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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.

Network65.40.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
65.40.0.0
Broadcast address
65.47.255.255
First usable
65.40.0.1
Last usable
65.47.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 41280000 · Integer 1093140480 to 1093664767
Reverse DNS zones
40.65.in-addr.arpa
41.65.in-addr.arpa
42.65.in-addr.arpa
43.65.in-addr.arpa
44.65.in-addr.arpa
45.65.in-addr.arpa
46.65.in-addr.arpa
47.65.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000001.00101000.00000000.0000000065.40.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network01000001.00101000.00000000.0000000065.40.0.0
Broadcast01000001.00101111.11111111.1111111165.47.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

65.40.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
165.40.0.0/2365.40.0.1 to 65.40.1.25465.40.1.255510
265.40.2.0/2365.40.2.1 to 65.40.3.25465.40.3.255510
365.40.4.0/2365.40.4.1 to 65.40.5.25465.40.5.255510
465.40.6.0/2365.40.6.1 to 65.40.7.25465.40.7.255510
565.40.8.0/2365.40.8.1 to 65.40.9.25465.40.9.255510
665.40.10.0/2365.40.10.1 to 65.40.11.25465.40.11.255510
765.40.12.0/2365.40.12.1 to 65.40.13.25465.40.13.255510
865.40.14.0/2365.40.14.1 to 65.40.15.25465.40.15.255510
965.40.16.0/2365.40.16.1 to 65.40.17.25465.40.17.255510
1065.40.18.0/2365.40.18.1 to 65.40.19.25465.40.19.255510
1165.40.20.0/2365.40.20.1 to 65.40.21.25465.40.21.255510
1265.40.22.0/2365.40.22.1 to 65.40.23.25465.40.23.255510
1365.40.24.0/2365.40.24.1 to 65.40.25.25465.40.25.255510
1465.40.26.0/2365.40.26.1 to 65.40.27.25465.40.27.255510
1565.40.28.0/2365.40.28.1 to 65.40.29.25465.40.29.255510
1665.40.30.0/2365.40.30.1 to 65.40.31.25465.40.31.255510
1765.40.32.0/2365.40.32.1 to 65.40.33.25465.40.33.255510
1865.40.34.0/2365.40.34.1 to 65.40.35.25465.40.35.255510
1965.40.36.0/2365.40.36.1 to 65.40.37.25465.40.37.255510
2065.40.38.0/2365.40.38.1 to 65.40.39.25465.40.39.255510
2165.40.40.0/2365.40.40.1 to 65.40.41.25465.40.41.255510
2265.40.42.0/2365.40.42.1 to 65.40.43.25465.40.43.255510
2365.40.44.0/2365.40.44.1 to 65.40.45.25465.40.45.255510
2465.40.46.0/2365.40.46.1 to 65.40.47.25465.40.47.255510
2565.40.48.0/2365.40.48.1 to 65.40.49.25465.40.49.255510
2665.40.50.0/2365.40.50.1 to 65.40.51.25465.40.51.255510
2765.40.52.0/2365.40.52.1 to 65.40.53.25465.40.53.255510
2865.40.54.0/2365.40.54.1 to 65.40.55.25465.40.55.255510
2965.40.56.0/2365.40.56.1 to 65.40.57.25465.40.57.255510
3065.40.58.0/2365.40.58.1 to 65.40.59.25465.40.59.255510
3165.40.60.0/2365.40.60.1 to 65.40.61.25465.40.61.255510
3265.40.62.0/2365.40.62.1 to 65.40.63.25465.40.63.255510
3365.40.64.0/2365.40.64.1 to 65.40.65.25465.40.65.255510
