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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.

Network31.64.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
31.64.0.0
Broadcast address
31.95.255.255
First usable
31.64.0.1
Last usable
31.95.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 1F400000 · Integer 524288000 to 526385151
Reverse DNS zones
64.31.in-addr.arpa
65.31.in-addr.arpa
66.31.in-addr.arpa
67.31.in-addr.arpa
68.31.in-addr.arpa
69.31.in-addr.arpa
70.31.in-addr.arpa
71.31.in-addr.arpa
72.31.in-addr.arpa
73.31.in-addr.arpa
74.31.in-addr.arpa
75.31.in-addr.arpa
76.31.in-addr.arpa
77.31.in-addr.arpa
78.31.in-addr.arpa
79.31.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011111.01000000.00000000.0000000031.64.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00011111.01000000.00000000.0000000031.64.0.0
Broadcast00011111.01011111.11111111.1111111131.95.255.255
Split into smaller subnets/23
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

31.64.0.0/11 makes 4,096 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
131.64.0.0/2331.64.0.1 to 31.64.1.25431.64.1.255510
231.64.2.0/2331.64.2.1 to 31.64.3.25431.64.3.255510
331.64.4.0/2331.64.4.1 to 31.64.5.25431.64.5.255510
431.64.6.0/2331.64.6.1 to 31.64.7.25431.64.7.255510
531.64.8.0/2331.64.8.1 to 31.64.9.25431.64.9.255510
631.64.10.0/2331.64.10.1 to 31.64.11.25431.64.11.255510
731.64.12.0/2331.64.12.1 to 31.64.13.25431.64.13.255510
831.64.14.0/2331.64.14.1 to 31.64.15.25431.64.15.255510
931.64.16.0/2331.64.16.1 to 31.64.17.25431.64.17.255510
1031.64.18.0/2331.64.18.1 to 31.64.19.25431.64.19.255510
1131.64.20.0/2331.64.20.1 to 31.64.21.25431.64.21.255510
1231.64.22.0/2331.64.22.1 to 31.64.23.25431.64.23.255510
1331.64.24.0/2331.64.24.1 to 31.64.25.25431.64.25.255510
1431.64.26.0/2331.64.26.1 to 31.64.27.25431.64.27.255510
1531.64.28.0/2331.64.28.1 to 31.64.29.25431.64.29.255510
1631.64.30.0/2331.64.30.1 to 31.64.31.25431.64.31.255510
1731.64.32.0/2331.64.32.1 to 31.64.33.25431.64.33.255510
1831.64.34.0/2331.64.34.1 to 31.64.35.25431.64.35.255510
1931.64.36.0/2331.64.36.1 to 31.64.37.25431.64.37.255510
2031.64.38.0/2331.64.38.1 to 31.64.39.25431.64.39.255510
2131.64.40.0/2331.64.40.1 to 31.64.41.25431.64.41.255510
2231.64.42.0/2331.64.42.1 to 31.64.43.25431.64.43.255510
2331.64.44.0/2331.64.44.1 to 31.64.45.25431.64.45.255510
2431.64.46.0/2331.64.46.1 to 31.64.47.25431.64.47.255510
2531.64.48.0/2331.64.48.1 to 31.64.49.25431.64.49.255510
2631.64.50.0/2331.64.50.1 to 31.64.51.25431.64.51.255510
2731.64.52.0/2331.64.52.1 to 31.64.53.25431.64.53.255510
2831.64.54.0/2331.64.54.1 to 31.64.55.25431.64.55.255510
2931.64.56.0/2331.64.56.1 to 31.64.57.25431.64.57.255510
3031.64.58.0/2331.64.58.1 to 31.64.59.25431.64.59.255510
