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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.

Network48.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
48.166.0.0
Broadcast address
48.167.255.255
First usable
48.166.0.1
Last usable
48.167.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 30A60000 · Integer 816185344 to 816316415
Reverse DNS zones
166.48.in-addr.arpa
167.48.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110000.10100110.00000000.0000000048.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00110000.10100110.00000000.0000000048.166.0.0
Broadcast00110000.10100111.11111111.1111111148.167.255.255
Split into smaller subnets/23
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

48.166.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
148.166.0.0/2348.166.0.1 to 48.166.1.25448.166.1.255510
248.166.2.0/2348.166.2.1 to 48.166.3.25448.166.3.255510
348.166.4.0/2348.166.4.1 to 48.166.5.25448.166.5.255510
448.166.6.0/2348.166.6.1 to 48.166.7.25448.166.7.255510
548.166.8.0/2348.166.8.1 to 48.166.9.25448.166.9.255510
648.166.10.0/2348.166.10.1 to 48.166.11.25448.166.11.255510
748.166.12.0/2348.166.12.1 to 48.166.13.25448.166.13.255510
848.166.14.0/2348.166.14.1 to 48.166.15.25448.166.15.255510
948.166.16.0/2348.166.16.1 to 48.166.17.25448.166.17.255510
1048.166.18.0/2348.166.18.1 to 48.166.19.25448.166.19.255510
1148.166.20.0/2348.166.20.1 to 48.166.21.25448.166.21.255510
1248.166.22.0/2348.166.22.1 to 48.166.23.25448.166.23.255510
1348.166.24.0/2348.166.24.1 to 48.166.25.25448.166.25.255510
1448.166.26.0/2348.166.26.1 to 48.166.27.25448.166.27.255510
1548.166.28.0/2348.166.28.1 to 48.166.29.25448.166.29.255510
1648.166.30.0/2348.166.30.1 to 48.166.31.25448.166.31.255510
1748.166.32.0/2348.166.32.1 to 48.166.33.25448.166.33.255510
1848.166.34.0/2348.166.34.1 to 48.166.35.25448.166.35.255510
1948.166.36.0/2348.166.36.1 to 48.166.37.25448.166.37.255510
2048.166.38.0/2348.166.38.1 to 48.166.39.25448.166.39.255510
2148.166.40.0/2348.166.40.1 to 48.166.41.25448.166.41.255510
2248.166.42.0/2348.166.42.1 to 48.166.43.25448.166.43.255510
2348.166.44.0/2348.166.44.1 to 48.166.45.25448.166.45.255510
2448.166.46.0/2348.166.46.1 to 48.166.47.25448.166.47.255510
2548.166.48.0/2348.166.48.1 to 48.166.49.25448.166.49.255510
2648.166.50.0/2348.166.50.1 to 48.166.51.25448.166.51.255510
2748.166.52.0/2348.166.52.1 to 48.166.53.25448.166.53.255510
2848.166.54.0/2348.166.54.1 to 48.166.55.25448.166.55.255510
2948.166.56.0/2348.166.56.1 to 48.166.57.25448.166.57.255510
3048.166.58.0/2348.166.58.1 to 48.166.59.25448.166.59.255510
3148.166.60.0/2348.166.60.1 to 48.166.61.25448.166.61.255510
3248.166.62.0/2348.166.62.1 to 48.166.63.25448.166.63.255510
3348.166.64.0/2348.166.64.1 to 48.166.65.25448.166.65.255510
3448.166.66.0/2348.166.66.1 to 48.166.67.25448.166.67.255510
