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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.

Network97.80.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
97.80.0.0
Broadcast address
97.95.255.255
First usable
97.80.0.1
Last usable
97.95.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 61500000 · Integer 1632632832 to 1633681407
Reverse DNS zones
80.97.in-addr.arpa
81.97.in-addr.arpa
82.97.in-addr.arpa
83.97.in-addr.arpa
84.97.in-addr.arpa
85.97.in-addr.arpa
86.97.in-addr.arpa
87.97.in-addr.arpa
88.97.in-addr.arpa
89.97.in-addr.arpa
90.97.in-addr.arpa
91.97.in-addr.arpa
92.97.in-addr.arpa
93.97.in-addr.arpa
94.97.in-addr.arpa
95.97.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100001.01010000.00000000.0000000097.80.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01100001.01010000.00000000.0000000097.80.0.0
Broadcast01100001.01011111.11111111.1111111197.95.255.255
Split into smaller subnets/21
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

97.80.0.0/12 makes 512 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
197.80.0.0/2197.80.0.1 to 97.80.7.25497.80.7.2552,046
297.80.8.0/2197.80.8.1 to 97.80.15.25497.80.15.2552,046
397.80.16.0/2197.80.16.1 to 97.80.23.25497.80.23.2552,046
497.80.24.0/2197.80.24.1 to 97.80.31.25497.80.31.2552,046
597.80.32.0/2197.80.32.1 to 97.80.39.25497.80.39.2552,046
697.80.40.0/2197.80.40.1 to 97.80.47.25497.80.47.2552,046
797.80.48.0/2197.80.48.1 to 97.80.55.25497.80.55.2552,046
897.80.56.0/2197.80.56.1 to 97.80.63.25497.80.63.2552,046
997.80.64.0/2197.80.64.1 to 97.80.71.25497.80.71.2552,046
1097.80.72.0/2197.80.72.1 to 97.80.79.25497.80.79.2552,046
1197.80.80.0/2197.80.80.1 to 97.80.87.25497.80.87.2552,046
1297.80.88.0/2197.80.88.1 to 97.80.95.25497.80.95.2552,046
1397.80.96.0/2197.80.96.1 to 97.80.103.25497.80.103.2552,046
1497.80.104.0/2197.80.104.1 to 97.80.111.25497.80.111.2552,046
1597.80.112.0/2197.80.112.1 to 97.80.119.25497.80.119.2552,046
1697.80.120.0/2197.80.120.1 to 97.80.127.25497.80.127.2552,046
1797.80.128.0/2197.80.128.1 to 97.80.135.25497.80.135.2552,046
1897.80.136.0/2197.80.136.1 to 97.80.143.25497.80.143.2552,046
1997.80.144.0/2197.80.144.1 to 97.80.151.25497.80.151.2552,046
2097.80.152.0/2197.80.152.1 to 97.80.159.25497.80.159.2552,046
2197.80.160.0/2197.80.160.1 to 97.80.167.25497.80.167.2552,046
2297.80.168.0/2197.80.168.1 to 97.80.175.25497.80.175.2552,046
2397.80.176.0/2197.80.176.1 to 97.80.183.25497.80.183.2552,046
2497.80.184.0/2197.80.184.1 to 97.80.191.25497.80.191.2552,046
2597.80.192.0/2197.80.192.1 to 97.80.199.25497.80.199.2552,046
2697.80.200.0/2197.80.200.1 to 97.80.207.25497.80.207.2552,046
2797.80.208.0/2197.80.208.1 to 97.80.215.25497.80.215.2552,046
2897.80.216.0/2197.80.216.1 to 97.80.223.25497.80.223.2552,046
2997.80.224.0/2197.80.224.1 to 97.80.231.25497.80.231.2552,046
