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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.

Network57.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
57.2.0.0
Broadcast address
57.3.255.255
First usable
57.2.0.1
Last usable
57.3.255.254
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 39020000 · Integer 956432384 to 956563455
Reverse DNS zones
2.57.in-addr.arpa
3.57.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
Address00111001.00000010.00000000.0000000057.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00111001.00000010.00000000.0000000057.2.0.0
Broadcast00111001.00000011.11111111.1111111157.3.255.255
Split into smaller subnets/24
/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)

57.2.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.2.0.0/2457.2.0.1 to 57.2.0.25457.2.0.255254
257.2.1.0/2457.2.1.1 to 57.2.1.25457.2.1.255254
357.2.2.0/2457.2.2.1 to 57.2.2.25457.2.2.255254
457.2.3.0/2457.2.3.1 to 57.2.3.25457.2.3.255254
557.2.4.0/2457.2.4.1 to 57.2.4.25457.2.4.255254
657.2.5.0/2457.2.5.1 to 57.2.5.25457.2.5.255254
757.2.6.0/2457.2.6.1 to 57.2.6.25457.2.6.255254
857.2.7.0/2457.2.7.1 to 57.2.7.25457.2.7.255254
957.2.8.0/2457.2.8.1 to 57.2.8.25457.2.8.255254
1057.2.9.0/2457.2.9.1 to 57.2.9.25457.2.9.255254
1157.2.10.0/2457.2.10.1 to 57.2.10.25457.2.10.255254
1257.2.11.0/2457.2.11.1 to 57.2.11.25457.2.11.255254
1357.2.12.0/2457.2.12.1 to 57.2.12.25457.2.12.255254
1457.2.13.0/2457.2.13.1 to 57.2.13.25457.2.13.255254
1557.2.14.0/2457.2.14.1 to 57.2.14.25457.2.14.255254
1657.2.15.0/2457.2.15.1 to 57.2.15.25457.2.15.255254
1757.2.16.0/2457.2.16.1 to 57.2.16.25457.2.16.255254
1857.2.17.0/2457.2.17.1 to 57.2.17.25457.2.17.255254
1957.2.18.0/2457.2.18.1 to 57.2.18.25457.2.18.255254
2057.2.19.0/2457.2.19.1 to 57.2.19.25457.2.19.255254
2157.2.20.0/2457.2.20.1 to 57.2.20.25457.2.20.255254
2257.2.21.0/2457.2.21.1 to 57.2.21.25457.2.21.255254
2357.2.22.0/2457.2.22.1 to 57.2.22.25457.2.22.255254
2457.2.23.0/2457.2.23.1 to 57.2.23.25457.2.23.255254
2557.2.24.0/2457.2.24.1 to 57.2.24.25457.2.24.255254
2657.2.25.0/2457.2.25.1 to 57.2.25.25457.2.25.255254
2757.2.26.0/2457.2.26.1 to 57.2.26.25457.2.26.255254
2857.2.27.0/2457.2.27.1 to 57.2.27.25457.2.27.255254
2957.2.28.0/2457.2.28.1 to 57.2.28.25457.2.28.255254
3057.2.29.0/2457.2.29.1 to 57.2.29.25457.2.29.255254
3157.2.30.0/2457.2.30.1 to 57.2.30.25457.2.30.255254
3257.2.31.0/2457.2.31.1 to 57.2.31.25457.2.31.255254
3357.2.32.0/2457.2.32.1 to 57.2.32.25457.2.32.255254
3457.2.33.0/2457.2.33.1 to 57.2.33.25457.2.33.255254
