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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.

Network4.16.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
4.16.0.0
Broadcast address
4.31.255.255
First usable
4.16.0.1
Last usable
4.31.255.254
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 04100000 · Integer 68157440 to 69206015
Reverse DNS zones
16.4.in-addr.arpa
17.4.in-addr.arpa
18.4.in-addr.arpa
19.4.in-addr.arpa
20.4.in-addr.arpa
21.4.in-addr.arpa
22.4.in-addr.arpa
23.4.in-addr.arpa
24.4.in-addr.arpa
25.4.in-addr.arpa
26.4.in-addr.arpa
27.4.in-addr.arpa
28.4.in-addr.arpa
29.4.in-addr.arpa
30.4.in-addr.arpa
31.4.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
Address00000100.00010000.00000000.000000004.16.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00000100.00010000.00000000.000000004.16.0.0
Broadcast00000100.00011111.11111111.111111114.31.255.255
Split into smaller subnets/22
/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)

4.16.0.0/12 makes 1,024 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.16.0.0/224.16.0.1 to 4.16.3.2544.16.3.2551,022
24.16.4.0/224.16.4.1 to 4.16.7.2544.16.7.2551,022
34.16.8.0/224.16.8.1 to 4.16.11.2544.16.11.2551,022
44.16.12.0/224.16.12.1 to 4.16.15.2544.16.15.2551,022
54.16.16.0/224.16.16.1 to 4.16.19.2544.16.19.2551,022
64.16.20.0/224.16.20.1 to 4.16.23.2544.16.23.2551,022
74.16.24.0/224.16.24.1 to 4.16.27.2544.16.27.2551,022
84.16.28.0/224.16.28.1 to 4.16.31.2544.16.31.2551,022
94.16.32.0/224.16.32.1 to 4.16.35.2544.16.35.2551,022
104.16.36.0/224.16.36.1 to 4.16.39.2544.16.39.2551,022
114.16.40.0/224.16.40.1 to 4.16.43.2544.16.43.2551,022
124.16.44.0/224.16.44.1 to 4.16.47.2544.16.47.2551,022
134.16.48.0/224.16.48.1 to 4.16.51.2544.16.51.2551,022
144.16.52.0/224.16.52.1 to 4.16.55.2544.16.55.2551,022
154.16.56.0/224.16.56.1 to 4.16.59.2544.16.59.2551,022
164.16.60.0/224.16.60.1 to 4.16.63.2544.16.63.2551,022
174.16.64.0/224.16.64.1 to 4.16.67.2544.16.67.2551,022
184.16.68.0/224.16.68.1 to 4.16.71.2544.16.71.2551,022
194.16.72.0/224.16.72.1 to 4.16.75.2544.16.75.2551,022
204.16.76.0/224.16.76.1 to 4.16.79.2544.16.79.2551,022
214.16.80.0/224.16.80.1 to 4.16.83.2544.16.83.2551,022
224.16.84.0/224.16.84.1 to 4.16.87.2544.16.87.2551,022
234.16.88.0/224.16.88.1 to 4.16.91.2544.16.91.2551,022
244.16.92.0/224.16.92.1 to 4.16.95.2544.16.95.2551,022
254.16.96.0/224.16.96.1 to 4.16.99.2544.16.99.2551,022
264.16.100.0/224.16.100.1 to 4.16.103.2544.16.103.2551,022
274.16.104.0/224.16.104.1 to 4.16.107.2544.16.107.2551,022