3097.80.232.0/2197.80.232.1 to 97.80.239.25497.80.239.2552,046
3197.80.240.0/2197.80.240.1 to 97.80.247.25497.80.247.2552,046
3297.80.248.0/2197.80.248.1 to 97.80.255.25497.80.255.2552,046
3397.81.0.0/2197.81.0.1 to 97.81.7.25497.81.7.2552,046
3497.81.8.0/2197.81.8.1 to 97.81.15.25497.81.15.2552,046
3597.81.16.0/2197.81.16.1 to 97.81.23.25497.81.23.2552,046
3697.81.24.0/2197.81.24.1 to 97.81.31.25497.81.31.2552,046
3797.81.32.0/2197.81.32.1 to 97.81.39.25497.81.39.2552,046
3897.81.40.0/2197.81.40.1 to 97.81.47.25497.81.47.2552,046
3997.81.48.0/2197.81.48.1 to 97.81.55.25497.81.55.2552,046
4097.81.56.0/2197.81.56.1 to 97.81.63.25497.81.63.2552,046
4197.81.64.0/2197.81.64.1 to 97.81.71.25497.81.71.2552,046
4297.81.72.0/2197.81.72.1 to 97.81.79.25497.81.79.2552,046
4397.81.80.0/2197.81.80.1 to 97.81.87.25497.81.87.2552,046
4497.81.88.0/2197.81.88.1 to 97.81.95.25497.81.95.2552,046
4597.81.96.0/2197.81.96.1 to 97.81.103.25497.81.103.2552,046
4697.81.104.0/2197.81.104.1 to 97.81.111.25497.81.111.2552,046
4797.81.112.0/2197.81.112.1 to 97.81.119.25497.81.119.2552,046
4897.81.120.0/2197.81.120.1 to 97.81.127.25497.81.127.2552,046
4997.81.128.0/2197.81.128.1 to 97.81.135.25497.81.135.2552,046
5097.81.136.0/2197.81.136.1 to 97.81.143.25497.81.143.2552,046
5197.81.144.0/2197.81.144.1 to 97.81.151.25497.81.151.2552,046
5297.81.152.0/2197.81.152.1 to 97.81.159.25497.81.159.2552,046
5397.81.160.0/2197.81.160.1 to 97.81.167.25497.81.167.2552,046
5497.81.168.0/2197.81.168.1 to 97.81.175.25497.81.175.2552,046
5597.81.176.0/2197.81.176.1 to 97.81.183.25497.81.183.2552,046
5697.81.184.0/2197.81.184.1 to 97.81.191.25497.81.191.2552,046
5797.81.192.0/2197.81.192.1 to 97.81.199.25497.81.199.2552,046
5897.81.200.0/2197.81.200.1 to 97.81.207.25497.81.207.2552,046
5997.81.208.0/2197.81.208.1 to 97.81.215.25497.81.215.2552,046
6097.81.216.0/2197.81.216.1 to 97.81.223.25497.81.223.2552,046
6197.81.224.0/2197.81.224.1 to 97.81.231.25497.81.231.2552,046
6297.81.232.0/2197.81.232.1 to 97.81.239.25497.81.239.2552,046
6397.81.240.0/2197.81.240.1 to 97.81.247.25497.81.247.2552,046
6497.81.248.0/2197.81.248.1 to 97.81.255.25497.81.255.2552,046
6597.82.0.0/2197.82.0.1 to 97.82.7.25497.82.7.2552,046
6697.82.8.0/2197.82.8.1 to 97.82.15.25497.82.15.2552,046
6797.82.16.0/2197.82.16.1 to 97.82.23.25497.82.23.2552,046
6897.82.24.0/2197.82.24.1 to 97.82.31.25497.82.31.2552,046
6997.82.32.0/2197.82.32.1 to 97.82.39.25497.82.39.2552,046
7097.82.40.0/2197.82.40.1 to 97.82.47.25497.82.47.2552,046
7197.82.48.0/2197.82.48.1 to 97.82.55.25497.82.55.2552,046
7297.82.56.0/2197.82.56.1 to 97.82.63.25497.82.63.2552,046
7397.82.64.0/2197.82.64.1 to 97.82.71.25497.82.71.2552,046
7497.82.72.0/2197.82.72.1 to 97.82.79.25497.82.79.2552,046
7597.82.80.0/2197.82.80.1 to 97.82.87.25497.82.87.2552,046