3557.2.34.0/2457.2.34.1 to 57.2.34.25457.2.34.255254
3657.2.35.0/2457.2.35.1 to 57.2.35.25457.2.35.255254
3757.2.36.0/2457.2.36.1 to 57.2.36.25457.2.36.255254
3857.2.37.0/2457.2.37.1 to 57.2.37.25457.2.37.255254
3957.2.38.0/2457.2.38.1 to 57.2.38.25457.2.38.255254
4057.2.39.0/2457.2.39.1 to 57.2.39.25457.2.39.255254
4157.2.40.0/2457.2.40.1 to 57.2.40.25457.2.40.255254
4257.2.41.0/2457.2.41.1 to 57.2.41.25457.2.41.255254
4357.2.42.0/2457.2.42.1 to 57.2.42.25457.2.42.255254
4457.2.43.0/2457.2.43.1 to 57.2.43.25457.2.43.255254
4557.2.44.0/2457.2.44.1 to 57.2.44.25457.2.44.255254
4657.2.45.0/2457.2.45.1 to 57.2.45.25457.2.45.255254
4757.2.46.0/2457.2.46.1 to 57.2.46.25457.2.46.255254
4857.2.47.0/2457.2.47.1 to 57.2.47.25457.2.47.255254
4957.2.48.0/2457.2.48.1 to 57.2.48.25457.2.48.255254
5057.2.49.0/2457.2.49.1 to 57.2.49.25457.2.49.255254
5157.2.50.0/2457.2.50.1 to 57.2.50.25457.2.50.255254
5257.2.51.0/2457.2.51.1 to 57.2.51.25457.2.51.255254
5357.2.52.0/2457.2.52.1 to 57.2.52.25457.2.52.255254
5457.2.53.0/2457.2.53.1 to 57.2.53.25457.2.53.255254
5557.2.54.0/2457.2.54.1 to 57.2.54.25457.2.54.255254
5657.2.55.0/2457.2.55.1 to 57.2.55.25457.2.55.255254
5757.2.56.0/2457.2.56.1 to 57.2.56.25457.2.56.255254
5857.2.57.0/2457.2.57.1 to 57.2.57.25457.2.57.255254
5957.2.58.0/2457.2.58.1 to 57.2.58.25457.2.58.255254
6057.2.59.0/2457.2.59.1 to 57.2.59.25457.2.59.255254
6157.2.60.0/2457.2.60.1 to 57.2.60.25457.2.60.255254
6257.2.61.0/2457.2.61.1 to 57.2.61.25457.2.61.255254
6357.2.62.0/2457.2.62.1 to 57.2.62.25457.2.62.255254
6457.2.63.0/2457.2.63.1 to 57.2.63.25457.2.63.255254
6557.2.64.0/2457.2.64.1 to 57.2.64.25457.2.64.255254
6657.2.65.0/2457.2.65.1 to 57.2.65.25457.2.65.255254
6757.2.66.0/2457.2.66.1 to 57.2.66.25457.2.66.255254
6857.2.67.0/2457.2.67.1 to 57.2.67.25457.2.67.255254
6957.2.68.0/2457.2.68.1 to 57.2.68.25457.2.68.255254
7057.2.69.0/2457.2.69.1 to 57.2.69.25457.2.69.255254
7157.2.70.0/2457.2.70.1 to 57.2.70.25457.2.70.255254
7257.2.71.0/2457.2.71.1 to 57.2.71.25457.2.71.255254
7357.2.72.0/2457.2.72.1 to 57.2.72.25457.2.72.255254
7457.2.73.0/2457.2.73.1 to 57.2.73.25457.2.73.255254
7557.2.74.0/2457.2.74.1 to 57.2.74.25457.2.74.255254
7657.2.75.0/2457.2.75.1 to 57.2.75.25457.2.75.255254
7757.2.76.0/2457.2.76.1 to 57.2.76.25457.2.76.255254
7857.2.77.0/2457.2.77.1 to 57.2.77.25457.2.77.255254
7957.2.78.0/2457.2.78.1 to 57.2.78.25457.2.78.255254
8057.2.79.0/2457.2.79.1 to 57.2.79.25457.2.79.255254
8157.2.80.0/2457.2.80.1 to 57.2.80.25457.2.80.255254
