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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.

Network36.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
36.0.0.0
Broadcast address
37.255.255.255
First usable
36.0.0.1
Last usable
37.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 24000000 · Integer 603979776 to 637534207
Reverse DNS zones
36.in-addr.arpa
37.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100100.00000000.00000000.0000000036.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00100100.00000000.00000000.0000000036.0.0.0
Broadcast00100101.11111111.11111111.1111111137.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

36.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
136.0.0.0/1536.0.0.1 to 36.1.255.25436.1.255.255131,070
236.2.0.0/1536.2.0.1 to 36.3.255.25436.3.255.255131,070
336.4.0.0/1536.4.0.1 to 36.5.255.25436.5.255.255131,070
436.6.0.0/1536.6.0.1 to 36.7.255.25436.7.255.255131,070
536.8.0.0/1536.8.0.1 to 36.9.255.25436.9.255.255131,070
636.10.0.0/1536.10.0.1 to 36.11.255.25436.11.255.255131,070
736.12.0.0/1536.12.0.1 to 36.13.255.25436.13.255.255131,070
836.14.0.0/1536.14.0.1 to 36.15.255.25436.15.255.255131,070
936.16.0.0/1536.16.0.1 to 36.17.255.25436.17.255.255131,070
1036.18.0.0/1536.18.0.1 to 36.19.255.25436.19.255.255131,070
1136.20.0.0/1536.20.0.1 to 36.21.255.25436.21.255.255131,070
1236.22.0.0/1536.22.0.1 to 36.23.255.25436.23.255.255131,070
1336.24.0.0/1536.24.0.1 to 36.25.255.25436.25.255.255131,070
1436.26.0.0/1536.26.0.1 to 36.27.255.25436.27.255.255131,070
1536.28.0.0/1536.28.0.1 to 36.29.255.25436.29.255.255131,070
1636.30.0.0/1536.30.0.1 to 36.31.255.25436.31.255.255131,070
1736.32.0.0/1536.32.0.1 to 36.33.255.25436.33.255.255131,070
1836.34.0.0/1536.34.0.1 to 36.35.255.25436.35.255.255131,070
1936.36.0.0/1536.36.0.1 to 36.37.255.25436.37.255.255131,070
2036.38.0.0/1536.38.0.1 to 36.39.255.25436.39.255.255131,070
2136.40.0.0/1536.40.0.1 to 36.41.255.25436.41.255.255131,070
2236.42.0.0/1536.42.0.1 to 36.43.255.25436.43.255.255131,070
2336.44.0.0/1536.44.0.1 to 36.45.255.25436.45.255.255131,070
2436.46.0.0/1536.46.0.1 to 36.47.255.25436.47.255.255131,070
2536.48.0.0/1536.48.0.1 to 36.49.255.25436.49.255.255131,070
2636.50.0.0/1536.50.0.1 to 36.51.255.25436.51.255.255131,070
2736.52.0.0/1536.52.0.1 to 36.53.255.25436.53.255.255131,070
2836.54.0.0/1536.54.0.1 to 36.55.255.25436.55.255.255131,070
2936.56.0.0/1536.56.0.1 to 36.57.255.25436.57.255.255131,070
3036.58.0.0/1536.58.0.1 to 36.59.255.25436.59.255.255131,070
3136.60.0.0/1536.60.0.1 to 36.61.255.25436.61.255.255131,070
3236.62.0.0/1536.62.0.1 to 36.63.255.25436.63.255.255131,070
3336.64.0.0/1536.64.0.1 to 36.65.255.25436.65.255.255131,070
3436.66.0.0/1536.66.0.1 to 36.67.255.25436.67.255.255131,070
3536.68.0.0/1536.68.0.1 to 36.69.255.25436.69.255.255131,070