3548.166.68.0/2348.166.68.1 to 48.166.69.25448.166.69.255510
3648.166.70.0/2348.166.70.1 to 48.166.71.25448.166.71.255510
3748.166.72.0/2348.166.72.1 to 48.166.73.25448.166.73.255510
3848.166.74.0/2348.166.74.1 to 48.166.75.25448.166.75.255510
3948.166.76.0/2348.166.76.1 to 48.166.77.25448.166.77.255510
4048.166.78.0/2348.166.78.1 to 48.166.79.25448.166.79.255510
4148.166.80.0/2348.166.80.1 to 48.166.81.25448.166.81.255510
4248.166.82.0/2348.166.82.1 to 48.166.83.25448.166.83.255510
4348.166.84.0/2348.166.84.1 to 48.166.85.25448.166.85.255510
4448.166.86.0/2348.166.86.1 to 48.166.87.25448.166.87.255510
4548.166.88.0/2348.166.88.1 to 48.166.89.25448.166.89.255510
4648.166.90.0/2348.166.90.1 to 48.166.91.25448.166.91.255510
4748.166.92.0/2348.166.92.1 to 48.166.93.25448.166.93.255510
4848.166.94.0/2348.166.94.1 to 48.166.95.25448.166.95.255510
4948.166.96.0/2348.166.96.1 to 48.166.97.25448.166.97.255510
5048.166.98.0/2348.166.98.1 to 48.166.99.25448.166.99.255510
5148.166.100.0/2348.166.100.1 to 48.166.101.25448.166.101.255510
5248.166.102.0/2348.166.102.1 to 48.166.103.25448.166.103.255510
5348.166.104.0/2348.166.104.1 to 48.166.105.25448.166.105.255510
5448.166.106.0/2348.166.106.1 to 48.166.107.25448.166.107.255510
5548.166.108.0/2348.166.108.1 to 48.166.109.25448.166.109.255510
5648.166.110.0/2348.166.110.1 to 48.166.111.25448.166.111.255510
5748.166.112.0/2348.166.112.1 to 48.166.113.25448.166.113.255510
5848.166.114.0/2348.166.114.1 to 48.166.115.25448.166.115.255510
5948.166.116.0/2348.166.116.1 to 48.166.117.25448.166.117.255510
6048.166.118.0/2348.166.118.1 to 48.166.119.25448.166.119.255510
6148.166.120.0/2348.166.120.1 to 48.166.121.25448.166.121.255510
6248.166.122.0/2348.166.122.1 to 48.166.123.25448.166.123.255510
6348.166.124.0/2348.166.124.1 to 48.166.125.25448.166.125.255510
6448.166.126.0/2348.166.126.1 to 48.166.127.25448.166.127.255510
6548.166.128.0/2348.166.128.1 to 48.166.129.25448.166.129.255510
6648.166.130.0/2348.166.130.1 to 48.166.131.25448.166.131.255510
6748.166.132.0/2348.166.132.1 to 48.166.133.25448.166.133.255510
6848.166.134.0/2348.166.134.1 to 48.166.135.25448.166.135.255510
6948.166.136.0/2348.166.136.1 to 48.166.137.25448.166.137.255510
7048.166.138.0/2348.166.138.1 to 48.166.139.25448.166.139.255510
7148.166.140.0/2348.166.140.1 to 48.166.141.25448.166.141.255510
7248.166.142.0/2348.166.142.1 to 48.166.143.25448.166.143.255510
7348.166.144.0/2348.166.144.1 to 48.166.145.25448.166.145.255510
7448.166.146.0/2348.166.146.1 to 48.166.147.25448.166.147.255510
7548.166.148.0/2348.166.148.1 to 48.166.149.25448.166.149.255510
7648.166.150.0/2348.166.150.1 to 48.166.151.25448.166.151.255510
7748.166.152.0/2348.166.152.1 to 48.166.153.25448.166.153.255510
7848.166.154.0/2348.166.154.1 to 48.166.155.25448.166.155.255510
7948.166.156.0/2348.166.156.1 to 48.166.157.25448.166.157.255510