3131.64.60.0/2331.64.60.1 to 31.64.61.25431.64.61.255510
3231.64.62.0/2331.64.62.1 to 31.64.63.25431.64.63.255510
3331.64.64.0/2331.64.64.1 to 31.64.65.25431.64.65.255510
3431.64.66.0/2331.64.66.1 to 31.64.67.25431.64.67.255510
3531.64.68.0/2331.64.68.1 to 31.64.69.25431.64.69.255510
3631.64.70.0/2331.64.70.1 to 31.64.71.25431.64.71.255510
3731.64.72.0/2331.64.72.1 to 31.64.73.25431.64.73.255510
3831.64.74.0/2331.64.74.1 to 31.64.75.25431.64.75.255510
3931.64.76.0/2331.64.76.1 to 31.64.77.25431.64.77.255510
4031.64.78.0/2331.64.78.1 to 31.64.79.25431.64.79.255510
4131.64.80.0/2331.64.80.1 to 31.64.81.25431.64.81.255510
4231.64.82.0/2331.64.82.1 to 31.64.83.25431.64.83.255510
4331.64.84.0/2331.64.84.1 to 31.64.85.25431.64.85.255510
4431.64.86.0/2331.64.86.1 to 31.64.87.25431.64.87.255510
4531.64.88.0/2331.64.88.1 to 31.64.89.25431.64.89.255510
4631.64.90.0/2331.64.90.1 to 31.64.91.25431.64.91.255510
4731.64.92.0/2331.64.92.1 to 31.64.93.25431.64.93.255510
4831.64.94.0/2331.64.94.1 to 31.64.95.25431.64.95.255510
4931.64.96.0/2331.64.96.1 to 31.64.97.25431.64.97.255510
5031.64.98.0/2331.64.98.1 to 31.64.99.25431.64.99.255510
5131.64.100.0/2331.64.100.1 to 31.64.101.25431.64.101.255510
5231.64.102.0/2331.64.102.1 to 31.64.103.25431.64.103.255510
5331.64.104.0/2331.64.104.1 to 31.64.105.25431.64.105.255510
5431.64.106.0/2331.64.106.1 to 31.64.107.25431.64.107.255510
5531.64.108.0/2331.64.108.1 to 31.64.109.25431.64.109.255510
5631.64.110.0/2331.64.110.1 to 31.64.111.25431.64.111.255510
5731.64.112.0/2331.64.112.1 to 31.64.113.25431.64.113.255510
5831.64.114.0/2331.64.114.1 to 31.64.115.25431.64.115.255510
5931.64.116.0/2331.64.116.1 to 31.64.117.25431.64.117.255510
6031.64.118.0/2331.64.118.1 to 31.64.119.25431.64.119.255510
6131.64.120.0/2331.64.120.1 to 31.64.121.25431.64.121.255510
6231.64.122.0/2331.64.122.1 to 31.64.123.25431.64.123.255510
6331.64.124.0/2331.64.124.1 to 31.64.125.25431.64.125.255510
6431.64.126.0/2331.64.126.1 to 31.64.127.25431.64.127.255510
6531.64.128.0/2331.64.128.1 to 31.64.129.25431.64.129.255510
6631.64.130.0/2331.64.130.1 to 31.64.131.25431.64.131.255510
6731.64.132.0/2331.64.132.1 to 31.64.133.25431.64.133.255510
6831.64.134.0/2331.64.134.1 to 31.64.135.25431.64.135.255510
6931.64.136.0/2331.64.136.1 to 31.64.137.25431.64.137.255510
7031.64.138.0/2331.64.138.1 to 31.64.139.25431.64.139.255510
7131.64.140.0/2331.64.140.1 to 31.64.141.25431.64.141.255510
7231.64.142.0/2331.64.142.1 to 31.64.143.25431.64.143.255510
7331.64.144.0/2331.64.144.1 to 31.64.145.25431.64.145.255510
7431.64.146.0/2331.64.146.1 to 31.64.147.25431.64.147.255510
7531.64.148.0/2331.64.148.1 to 31.64.149.25431.64.149.255510
7631.64.150.0/2331.64.150.1 to 31.64.151.25431.64.151.255510
