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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.

Network10.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
10.0.0.0
Broadcast address
11.255.255.255
First usable
10.0.0.1
Last usable
11.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 0A000000 · Integer 167772160 to 201326591
Reverse DNS zones
10.in-addr.arpa
11.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001010.00000000.00000000.0000000010.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00001010.00000000.00000000.0000000010.0.0.0
Broadcast00001011.11111111.11111111.1111111111.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

10.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
110.0.0.0/1510.0.0.1 to 10.1.255.25410.1.255.255131,070
210.2.0.0/1510.2.0.1 to 10.3.255.25410.3.255.255131,070
310.4.0.0/1510.4.0.1 to 10.5.255.25410.5.255.255131,070
410.6.0.0/1510.6.0.1 to 10.7.255.25410.7.255.255131,070
510.8.0.0/1510.8.0.1 to 10.9.255.25410.9.255.255131,070
610.10.0.0/1510.10.0.1 to 10.11.255.25410.11.255.255131,070
710.12.0.0/1510.12.0.1 to 10.13.255.25410.13.255.255131,070
810.14.0.0/1510.14.0.1 to 10.15.255.25410.15.255.255131,070
910.16.0.0/1510.16.0.1 to 10.17.255.25410.17.255.255131,070
1010.18.0.0/1510.18.0.1 to 10.19.255.25410.19.255.255131,070
1110.20.0.0/1510.20.0.1 to 10.21.255.25410.21.255.255131,070
1210.22.0.0/1510.22.0.1 to 10.23.255.25410.23.255.255131,070
1310.24.0.0/1510.24.0.1 to 10.25.255.25410.25.255.255131,070
1410.26.0.0/1510.26.0.1 to 10.27.255.25410.27.255.255131,070
1510.28.0.0/1510.28.0.1 to 10.29.255.25410.29.255.255131,070
1610.30.0.0/1510.30.0.1 to 10.31.255.25410.31.255.255131,070
1710.32.0.0/1510.32.0.1 to 10.33.255.25410.33.255.255131,070
1810.34.0.0/1510.34.0.1 to 10.35.255.25410.35.255.255131,070
1910.36.0.0/1510.36.0.1 to 10.37.255.25410.37.255.255131,070
2010.38.0.0/1510.38.0.1 to 10.39.255.25410.39.255.255131,070
2110.40.0.0/1510.40.0.1 to 10.41.255.25410.41.255.255131,070
2210.42.0.0/1510.42.0.1 to 10.43.255.25410.43.255.255131,070
2310.44.0.0/1510.44.0.1 to 10.45.255.25410.45.255.255131,070
2410.46.0.0/1510.46.0.1 to 10.47.255.25410.47.255.255131,070
2510.48.0.0/1510.48.0.1 to 10.49.255.25410.49.255.255131,070
2610.50.0.0/1510.50.0.1 to 10.51.255.25410.51.255.255131,070
2710.52.0.0/1510.52.0.1 to 10.53.255.25410.53.255.255131,070
2810.54.0.0/1510.54.0.1 to 10.55.255.25410.55.255.255131,070
2910.56.0.0/1510.56.0.1 to 10.57.255.25410.57.255.255131,070
3010.58.0.0/1510.58.0.1 to 10.59.255.25410.59.255.255131,070
3110.60.0.0/1510.60.0.1 to 10.61.255.25410.61.255.255131,070
3210.62.0.0/1510.62.0.1 to 10.63.255.25410.63.255.255131,070
3310.64.0.0/1510.64.0.1 to 10.65.255.25410.65.255.255131,070
3410.66.0.0/1510.66.0.1 to 10.67.255.25410.67.255.255131,070
3510.68.0.0/1510.68.0.1 to 10.69.255.25410.69.255.255131,070