8048.166.158.0/2348.166.158.1 to 48.166.159.25448.166.159.255510
8148.166.160.0/2348.166.160.1 to 48.166.161.25448.166.161.255510
8248.166.162.0/2348.166.162.1 to 48.166.163.25448.166.163.255510
8348.166.164.0/2348.166.164.1 to 48.166.165.25448.166.165.255510
8448.166.166.0/2348.166.166.1 to 48.166.167.25448.166.167.255510
8548.166.168.0/2348.166.168.1 to 48.166.169.25448.166.169.255510
8648.166.170.0/2348.166.170.1 to 48.166.171.25448.166.171.255510
8748.166.172.0/2348.166.172.1 to 48.166.173.25448.166.173.255510
8848.166.174.0/2348.166.174.1 to 48.166.175.25448.166.175.255510
8948.166.176.0/2348.166.176.1 to 48.166.177.25448.166.177.255510
9048.166.178.0/2348.166.178.1 to 48.166.179.25448.166.179.255510
9148.166.180.0/2348.166.180.1 to 48.166.181.25448.166.181.255510
9248.166.182.0/2348.166.182.1 to 48.166.183.25448.166.183.255510
9348.166.184.0/2348.166.184.1 to 48.166.185.25448.166.185.255510
9448.166.186.0/2348.166.186.1 to 48.166.187.25448.166.187.255510
9548.166.188.0/2348.166.188.1 to 48.166.189.25448.166.189.255510
9648.166.190.0/2348.166.190.1 to 48.166.191.25448.166.191.255510
9748.166.192.0/2348.166.192.1 to 48.166.193.25448.166.193.255510
9848.166.194.0/2348.166.194.1 to 48.166.195.25448.166.195.255510
9948.166.196.0/2348.166.196.1 to 48.166.197.25448.166.197.255510
10048.166.198.0/2348.166.198.1 to 48.166.199.25448.166.199.255510
10148.166.200.0/2348.166.200.1 to 48.166.201.25448.166.201.255510
10248.166.202.0/2348.166.202.1 to 48.166.203.25448.166.203.255510
10348.166.204.0/2348.166.204.1 to 48.166.205.25448.166.205.255510
10448.166.206.0/2348.166.206.1 to 48.166.207.25448.166.207.255510
10548.166.208.0/2348.166.208.1 to 48.166.209.25448.166.209.255510
10648.166.210.0/2348.166.210.1 to 48.166.211.25448.166.211.255510
10748.166.212.0/2348.166.212.1 to 48.166.213.25448.166.213.255510
10848.166.214.0/2348.166.214.1 to 48.166.215.25448.166.215.255510
10948.166.216.0/2348.166.216.1 to 48.166.217.25448.166.217.255510
11048.166.218.0/2348.166.218.1 to 48.166.219.25448.166.219.255510
11148.166.220.0/2348.166.220.1 to 48.166.221.25448.166.221.255510
11248.166.222.0/2348.166.222.1 to 48.166.223.25448.166.223.255510
11348.166.224.0/2348.166.224.1 to 48.166.225.25448.166.225.255510
11448.166.226.0/2348.166.226.1 to 48.166.227.25448.166.227.255510
11548.166.228.0/2348.166.228.1 to 48.166.229.25448.166.229.255510
11648.166.230.0/2348.166.230.1 to 48.166.231.25448.166.231.255510
11748.166.232.0/2348.166.232.1 to 48.166.233.25448.166.233.255510
11848.166.234.0/2348.166.234.1 to 48.166.235.25448.166.235.255510
11948.166.236.0/2348.166.236.1 to 48.166.237.25448.166.237.255510
12048.166.238.0/2348.166.238.1 to 48.166.239.25448.166.239.255510
12148.166.240.0/2348.166.240.1 to 48.166.241.25448.166.241.255510
12248.166.242.0/2348.166.242.1 to 48.166.243.25448.166.243.255510
12348.166.244.0/2348.166.244.1 to 48.166.245.25448.166.245.255510