7731.64.152.0/2331.64.152.1 to 31.64.153.25431.64.153.255510
7831.64.154.0/2331.64.154.1 to 31.64.155.25431.64.155.255510
7931.64.156.0/2331.64.156.1 to 31.64.157.25431.64.157.255510
8031.64.158.0/2331.64.158.1 to 31.64.159.25431.64.159.255510
8131.64.160.0/2331.64.160.1 to 31.64.161.25431.64.161.255510
8231.64.162.0/2331.64.162.1 to 31.64.163.25431.64.163.255510
8331.64.164.0/2331.64.164.1 to 31.64.165.25431.64.165.255510
8431.64.166.0/2331.64.166.1 to 31.64.167.25431.64.167.255510
8531.64.168.0/2331.64.168.1 to 31.64.169.25431.64.169.255510
8631.64.170.0/2331.64.170.1 to 31.64.171.25431.64.171.255510
8731.64.172.0/2331.64.172.1 to 31.64.173.25431.64.173.255510
8831.64.174.0/2331.64.174.1 to 31.64.175.25431.64.175.255510
8931.64.176.0/2331.64.176.1 to 31.64.177.25431.64.177.255510
9031.64.178.0/2331.64.178.1 to 31.64.179.25431.64.179.255510
9131.64.180.0/2331.64.180.1 to 31.64.181.25431.64.181.255510
9231.64.182.0/2331.64.182.1 to 31.64.183.25431.64.183.255510
9331.64.184.0/2331.64.184.1 to 31.64.185.25431.64.185.255510
9431.64.186.0/2331.64.186.1 to 31.64.187.25431.64.187.255510
9531.64.188.0/2331.64.188.1 to 31.64.189.25431.64.189.255510
9631.64.190.0/2331.64.190.1 to 31.64.191.25431.64.191.255510
9731.64.192.0/2331.64.192.1 to 31.64.193.25431.64.193.255510
9831.64.194.0/2331.64.194.1 to 31.64.195.25431.64.195.255510
9931.64.196.0/2331.64.196.1 to 31.64.197.25431.64.197.255510
10031.64.198.0/2331.64.198.1 to 31.64.199.25431.64.199.255510
10131.64.200.0/2331.64.200.1 to 31.64.201.25431.64.201.255510
10231.64.202.0/2331.64.202.1 to 31.64.203.25431.64.203.255510
10331.64.204.0/2331.64.204.1 to 31.64.205.25431.64.205.255510
10431.64.206.0/2331.64.206.1 to 31.64.207.25431.64.207.255510
10531.64.208.0/2331.64.208.1 to 31.64.209.25431.64.209.255510
10631.64.210.0/2331.64.210.1 to 31.64.211.25431.64.211.255510
10731.64.212.0/2331.64.212.1 to 31.64.213.25431.64.213.255510
10831.64.214.0/2331.64.214.1 to 31.64.215.25431.64.215.255510
10931.64.216.0/2331.64.216.1 to 31.64.217.25431.64.217.255510
11031.64.218.0/2331.64.218.1 to 31.64.219.25431.64.219.255510
11131.64.220.0/2331.64.220.1 to 31.64.221.25431.64.221.255510
11231.64.222.0/2331.64.222.1 to 31.64.223.25431.64.223.255510
11331.64.224.0/2331.64.224.1 to 31.64.225.25431.64.225.255510
11431.64.226.0/2331.64.226.1 to 31.64.227.25431.64.227.255510
11531.64.228.0/2331.64.228.1 to 31.64.229.25431.64.229.255510
11631.64.230.0/2331.64.230.1 to 31.64.231.25431.64.231.255510
11731.64.232.0/2331.64.232.1 to 31.64.233.25431.64.233.255510
11831.64.234.0/2331.64.234.1 to 31.64.235.25431.64.235.255510
11931.64.236.0/2331.64.236.1 to 31.64.237.25431.64.237.255510
12031.64.238.0/2331.64.238.1 to 31.64.239.25431.64.239.255510
12131.64.240.0/2331.64.240.1 to 31.64.241.25431.64.241.255510