3610.70.0.0/1510.70.0.1 to 10.71.255.25410.71.255.255131,070
3710.72.0.0/1510.72.0.1 to 10.73.255.25410.73.255.255131,070
3810.74.0.0/1510.74.0.1 to 10.75.255.25410.75.255.255131,070
3910.76.0.0/1510.76.0.1 to 10.77.255.25410.77.255.255131,070
4010.78.0.0/1510.78.0.1 to 10.79.255.25410.79.255.255131,070
4110.80.0.0/1510.80.0.1 to 10.81.255.25410.81.255.255131,070
4210.82.0.0/1510.82.0.1 to 10.83.255.25410.83.255.255131,070
4310.84.0.0/1510.84.0.1 to 10.85.255.25410.85.255.255131,070
4410.86.0.0/1510.86.0.1 to 10.87.255.25410.87.255.255131,070
4510.88.0.0/1510.88.0.1 to 10.89.255.25410.89.255.255131,070
4610.90.0.0/1510.90.0.1 to 10.91.255.25410.91.255.255131,070
4710.92.0.0/1510.92.0.1 to 10.93.255.25410.93.255.255131,070
4810.94.0.0/1510.94.0.1 to 10.95.255.25410.95.255.255131,070
4910.96.0.0/1510.96.0.1 to 10.97.255.25410.97.255.255131,070
5010.98.0.0/1510.98.0.1 to 10.99.255.25410.99.255.255131,070
5110.100.0.0/1510.100.0.1 to 10.101.255.25410.101.255.255131,070
5210.102.0.0/1510.102.0.1 to 10.103.255.25410.103.255.255131,070
5310.104.0.0/1510.104.0.1 to 10.105.255.25410.105.255.255131,070
5410.106.0.0/1510.106.0.1 to 10.107.255.25410.107.255.255131,070
5510.108.0.0/1510.108.0.1 to 10.109.255.25410.109.255.255131,070
5610.110.0.0/1510.110.0.1 to 10.111.255.25410.111.255.255131,070
5710.112.0.0/1510.112.0.1 to 10.113.255.25410.113.255.255131,070
5810.114.0.0/1510.114.0.1 to 10.115.255.25410.115.255.255131,070
5910.116.0.0/1510.116.0.1 to 10.117.255.25410.117.255.255131,070
6010.118.0.0/1510.118.0.1 to 10.119.255.25410.119.255.255131,070
6110.120.0.0/1510.120.0.1 to 10.121.255.25410.121.255.255131,070
6210.122.0.0/1510.122.0.1 to 10.123.255.25410.123.255.255131,070
6310.124.0.0/1510.124.0.1 to 10.125.255.25410.125.255.255131,070
6410.126.0.0/1510.126.0.1 to 10.127.255.25410.127.255.255131,070
6510.128.0.0/1510.128.0.1 to 10.129.255.25410.129.255.255131,070
6610.130.0.0/1510.130.0.1 to 10.131.255.25410.131.255.255131,070
6710.132.0.0/1510.132.0.1 to 10.133.255.25410.133.255.255131,070
6810.134.0.0/1510.134.0.1 to 10.135.255.25410.135.255.255131,070
6910.136.0.0/1510.136.0.1 to 10.137.255.25410.137.255.255131,070
7010.138.0.0/1510.138.0.1 to 10.139.255.25410.139.255.255131,070
7110.140.0.0/1510.140.0.1 to 10.141.255.25410.141.255.255131,070
7210.142.0.0/1510.142.0.1 to 10.143.255.25410.143.255.255131,070
7310.144.0.0/1510.144.0.1 to 10.145.255.25410.145.255.255131,070
7410.146.0.0/1510.146.0.1 to 10.147.255.25410.147.255.255131,070
7510.148.0.0/1510.148.0.1 to 10.149.255.25410.149.255.255131,070
7610.150.0.0/1510.150.0.1 to 10.151.255.25410.151.255.255131,070
7710.152.0.0/1510.152.0.1 to 10.153.255.25410.153.255.255131,070
7810.154.0.0/1510.154.0.1 to 10.155.255.25410.155.255.255131,070
7910.156.0.0/1510.156.0.1 to 10.157.255.25410.157.255.255131,070
8010.158.0.0/1510.158.0.1 to 10.159.255.25410.159.255.255131,070