12448.166.246.0/2348.166.246.1 to 48.166.247.25448.166.247.255510
12548.166.248.0/2348.166.248.1 to 48.166.249.25448.166.249.255510
12648.166.250.0/2348.166.250.1 to 48.166.251.25448.166.251.255510
12748.166.252.0/2348.166.252.1 to 48.166.253.25448.166.253.255510
12848.166.254.0/2348.166.254.1 to 48.166.255.25448.166.255.255510
12948.167.0.0/2348.167.0.1 to 48.167.1.25448.167.1.255510
13048.167.2.0/2348.167.2.1 to 48.167.3.25448.167.3.255510
13148.167.4.0/2348.167.4.1 to 48.167.5.25448.167.5.255510
13248.167.6.0/2348.167.6.1 to 48.167.7.25448.167.7.255510
13348.167.8.0/2348.167.8.1 to 48.167.9.25448.167.9.255510
13448.167.10.0/2348.167.10.1 to 48.167.11.25448.167.11.255510
13548.167.12.0/2348.167.12.1 to 48.167.13.25448.167.13.255510
13648.167.14.0/2348.167.14.1 to 48.167.15.25448.167.15.255510
13748.167.16.0/2348.167.16.1 to 48.167.17.25448.167.17.255510
13848.167.18.0/2348.167.18.1 to 48.167.19.25448.167.19.255510
13948.167.20.0/2348.167.20.1 to 48.167.21.25448.167.21.255510
14048.167.22.0/2348.167.22.1 to 48.167.23.25448.167.23.255510
14148.167.24.0/2348.167.24.1 to 48.167.25.25448.167.25.255510
14248.167.26.0/2348.167.26.1 to 48.167.27.25448.167.27.255510
14348.167.28.0/2348.167.28.1 to 48.167.29.25448.167.29.255510
14448.167.30.0/2348.167.30.1 to 48.167.31.25448.167.31.255510
14548.167.32.0/2348.167.32.1 to 48.167.33.25448.167.33.255510
14648.167.34.0/2348.167.34.1 to 48.167.35.25448.167.35.255510
14748.167.36.0/2348.167.36.1 to 48.167.37.25448.167.37.255510
14848.167.38.0/2348.167.38.1 to 48.167.39.25448.167.39.255510
14948.167.40.0/2348.167.40.1 to 48.167.41.25448.167.41.255510
15048.167.42.0/2348.167.42.1 to 48.167.43.25448.167.43.255510
15148.167.44.0/2348.167.44.1 to 48.167.45.25448.167.45.255510
15248.167.46.0/2348.167.46.1 to 48.167.47.25448.167.47.255510
15348.167.48.0/2348.167.48.1 to 48.167.49.25448.167.49.255510
15448.167.50.0/2348.167.50.1 to 48.167.51.25448.167.51.255510
15548.167.52.0/2348.167.52.1 to 48.167.53.25448.167.53.255510
15648.167.54.0/2348.167.54.1 to 48.167.55.25448.167.55.255510
15748.167.56.0/2348.167.56.1 to 48.167.57.25448.167.57.255510
15848.167.58.0/2348.167.58.1 to 48.167.59.25448.167.59.255510
15948.167.60.0/2348.167.60.1 to 48.167.61.25448.167.61.255510
16048.167.62.0/2348.167.62.1 to 48.167.63.25448.167.63.255510
16148.167.64.0/2348.167.64.1 to 48.167.65.25448.167.65.255510
16248.167.66.0/2348.167.66.1 to 48.167.67.25448.167.67.255510
16348.167.68.0/2348.167.68.1 to 48.167.69.25448.167.69.255510
16448.167.70.0/2348.167.70.1 to 48.167.71.25448.167.71.255510
16548.167.72.0/2348.167.72.1 to 48.167.73.25448.167.73.255510
16648.167.74.0/2348.167.74.1 to 48.167.75.25448.167.75.255510
16748.167.76.0/2348.167.76.1 to 48.167.77.25448.167.77.255510
16848.167.78.0/2348.167.78.1 to 48.167.79.25448.167.79.255510
16948.167.80.0/2348.167.80.1 to 48.167.81.25448.167.81.255510