8257.2.81.0/2457.2.81.1 to 57.2.81.25457.2.81.255254
8357.2.82.0/2457.2.82.1 to 57.2.82.25457.2.82.255254
8457.2.83.0/2457.2.83.1 to 57.2.83.25457.2.83.255254
8557.2.84.0/2457.2.84.1 to 57.2.84.25457.2.84.255254
8657.2.85.0/2457.2.85.1 to 57.2.85.25457.2.85.255254
8757.2.86.0/2457.2.86.1 to 57.2.86.25457.2.86.255254
8857.2.87.0/2457.2.87.1 to 57.2.87.25457.2.87.255254
8957.2.88.0/2457.2.88.1 to 57.2.88.25457.2.88.255254
9057.2.89.0/2457.2.89.1 to 57.2.89.25457.2.89.255254
9157.2.90.0/2457.2.90.1 to 57.2.90.25457.2.90.255254
9257.2.91.0/2457.2.91.1 to 57.2.91.25457.2.91.255254
9357.2.92.0/2457.2.92.1 to 57.2.92.25457.2.92.255254
9457.2.93.0/2457.2.93.1 to 57.2.93.25457.2.93.255254
9557.2.94.0/2457.2.94.1 to 57.2.94.25457.2.94.255254
9657.2.95.0/2457.2.95.1 to 57.2.95.25457.2.95.255254
9757.2.96.0/2457.2.96.1 to 57.2.96.25457.2.96.255254
9857.2.97.0/2457.2.97.1 to 57.2.97.25457.2.97.255254
9957.2.98.0/2457.2.98.1 to 57.2.98.25457.2.98.255254
10057.2.99.0/2457.2.99.1 to 57.2.99.25457.2.99.255254
10157.2.100.0/2457.2.100.1 to 57.2.100.25457.2.100.255254
10257.2.101.0/2457.2.101.1 to 57.2.101.25457.2.101.255254
10357.2.102.0/2457.2.102.1 to 57.2.102.25457.2.102.255254
10457.2.103.0/2457.2.103.1 to 57.2.103.25457.2.103.255254
10557.2.104.0/2457.2.104.1 to 57.2.104.25457.2.104.255254
10657.2.105.0/2457.2.105.1 to 57.2.105.25457.2.105.255254
10757.2.106.0/2457.2.106.1 to 57.2.106.25457.2.106.255254
10857.2.107.0/2457.2.107.1 to 57.2.107.25457.2.107.255254
10957.2.108.0/2457.2.108.1 to 57.2.108.25457.2.108.255254
11057.2.109.0/2457.2.109.1 to 57.2.109.25457.2.109.255254
11157.2.110.0/2457.2.110.1 to 57.2.110.25457.2.110.255254
11257.2.111.0/2457.2.111.1 to 57.2.111.25457.2.111.255254
11357.2.112.0/2457.2.112.1 to 57.2.112.25457.2.112.255254
11457.2.113.0/2457.2.113.1 to 57.2.113.25457.2.113.255254
11557.2.114.0/2457.2.114.1 to 57.2.114.25457.2.114.255254
11657.2.115.0/2457.2.115.1 to 57.2.115.25457.2.115.255254
11757.2.116.0/2457.2.116.1 to 57.2.116.25457.2.116.255254
11857.2.117.0/2457.2.117.1 to 57.2.117.25457.2.117.255254
11957.2.118.0/2457.2.118.1 to 57.2.118.25457.2.118.255254
12057.2.119.0/2457.2.119.1 to 57.2.119.25457.2.119.255254
12157.2.120.0/2457.2.120.1 to 57.2.120.25457.2.120.255254
12257.2.121.0/2457.2.121.1 to 57.2.121.25457.2.121.255254
12357.2.122.0/2457.2.122.1 to 57.2.122.25457.2.122.255254
12457.2.123.0/2457.2.123.1 to 57.2.123.25457.2.123.255254
12557.2.124.0/2457.2.124.1 to 57.2.124.25457.2.124.255254
12657.2.125.0/2457.2.125.1 to 57.2.125.25457.2.125.255254