284.16.108.0/224.16.108.1 to 4.16.111.2544.16.111.2551,022
294.16.112.0/224.16.112.1 to 4.16.115.2544.16.115.2551,022
304.16.116.0/224.16.116.1 to 4.16.119.2544.16.119.2551,022
314.16.120.0/224.16.120.1 to 4.16.123.2544.16.123.2551,022
324.16.124.0/224.16.124.1 to 4.16.127.2544.16.127.2551,022
334.16.128.0/224.16.128.1 to 4.16.131.2544.16.131.2551,022
344.16.132.0/224.16.132.1 to 4.16.135.2544.16.135.2551,022
354.16.136.0/224.16.136.1 to 4.16.139.2544.16.139.2551,022
364.16.140.0/224.16.140.1 to 4.16.143.2544.16.143.2551,022
374.16.144.0/224.16.144.1 to 4.16.147.2544.16.147.2551,022
384.16.148.0/224.16.148.1 to 4.16.151.2544.16.151.2551,022
394.16.152.0/224.16.152.1 to 4.16.155.2544.16.155.2551,022
404.16.156.0/224.16.156.1 to 4.16.159.2544.16.159.2551,022
414.16.160.0/224.16.160.1 to 4.16.163.2544.16.163.2551,022
424.16.164.0/224.16.164.1 to 4.16.167.2544.16.167.2551,022
434.16.168.0/224.16.168.1 to 4.16.171.2544.16.171.2551,022
444.16.172.0/224.16.172.1 to 4.16.175.2544.16.175.2551,022
454.16.176.0/224.16.176.1 to 4.16.179.2544.16.179.2551,022
464.16.180.0/224.16.180.1 to 4.16.183.2544.16.183.2551,022
474.16.184.0/224.16.184.1 to 4.16.187.2544.16.187.2551,022
484.16.188.0/224.16.188.1 to 4.16.191.2544.16.191.2551,022
494.16.192.0/224.16.192.1 to 4.16.195.2544.16.195.2551,022
504.16.196.0/224.16.196.1 to 4.16.199.2544.16.199.2551,022
514.16.200.0/224.16.200.1 to 4.16.203.2544.16.203.2551,022
524.16.204.0/224.16.204.1 to 4.16.207.2544.16.207.2551,022
534.16.208.0/224.16.208.1 to 4.16.211.2544.16.211.2551,022
544.16.212.0/224.16.212.1 to 4.16.215.2544.16.215.2551,022
554.16.216.0/224.16.216.1 to 4.16.219.2544.16.219.2551,022
564.16.220.0/224.16.220.1 to 4.16.223.2544.16.223.2551,022
574.16.224.0/224.16.224.1 to 4.16.227.2544.16.227.2551,022
584.16.228.0/224.16.228.1 to 4.16.231.2544.16.231.2551,022
594.16.232.0/224.16.232.1 to 4.16.235.2544.16.235.2551,022
604.16.236.0/224.16.236.1 to 4.16.239.2544.16.239.2551,022
614.16.240.0/224.16.240.1 to 4.16.243.2544.16.243.2551,022
624.16.244.0/224.16.244.1 to 4.16.247.2544.16.247.2551,022
634.16.248.0/224.16.248.1 to 4.16.251.2544.16.251.2551,022
644.16.252.0/224.16.252.1 to 4.16.255.2544.16.255.2551,022
654.17.0.0/224.17.0.1 to 4.17.3.2544.17.3.2551,022
664.17.4.0/224.17.4.1 to 4.17.7.2544.17.7.2551,022
674.17.8.0/224.17.8.1 to 4.17.11.2544.17.11.2551,022
684.17.12.0/224.17.12.1 to 4.17.15.2544.17.15.2551,022
694.17.16.0/224.17.16.1 to 4.17.19.2544.17.19.2551,022
704.17.20.0/224.17.20.1 to 4.17.23.2544.17.23.2551,022
714.17.24.0/224.17.24.1 to 4.17.27.2544.17.27.2551,022