3465.40.66.0/2365.40.66.1 to 65.40.67.25465.40.67.255510
3565.40.68.0/2365.40.68.1 to 65.40.69.25465.40.69.255510
3665.40.70.0/2365.40.70.1 to 65.40.71.25465.40.71.255510
3765.40.72.0/2365.40.72.1 to 65.40.73.25465.40.73.255510
3865.40.74.0/2365.40.74.1 to 65.40.75.25465.40.75.255510
3965.40.76.0/2365.40.76.1 to 65.40.77.25465.40.77.255510
4065.40.78.0/2365.40.78.1 to 65.40.79.25465.40.79.255510
4165.40.80.0/2365.40.80.1 to 65.40.81.25465.40.81.255510
4265.40.82.0/2365.40.82.1 to 65.40.83.25465.40.83.255510
4365.40.84.0/2365.40.84.1 to 65.40.85.25465.40.85.255510
4465.40.86.0/2365.40.86.1 to 65.40.87.25465.40.87.255510
4565.40.88.0/2365.40.88.1 to 65.40.89.25465.40.89.255510
4665.40.90.0/2365.40.90.1 to 65.40.91.25465.40.91.255510
4765.40.92.0/2365.40.92.1 to 65.40.93.25465.40.93.255510
4865.40.94.0/2365.40.94.1 to 65.40.95.25465.40.95.255510
4965.40.96.0/2365.40.96.1 to 65.40.97.25465.40.97.255510
5065.40.98.0/2365.40.98.1 to 65.40.99.25465.40.99.255510
5165.40.100.0/2365.40.100.1 to 65.40.101.25465.40.101.255510
5265.40.102.0/2365.40.102.1 to 65.40.103.25465.40.103.255510
5365.40.104.0/2365.40.104.1 to 65.40.105.25465.40.105.255510
5465.40.106.0/2365.40.106.1 to 65.40.107.25465.40.107.255510
5565.40.108.0/2365.40.108.1 to 65.40.109.25465.40.109.255510
5665.40.110.0/2365.40.110.1 to 65.40.111.25465.40.111.255510
5765.40.112.0/2365.40.112.1 to 65.40.113.25465.40.113.255510
5865.40.114.0/2365.40.114.1 to 65.40.115.25465.40.115.255510
5965.40.116.0/2365.40.116.1 to 65.40.117.25465.40.117.255510
6065.40.118.0/2365.40.118.1 to 65.40.119.25465.40.119.255510
6165.40.120.0/2365.40.120.1 to 65.40.121.25465.40.121.255510
6265.40.122.0/2365.40.122.1 to 65.40.123.25465.40.123.255510
6365.40.124.0/2365.40.124.1 to 65.40.125.25465.40.125.255510
6465.40.126.0/2365.40.126.1 to 65.40.127.25465.40.127.255510
6565.40.128.0/2365.40.128.1 to 65.40.129.25465.40.129.255510
6665.40.130.0/2365.40.130.1 to 65.40.131.25465.40.131.255510
6765.40.132.0/2365.40.132.1 to 65.40.133.25465.40.133.255510
6865.40.134.0/2365.40.134.1 to 65.40.135.25465.40.135.255510
6965.40.136.0/2365.40.136.1 to 65.40.137.25465.40.137.255510
7065.40.138.0/2365.40.138.1 to 65.40.139.25465.40.139.255510
7165.40.140.0/2365.40.140.1 to 65.40.141.25465.40.141.255510
7265.40.142.0/2365.40.142.1 to 65.40.143.25465.40.143.255510
7365.40.144.0/2365.40.144.1 to 65.40.145.25465.40.145.255510
7465.40.146.0/2365.40.146.1 to 65.40.147.25465.40.147.255510
7565.40.148.0/2365.40.148.1 to 65.40.149.25465.40.149.255510
7665.40.150.0/2365.40.150.1 to 65.40.151.25465.40.151.255510
7765.40.152.0/2365.40.152.1 to 65.40.153.25465.40.153.255510
7865.40.154.0/2365.40.154.1 to 65.40.155.25465.40.155.255510