3636.70.0.0/1536.70.0.1 to 36.71.255.25436.71.255.255131,070
3736.72.0.0/1536.72.0.1 to 36.73.255.25436.73.255.255131,070
3836.74.0.0/1536.74.0.1 to 36.75.255.25436.75.255.255131,070
3936.76.0.0/1536.76.0.1 to 36.77.255.25436.77.255.255131,070
4036.78.0.0/1536.78.0.1 to 36.79.255.25436.79.255.255131,070
4136.80.0.0/1536.80.0.1 to 36.81.255.25436.81.255.255131,070
4236.82.0.0/1536.82.0.1 to 36.83.255.25436.83.255.255131,070
4336.84.0.0/1536.84.0.1 to 36.85.255.25436.85.255.255131,070
4436.86.0.0/1536.86.0.1 to 36.87.255.25436.87.255.255131,070
4536.88.0.0/1536.88.0.1 to 36.89.255.25436.89.255.255131,070
4636.90.0.0/1536.90.0.1 to 36.91.255.25436.91.255.255131,070
4736.92.0.0/1536.92.0.1 to 36.93.255.25436.93.255.255131,070
4836.94.0.0/1536.94.0.1 to 36.95.255.25436.95.255.255131,070
4936.96.0.0/1536.96.0.1 to 36.97.255.25436.97.255.255131,070
5036.98.0.0/1536.98.0.1 to 36.99.255.25436.99.255.255131,070
5136.100.0.0/1536.100.0.1 to 36.101.255.25436.101.255.255131,070
5236.102.0.0/1536.102.0.1 to 36.103.255.25436.103.255.255131,070
5336.104.0.0/1536.104.0.1 to 36.105.255.25436.105.255.255131,070
5436.106.0.0/1536.106.0.1 to 36.107.255.25436.107.255.255131,070
5536.108.0.0/1536.108.0.1 to 36.109.255.25436.109.255.255131,070
5636.110.0.0/1536.110.0.1 to 36.111.255.25436.111.255.255131,070
5736.112.0.0/1536.112.0.1 to 36.113.255.25436.113.255.255131,070
5836.114.0.0/1536.114.0.1 to 36.115.255.25436.115.255.255131,070
5936.116.0.0/1536.116.0.1 to 36.117.255.25436.117.255.255131,070
6036.118.0.0/1536.118.0.1 to 36.119.255.25436.119.255.255131,070
6136.120.0.0/1536.120.0.1 to 36.121.255.25436.121.255.255131,070
6236.122.0.0/1536.122.0.1 to 36.123.255.25436.123.255.255131,070
6336.124.0.0/1536.124.0.1 to 36.125.255.25436.125.255.255131,070
6436.126.0.0/1536.126.0.1 to 36.127.255.25436.127.255.255131,070
6536.128.0.0/1536.128.0.1 to 36.129.255.25436.129.255.255131,070
6636.130.0.0/1536.130.0.1 to 36.131.255.25436.131.255.255131,070
6736.132.0.0/1536.132.0.1 to 36.133.255.25436.133.255.255131,070
6836.134.0.0/1536.134.0.1 to 36.135.255.25436.135.255.255131,070
6936.136.0.0/1536.136.0.1 to 36.137.255.25436.137.255.255131,070
7036.138.0.0/1536.138.0.1 to 36.139.255.25436.139.255.255131,070
7136.140.0.0/1536.140.0.1 to 36.141.255.25436.141.255.255131,070
7236.142.0.0/1536.142.0.1 to 36.143.255.25436.143.255.255131,070
7336.144.0.0/1536.144.0.1 to 36.145.255.25436.145.255.255131,070
7436.146.0.0/1536.146.0.1 to 36.147.255.25436.147.255.255131,070
7536.148.0.0/1536.148.0.1 to 36.149.255.25436.149.255.255131,070
7636.150.0.0/1536.150.0.1 to 36.151.255.25436.151.255.255131,070
7736.152.0.0/1536.152.0.1 to 36.153.255.25436.153.255.255131,070
7836.154.0.0/1536.154.0.1 to 36.155.255.25436.155.255.255131,070
7936.156.0.0/1536.156.0.1 to 36.157.255.25436.157.255.255131,070
8036.158.0.0/1536.158.0.1 to 36.159.255.25436.159.255.255131,070
