.25434.81.119.255510
18934.81.120.0/2334.81.120.1 to 34.81.121.25434.81.121.255510
19034.81.122.0/2334.81.122.1 to 34.81.123.25434.81.123.255510
19134.81.124.0/2334.81.124.1 to 34.81.125.25434.81.125.255510
19234.81.126.0/2334.81.126.1 to 34.81.127.25434.81.127.255510
19334.81.128.0/2334.81.128.1 to 34.81.129.25434.81.129.255510
19434.81.130.0/2334.81.130.1 to 34.81.131.25434.81.131.255510
19534.81.132.0/2334.81.132.1 to 34.81.133.25434.81.133.255510
19634.81.134.0/2334.81.134.1 to 34.81.135.25434.81.135.255510
19734.81.136.0/2334.81.136.1 to 34.81.137.25434.81.137.255510
19834.81.138.0/2334.81.138.1 to 34.81.139.25434.81.139.255510
19934.81.140.0/2334.81.140.1 to 34.81.141.25434.81.141.255510
20034.81.142.0/2334.81.142.1 to 34.81.143.25434.81.143.255510
20134.81.144.0/2334.81.144.1 to 34.81.145.25434.81.145.255510
20234.81.146.0/2334.81.146.1 to 34.81.147.25434.81.147.255510
20334.81.148.0/2334.81.148.1 to 34.81.149.25434.81.149.255510
20434.81.150.0/2334.81.150.1 to 34.81.151.25434.81.151.255510
20534.81.152.0/2334.81.152.1 to 34.81.153.25434.81.153.255510
20634.81.154.0/2334.81.154.1 to 34.81.155.25434.81.155.255510
20734.81.156.0/2334.81.156.1 to 34.81.157.25434.81.157.255510
20834.81.158.0/2334.81.158.1 to 34.81.159.25434.81.159.255510
20934.81.160.0/2334.81.160.1 to 34.81.161.25434.81.161.255510
21034.81.162.0/2334.81.162.1 to 34.81.163.25434.81.163.255510
21134.81.164.0/2334.81.164.1 to 34.81.165.25434.81.165.255510
21234.81.166.0/2334.81.166.1 to 34.81.167.25434.81.167.255510
21334.81.168.0/2334.81.168.1 to 34.81.169.25434.81.169.255510
21434.81.170.0/2334.81.170.1 to 34.81.171.25434.81.171.255510
21534.81.172.0/2334.81.172.1 to 34.81.173.25434.81.173.255510
21634.81.174.0/2334.81.174.1 to 34.81.175.25434.81.175.255510
21734.81.176.0/2334.81.176.1 to 34.81.177.25434.81.177.255510
21834.81.178.0/2334.81.178.1 to 34.81.179.25434.81.179.255510
21934.81.180.0/2334.81.180.1 to 34.81.181.25434.81.181.255510
22034.81.182.0/2334.81.182.1 to 34.81.183.25434.81.183.255510
22134.81.184.0/2334.81.184.1 to 34.81.185.25434.81.185.255510
22234.81.186.0/2334.81.186.1 to 34.81.187.25434.81.187.255510
22334.81.188.0/2334.81.188.1 to 34.81.189.25434.81.189.255510
22434.81.190.0/2334.81.190.1 to 34.81.191.25434.81.191.255510
22534.81.192.0/2334.81.192.1 to 34.81.193.25434.81.193.255510
22634.81.194.0/2334.81.194.1 to 34.81.195.25434.81.195.255510
22734.81.196.0/2334.81.196.1 to 34.81.197.25434.81.197.255510
22834.81.198.0/2334.81.198.1 to 34.81.199.25434.81.199.255510
22934.81.200.0/2334.81.200.1 to 34.81.201.25434.81.201.255510
23034.81.202.0/2334.81.202.1 to 34.81.203.25434.81.203.255510
23134.81.204.0/2334.81.204.1 to 34.81.205.25434.81.205.255510
23234.81.206.0/2334.81.206.1 to 34.81.207.25434.81.207.255510
23334.81.208.0/2334.81.208.1 to 34.81.209.25434.81.209.255510
23434.81.210.0/2334.81.210.1 to 34.81.211.25434.81.211.255510
23534.81.212.0/2334.81.212.1 to 34.81.213.25434.81.213.255510
23634.81.214.0/2334.81.214.1 to 34.81.215.25434.81.215.255510
23734.81.216.0/2334.81.216.1 to 34.81.217.25434.81.217.255510
23834.81.218.0/2334.81.218.1 to 34.81.219.25434.81.219.255510
23934.81.220.0/2334.81.220.1 to 34.81.221.25434.81.221.255510
24034.81.222.0/2334.81.222.1 to 34.81.223.25434.81.223.255510
24134.81.224.0/2334.81.224.1 to 34.81.225.25434.81.225.255510
24234.81.226.0/2334.81.226.1 to 34.81.227.25434.81.227.255510
24334.81.228.0/2334.81.228.1 to 34.81.229.25434.81.229.255510
24434.81.230.0/2334.81.230.1 to 34.81.231.25434.81.231.255510
24534.81.232.0/2334.81.232.1 to 34.81.233.25434.81.233.255510
24634.81.234.0/2334.81.234.1 to 34.81.235.25434.81.235.255510
24734.81.236.0/2334.81.236.1 to 34.81.237.25434.81.237.255510
24834.81.238.0/2334.81.238.1 to 34.81.239.25434.81.239.255510
24934.81.240.0/2334.81.240.1 to 34.81.241.25434.81.241.255510
25034.81.242.0/2334.81.242.1 to 34.81.243.25434.81.243.255510
25134.81.244.0/2334.81.244.1 to 34.81.245.25434.81.245.255510
25234.81.246.0/2334.81.246.1 to 34.81.247.25434.81.247.255510
25334.81.248.0/2334.81.248.1 to 34.81.249.25434.81.249.255510
25434.81.250.0/2334.81.250.1 to 34.81.251.25434.81.251.255510
25534.81.252.0/2334.81.252.1 to 34.81.253.25434.81.253.255510
25634.81.254.0/2334.81.254.1 to 34.81.255.25434.81.255.255510

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.