724.17.28.0/224.17.28.1 to 4.17.31.2544.17.31.2551,022
734.17.32.0/224.17.32.1 to 4.17.35.2544.17.35.2551,022
744.17.36.0/224.17.36.1 to 4.17.39.2544.17.39.2551,022
754.17.40.0/224.17.40.1 to 4.17.43.2544.17.43.2551,022
764.17.44.0/224.17.44.1 to 4.17.47.2544.17.47.2551,022
774.17.48.0/224.17.48.1 to 4.17.51.2544.17.51.2551,022
784.17.52.0/224.17.52.1 to 4.17.55.2544.17.55.2551,022
794.17.56.0/224.17.56.1 to 4.17.59.2544.17.59.2551,022
804.17.60.0/224.17.60.1 to 4.17.63.2544.17.63.2551,022
814.17.64.0/224.17.64.1 to 4.17.67.2544.17.67.2551,022
824.17.68.0/224.17.68.1 to 4.17.71.2544.17.71.2551,022
834.17.72.0/224.17.72.1 to 4.17.75.2544.17.75.2551,022
844.17.76.0/224.17.76.1 to 4.17.79.2544.17.79.2551,022
854.17.80.0/224.17.80.1 to 4.17.83.2544.17.83.2551,022
864.17.84.0/224.17.84.1 to 4.17.87.2544.17.87.2551,022
874.17.88.0/224.17.88.1 to 4.17.91.2544.17.91.2551,022
884.17.92.0/224.17.92.1 to 4.17.95.2544.17.95.2551,022
894.17.96.0/224.17.96.1 to 4.17.99.2544.17.99.2551,022
904.17.100.0/224.17.100.1 to 4.17.103.2544.17.103.2551,022
914.17.104.0/224.17.104.1 to 4.17.107.2544.17.107.2551,022
924.17.108.0/224.17.108.1 to 4.17.111.2544.17.111.2551,022
934.17.112.0/224.17.112.1 to 4.17.115.2544.17.115.2551,022
944.17.116.0/224.17.116.1 to 4.17.119.2544.17.119.2551,022
954.17.120.0/224.17.120.1 to 4.17.123.2544.17.123.2551,022
964.17.124.0/224.17.124.1 to 4.17.127.2544.17.127.2551,022
974.17.128.0/224.17.128.1 to 4.17.131.2544.17.131.2551,022
984.17.132.0/224.17.132.1 to 4.17.135.2544.17.135.2551,022
994.17.136.0/224.17.136.1 to 4.17.139.2544.17.139.2551,022
1004.17.140.0/224.17.140.1 to 4.17.143.2544.17.143.2551,022
1014.17.144.0/224.17.144.1 to 4.17.147.2544.17.147.2551,022
1024.17.148.0/224.17.148.1 to 4.17.151.2544.17.151.2551,022
1034.17.152.0/224.17.152.1 to 4.17.155.2544.17.155.2551,022
1044.17.156.0/224.17.156.1 to 4.17.159.2544.17.159.2551,022
1054.17.160.0/224.17.160.1 to 4.17.163.2544.17.163.2551,022
1064.17.164.0/224.17.164.1 to 4.17.167.2544.17.167.2551,022
1074.17.168.0/224.17.168.1 to 4.17.171.2544.17.171.2551,022
1084.17.172.0/224.17.172.1 to 4.17.175.2544.17.175.2551,022
1094.17.176.0/224.17.176.1 to 4.17.179.2544.17.179.2551,022
1104.17.180.0/224.17.180.1 to 4.17.183.2544.17.183.2551,022
1114.17.184.0/224.17.184.1 to 4.17.187.2544.17.187.2551,022
1124.17.188.0/224.17.188.1 to 4.17.191.2544.17.191.2551,022
1134.17.192.0/224.17.192.1 to 4.17.195.2544.17.195.2551,022
1144.17.196.0/224.17.196.1 to 4.17.199.2544.17.199.2551,022
1154.17.200.0/224.17.200.1 to 4.17.203.2544.17.203.2551,022
1164.17.204.0/224.17.204.1 to 4.17.207.2544.17.207.2551,022