7697.82.88.0/2197.82.88.1 to 97.82.95.25497.82.95.2552,046
7797.82.96.0/2197.82.96.1 to 97.82.103.25497.82.103.2552,046
7897.82.104.0/2197.82.104.1 to 97.82.111.25497.82.111.2552,046
7997.82.112.0/2197.82.112.1 to 97.82.119.25497.82.119.2552,046
8097.82.120.0/2197.82.120.1 to 97.82.127.25497.82.127.2552,046
8197.82.128.0/2197.82.128.1 to 97.82.135.25497.82.135.2552,046
8297.82.136.0/2197.82.136.1 to 97.82.143.25497.82.143.2552,046
8397.82.144.0/2197.82.144.1 to 97.82.151.25497.82.151.2552,046
8497.82.152.0/2197.82.152.1 to 97.82.159.25497.82.159.2552,046
8597.82.160.0/2197.82.160.1 to 97.82.167.25497.82.167.2552,046
8697.82.168.0/2197.82.168.1 to 97.82.175.25497.82.175.2552,046
8797.82.176.0/2197.82.176.1 to 97.82.183.25497.82.183.2552,046
8897.82.184.0/2197.82.184.1 to 97.82.191.25497.82.191.2552,046
8997.82.192.0/2197.82.192.1 to 97.82.199.25497.82.199.2552,046
9097.82.200.0/2197.82.200.1 to 97.82.207.25497.82.207.2552,046
9197.82.208.0/2197.82.208.1 to 97.82.215.25497.82.215.2552,046
9297.82.216.0/2197.82.216.1 to 97.82.223.25497.82.223.2552,046
9397.82.224.0/2197.82.224.1 to 97.82.231.25497.82.231.2552,046
9497.82.232.0/2197.82.232.1 to 97.82.239.25497.82.239.2552,046
9597.82.240.0/2197.82.240.1 to 97.82.247.25497.82.247.2552,046
9697.82.248.0/2197.82.248.1 to 97.82.255.25497.82.255.2552,046
9797.83.0.0/2197.83.0.1 to 97.83.7.25497.83.7.2552,046
9897.83.8.0/2197.83.8.1 to 97.83.15.25497.83.15.2552,046
9997.83.16.0/2197.83.16.1 to 97.83.23.25497.83.23.2552,046
10097.83.24.0/2197.83.24.1 to 97.83.31.25497.83.31.2552,046
10197.83.32.0/2197.83.32.1 to 97.83.39.25497.83.39.2552,046
10297.83.40.0/2197.83.40.1 to 97.83.47.25497.83.47.2552,046
10397.83.48.0/2197.83.48.1 to 97.83.55.25497.83.55.2552,046
10497.83.56.0/2197.83.56.1 to 97.83.63.25497.83.63.2552,046
10597.83.64.0/2197.83.64.1 to 97.83.71.25497.83.71.2552,046
10697.83.72.0/2197.83.72.1 to 97.83.79.25497.83.79.2552,046
10797.83.80.0/2197.83.80.1 to 97.83.87.25497.83.87.2552,046
10897.83.88.0/2197.83.88.1 to 97.83.95.25497.83.95.2552,046
10997.83.96.0/2197.83.96.1 to 97.83.103.25497.83.103.2552,046
11097.83.104.0/2197.83.104.1 to 97.83.111.25497.83.111.2552,046
11197.83.112.0/2197.83.112.1 to 97.83.119.25497.83.119.2552,046
11297.83.120.0/2197.83.120.1 to 97.83.127.25497.83.127.2552,046
11397.83.128.0/2197.83.128.1 to 97.83.135.25497.83.135.2552,046
11497.83.136.0/2197.83.136.1 to 97.83.143.25497.83.143.2552,046
11597.83.144.0/2197.83.144.1 to 97.83.151.25497.83.151.2552,046
11697.83.152.0/2197.83.152.1 to 97.83.159.25497.83.159.2552,046
11797.83.160.0/2197.83.160.1 to 97.83.167.25497.83.167.2552,046
11897.83.168.0/2197.83.168.1 to 97.83.175.25497.83.175.2552,046
11997.83.176.0/2197.83.176.1 to 97.83.183.25497.83.183.2552,046
12097.83.184.0/2197.83.184.1 to 97.83.191.25497.83.191.2552,046
12197.83.192.0/2197.83.192.1 to 97.83.199.25497.83.199.2552,046