12231.64.242.0/2331.64.242.1 to 31.64.243.25431.64.243.255510
12331.64.244.0/2331.64.244.1 to 31.64.245.25431.64.245.255510
12431.64.246.0/2331.64.246.1 to 31.64.247.25431.64.247.255510
12531.64.248.0/2331.64.248.1 to 31.64.249.25431.64.249.255510
12631.64.250.0/2331.64.250.1 to 31.64.251.25431.64.251.255510
12731.64.252.0/2331.64.252.1 to 31.64.253.25431.64.253.255510
12831.64.254.0/2331.64.254.1 to 31.64.255.25431.64.255.255510
12931.65.0.0/2331.65.0.1 to 31.65.1.25431.65.1.255510
13031.65.2.0/2331.65.2.1 to 31.65.3.25431.65.3.255510
13131.65.4.0/2331.65.4.1 to 31.65.5.25431.65.5.255510
13231.65.6.0/2331.65.6.1 to 31.65.7.25431.65.7.255510
13331.65.8.0/2331.65.8.1 to 31.65.9.25431.65.9.255510
13431.65.10.0/2331.65.10.1 to 31.65.11.25431.65.11.255510
13531.65.12.0/2331.65.12.1 to 31.65.13.25431.65.13.255510
13631.65.14.0/2331.65.14.1 to 31.65.15.25431.65.15.255510
13731.65.16.0/2331.65.16.1 to 31.65.17.25431.65.17.255510
13831.65.18.0/2331.65.18.1 to 31.65.19.25431.65.19.255510
13931.65.20.0/2331.65.20.1 to 31.65.21.25431.65.21.255510
14031.65.22.0/2331.65.22.1 to 31.65.23.25431.65.23.255510
14131.65.24.0/2331.65.24.1 to 31.65.25.25431.65.25.255510
14231.65.26.0/2331.65.26.1 to 31.65.27.25431.65.27.255510
14331.65.28.0/2331.65.28.1 to 31.65.29.25431.65.29.255510
14431.65.30.0/2331.65.30.1 to 31.65.31.25431.65.31.255510
14531.65.32.0/2331.65.32.1 to 31.65.33.25431.65.33.255510
14631.65.34.0/2331.65.34.1 to 31.65.35.25431.65.35.255510
14731.65.36.0/2331.65.36.1 to 31.65.37.25431.65.37.255510
14831.65.38.0/2331.65.38.1 to 31.65.39.25431.65.39.255510
14931.65.40.0/2331.65.40.1 to 31.65.41.25431.65.41.255510
15031.65.42.0/2331.65.42.1 to 31.65.43.25431.65.43.255510
15131.65.44.0/2331.65.44.1 to 31.65.45.25431.65.45.255510
15231.65.46.0/2331.65.46.1 to 31.65.47.25431.65.47.255510
15331.65.48.0/2331.65.48.1 to 31.65.49.25431.65.49.255510
15431.65.50.0/2331.65.50.1 to 31.65.51.25431.65.51.255510
15531.65.52.0/2331.65.52.1 to 31.65.53.25431.65.53.255510
15631.65.54.0/2331.65.54.1 to 31.65.55.25431.65.55.255510
15731.65.56.0/2331.65.56.1 to 31.65.57.25431.65.57.255510
15831.65.58.0/2331.65.58.1 to 31.65.59.25431.65.59.255510
15931.65.60.0/2331.65.60.1 to 31.65.61.25431.65.61.255510
16031.65.62.0/2331.65.62.1 to 31.65.63.25431.65.63.255510
16131.65.64.0/2331.65.64.1 to 31.65.65.25431.65.65.255510
16231.65.66.0/2331.65.66.1 to 31.65.67.25431.65.67.255510
16331.65.68.0/2331.65.68.1 to 31.65.69.25431.65.69.255510
16431.65.70.0/2331.65.70.1 to 31.65.71.25431.65.71.255510
16531.65.72.0/2331.65.72.1 to 31.65.73.25431.65.73.255510
16631.65.74.0/2331.65.74.1 to 31.65.75.25431.65.75.255510
16731.65.76.0/2331.65.76.1 to 31.65.77.25431.65.77.255510
16831.65.78.0/2331.65.78.1 to 31.65.79.25431.65.79.255510