1174.17.208.0/224.17.208.1 to 4.17.211.2544.17.211.2551,022
1184.17.212.0/224.17.212.1 to 4.17.215.2544.17.215.2551,022
1194.17.216.0/224.17.216.1 to 4.17.219.2544.17.219.2551,022
1204.17.220.0/224.17.220.1 to 4.17.223.2544.17.223.2551,022
1214.17.224.0/224.17.224.1 to 4.17.227.2544.17.227.2551,022
1224.17.228.0/224.17.228.1 to 4.17.231.2544.17.231.2551,022
1234.17.232.0/224.17.232.1 to 4.17.235.2544.17.235.2551,022
1244.17.236.0/224.17.236.1 to 4.17.239.2544.17.239.2551,022
1254.17.240.0/224.17.240.1 to 4.17.243.2544.17.243.2551,022
1264.17.244.0/224.17.244.1 to 4.17.247.2544.17.247.2551,022
1274.17.248.0/224.17.248.1 to 4.17.251.2544.17.251.2551,022
1284.17.252.0/224.17.252.1 to 4.17.255.2544.17.255.2551,022
1294.18.0.0/224.18.0.1 to 4.18.3.2544.18.3.2551,022
1304.18.4.0/224.18.4.1 to 4.18.7.2544.18.7.2551,022
1314.18.8.0/224.18.8.1 to 4.18.11.2544.18.11.2551,022
1324.18.12.0/224.18.12.1 to 4.18.15.2544.18.15.2551,022
1334.18.16.0/224.18.16.1 to 4.18.19.2544.18.19.2551,022
1344.18.20.0/224.18.20.1 to 4.18.23.2544.18.23.2551,022
1354.18.24.0/224.18.24.1 to 4.18.27.2544.18.27.2551,022
1364.18.28.0/224.18.28.1 to 4.18.31.2544.18.31.2551,022
1374.18.32.0/224.18.32.1 to 4.18.35.2544.18.35.2551,022
1384.18.36.0/224.18.36.1 to 4.18.39.2544.18.39.2551,022
1394.18.40.0/224.18.40.1 to 4.18.43.2544.18.43.2551,022
1404.18.44.0/224.18.44.1 to 4.18.47.2544.18.47.2551,022
1414.18.48.0/224.18.48.1 to 4.18.51.2544.18.51.2551,022
1424.18.52.0/224.18.52.1 to 4.18.55.2544.18.55.2551,022
1434.18.56.0/224.18.56.1 to 4.18.59.2544.18.59.2551,022
1444.18.60.0/224.18.60.1 to 4.18.63.2544.18.63.2551,022
1454.18.64.0/224.18.64.1 to 4.18.67.2544.18.67.2551,022
1464.18.68.0/224.18.68.1 to 4.18.71.2544.18.71.2551,022
1474.18.72.0/224.18.72.1 to 4.18.75.2544.18.75.2551,022
1484.18.76.0/224.18.76.1 to 4.18.79.2544.18.79.2551,022
1494.18.80.0/224.18.80.1 to 4.18.83.2544.18.83.2551,022
1504.18.84.0/224.18.84.1 to 4.18.87.2544.18.87.2551,022
1514.18.88.0/224.18.88.1 to 4.18.91.2544.18.91.2551,022
1524.18.92.0/224.18.92.1 to 4.18.95.2544.18.95.2551,022
1534.18.96.0/224.18.96.1 to 4.18.99.2544.18.99.2551,022
1544.18.100.0/224.18.100.1 to 4.18.103.2544.18.103.2551,022
1554.18.104.0/224.18.104.1 to 4.18.107.2544.18.107.2551,022
1564.18.108.0/224.18.108.1 to 4.18.111.2544.18.111.2551,022
1574.18.112.0/224.18.112.1 to 4.18.115.2544.18.115.2551,022
1584.18.116.0/224.18.116.1 to 4.18.119.2544.18.119.2551,022
1594.18.120.0/224.18.120.1 to 4.18.123.2544.18.123.2551,022
1604.18.124.0/224.18.124.1 to 4.18.127.2544.18.127.2551,022