8136.160.0.0/1536.160.0.1 to 36.161.255.25436.161.255.255131,070
8236.162.0.0/1536.162.0.1 to 36.163.255.25436.163.255.255131,070
8336.164.0.0/1536.164.0.1 to 36.165.255.25436.165.255.255131,070
8436.166.0.0/1536.166.0.1 to 36.167.255.25436.167.255.255131,070
8536.168.0.0/1536.168.0.1 to 36.169.255.25436.169.255.255131,070
8636.170.0.0/1536.170.0.1 to 36.171.255.25436.171.255.255131,070
8736.172.0.0/1536.172.0.1 to 36.173.255.25436.173.255.255131,070
8836.174.0.0/1536.174.0.1 to 36.175.255.25436.175.255.255131,070
8936.176.0.0/1536.176.0.1 to 36.177.255.25436.177.255.255131,070
9036.178.0.0/1536.178.0.1 to 36.179.255.25436.179.255.255131,070
9136.180.0.0/1536.180.0.1 to 36.181.255.25436.181.255.255131,070
9236.182.0.0/1536.182.0.1 to 36.183.255.25436.183.255.255131,070
9336.184.0.0/1536.184.0.1 to 36.185.255.25436.185.255.255131,070
9436.186.0.0/1536.186.0.1 to 36.187.255.25436.187.255.255131,070
9536.188.0.0/1536.188.0.1 to 36.189.255.25436.189.255.255131,070
9636.190.0.0/1536.190.0.1 to 36.191.255.25436.191.255.255131,070
9736.192.0.0/1536.192.0.1 to 36.193.255.25436.193.255.255131,070
9836.194.0.0/1536.194.0.1 to 36.195.255.25436.195.255.255131,070
9936.196.0.0/1536.196.0.1 to 36.197.255.25436.197.255.255131,070
10036.198.0.0/1536.198.0.1 to 36.199.255.25436.199.255.255131,070
10136.200.0.0/1536.200.0.1 to 36.201.255.25436.201.255.255131,070
10236.202.0.0/1536.202.0.1 to 36.203.255.25436.203.255.255131,070
10336.204.0.0/1536.204.0.1 to 36.205.255.25436.205.255.255131,070
10436.206.0.0/1536.206.0.1 to 36.207.255.25436.207.255.255131,070
10536.208.0.0/1536.208.0.1 to 36.209.255.25436.209.255.255131,070
10636.210.0.0/1536.210.0.1 to 36.211.255.25436.211.255.255131,070
10736.212.0.0/1536.212.0.1 to 36.213.255.25436.213.255.255131,070
10836.214.0.0/1536.214.0.1 to 36.215.255.25436.215.255.255131,070
10936.216.0.0/1536.216.0.1 to 36.217.255.25436.217.255.255131,070
11036.218.0.0/1536.218.0.1 to 36.219.255.25436.219.255.255131,070
11136.220.0.0/1536.220.0.1 to 36.221.255.25436.221.255.255131,070
11236.222.0.0/1536.222.0.1 to 36.223.255.25436.223.255.255131,070
11336.224.0.0/1536.224.0.1 to 36.225.255.25436.225.255.255131,070
11436.226.0.0/1536.226.0.1 to 36.227.255.25436.227.255.255131,070
11536.228.0.0/1536.228.0.1 to 36.229.255.25436.229.255.255131,070
11636.230.0.0/1536.230.0.1 to 36.231.255.25436.231.255.255131,070
11736.232.0.0/1536.232.0.1 to 36.233.255.25436.233.255.255131,070
11836.234.0.0/1536.234.0.1 to 36.235.255.25436.235.255.255131,070
11936.236.0.0/1536.236.0.1 to 36.237.255.25436.237.255.255131,070
12036.238.0.0/1536.238.0.1 to 36.239.255.25436.239.255.255131,070
12136.240.0.0/1536.240.0.1 to 36.241.255.25436.241.255.255131,070
12236.242.0.0/1536.242.0.1 to 36.243.255.25436.243.255.255131,070
12336.244.0.0/1536.244.0.1 to 36.245.255.25436.245.255.255131,070
12436.246.0.0/1536.246.0.1 to 36.247.255.25436.247.255.255131,070