16931.65.80.0/2331.65.80.1 to 31.65.81.25431.65.81.255510
17031.65.82.0/2331.65.82.1 to 31.65.83.25431.65.83.255510
17131.65.84.0/2331.65.84.1 to 31.65.85.25431.65.85.255510
17231.65.86.0/2331.65.86.1 to 31.65.87.25431.65.87.255510
17331.65.88.0/2331.65.88.1 to 31.65.89.25431.65.89.255510
17431.65.90.0/2331.65.90.1 to 31.65.91.25431.65.91.255510
17531.65.92.0/2331.65.92.1 to 31.65.93.25431.65.93.255510
17631.65.94.0/2331.65.94.1 to 31.65.95.25431.65.95.255510
17731.65.96.0/2331.65.96.1 to 31.65.97.25431.65.97.255510
17831.65.98.0/2331.65.98.1 to 31.65.99.25431.65.99.255510
17931.65.100.0/2331.65.100.1 to 31.65.101.25431.65.101.255510
18031.65.102.0/2331.65.102.1 to 31.65.103.25431.65.103.255510
18131.65.104.0/2331.65.104.1 to 31.65.105.25431.65.105.255510
18231.65.106.0/2331.65.106.1 to 31.65.107.25431.65.107.255510
18331.65.108.0/2331.65.108.1 to 31.65.109.25431.65.109.255510
18431.65.110.0/2331.65.110.1 to 31.65.111.25431.65.111.255510
18531.65.112.0/2331.65.112.1 to 31.65.113.25431.65.113.255510
18631.65.114.0/2331.65.114.1 to 31.65.115.25431.65.115.255510
18731.65.116.0/2331.65.116.1 to 31.65.117.25431.65.117.255510
18831.65.118.0/2331.65.118.1 to 31.65.119.25431.65.119.255510
18931.65.120.0/2331.65.120.1 to 31.65.121.25431.65.121.255510
19031.65.122.0/2331.65.122.1 to 31.65.123.25431.65.123.255510
19131.65.124.0/2331.65.124.1 to 31.65.125.25431.65.125.255510
19231.65.126.0/2331.65.126.1 to 31.65.127.25431.65.127.255510
19331.65.128.0/2331.65.128.1 to 31.65.129.25431.65.129.255510
19431.65.130.0/2331.65.130.1 to 31.65.131.25431.65.131.255510
19531.65.132.0/2331.65.132.1 to 31.65.133.25431.65.133.255510
19631.65.134.0/2331.65.134.1 to 31.65.135.25431.65.135.255510
19731.65.136.0/2331.65.136.1 to 31.65.137.25431.65.137.255510
19831.65.138.0/2331.65.138.1 to 31.65.139.25431.65.139.255510
19931.65.140.0/2331.65.140.1 to 31.65.141.25431.65.141.255510
20031.65.142.0/2331.65.142.1 to 31.65.143.25431.65.143.255510
20131.65.144.0/2331.65.144.1 to 31.65.145.25431.65.145.255510
20231.65.146.0/2331.65.146.1 to 31.65.147.25431.65.147.255510
20331.65.148.0/2331.65.148.1 to 31.65.149.25431.65.149.255510
20431.65.150.0/2331.65.150.1 to 31.65.151.25431.65.151.255510
20531.65.152.0/2331.65.152.1 to 31.65.153.25431.65.153.255510
20631.65.154.0/2331.65.154.1 to 31.65.155.25431.65.155.255510
20731.65.156.0/2331.65.156.1 to 31.65.157.25431.65.157.255510
20831.65.158.0/2331.65.158.1 to 31.65.159.25431.65.159.255510
20931.65.160.0/2331.65.160.1 to 31.65.161.25431.65.161.255510
21031.65.162.0/2331.65.162.1 to 31.65.163.25431.65.163.255510
21131.65.164.0/2331.65.164.1 to 31.65.165.25431.65.165.255510
21231.65.166.0/2331.65.166.1 to 31.65.167.25431.65.167.255510
21331.65.168.0/2331.65.168.1 to 31.65.169.25431.65.169.255510