7965.40.156.0/2365.40.156.1 to 65.40.157.25465.40.157.255510
8065.40.158.0/2365.40.158.1 to 65.40.159.25465.40.159.255510
8165.40.160.0/2365.40.160.1 to 65.40.161.25465.40.161.255510
8265.40.162.0/2365.40.162.1 to 65.40.163.25465.40.163.255510
8365.40.164.0/2365.40.164.1 to 65.40.165.25465.40.165.255510
8465.40.166.0/2365.40.166.1 to 65.40.167.25465.40.167.255510
8565.40.168.0/2365.40.168.1 to 65.40.169.25465.40.169.255510
8665.40.170.0/2365.40.170.1 to 65.40.171.25465.40.171.255510
8765.40.172.0/2365.40.172.1 to 65.40.173.25465.40.173.255510
8865.40.174.0/2365.40.174.1 to 65.40.175.25465.40.175.255510
8965.40.176.0/2365.40.176.1 to 65.40.177.25465.40.177.255510
9065.40.178.0/2365.40.178.1 to 65.40.179.25465.40.179.255510
9165.40.180.0/2365.40.180.1 to 65.40.181.25465.40.181.255510
9265.40.182.0/2365.40.182.1 to 65.40.183.25465.40.183.255510
9365.40.184.0/2365.40.184.1 to 65.40.185.25465.40.185.255510
9465.40.186.0/2365.40.186.1 to 65.40.187.25465.40.187.255510
9565.40.188.0/2365.40.188.1 to 65.40.189.25465.40.189.255510
9665.40.190.0/2365.40.190.1 to 65.40.191.25465.40.191.255510
9765.40.192.0/2365.40.192.1 to 65.40.193.25465.40.193.255510
9865.40.194.0/2365.40.194.1 to 65.40.195.25465.40.195.255510
9965.40.196.0/2365.40.196.1 to 65.40.197.25465.40.197.255510
10065.40.198.0/2365.40.198.1 to 65.40.199.25465.40.199.255510
10165.40.200.0/2365.40.200.1 to 65.40.201.25465.40.201.255510
10265.40.202.0/2365.40.202.1 to 65.40.203.25465.40.203.255510
10365.40.204.0/2365.40.204.1 to 65.40.205.25465.40.205.255510
10465.40.206.0/2365.40.206.1 to 65.40.207.25465.40.207.255510
10565.40.208.0/2365.40.208.1 to 65.40.209.25465.40.209.255510
10665.40.210.0/2365.40.210.1 to 65.40.211.25465.40.211.255510
10765.40.212.0/2365.40.212.1 to 65.40.213.25465.40.213.255510
10865.40.214.0/2365.40.214.1 to 65.40.215.25465.40.215.255510
10965.40.216.0/2365.40.216.1 to 65.40.217.25465.40.217.255510
11065.40.218.0/2365.40.218.1 to 65.40.219.25465.40.219.255510
11165.40.220.0/2365.40.220.1 to 65.40.221.25465.40.221.255510
11265.40.222.0/2365.40.222.1 to 65.40.223.25465.40.223.255510
11365.40.224.0/2365.40.224.1 to 65.40.225.25465.40.225.255510
11465.40.226.0/2365.40.226.1 to 65.40.227.25465.40.227.255510
11565.40.228.0/2365.40.228.1 to 65.40.229.25465.40.229.255510
11665.40.230.0/2365.40.230.1 to 65.40.231.25465.40.231.255510
11765.40.232.0/2365.40.232.1 to 65.40.233.25465.40.233.255510
11865.40.234.0/2365.40.234.1 to 65.40.235.25465.40.235.255510
11965.40.236.0/2365.40.236.1 to 65.40.237.25465.40.237.255510
12065.40.238.0/2365.40.238.1 to 65.40.239.25465.40.239.255510
12165.40.240.0/2365.40.240.1 to 65.40.241.25465.40.241.255510
12265.40.242.0/2365.40.242.1 to 65.40.243.25465.40.243.255510