12297.83.200.0/2197.83.200.1 to 97.83.207.25497.83.207.2552,046
12397.83.208.0/2197.83.208.1 to 97.83.215.25497.83.215.2552,046
12497.83.216.0/2197.83.216.1 to 97.83.223.25497.83.223.2552,046
12597.83.224.0/2197.83.224.1 to 97.83.231.25497.83.231.2552,046
12697.83.232.0/2197.83.232.1 to 97.83.239.25497.83.239.2552,046
12797.83.240.0/2197.83.240.1 to 97.83.247.25497.83.247.2552,046
12897.83.248.0/2197.83.248.1 to 97.83.255.25497.83.255.2552,046
12997.84.0.0/2197.84.0.1 to 97.84.7.25497.84.7.2552,046
13097.84.8.0/2197.84.8.1 to 97.84.15.25497.84.15.2552,046
13197.84.16.0/2197.84.16.1 to 97.84.23.25497.84.23.2552,046
13297.84.24.0/2197.84.24.1 to 97.84.31.25497.84.31.2552,046
13397.84.32.0/2197.84.32.1 to 97.84.39.25497.84.39.2552,046
13497.84.40.0/2197.84.40.1 to 97.84.47.25497.84.47.2552,046
13597.84.48.0/2197.84.48.1 to 97.84.55.25497.84.55.2552,046
13697.84.56.0/2197.84.56.1 to 97.84.63.25497.84.63.2552,046
13797.84.64.0/2197.84.64.1 to 97.84.71.25497.84.71.2552,046
13897.84.72.0/2197.84.72.1 to 97.84.79.25497.84.79.2552,046
13997.84.80.0/2197.84.80.1 to 97.84.87.25497.84.87.2552,046
14097.84.88.0/2197.84.88.1 to 97.84.95.25497.84.95.2552,046
14197.84.96.0/2197.84.96.1 to 97.84.103.25497.84.103.2552,046
14297.84.104.0/2197.84.104.1 to 97.84.111.25497.84.111.2552,046
14397.84.112.0/2197.84.112.1 to 97.84.119.25497.84.119.2552,046
14497.84.120.0/2197.84.120.1 to 97.84.127.25497.84.127.2552,046
14597.84.128.0/2197.84.128.1 to 97.84.135.25497.84.135.2552,046
14697.84.136.0/2197.84.136.1 to 97.84.143.25497.84.143.2552,046
14797.84.144.0/2197.84.144.1 to 97.84.151.25497.84.151.2552,046
14897.84.152.0/2197.84.152.1 to 97.84.159.25497.84.159.2552,046
14997.84.160.0/2197.84.160.1 to 97.84.167.25497.84.167.2552,046
15097.84.168.0/2197.84.168.1 to 97.84.175.25497.84.175.2552,046
15197.84.176.0/2197.84.176.1 to 97.84.183.25497.84.183.2552,046
15297.84.184.0/2197.84.184.1 to 97.84.191.25497.84.191.2552,046
15397.84.192.0/2197.84.192.1 to 97.84.199.25497.84.199.2552,046
15497.84.200.0/2197.84.200.1 to 97.84.207.25497.84.207.2552,046
15597.84.208.0/2197.84.208.1 to 97.84.215.25497.84.215.2552,046
15697.84.216.0/2197.84.216.1 to 97.84.223.25497.84.223.2552,046
15797.84.224.0/2197.84.224.1 to 97.84.231.25497.84.231.2552,046
15897.84.232.0/2197.84.232.1 to 97.84.239.25497.84.239.2552,046
15997.84.240.0/2197.84.240.1 to 97.84.247.25497.84.247.2552,046
16097.84.248.0/2197.84.248.1 to 97.84.255.25497.84.255.2552,046
16197.85.0.0/2197.85.0.1 to 97.85.7.25497.85.7.2552,046
16297.85.8.0/2197.85.8.1 to 97.85.15.25497.85.15.2552,046
16397.85.16.0/2197.85.16.1 to 97.85.23.25497.85.23.2552,046
16497.85.24.0/2197.85.24.1 to 97.85.31.25497.85.31.2552,046
16597.85.32.0/2197.85.32.1 to 97.85.39.25497.85.39.2552,046
16697.85.40.0/2197.85.40.1 to 97.85.47.25497.85.47.2552,046