21431.65.170.0/2331.65.170.1 to 31.65.171.25431.65.171.255510
21531.65.172.0/2331.65.172.1 to 31.65.173.25431.65.173.255510
21631.65.174.0/2331.65.174.1 to 31.65.175.25431.65.175.255510
21731.65.176.0/2331.65.176.1 to 31.65.177.25431.65.177.255510
21831.65.178.0/2331.65.178.1 to 31.65.179.25431.65.179.255510
21931.65.180.0/2331.65.180.1 to 31.65.181.25431.65.181.255510
22031.65.182.0/2331.65.182.1 to 31.65.183.25431.65.183.255510
22131.65.184.0/2331.65.184.1 to 31.65.185.25431.65.185.255510
22231.65.186.0/2331.65.186.1 to 31.65.187.25431.65.187.255510
22331.65.188.0/2331.65.188.1 to 31.65.189.25431.65.189.255510
22431.65.190.0/2331.65.190.1 to 31.65.191.25431.65.191.255510
22531.65.192.0/2331.65.192.1 to 31.65.193.25431.65.193.255510
22631.65.194.0/2331.65.194.1 to 31.65.195.25431.65.195.255510
22731.65.196.0/2331.65.196.1 to 31.65.197.25431.65.197.255510
22831.65.198.0/2331.65.198.1 to 31.65.199.25431.65.199.255510
22931.65.200.0/2331.65.200.1 to 31.65.201.25431.65.201.255510
23031.65.202.0/2331.65.202.1 to 31.65.203.25431.65.203.255510
23131.65.204.0/2331.65.204.1 to 31.65.205.25431.65.205.255510
23231.65.206.0/2331.65.206.1 to 31.65.207.25431.65.207.255510
23331.65.208.0/2331.65.208.1 to 31.65.209.25431.65.209.255510
23431.65.210.0/2331.65.210.1 to 31.65.211.25431.65.211.255510
23531.65.212.0/2331.65.212.1 to 31.65.213.25431.65.213.255510
23631.65.214.0/2331.65.214.1 to 31.65.215.25431.65.215.255510
23731.65.216.0/2331.65.216.1 to 31.65.217.25431.65.217.255510
23831.65.218.0/2331.65.218.1 to 31.65.219.25431.65.219.255510
23931.65.220.0/2331.65.220.1 to 31.65.221.25431.65.221.255510
24031.65.222.0/2331.65.222.1 to 31.65.223.25431.65.223.255510
24131.65.224.0/2331.65.224.1 to 31.65.225.25431.65.225.255510
24231.65.226.0/2331.65.226.1 to 31.65.227.25431.65.227.255510
24331.65.228.0/2331.65.228.1 to 31.65.229.25431.65.229.255510
24431.65.230.0/2331.65.230.1 to 31.65.231.25431.65.231.255510
24531.65.232.0/2331.65.232.1 to 31.65.233.25431.65.233.255510
24631.65.234.0/2331.65.234.1 to 31.65.235.25431.65.235.255510
24731.65.236.0/2331.65.236.1 to 31.65.237.25431.65.237.255510
24831.65.238.0/2331.65.238.1 to 31.65.239.25431.65.239.255510
24931.65.240.0/2331.65.240.1 to 31.65.241.25431.65.241.255510
25031.65.242.0/2331.65.242.1 to 31.65.243.25431.65.243.255510
25131.65.244.0/2331.65.244.1 to 31.65.245.25431.65.245.255510
25231.65.246.0/2331.65.246.1 to 31.65.247.25431.65.247.255510
25331.65.248.0/2331.65.248.1 to 31.65.249.25431.65.249.255510
25431.65.250.0/2331.65.250.1 to 31.65.251.25431.65.251.255510
25531.65.252.0/2331.65.252.1 to 31.65.253.25431.65.253.255510
25631.65.254.0/2331.65.254.1 to 31.65.255.25431.65.255.255510

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.