12536.248.0.0/1536.248.0.1 to 36.249.255.25436.249.255.255131,070
12636.250.0.0/1536.250.0.1 to 36.251.255.25436.251.255.255131,070
12736.252.0.0/1536.252.0.1 to 36.253.255.25436.253.255.255131,070
12836.254.0.0/1536.254.0.1 to 36.255.255.25436.255.255.255131,070
12937.0.0.0/1537.0.0.1 to 37.1.255.25437.1.255.255131,070
13037.2.0.0/1537.2.0.1 to 37.3.255.25437.3.255.255131,070
13137.4.0.0/1537.4.0.1 to 37.5.255.25437.5.255.255131,070
13237.6.0.0/1537.6.0.1 to 37.7.255.25437.7.255.255131,070
13337.8.0.0/1537.8.0.1 to 37.9.255.25437.9.255.255131,070
13437.10.0.0/1537.10.0.1 to 37.11.255.25437.11.255.255131,070
13537.12.0.0/1537.12.0.1 to 37.13.255.25437.13.255.255131,070
13637.14.0.0/1537.14.0.1 to 37.15.255.25437.15.255.255131,070
13737.16.0.0/1537.16.0.1 to 37.17.255.25437.17.255.255131,070
13837.18.0.0/1537.18.0.1 to 37.19.255.25437.19.255.255131,070
13937.20.0.0/1537.20.0.1 to 37.21.255.25437.21.255.255131,070
14037.22.0.0/1537.22.0.1 to 37.23.255.25437.23.255.255131,070
14137.24.0.0/1537.24.0.1 to 37.25.255.25437.25.255.255131,070
14237.26.0.0/1537.26.0.1 to 37.27.255.25437.27.255.255131,070
14337.28.0.0/1537.28.0.1 to 37.29.255.25437.29.255.255131,070
14437.30.0.0/1537.30.0.1 to 37.31.255.25437.31.255.255131,070
14537.32.0.0/1537.32.0.1 to 37.33.255.25437.33.255.255131,070
14637.34.0.0/1537.34.0.1 to 37.35.255.25437.35.255.255131,070
14737.36.0.0/1537.36.0.1 to 37.37.255.25437.37.255.255131,070
14837.38.0.0/1537.38.0.1 to 37.39.255.25437.39.255.255131,070
14937.40.0.0/1537.40.0.1 to 37.41.255.25437.41.255.255131,070
15037.42.0.0/1537.42.0.1 to 37.43.255.25437.43.255.255131,070
15137.44.0.0/1537.44.0.1 to 37.45.255.25437.45.255.255131,070
15237.46.0.0/1537.46.0.1 to 37.47.255.25437.47.255.255131,070
15337.48.0.0/1537.48.0.1 to 37.49.255.25437.49.255.255131,070
15437.50.0.0/1537.50.0.1 to 37.51.255.25437.51.255.255131,070
15537.52.0.0/1537.52.0.1 to 37.53.255.25437.53.255.255131,070
15637.54.0.0/1537.54.0.1 to 37.55.255.25437.55.255.255131,070
15737.56.0.0/1537.56.0.1 to 37.57.255.25437.57.255.255131,070
15837.58.0.0/1537.58.0.1 to 37.59.255.25437.59.255.255131,070
15937.60.0.0/1537.60.0.1 to 37.61.255.25437.61.255.255131,070
16037.62.0.0/1537.62.0.1 to 37.63.255.25437.63.255.255131,070
16137.64.0.0/1537.64.0.1 to 37.65.255.25437.65.255.255131,070
16237.66.0.0/1537.66.0.1 to 37.67.255.25437.67.255.255131,070
16337.68.0.0/1537.68.0.1 to 37.69.255.25437.69.255.255131,070
16437.70.0.0/1537.70.0.1 to 37.71.255.25437.71.255.255131,070
16537.72.0.0/1537.72.0.1 to 37.73.255.25437.73.255.255131,070
16637.74.0.0/1537.74.0.1 to 37.75.255.25437.75.255.255131,070
16737.76.0.0/1537.76.0.1 to 37.77.255.25437.77.255.255131,070
16837.78.0.0/1537.78.0.1 to 37.79.255.25437.79.255.255131,070
16937.80.0.0/1537.80.0.1 to 37.81.255.25437.81.255.255131,070
17037.82.0.0/1537.82.0.1 to 37.83.255.25437.83.255.255131,070