12757.2.126.0/2457.2.126.1 to 57.2.126.25457.2.126.255254
12857.2.127.0/2457.2.127.1 to 57.2.127.25457.2.127.255254
12957.2.128.0/2457.2.128.1 to 57.2.128.25457.2.128.255254
13057.2.129.0/2457.2.129.1 to 57.2.129.25457.2.129.255254
13157.2.130.0/2457.2.130.1 to 57.2.130.25457.2.130.255254
13257.2.131.0/2457.2.131.1 to 57.2.131.25457.2.131.255254
13357.2.132.0/2457.2.132.1 to 57.2.132.25457.2.132.255254
13457.2.133.0/2457.2.133.1 to 57.2.133.25457.2.133.255254
13557.2.134.0/2457.2.134.1 to 57.2.134.25457.2.134.255254
13657.2.135.0/2457.2.135.1 to 57.2.135.25457.2.135.255254
13757.2.136.0/2457.2.136.1 to 57.2.136.25457.2.136.255254
13857.2.137.0/2457.2.137.1 to 57.2.137.25457.2.137.255254
13957.2.138.0/2457.2.138.1 to 57.2.138.25457.2.138.255254
14057.2.139.0/2457.2.139.1 to 57.2.139.25457.2.139.255254
14157.2.140.0/2457.2.140.1 to 57.2.140.25457.2.140.255254
14257.2.141.0/2457.2.141.1 to 57.2.141.25457.2.141.255254
14357.2.142.0/2457.2.142.1 to 57.2.142.25457.2.142.255254
14457.2.143.0/2457.2.143.1 to 57.2.143.25457.2.143.255254
14557.2.144.0/2457.2.144.1 to 57.2.144.25457.2.144.255254
14657.2.145.0/2457.2.145.1 to 57.2.145.25457.2.145.255254
14757.2.146.0/2457.2.146.1 to 57.2.146.25457.2.146.255254
14857.2.147.0/2457.2.147.1 to 57.2.147.25457.2.147.255254
14957.2.148.0/2457.2.148.1 to 57.2.148.25457.2.148.255254
15057.2.149.0/2457.2.149.1 to 57.2.149.25457.2.149.255254
15157.2.150.0/2457.2.150.1 to 57.2.150.25457.2.150.255254
15257.2.151.0/2457.2.151.1 to 57.2.151.25457.2.151.255254
15357.2.152.0/2457.2.152.1 to 57.2.152.25457.2.152.255254
15457.2.153.0/2457.2.153.1 to 57.2.153.25457.2.153.255254
15557.2.154.0/2457.2.154.1 to 57.2.154.25457.2.154.255254
15657.2.155.0/2457.2.155.1 to 57.2.155.25457.2.155.255254
15757.2.156.0/2457.2.156.1 to 57.2.156.25457.2.156.255254
15857.2.157.0/2457.2.157.1 to 57.2.157.25457.2.157.255254
15957.2.158.0/2457.2.158.1 to 57.2.158.25457.2.158.255254
16057.2.159.0/2457.2.159.1 to 57.2.159.25457.2.159.255254
16157.2.160.0/2457.2.160.1 to 57.2.160.25457.2.160.255254
16257.2.161.0/2457.2.161.1 to 57.2.161.25457.2.161.255254
16357.2.162.0/2457.2.162.1 to 57.2.162.25457.2.162.255254
16457.2.163.0/2457.2.163.1 to 57.2.163.25457.2.163.255254
16557.2.164.0/2457.2.164.1 to 57.2.164.25457.2.164.255254
16657.2.165.0/2457.2.165.1 to 57.2.165.25457.2.165.255254
16757.2.166.0/2457.2.166.1 to 57.2.166.25457.2.166.255254
16857.2.167.0/2457.2.167.1 to 57.2.167.25457.2.167.255254
16957.2.168.0/2457.2.168.1 to 57.2.168.25457.2.168.255254
17057.2.169.0/2457.2.169.1 to 57.2.169.25457.2.169.255254