16797.85.48.0/2197.85.48.1 to 97.85.55.25497.85.55.2552,046
16897.85.56.0/2197.85.56.1 to 97.85.63.25497.85.63.2552,046
16997.85.64.0/2197.85.64.1 to 97.85.71.25497.85.71.2552,046
17097.85.72.0/2197.85.72.1 to 97.85.79.25497.85.79.2552,046
17197.85.80.0/2197.85.80.1 to 97.85.87.25497.85.87.2552,046
17297.85.88.0/2197.85.88.1 to 97.85.95.25497.85.95.2552,046
17397.85.96.0/2197.85.96.1 to 97.85.103.25497.85.103.2552,046
17497.85.104.0/2197.85.104.1 to 97.85.111.25497.85.111.2552,046
17597.85.112.0/2197.85.112.1 to 97.85.119.25497.85.119.2552,046
17697.85.120.0/2197.85.120.1 to 97.85.127.25497.85.127.2552,046
17797.85.128.0/2197.85.128.1 to 97.85.135.25497.85.135.2552,046
17897.85.136.0/2197.85.136.1 to 97.85.143.25497.85.143.2552,046
17997.85.144.0/2197.85.144.1 to 97.85.151.25497.85.151.2552,046
18097.85.152.0/2197.85.152.1 to 97.85.159.25497.85.159.2552,046
18197.85.160.0/2197.85.160.1 to 97.85.167.25497.85.167.2552,046
18297.85.168.0/2197.85.168.1 to 97.85.175.25497.85.175.2552,046
18397.85.176.0/2197.85.176.1 to 97.85.183.25497.85.183.2552,046
18497.85.184.0/2197.85.184.1 to 97.85.191.25497.85.191.2552,046
18597.85.192.0/2197.85.192.1 to 97.85.199.25497.85.199.2552,046
18697.85.200.0/2197.85.200.1 to 97.85.207.25497.85.207.2552,046
18797.85.208.0/2197.85.208.1 to 97.85.215.25497.85.215.2552,046
18897.85.216.0/2197.85.216.1 to 97.85.223.25497.85.223.2552,046
18997.85.224.0/2197.85.224.1 to 97.85.231.25497.85.231.2552,046
19097.85.232.0/2197.85.232.1 to 97.85.239.25497.85.239.2552,046
19197.85.240.0/2197.85.240.1 to 97.85.247.25497.85.247.2552,046
19297.85.248.0/2197.85.248.1 to 97.85.255.25497.85.255.2552,046
19397.86.0.0/2197.86.0.1 to 97.86.7.25497.86.7.2552,046
19497.86.8.0/2197.86.8.1 to 97.86.15.25497.86.15.2552,046
19597.86.16.0/2197.86.16.1 to 97.86.23.25497.86.23.2552,046
19697.86.24.0/2197.86.24.1 to 97.86.31.25497.86.31.2552,046
19797.86.32.0/2197.86.32.1 to 97.86.39.25497.86.39.2552,046
19897.86.40.0/2197.86.40.1 to 97.86.47.25497.86.47.2552,046
19997.86.48.0/2197.86.48.1 to 97.86.55.25497.86.55.2552,046
20097.86.56.0/2197.86.56.1 to 97.86.63.25497.86.63.2552,046
20197.86.64.0/2197.86.64.1 to 97.86.71.25497.86.71.2552,046
20297.86.72.0/2197.86.72.1 to 97.86.79.25497.86.79.2552,046
20397.86.80.0/2197.86.80.1 to 97.86.87.25497.86.87.2552,046
20497.86.88.0/2197.86.88.1 to 97.86.95.25497.86.95.2552,046
20597.86.96.0/2197.86.96.1 to 97.86.103.25497.86.103.2552,046
20697.86.104.0/2197.86.104.1 to 97.86.111.25497.86.111.2552,046
20797.86.112.0/2197.86.112.1 to 97.86.119.25497.86.119.2552,046
20897.86.120.0/2197.86.120.1 to 97.86.127.25497.86.127.2552,046
20997.86.128.0/2197.86.128.1 to 97.86.135.25497.86.135.2552,046
21097.86.136.0/2197.86.136.1 to 97.86.143.25497.86.143.2552,046
21197.86.144.0/2197.86.144.1 to 97.86.151.25497.86.151.2552,046
21297.86.152.0/2197.86.152.1 to 97.86.159.25497.86.159.2552,046