17048.167.82.0/2348.167.82.1 to 48.167.83.25448.167.83.255510
17148.167.84.0/2348.167.84.1 to 48.167.85.25448.167.85.255510
17248.167.86.0/2348.167.86.1 to 48.167.87.25448.167.87.255510
17348.167.88.0/2348.167.88.1 to 48.167.89.25448.167.89.255510
17448.167.90.0/2348.167.90.1 to 48.167.91.25448.167.91.255510
17548.167.92.0/2348.167.92.1 to 48.167.93.25448.167.93.255510
17648.167.94.0/2348.167.94.1 to 48.167.95.25448.167.95.255510
17748.167.96.0/2348.167.96.1 to 48.167.97.25448.167.97.255510
17848.167.98.0/2348.167.98.1 to 48.167.99.25448.167.99.255510
17948.167.100.0/2348.167.100.1 to 48.167.101.25448.167.101.255510
18048.167.102.0/2348.167.102.1 to 48.167.103.25448.167.103.255510
18148.167.104.0/2348.167.104.1 to 48.167.105.25448.167.105.255510
18248.167.106.0/2348.167.106.1 to 48.167.107.25448.167.107.255510
18348.167.108.0/2348.167.108.1 to 48.167.109.25448.167.109.255510
18448.167.110.0/2348.167.110.1 to 48.167.111.25448.167.111.255510
18548.167.112.0/2348.167.112.1 to 48.167.113.25448.167.113.255510
18648.167.114.0/2348.167.114.1 to 48.167.115.25448.167.115.255510
18748.167.116.0/2348.167.116.1 to 48.167.117.25448.167.117.255510
18848.167.118.0/2348.167.118.1 to 48.167.119.25448.167.119.255510
18948.167.120.0/2348.167.120.1 to 48.167.121.25448.167.121.255510
19048.167.122.0/2348.167.122.1 to 48.167.123.25448.167.123.255510
19148.167.124.0/2348.167.124.1 to 48.167.125.25448.167.125.255510
19248.167.126.0/2348.167.126.1 to 48.167.127.25448.167.127.255510
19348.167.128.0/2348.167.128.1 to 48.167.129.25448.167.129.255510
19448.167.130.0/2348.167.130.1 to 48.167.131.25448.167.131.255510
19548.167.132.0/2348.167.132.1 to 48.167.133.25448.167.133.255510
19648.167.134.0/2348.167.134.1 to 48.167.135.25448.167.135.255510
19748.167.136.0/2348.167.136.1 to 48.167.137.25448.167.137.255510
19848.167.138.0/2348.167.138.1 to 48.167.139.25448.167.139.255510
19948.167.140.0/2348.167.140.1 to 48.167.141.25448.167.141.255510
20048.167.142.0/2348.167.142.1 to 48.167.143.25448.167.143.255510
20148.167.144.0/2348.167.144.1 to 48.167.145.25448.167.145.255510
20248.167.146.0/2348.167.146.1 to 48.167.147.25448.167.147.255510
20348.167.148.0/2348.167.148.1 to 48.167.149.25448.167.149.255510
20448.167.150.0/2348.167.150.1 to 48.167.151.25448.167.151.255510
20548.167.152.0/2348.167.152.1 to 48.167.153.25448.167.153.255510
20648.167.154.0/2348.167.154.1 to 48.167.155.25448.167.155.255510
20748.167.156.0/2348.167.156.1 to 48.167.157.25448.167.157.255510
20848.167.158.0/2348.167.158.1 to 48.167.159.25448.167.159.255510
20948.167.160.0/2348.167.160.1 to 48.167.161.25448.167.161.255510
21048.167.162.0/2348.167.162.1 to 48.167.163.25448.167.163.255510
21148.167.164.0/2348.167.164.1 to 48.167.165.25448.167.165.255510
21248.167.166.0/2348.167.166.1 to 48.167.167.25448.167.167.255510
21348.167.168.0/2348.167.168.1 to 48.167.169.25448.167.169.255510