12365.40.244.0/2365.40.244.1 to 65.40.245.25465.40.245.255510
12465.40.246.0/2365.40.246.1 to 65.40.247.25465.40.247.255510
12565.40.248.0/2365.40.248.1 to 65.40.249.25465.40.249.255510
12665.40.250.0/2365.40.250.1 to 65.40.251.25465.40.251.255510
12765.40.252.0/2365.40.252.1 to 65.40.253.25465.40.253.255510
12865.40.254.0/2365.40.254.1 to 65.40.255.25465.40.255.255510
12965.41.0.0/2365.41.0.1 to 65.41.1.25465.41.1.255510
13065.41.2.0/2365.41.2.1 to 65.41.3.25465.41.3.255510
13165.41.4.0/2365.41.4.1 to 65.41.5.25465.41.5.255510
13265.41.6.0/2365.41.6.1 to 65.41.7.25465.41.7.255510
13365.41.8.0/2365.41.8.1 to 65.41.9.25465.41.9.255510
13465.41.10.0/2365.41.10.1 to 65.41.11.25465.41.11.255510
13565.41.12.0/2365.41.12.1 to 65.41.13.25465.41.13.255510
13665.41.14.0/2365.41.14.1 to 65.41.15.25465.41.15.255510
13765.41.16.0/2365.41.16.1 to 65.41.17.25465.41.17.255510
13865.41.18.0/2365.41.18.1 to 65.41.19.25465.41.19.255510
13965.41.20.0/2365.41.20.1 to 65.41.21.25465.41.21.255510
14065.41.22.0/2365.41.22.1 to 65.41.23.25465.41.23.255510
14165.41.24.0/2365.41.24.1 to 65.41.25.25465.41.25.255510
14265.41.26.0/2365.41.26.1 to 65.41.27.25465.41.27.255510
14365.41.28.0/2365.41.28.1 to 65.41.29.25465.41.29.255510
14465.41.30.0/2365.41.30.1 to 65.41.31.25465.41.31.255510
14565.41.32.0/2365.41.32.1 to 65.41.33.25465.41.33.255510
14665.41.34.0/2365.41.34.1 to 65.41.35.25465.41.35.255510
14765.41.36.0/2365.41.36.1 to 65.41.37.25465.41.37.255510
14865.41.38.0/2365.41.38.1 to 65.41.39.25465.41.39.255510
14965.41.40.0/2365.41.40.1 to 65.41.41.25465.41.41.255510
15065.41.42.0/2365.41.42.1 to 65.41.43.25465.41.43.255510
15165.41.44.0/2365.41.44.1 to 65.41.45.25465.41.45.255510
15265.41.46.0/2365.41.46.1 to 65.41.47.25465.41.47.255510
15365.41.48.0/2365.41.48.1 to 65.41.49.25465.41.49.255510
15465.41.50.0/2365.41.50.1 to 65.41.51.25465.41.51.255510
15565.41.52.0/2365.41.52.1 to 65.41.53.25465.41.53.255510
15665.41.54.0/2365.41.54.1 to 65.41.55.25465.41.55.255510
15765.41.56.0/2365.41.56.1 to 65.41.57.25465.41.57.255510
15865.41.58.0/2365.41.58.1 to 65.41.59.25465.41.59.255510
15965.41.60.0/2365.41.60.1 to 65.41.61.25465.41.61.255510
16065.41.62.0/2365.41.62.1 to 65.41.63.25465.41.63.255510
16165.41.64.0/2365.41.64.1 to 65.41.65.25465.41.65.255510
16265.41.66.0/2365.41.66.1 to 65.41.67.25465.41.67.255510
16365.41.68.0/2365.41.68.1 to 65.41.69.25465.41.69.255510
16465.41.70.0/2365.41.70.1 to 65.41.71.25465.41.71.255510
16565.41.72.0/2365.41.72.1 to 65.41.73.25465.41.73.255510
16665.41.74.0/2365.41.74.1 to 65.41.75.25465.41.75.255510
16765.41.76.0/2365.41.76.1 to 65.41.77.25465.41.77.255510
16865.41.78.0/2365.41.78.1 to 65.41.79.25465.41.79.255510
16965.41.80.0/2365.41.80.1 to 65.41.81.25465.41.81.255510