17157.2.170.0/2457.2.170.1 to 57.2.170.25457.2.170.255254
17257.2.171.0/2457.2.171.1 to 57.2.171.25457.2.171.255254
17357.2.172.0/2457.2.172.1 to 57.2.172.25457.2.172.255254
17457.2.173.0/2457.2.173.1 to 57.2.173.25457.2.173.255254
17557.2.174.0/2457.2.174.1 to 57.2.174.25457.2.174.255254
17657.2.175.0/2457.2.175.1 to 57.2.175.25457.2.175.255254
17757.2.176.0/2457.2.176.1 to 57.2.176.25457.2.176.255254
17857.2.177.0/2457.2.177.1 to 57.2.177.25457.2.177.255254
17957.2.178.0/2457.2.178.1 to 57.2.178.25457.2.178.255254
18057.2.179.0/2457.2.179.1 to 57.2.179.25457.2.179.255254
18157.2.180.0/2457.2.180.1 to 57.2.180.25457.2.180.255254
18257.2.181.0/2457.2.181.1 to 57.2.181.25457.2.181.255254
18357.2.182.0/2457.2.182.1 to 57.2.182.25457.2.182.255254
18457.2.183.0/2457.2.183.1 to 57.2.183.25457.2.183.255254
18557.2.184.0/2457.2.184.1 to 57.2.184.25457.2.184.255254
18657.2.185.0/2457.2.185.1 to 57.2.185.25457.2.185.255254
18757.2.186.0/2457.2.186.1 to 57.2.186.25457.2.186.255254
18857.2.187.0/2457.2.187.1 to 57.2.187.25457.2.187.255254
18957.2.188.0/2457.2.188.1 to 57.2.188.25457.2.188.255254
19057.2.189.0/2457.2.189.1 to 57.2.189.25457.2.189.255254
19157.2.190.0/2457.2.190.1 to 57.2.190.25457.2.190.255254
19257.2.191.0/2457.2.191.1 to 57.2.191.25457.2.191.255254
19357.2.192.0/2457.2.192.1 to 57.2.192.25457.2.192.255254
19457.2.193.0/2457.2.193.1 to 57.2.193.25457.2.193.255254
19557.2.194.0/2457.2.194.1 to 57.2.194.25457.2.194.255254
19657.2.195.0/2457.2.195.1 to 57.2.195.25457.2.195.255254
19757.2.196.0/2457.2.196.1 to 57.2.196.25457.2.196.255254
19857.2.197.0/2457.2.197.1 to 57.2.197.25457.2.197.255254
19957.2.198.0/2457.2.198.1 to 57.2.198.25457.2.198.255254
20057.2.199.0/2457.2.199.1 to 57.2.199.25457.2.199.255254
20157.2.200.0/2457.2.200.1 to 57.2.200.25457.2.200.255254
20257.2.201.0/2457.2.201.1 to 57.2.201.25457.2.201.255254
20357.2.202.0/2457.2.202.1 to 57.2.202.25457.2.202.255254
20457.2.203.0/2457.2.203.1 to 57.2.203.25457.2.203.255254
20557.2.204.0/2457.2.204.1 to 57.2.204.25457.2.204.255254
20657.2.205.0/2457.2.205.1 to 57.2.205.25457.2.205.255254
20757.2.206.0/2457.2.206.1 to 57.2.206.25457.2.206.255254
20857.2.207.0/2457.2.207.1 to 57.2.207.25457.2.207.255254
20957.2.208.0/2457.2.208.1 to 57.2.208.25457.2.208.255254
21057.2.209.0/2457.2.209.1 to 57.2.209.25457.2.209.255254
21157.2.210.0/2457.2.210.1 to 57.2.210.25457.2.210.255254
21257.2.211.0/2457.2.211.1 to 57.2.211.25457.2.211.255254
21357.2.212.0/2457.2.212.1 to 57.2.212.25457.2.212.255254