17137.84.0.0/1537.84.0.1 to 37.85.255.25437.85.255.255131,070
17237.86.0.0/1537.86.0.1 to 37.87.255.25437.87.255.255131,070
17337.88.0.0/1537.88.0.1 to 37.89.255.25437.89.255.255131,070
17437.90.0.0/1537.90.0.1 to 37.91.255.25437.91.255.255131,070
17537.92.0.0/1537.92.0.1 to 37.93.255.25437.93.255.255131,070
17637.94.0.0/1537.94.0.1 to 37.95.255.25437.95.255.255131,070
17737.96.0.0/1537.96.0.1 to 37.97.255.25437.97.255.255131,070
17837.98.0.0/1537.98.0.1 to 37.99.255.25437.99.255.255131,070
17937.100.0.0/1537.100.0.1 to 37.101.255.25437.101.255.255131,070
18037.102.0.0/1537.102.0.1 to 37.103.255.25437.103.255.255131,070
18137.104.0.0/1537.104.0.1 to 37.105.255.25437.105.255.255131,070
18237.106.0.0/1537.106.0.1 to 37.107.255.25437.107.255.255131,070
18337.108.0.0/1537.108.0.1 to 37.109.255.25437.109.255.255131,070
18437.110.0.0/1537.110.0.1 to 37.111.255.25437.111.255.255131,070
18537.112.0.0/1537.112.0.1 to 37.113.255.25437.113.255.255131,070
18637.114.0.0/1537.114.0.1 to 37.115.255.25437.115.255.255131,070
18737.116.0.0/1537.116.0.1 to 37.117.255.25437.117.255.255131,070
18837.118.0.0/1537.118.0.1 to 37.119.255.25437.119.255.255131,070
18937.120.0.0/1537.120.0.1 to 37.121.255.25437.121.255.255131,070
19037.122.0.0/1537.122.0.1 to 37.123.255.25437.123.255.255131,070
19137.124.0.0/1537.124.0.1 to 37.125.255.25437.125.255.255131,070
19237.126.0.0/1537.126.0.1 to 37.127.255.25437.127.255.255131,070
19337.128.0.0/1537.128.0.1 to 37.129.255.25437.129.255.255131,070
19437.130.0.0/1537.130.0.1 to 37.131.255.25437.131.255.255131,070
19537.132.0.0/1537.132.0.1 to 37.133.255.25437.133.255.255131,070
19637.134.0.0/1537.134.0.1 to 37.135.255.25437.135.255.255131,070
19737.136.0.0/1537.136.0.1 to 37.137.255.25437.137.255.255131,070
19837.138.0.0/1537.138.0.1 to 37.139.255.25437.139.255.255131,070
19937.140.0.0/1537.140.0.1 to 37.141.255.25437.141.255.255131,070
20037.142.0.0/1537.142.0.1 to 37.143.255.25437.143.255.255131,070
20137.144.0.0/1537.144.0.1 to 37.145.255.25437.145.255.255131,070
20237.146.0.0/1537.146.0.1 to 37.147.255.25437.147.255.255131,070
20337.148.0.0/1537.148.0.1 to 37.149.255.25437.149.255.255131,070
20437.150.0.0/1537.150.0.1 to 37.151.255.25437.151.255.255131,070
20537.152.0.0/1537.152.0.1 to 37.153.255.25437.153.255.255131,070
20637.154.0.0/1537.154.0.1 to 37.155.255.25437.155.255.255131,070
20737.156.0.0/1537.156.0.1 to 37.157.255.25437.157.255.255131,070
20837.158.0.0/1537.158.0.1 to 37.159.255.25437.159.255.255131,070
20937.160.0.0/1537.160.0.1 to 37.161.255.25437.161.255.255131,070
21037.162.0.0/1537.162.0.1 to 37.163.255.25437.163.255.255131,070
21137.164.0.0/1537.164.0.1 to 37.165.255.25437.165.255.255131,070
21237.166.0.0/1537.166.0.1 to 37.167.255.25437.167.255.255131,070
21337.168.0.0/1537.168.0.1 to 37.169.255.25437.169.255.255131,070
21437.170.0.0/1537.170.0.1 to 37.171.255.25437.171.255.255131,070