21397.86.160.0/2197.86.160.1 to 97.86.167.25497.86.167.2552,046
21497.86.168.0/2197.86.168.1 to 97.86.175.25497.86.175.2552,046
21597.86.176.0/2197.86.176.1 to 97.86.183.25497.86.183.2552,046
21697.86.184.0/2197.86.184.1 to 97.86.191.25497.86.191.2552,046
21797.86.192.0/2197.86.192.1 to 97.86.199.25497.86.199.2552,046
21897.86.200.0/2197.86.200.1 to 97.86.207.25497.86.207.2552,046
21997.86.208.0/2197.86.208.1 to 97.86.215.25497.86.215.2552,046
22097.86.216.0/2197.86.216.1 to 97.86.223.25497.86.223.2552,046
22197.86.224.0/2197.86.224.1 to 97.86.231.25497.86.231.2552,046
22297.86.232.0/2197.86.232.1 to 97.86.239.25497.86.239.2552,046
22397.86.240.0/2197.86.240.1 to 97.86.247.25497.86.247.2552,046
22497.86.248.0/2197.86.248.1 to 97.86.255.25497.86.255.2552,046
22597.87.0.0/2197.87.0.1 to 97.87.7.25497.87.7.2552,046
22697.87.8.0/2197.87.8.1 to 97.87.15.25497.87.15.2552,046
22797.87.16.0/2197.87.16.1 to 97.87.23.25497.87.23.2552,046
22897.87.24.0/2197.87.24.1 to 97.87.31.25497.87.31.2552,046
22997.87.32.0/2197.87.32.1 to 97.87.39.25497.87.39.2552,046
23097.87.40.0/2197.87.40.1 to 97.87.47.25497.87.47.2552,046
23197.87.48.0/2197.87.48.1 to 97.87.55.25497.87.55.2552,046
23297.87.56.0/2197.87.56.1 to 97.87.63.25497.87.63.2552,046
23397.87.64.0/2197.87.64.1 to 97.87.71.25497.87.71.2552,046
23497.87.72.0/2197.87.72.1 to 97.87.79.25497.87.79.2552,046
23597.87.80.0/2197.87.80.1 to 97.87.87.25497.87.87.2552,046
23697.87.88.0/2197.87.88.1 to 97.87.95.25497.87.95.2552,046
23797.87.96.0/2197.87.96.1 to 97.87.103.25497.87.103.2552,046
23897.87.104.0/2197.87.104.1 to 97.87.111.25497.87.111.2552,046
23997.87.112.0/2197.87.112.1 to 97.87.119.25497.87.119.2552,046
24097.87.120.0/2197.87.120.1 to 97.87.127.25497.87.127.2552,046
24197.87.128.0/2197.87.128.1 to 97.87.135.25497.87.135.2552,046
24297.87.136.0/2197.87.136.1 to 97.87.143.25497.87.143.2552,046
24397.87.144.0/2197.87.144.1 to 97.87.151.25497.87.151.2552,046
24497.87.152.0/2197.87.152.1 to 97.87.159.25497.87.159.2552,046
24597.87.160.0/2197.87.160.1 to 97.87.167.25497.87.167.2552,046
24697.87.168.0/2197.87.168.1 to 97.87.175.25497.87.175.2552,046
24797.87.176.0/2197.87.176.1 to 97.87.183.25497.87.183.2552,046
24897.87.184.0/2197.87.184.1 to 97.87.191.25497.87.191.2552,046
24997.87.192.0/2197.87.192.1 to 97.87.199.25497.87.199.2552,046
25097.87.200.0/2197.87.200.1 to 97.87.207.25497.87.207.2552,046
25197.87.208.0/2197.87.208.1 to 97.87.215.25497.87.215.2552,046
25297.87.216.0/2197.87.216.1 to 97.87.223.25497.87.223.2552,046
25397.87.224.0/2197.87.224.1 to 97.87.231.25497.87.231.2552,046
25497.87.232.0/2197.87.232.1 to 97.87.239.25497.87.239.2552,046
25597.87.240.0/2197.87.240.1 to 97.87.247.25497.87.247.2552,046
25697.87.248.0/2197.87.248.1 to 97.87.255.25497.87.255.2552,046

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.