8110.160.0.0/1510.160.0.1 to 10.161.255.25410.161.255.255131,070
8210.162.0.0/1510.162.0.1 to 10.163.255.25410.163.255.255131,070
8310.164.0.0/1510.164.0.1 to 10.165.255.25410.165.255.255131,070
8410.166.0.0/1510.166.0.1 to 10.167.255.25410.167.255.255131,070
8510.168.0.0/1510.168.0.1 to 10.169.255.25410.169.255.255131,070
8610.170.0.0/1510.170.0.1 to 10.171.255.25410.171.255.255131,070
8710.172.0.0/1510.172.0.1 to 10.173.255.25410.173.255.255131,070
8810.174.0.0/1510.174.0.1 to 10.175.255.25410.175.255.255131,070
8910.176.0.0/1510.176.0.1 to 10.177.255.25410.177.255.255131,070
9010.178.0.0/1510.178.0.1 to 10.179.255.25410.179.255.255131,070
9110.180.0.0/1510.180.0.1 to 10.181.255.25410.181.255.255131,070
9210.182.0.0/1510.182.0.1 to 10.183.255.25410.183.255.255131,070
9310.184.0.0/1510.184.0.1 to 10.185.255.25410.185.255.255131,070
9410.186.0.0/1510.186.0.1 to 10.187.255.25410.187.255.255131,070
9510.188.0.0/1510.188.0.1 to 10.189.255.25410.189.255.255131,070
9610.190.0.0/1510.190.0.1 to 10.191.255.25410.191.255.255131,070
9710.192.0.0/1510.192.0.1 to 10.193.255.25410.193.255.255131,070
9810.194.0.0/1510.194.0.1 to 10.195.255.25410.195.255.255131,070
9910.196.0.0/1510.196.0.1 to 10.197.255.25410.197.255.255131,070
10010.198.0.0/1510.198.0.1 to 10.199.255.25410.199.255.255131,070
10110.200.0.0/1510.200.0.1 to 10.201.255.25410.201.255.255131,070
10210.202.0.0/1510.202.0.1 to 10.203.255.25410.203.255.255131,070
10310.204.0.0/1510.204.0.1 to 10.205.255.25410.205.255.255131,070
10410.206.0.0/1510.206.0.1 to 10.207.255.25410.207.255.255131,070
10510.208.0.0/1510.208.0.1 to 10.209.255.25410.209.255.255131,070
10610.210.0.0/1510.210.0.1 to 10.211.255.25410.211.255.255131,070
10710.212.0.0/1510.212.0.1 to 10.213.255.25410.213.255.255131,070
10810.214.0.0/1510.214.0.1 to 10.215.255.25410.215.255.255131,070
10910.216.0.0/1510.216.0.1 to 10.217.255.25410.217.255.255131,070
11010.218.0.0/1510.218.0.1 to 10.219.255.25410.219.255.255131,070
11110.220.0.0/1510.220.0.1 to 10.221.255.25410.221.255.255131,070
11210.222.0.0/1510.222.0.1 to 10.223.255.25410.223.255.255131,070
11310.224.0.0/1510.224.0.1 to 10.225.255.25410.225.255.255131,070
11410.226.0.0/1510.226.0.1 to 10.227.255.25410.227.255.255131,070
11510.228.0.0/1510.228.0.1 to 10.229.255.25410.229.255.255131,070
11610.230.0.0/1510.230.0.1 to 10.231.255.25410.231.255.255131,070
11710.232.0.0/1510.232.0.1 to 10.233.255.25410.233.255.255131,070
11810.234.0.0/1510.234.0.1 to 10.235.255.25410.235.255.255131,070
11910.236.0.0/1510.236.0.1 to 10.237.255.25410.237.255.255131,070
12010.238.0.0/1510.238.0.1 to 10.239.255.25410.239.255.255131,070
12110.240.0.0/1510.240.0.1 to 10.241.255.25410.241.255.255131,070
12210.242.0.0/1510.242.0.1 to 10.243.255.25410.243.255.255131,070
12310.244.0.0/1510.244.0.1 to 10.245.255.25410.245.255.255131,070
12410.246.0.0/1510.246.0.1 to 10.247.255.25410.247.255.255131,070