17065.41.82.0/2365.41.82.1 to 65.41.83.25465.41.83.255510
17165.41.84.0/2365.41.84.1 to 65.41.85.25465.41.85.255510
17265.41.86.0/2365.41.86.1 to 65.41.87.25465.41.87.255510
17365.41.88.0/2365.41.88.1 to 65.41.89.25465.41.89.255510
17465.41.90.0/2365.41.90.1 to 65.41.91.25465.41.91.255510
17565.41.92.0/2365.41.92.1 to 65.41.93.25465.41.93.255510
17665.41.94.0/2365.41.94.1 to 65.41.95.25465.41.95.255510
17765.41.96.0/2365.41.96.1 to 65.41.97.25465.41.97.255510
17865.41.98.0/2365.41.98.1 to 65.41.99.25465.41.99.255510
17965.41.100.0/2365.41.100.1 to 65.41.101.25465.41.101.255510
18065.41.102.0/2365.41.102.1 to 65.41.103.25465.41.103.255510
18165.41.104.0/2365.41.104.1 to 65.41.105.25465.41.105.255510
18265.41.106.0/2365.41.106.1 to 65.41.107.25465.41.107.255510
18365.41.108.0/2365.41.108.1 to 65.41.109.25465.41.109.255510
18465.41.110.0/2365.41.110.1 to 65.41.111.25465.41.111.255510
18565.41.112.0/2365.41.112.1 to 65.41.113.25465.41.113.255510
18665.41.114.0/2365.41.114.1 to 65.41.115.25465.41.115.255510
18765.41.116.0/2365.41.116.1 to 65.41.117.25465.41.117.255510
18865.41.118.0/2365.41.118.1 to 65.41.119.25465.41.119.255510
18965.41.120.0/2365.41.120.1 to 65.41.121.25465.41.121.255510
19065.41.122.0/2365.41.122.1 to 65.41.123.25465.41.123.255510
19165.41.124.0/2365.41.124.1 to 65.41.125.25465.41.125.255510
19265.41.126.0/2365.41.126.1 to 65.41.127.25465.41.127.255510
19365.41.128.0/2365.41.128.1 to 65.41.129.25465.41.129.255510
19465.41.130.0/2365.41.130.1 to 65.41.131.25465.41.131.255510
19565.41.132.0/2365.41.132.1 to 65.41.133.25465.41.133.255510
19665.41.134.0/2365.41.134.1 to 65.41.135.25465.41.135.255510
19765.41.136.0/2365.41.136.1 to 65.41.137.25465.41.137.255510
19865.41.138.0/2365.41.138.1 to 65.41.139.25465.41.139.255510
19965.41.140.0/2365.41.140.1 to 65.41.141.25465.41.141.255510
20065.41.142.0/2365.41.142.1 to 65.41.143.25465.41.143.255510
20165.41.144.0/2365.41.144.1 to 65.41.145.25465.41.145.255510
20265.41.146.0/2365.41.146.1 to 65.41.147.25465.41.147.255510
20365.41.148.0/2365.41.148.1 to 65.41.149.25465.41.149.255510
20465.41.150.0/2365.41.150.1 to 65.41.151.25465.41.151.255510
20565.41.152.0/2365.41.152.1 to 65.41.153.25465.41.153.255510
20665.41.154.0/2365.41.154.1 to 65.41.155.25465.41.155.255510
20765.41.156.0/2365.41.156.1 to 65.41.157.25465.41.157.255510
20865.41.158.0/2365.41.158.1 to 65.41.159.25465.41.159.255510
20965.41.160.0/2365.41.160.1 to 65.41.161.25465.41.161.255510
21065.41.162.0/2365.41.162.1 to 65.41.163.25465.41.163.255510
21165.41.164.0/2365.41.164.1 to 65.41.165.25465.41.165.255510
21265.41.166.0/2365.41.166.1 to 65.41.167.25465.41.167.255510
21365.41.168.0/2365.41.168.1 to 65.41.169.25465.41.169.255510