21457.2.213.0/2457.2.213.1 to 57.2.213.25457.2.213.255254
21557.2.214.0/2457.2.214.1 to 57.2.214.25457.2.214.255254
21657.2.215.0/2457.2.215.1 to 57.2.215.25457.2.215.255254
21757.2.216.0/2457.2.216.1 to 57.2.216.25457.2.216.255254
21857.2.217.0/2457.2.217.1 to 57.2.217.25457.2.217.255254
21957.2.218.0/2457.2.218.1 to 57.2.218.25457.2.218.255254
22057.2.219.0/2457.2.219.1 to 57.2.219.25457.2.219.255254
22157.2.220.0/2457.2.220.1 to 57.2.220.25457.2.220.255254
22257.2.221.0/2457.2.221.1 to 57.2.221.25457.2.221.255254
22357.2.222.0/2457.2.222.1 to 57.2.222.25457.2.222.255254
22457.2.223.0/2457.2.223.1 to 57.2.223.25457.2.223.255254
22557.2.224.0/2457.2.224.1 to 57.2.224.25457.2.224.255254
22657.2.225.0/2457.2.225.1 to 57.2.225.25457.2.225.255254
22757.2.226.0/2457.2.226.1 to 57.2.226.25457.2.226.255254
22857.2.227.0/2457.2.227.1 to 57.2.227.25457.2.227.255254
22957.2.228.0/2457.2.228.1 to 57.2.228.25457.2.228.255254
23057.2.229.0/2457.2.229.1 to 57.2.229.25457.2.229.255254
23157.2.230.0/2457.2.230.1 to 57.2.230.25457.2.230.255254
23257.2.231.0/2457.2.231.1 to 57.2.231.25457.2.231.255254
23357.2.232.0/2457.2.232.1 to 57.2.232.25457.2.232.255254
23457.2.233.0/2457.2.233.1 to 57.2.233.25457.2.233.255254
23557.2.234.0/2457.2.234.1 to 57.2.234.25457.2.234.255254
23657.2.235.0/2457.2.235.1 to 57.2.235.25457.2.235.255254
23757.2.236.0/2457.2.236.1 to 57.2.236.25457.2.236.255254
23857.2.237.0/2457.2.237.1 to 57.2.237.25457.2.237.255254
23957.2.238.0/2457.2.238.1 to 57.2.238.25457.2.238.255254
24057.2.239.0/2457.2.239.1 to 57.2.239.25457.2.239.255254
24157.2.240.0/2457.2.240.1 to 57.2.240.25457.2.240.255254
24257.2.241.0/2457.2.241.1 to 57.2.241.25457.2.241.255254
24357.2.242.0/2457.2.242.1 to 57.2.242.25457.2.242.255254
24457.2.243.0/2457.2.243.1 to 57.2.243.25457.2.243.255254
24557.2.244.0/2457.2.244.1 to 57.2.244.25457.2.244.255254
24657.2.245.0/2457.2.245.1 to 57.2.245.25457.2.245.255254
24757.2.246.0/2457.2.246.1 to 57.2.246.25457.2.246.255254
24857.2.247.0/2457.2.247.1 to 57.2.247.25457.2.247.255254
24957.2.248.0/2457.2.248.1 to 57.2.248.25457.2.248.255254
25057.2.249.0/2457.2.249.1 to 57.2.249.25457.2.249.255254
25157.2.250.0/2457.2.250.1 to 57.2.250.25457.2.250.255254
25257.2.251.0/2457.2.251.1 to 57.2.251.25457.2.251.255254
25357.2.252.0/2457.2.252.1 to 57.2.252.25457.2.252.255254
25457.2.253.0/2457.2.253.1 to 57.2.253.25457.2.253.255254
25557.2.254.0/2457.2.254.1 to 57.2.254.25457.2.254.255254
25657.2.255.0/2457.2.255.1 to 57.2.255.25457.2.255.255254

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.