12510.248.0.0/1510.248.0.1 to 10.249.255.25410.249.255.255131,070
12610.250.0.0/1510.250.0.1 to 10.251.255.25410.251.255.255131,070
12710.252.0.0/1510.252.0.1 to 10.253.255.25410.253.255.255131,070
12810.254.0.0/1510.254.0.1 to 10.255.255.25410.255.255.255131,070
12911.0.0.0/1511.0.0.1 to 11.1.255.25411.1.255.255131,070
13011.2.0.0/1511.2.0.1 to 11.3.255.25411.3.255.255131,070
13111.4.0.0/1511.4.0.1 to 11.5.255.25411.5.255.255131,070
13211.6.0.0/1511.6.0.1 to 11.7.255.25411.7.255.255131,070
13311.8.0.0/1511.8.0.1 to 11.9.255.25411.9.255.255131,070
13411.10.0.0/1511.10.0.1 to 11.11.255.25411.11.255.255131,070
13511.12.0.0/1511.12.0.1 to 11.13.255.25411.13.255.255131,070
13611.14.0.0/1511.14.0.1 to 11.15.255.25411.15.255.255131,070
13711.16.0.0/1511.16.0.1 to 11.17.255.25411.17.255.255131,070
13811.18.0.0/1511.18.0.1 to 11.19.255.25411.19.255.255131,070
13911.20.0.0/1511.20.0.1 to 11.21.255.25411.21.255.255131,070
14011.22.0.0/1511.22.0.1 to 11.23.255.25411.23.255.255131,070
14111.24.0.0/1511.24.0.1 to 11.25.255.25411.25.255.255131,070
14211.26.0.0/1511.26.0.1 to 11.27.255.25411.27.255.255131,070
14311.28.0.0/1511.28.0.1 to 11.29.255.25411.29.255.255131,070
14411.30.0.0/1511.30.0.1 to 11.31.255.25411.31.255.255131,070
14511.32.0.0/1511.32.0.1 to 11.33.255.25411.33.255.255131,070
14611.34.0.0/1511.34.0.1 to 11.35.255.25411.35.255.255131,070
14711.36.0.0/1511.36.0.1 to 11.37.255.25411.37.255.255131,070
14811.38.0.0/1511.38.0.1 to 11.39.255.25411.39.255.255131,070
14911.40.0.0/1511.40.0.1 to 11.41.255.25411.41.255.255131,070
15011.42.0.0/1511.42.0.1 to 11.43.255.25411.43.255.255131,070
15111.44.0.0/1511.44.0.1 to 11.45.255.25411.45.255.255131,070
15211.46.0.0/1511.46.0.1 to 11.47.255.25411.47.255.255131,070
15311.48.0.0/1511.48.0.1 to 11.49.255.25411.49.255.255131,070
15411.50.0.0/1511.50.0.1 to 11.51.255.25411.51.255.255131,070
15511.52.0.0/1511.52.0.1 to 11.53.255.25411.53.255.255131,070
15611.54.0.0/1511.54.0.1 to 11.55.255.25411.55.255.255131,070
15711.56.0.0/1511.56.0.1 to 11.57.255.25411.57.255.255131,070
15811.58.0.0/1511.58.0.1 to 11.59.255.25411.59.255.255131,070
15911.60.0.0/1511.60.0.1 to 11.61.255.25411.61.255.255131,070
16011.62.0.0/1511.62.0.1 to 11.63.255.25411.63.255.255131,070
16111.64.0.0/1511.64.0.1 to 11.65.255.25411.65.255.255131,070
16211.66.0.0/1511.66.0.1 to 11.67.255.25411.67.255.255131,070
16311.68.0.0/1511.68.0.1 to 11.69.255.25411.69.255.255131,070
16411.70.0.0/1511.70.0.1 to 11.71.255.25411.71.255.255131,070
16511.72.0.0/1511.72.0.1 to 11.73.255.25411.73.255.255131,070
16611.74.0.0/1511.74.0.1 to 11.75.255.25411.75.255.255131,070
16711.76.0.0/1511.76.0.1 to 11.77.255.25411.77.255.255131,070
16811.78.0.0/1511.78.0.1 to 11.79.255.25411.79.255.255131,070
16911.80.0.0/1511.80.0.1 to 11.81.255.25411.81.255.255131,070
17011.82.0.0/1511.82.0.1 to 11.83.255.25411.83.255.255131,070