21537.172.0.0/1537.172.0.1 to 37.173.255.25437.173.255.255131,070
21637.174.0.0/1537.174.0.1 to 37.175.255.25437.175.255.255131,070
21737.176.0.0/1537.176.0.1 to 37.177.255.25437.177.255.255131,070
21837.178.0.0/1537.178.0.1 to 37.179.255.25437.179.255.255131,070
21937.180.0.0/1537.180.0.1 to 37.181.255.25437.181.255.255131,070
22037.182.0.0/1537.182.0.1 to 37.183.255.25437.183.255.255131,070
22137.184.0.0/1537.184.0.1 to 37.185.255.25437.185.255.255131,070
22237.186.0.0/1537.186.0.1 to 37.187.255.25437.187.255.255131,070
22337.188.0.0/1537.188.0.1 to 37.189.255.25437.189.255.255131,070
22437.190.0.0/1537.190.0.1 to 37.191.255.25437.191.255.255131,070
22537.192.0.0/1537.192.0.1 to 37.193.255.25437.193.255.255131,070
22637.194.0.0/1537.194.0.1 to 37.195.255.25437.195.255.255131,070
22737.196.0.0/1537.196.0.1 to 37.197.255.25437.197.255.255131,070
22837.198.0.0/1537.198.0.1 to 37.199.255.25437.199.255.255131,070
22937.200.0.0/1537.200.0.1 to 37.201.255.25437.201.255.255131,070
23037.202.0.0/1537.202.0.1 to 37.203.255.25437.203.255.255131,070
23137.204.0.0/1537.204.0.1 to 37.205.255.25437.205.255.255131,070
23237.206.0.0/1537.206.0.1 to 37.207.255.25437.207.255.255131,070
23337.208.0.0/1537.208.0.1 to 37.209.255.25437.209.255.255131,070
23437.210.0.0/1537.210.0.1 to 37.211.255.25437.211.255.255131,070
23537.212.0.0/1537.212.0.1 to 37.213.255.25437.213.255.255131,070
23637.214.0.0/1537.214.0.1 to 37.215.255.25437.215.255.255131,070
23737.216.0.0/1537.216.0.1 to 37.217.255.25437.217.255.255131,070
23837.218.0.0/1537.218.0.1 to 37.219.255.25437.219.255.255131,070
23937.220.0.0/1537.220.0.1 to 37.221.255.25437.221.255.255131,070
24037.222.0.0/1537.222.0.1 to 37.223.255.25437.223.255.255131,070
24137.224.0.0/1537.224.0.1 to 37.225.255.25437.225.255.255131,070
24237.226.0.0/1537.226.0.1 to 37.227.255.25437.227.255.255131,070
24337.228.0.0/1537.228.0.1 to 37.229.255.25437.229.255.255131,070
24437.230.0.0/1537.230.0.1 to 37.231.255.25437.231.255.255131,070
24537.232.0.0/1537.232.0.1 to 37.233.255.25437.233.255.255131,070
24637.234.0.0/1537.234.0.1 to 37.235.255.25437.235.255.255131,070
24737.236.0.0/1537.236.0.1 to 37.237.255.25437.237.255.255131,070
24837.238.0.0/1537.238.0.1 to 37.239.255.25437.239.255.255131,070
24937.240.0.0/1537.240.0.1 to 37.241.255.25437.241.255.255131,070
25037.242.0.0/1537.242.0.1 to 37.243.255.25437.243.255.255131,070
25137.244.0.0/1537.244.0.1 to 37.245.255.25437.245.255.255131,070
25237.246.0.0/1537.246.0.1 to 37.247.255.25437.247.255.255131,070
25337.248.0.0/1537.248.0.1 to 37.249.255.25437.249.255.255131,070
25437.250.0.0/1537.250.0.1 to 37.251.255.25437.251.255.255131,070
25537.252.0.0/1537.252.0.1 to 37.253.255.25437.253.255.255131,070
25637.254.0.0/1537.254.0.1 to 37.255.255.25437.255.255.255131,070

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.