21465.41.170.0/2365.41.170.1 to 65.41.171.25465.41.171.255510
21565.41.172.0/2365.41.172.1 to 65.41.173.25465.41.173.255510
21665.41.174.0/2365.41.174.1 to 65.41.175.25465.41.175.255510
21765.41.176.0/2365.41.176.1 to 65.41.177.25465.41.177.255510
21865.41.178.0/2365.41.178.1 to 65.41.179.25465.41.179.255510
21965.41.180.0/2365.41.180.1 to 65.41.181.25465.41.181.255510
22065.41.182.0/2365.41.182.1 to 65.41.183.25465.41.183.255510
22165.41.184.0/2365.41.184.1 to 65.41.185.25465.41.185.255510
22265.41.186.0/2365.41.186.1 to 65.41.187.25465.41.187.255510
22365.41.188.0/2365.41.188.1 to 65.41.189.25465.41.189.255510
22465.41.190.0/2365.41.190.1 to 65.41.191.25465.41.191.255510
22565.41.192.0/2365.41.192.1 to 65.41.193.25465.41.193.255510
22665.41.194.0/2365.41.194.1 to 65.41.195.25465.41.195.255510
22765.41.196.0/2365.41.196.1 to 65.41.197.25465.41.197.255510
22865.41.198.0/2365.41.198.1 to 65.41.199.25465.41.199.255510
22965.41.200.0/2365.41.200.1 to 65.41.201.25465.41.201.255510
23065.41.202.0/2365.41.202.1 to 65.41.203.25465.41.203.255510
23165.41.204.0/2365.41.204.1 to 65.41.205.25465.41.205.255510
23265.41.206.0/2365.41.206.1 to 65.41.207.25465.41.207.255510
23365.41.208.0/2365.41.208.1 to 65.41.209.25465.41.209.255510
23465.41.210.0/2365.41.210.1 to 65.41.211.25465.41.211.255510
23565.41.212.0/2365.41.212.1 to 65.41.213.25465.41.213.255510
23665.41.214.0/2365.41.214.1 to 65.41.215.25465.41.215.255510
23765.41.216.0/2365.41.216.1 to 65.41.217.25465.41.217.255510
23865.41.218.0/2365.41.218.1 to 65.41.219.25465.41.219.255510
23965.41.220.0/2365.41.220.1 to 65.41.221.25465.41.221.255510
24065.41.222.0/2365.41.222.1 to 65.41.223.25465.41.223.255510
24165.41.224.0/2365.41.224.1 to 65.41.225.25465.41.225.255510
24265.41.226.0/2365.41.226.1 to 65.41.227.25465.41.227.255510
24365.41.228.0/2365.41.228.1 to 65.41.229.25465.41.229.255510
24465.41.230.0/2365.41.230.1 to 65.41.231.25465.41.231.255510
24565.41.232.0/2365.41.232.1 to 65.41.233.25465.41.233.255510
24665.41.234.0/2365.41.234.1 to 65.41.235.25465.41.235.255510
24765.41.236.0/2365.41.236.1 to 65.41.237.25465.41.237.255510
24865.41.238.0/2365.41.238.1 to 65.41.239.25465.41.239.255510
24965.41.240.0/2365.41.240.1 to 65.41.241.25465.41.241.255510
25065.41.242.0/2365.41.242.1 to 65.41.243.25465.41.243.255510
25165.41.244.0/2365.41.244.1 to 65.41.245.25465.41.245.255510
25265.41.246.0/2365.41.246.1 to 65.41.247.25465.41.247.255510
25365.41.248.0/2365.41.248.1 to 65.41.249.25465.41.249.255510
25465.41.250.0/2365.41.250.1 to 65.41.251.25465.41.251.255510
25565.41.252.0/2365.41.252.1 to 65.41.253.25465.41.253.255510
25665.41.254.0/2365.41.254.1 to 65.41.255.25465.41.255.255510

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.