17111.84.0.0/1511.84.0.1 to 11.85.255.25411.85.255.255131,070
17211.86.0.0/1511.86.0.1 to 11.87.255.25411.87.255.255131,070
17311.88.0.0/1511.88.0.1 to 11.89.255.25411.89.255.255131,070
17411.90.0.0/1511.90.0.1 to 11.91.255.25411.91.255.255131,070
17511.92.0.0/1511.92.0.1 to 11.93.255.25411.93.255.255131,070
17611.94.0.0/1511.94.0.1 to 11.95.255.25411.95.255.255131,070
17711.96.0.0/1511.96.0.1 to 11.97.255.25411.97.255.255131,070
17811.98.0.0/1511.98.0.1 to 11.99.255.25411.99.255.255131,070
17911.100.0.0/1511.100.0.1 to 11.101.255.25411.101.255.255131,070
18011.102.0.0/1511.102.0.1 to 11.103.255.25411.103.255.255131,070
18111.104.0.0/1511.104.0.1 to 11.105.255.25411.105.255.255131,070
18211.106.0.0/1511.106.0.1 to 11.107.255.25411.107.255.255131,070
18311.108.0.0/1511.108.0.1 to 11.109.255.25411.109.255.255131,070
18411.110.0.0/1511.110.0.1 to 11.111.255.25411.111.255.255131,070
18511.112.0.0/1511.112.0.1 to 11.113.255.25411.113.255.255131,070
18611.114.0.0/1511.114.0.1 to 11.115.255.25411.115.255.255131,070
18711.116.0.0/1511.116.0.1 to 11.117.255.25411.117.255.255131,070
18811.118.0.0/1511.118.0.1 to 11.119.255.25411.119.255.255131,070
18911.120.0.0/1511.120.0.1 to 11.121.255.25411.121.255.255131,070
19011.122.0.0/1511.122.0.1 to 11.123.255.25411.123.255.255131,070
19111.124.0.0/1511.124.0.1 to 11.125.255.25411.125.255.255131,070
19211.126.0.0/1511.126.0.1 to 11.127.255.25411.127.255.255131,070
19311.128.0.0/1511.128.0.1 to 11.129.255.25411.129.255.255131,070
19411.130.0.0/1511.130.0.1 to 11.131.255.25411.131.255.255131,070
19511.132.0.0/1511.132.0.1 to 11.133.255.25411.133.255.255131,070
19611.134.0.0/1511.134.0.1 to 11.135.255.25411.135.255.255131,070
19711.136.0.0/1511.136.0.1 to 11.137.255.25411.137.255.255131,070
19811.138.0.0/1511.138.0.1 to 11.139.255.25411.139.255.255131,070
19911.140.0.0/1511.140.0.1 to 11.141.255.25411.141.255.255131,070
20011.142.0.0/1511.142.0.1 to 11.143.255.25411.143.255.255131,070
20111.144.0.0/1511.144.0.1 to 11.145.255.25411.145.255.255131,070
20211.146.0.0/1511.146.0.1 to 11.147.255.25411.147.255.255131,070
20311.148.0.0/1511.148.0.1 to 11.149.255.25411.149.255.255131,070
20411.150.0.0/1511.150.0.1 to 11.151.255.25411.151.255.255131,070
20511.152.0.0/1511.152.0.1 to 11.153.255.25411.153.255.255131,070
20611.154.0.0/1511.154.0.1 to 11.155.255.25411.155.255.255131,070
20711.156.0.0/1511.156.0.1 to 11.157.255.25411.157.255.255131,070
20811.158.0.0/1511.158.0.1 to 11.159.255.25411.159.255.255131,070
20911.160.0.0/1511.160.0.1 to 11.161.255.25411.161.255.255131,070
21011.162.0.0/1511.162.0.1 to 11.163.255.25411.163.255.255131,070
21111.164.0.0/1511.164.0.1 to 11.165.255.25411.165.255.255131,070
21211.166.0.0/1511.166.0.1 to 11.167.255.25411.167.255.255131,070
21311.168.0.0/1511.168.0.1 to 11.169.255.25411.169.255.255131,070
21411.170.0.0/1511.170.0.1 to 11.171.255.25411.171.255.255131,070