21448.167.170.0/2348.167.170.1 to 48.167.171.25448.167.171.255510
21548.167.172.0/2348.167.172.1 to 48.167.173.25448.167.173.255510
21648.167.174.0/2348.167.174.1 to 48.167.175.25448.167.175.255510
21748.167.176.0/2348.167.176.1 to 48.167.177.25448.167.177.255510
21848.167.178.0/2348.167.178.1 to 48.167.179.25448.167.179.255510
21948.167.180.0/2348.167.180.1 to 48.167.181.25448.167.181.255510
22048.167.182.0/2348.167.182.1 to 48.167.183.25448.167.183.255510
22148.167.184.0/2348.167.184.1 to 48.167.185.25448.167.185.255510
22248.167.186.0/2348.167.186.1 to 48.167.187.25448.167.187.255510
22348.167.188.0/2348.167.188.1 to 48.167.189.25448.167.189.255510
22448.167.190.0/2348.167.190.1 to 48.167.191.25448.167.191.255510
22548.167.192.0/2348.167.192.1 to 48.167.193.25448.167.193.255510
22648.167.194.0/2348.167.194.1 to 48.167.195.25448.167.195.255510
22748.167.196.0/2348.167.196.1 to 48.167.197.25448.167.197.255510
22848.167.198.0/2348.167.198.1 to 48.167.199.25448.167.199.255510
22948.167.200.0/2348.167.200.1 to 48.167.201.25448.167.201.255510
23048.167.202.0/2348.167.202.1 to 48.167.203.25448.167.203.255510
23148.167.204.0/2348.167.204.1 to 48.167.205.25448.167.205.255510
23248.167.206.0/2348.167.206.1 to 48.167.207.25448.167.207.255510
23348.167.208.0/2348.167.208.1 to 48.167.209.25448.167.209.255510
23448.167.210.0/2348.167.210.1 to 48.167.211.25448.167.211.255510
23548.167.212.0/2348.167.212.1 to 48.167.213.25448.167.213.255510
23648.167.214.0/2348.167.214.1 to 48.167.215.25448.167.215.255510
23748.167.216.0/2348.167.216.1 to 48.167.217.25448.167.217.255510
23848.167.218.0/2348.167.218.1 to 48.167.219.25448.167.219.255510
23948.167.220.0/2348.167.220.1 to 48.167.221.25448.167.221.255510
24048.167.222.0/2348.167.222.1 to 48.167.223.25448.167.223.255510
24148.167.224.0/2348.167.224.1 to 48.167.225.25448.167.225.255510
24248.167.226.0/2348.167.226.1 to 48.167.227.25448.167.227.255510
24348.167.228.0/2348.167.228.1 to 48.167.229.25448.167.229.255510
24448.167.230.0/2348.167.230.1 to 48.167.231.25448.167.231.255510
24548.167.232.0/2348.167.232.1 to 48.167.233.25448.167.233.255510
24648.167.234.0/2348.167.234.1 to 48.167.235.25448.167.235.255510
24748.167.236.0/2348.167.236.1 to 48.167.237.25448.167.237.255510
24848.167.238.0/2348.167.238.1 to 48.167.239.25448.167.239.255510
24948.167.240.0/2348.167.240.1 to 48.167.241.25448.167.241.255510
25048.167.242.0/2348.167.242.1 to 48.167.243.25448.167.243.255510
25148.167.244.0/2348.167.244.1 to 48.167.245.25448.167.245.255510
25248.167.246.0/2348.167.246.1 to 48.167.247.25448.167.247.255510
25348.167.248.0/2348.167.248.1 to 48.167.249.25448.167.249.255510
25448.167.250.0/2348.167.250.1 to 48.167.251.25448.167.251.255510
25548.167.252.0/2348.167.252.1 to 48.167.253.25448.167.253.255510
25648.167.254.0/2348.167.254.1 to 48.167.255.25448.167.255.255510

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.