21511.172.0.0/1511.172.0.1 to 11.173.255.25411.173.255.255131,070
21611.174.0.0/1511.174.0.1 to 11.175.255.25411.175.255.255131,070
21711.176.0.0/1511.176.0.1 to 11.177.255.25411.177.255.255131,070
21811.178.0.0/1511.178.0.1 to 11.179.255.25411.179.255.255131,070
21911.180.0.0/1511.180.0.1 to 11.181.255.25411.181.255.255131,070
22011.182.0.0/1511.182.0.1 to 11.183.255.25411.183.255.255131,070
22111.184.0.0/1511.184.0.1 to 11.185.255.25411.185.255.255131,070
22211.186.0.0/1511.186.0.1 to 11.187.255.25411.187.255.255131,070
22311.188.0.0/1511.188.0.1 to 11.189.255.25411.189.255.255131,070
22411.190.0.0/1511.190.0.1 to 11.191.255.25411.191.255.255131,070
22511.192.0.0/1511.192.0.1 to 11.193.255.25411.193.255.255131,070
22611.194.0.0/1511.194.0.1 to 11.195.255.25411.195.255.255131,070
22711.196.0.0/1511.196.0.1 to 11.197.255.25411.197.255.255131,070
22811.198.0.0/1511.198.0.1 to 11.199.255.25411.199.255.255131,070
22911.200.0.0/1511.200.0.1 to 11.201.255.25411.201.255.255131,070
23011.202.0.0/1511.202.0.1 to 11.203.255.25411.203.255.255131,070
23111.204.0.0/1511.204.0.1 to 11.205.255.25411.205.255.255131,070
23211.206.0.0/1511.206.0.1 to 11.207.255.25411.207.255.255131,070
23311.208.0.0/1511.208.0.1 to 11.209.255.25411.209.255.255131,070
23411.210.0.0/1511.210.0.1 to 11.211.255.25411.211.255.255131,070
23511.212.0.0/1511.212.0.1 to 11.213.255.25411.213.255.255131,070
23611.214.0.0/1511.214.0.1 to 11.215.255.25411.215.255.255131,070
23711.216.0.0/1511.216.0.1 to 11.217.255.25411.217.255.255131,070
23811.218.0.0/1511.218.0.1 to 11.219.255.25411.219.255.255131,070
23911.220.0.0/1511.220.0.1 to 11.221.255.25411.221.255.255131,070
24011.222.0.0/1511.222.0.1 to 11.223.255.25411.223.255.255131,070
24111.224.0.0/1511.224.0.1 to 11.225.255.25411.225.255.255131,070
24211.226.0.0/1511.226.0.1 to 11.227.255.25411.227.255.255131,070
24311.228.0.0/1511.228.0.1 to 11.229.255.25411.229.255.255131,070
24411.230.0.0/1511.230.0.1 to 11.231.255.25411.231.255.255131,070
24511.232.0.0/1511.232.0.1 to 11.233.255.25411.233.255.255131,070
24611.234.0.0/1511.234.0.1 to 11.235.255.25411.235.255.255131,070
24711.236.0.0/1511.236.0.1 to 11.237.255.25411.237.255.255131,070
24811.238.0.0/1511.238.0.1 to 11.239.255.25411.239.255.255131,070
24911.240.0.0/1511.240.0.1 to 11.241.255.25411.241.255.255131,070
25011.242.0.0/1511.242.0.1 to 11.243.255.25411.243.255.255131,070
25111.244.0.0/1511.244.0.1 to 11.245.255.25411.245.255.255131,070
25211.246.0.0/1511.246.0.1 to 11.247.255.25411.247.255.255131,070
25311.248.0.0/1511.248.0.1 to 11.249.255.25411.249.255.255131,070
25411.250.0.0/1511.250.0.1 to 11.251.255.25411.251.255.255131,070
25511.252.0.0/1511.252.0.1 to 11.253.255.25411.253.255.255131,070
25611.254.0.0/1511.254.0.1 to 11.255.255.25411.255.255.255131,070

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.