1614.18.128.0/224.18.128.1 to 4.18.131.2544.18.131.2551,022
1624.18.132.0/224.18.132.1 to 4.18.135.2544.18.135.2551,022
1634.18.136.0/224.18.136.1 to 4.18.139.2544.18.139.2551,022
1644.18.140.0/224.18.140.1 to 4.18.143.2544.18.143.2551,022
1654.18.144.0/224.18.144.1 to 4.18.147.2544.18.147.2551,022
1664.18.148.0/224.18.148.1 to 4.18.151.2544.18.151.2551,022
1674.18.152.0/224.18.152.1 to 4.18.155.2544.18.155.2551,022
1684.18.156.0/224.18.156.1 to 4.18.159.2544.18.159.2551,022
1694.18.160.0/224.18.160.1 to 4.18.163.2544.18.163.2551,022
1704.18.164.0/224.18.164.1 to 4.18.167.2544.18.167.2551,022
1714.18.168.0/224.18.168.1 to 4.18.171.2544.18.171.2551,022
1724.18.172.0/224.18.172.1 to 4.18.175.2544.18.175.2551,022
1734.18.176.0/224.18.176.1 to 4.18.179.2544.18.179.2551,022
1744.18.180.0/224.18.180.1 to 4.18.183.2544.18.183.2551,022
1754.18.184.0/224.18.184.1 to 4.18.187.2544.18.187.2551,022
1764.18.188.0/224.18.188.1 to 4.18.191.2544.18.191.2551,022
1774.18.192.0/224.18.192.1 to 4.18.195.2544.18.195.2551,022
1784.18.196.0/224.18.196.1 to 4.18.199.2544.18.199.2551,022
1794.18.200.0/224.18.200.1 to 4.18.203.2544.18.203.2551,022
1804.18.204.0/224.18.204.1 to 4.18.207.2544.18.207.2551,022
1814.18.208.0/224.18.208.1 to 4.18.211.2544.18.211.2551,022
1824.18.212.0/224.18.212.1 to 4.18.215.2544.18.215.2551,022
1834.18.216.0/224.18.216.1 to 4.18.219.2544.18.219.2551,022
1844.18.220.0/224.18.220.1 to 4.18.223.2544.18.223.2551,022
1854.18.224.0/224.18.224.1 to 4.18.227.2544.18.227.2551,022
1864.18.228.0/224.18.228.1 to 4.18.231.2544.18.231.2551,022
1874.18.232.0/224.18.232.1 to 4.18.235.2544.18.235.2551,022
1884.18.236.0/224.18.236.1 to 4.18.239.2544.18.239.2551,022
1894.18.240.0/224.18.240.1 to 4.18.243.2544.18.243.2551,022
1904.18.244.0/224.18.244.1 to 4.18.247.2544.18.247.2551,022
1914.18.248.0/224.18.248.1 to 4.18.251.2544.18.251.2551,022
1924.18.252.0/224.18.252.1 to 4.18.255.2544.18.255.2551,022
1934.19.0.0/224.19.0.1 to 4.19.3.2544.19.3.2551,022
1944.19.4.0/224.19.4.1 to 4.19.7.2544.19.7.2551,022
1954.19.8.0/224.19.8.1 to 4.19.11.2544.19.11.2551,022
1964.19.12.0/224.19.12.1 to 4.19.15.2544.19.15.2551,022
1974.19.16.0/224.19.16.1 to 4.19.19.2544.19.19.2551,022
1984.19.20.0/224.19.20.1 to 4.19.23.2544.19.23.2551,022
1994.19.24.0/224.19.24.1 to 4.19.27.2544.19.27.2551,022
2004.19.28.0/224.19.28.1 to 4.19.31.2544.19.31.2551,022
2014.19.32.0/224.19.32.1 to 4.19.35.2544.19.35.2551,022
2024.19.36.0/224.19.36.1 to 4.19.39.2544.19.39.2551,022
2034.19.40.0/224.19.40.1 to 4.19.43.2544.19.43.2551,022
2044.19.44.0/224.19.44.1 to 4.19.47.2544.19.47.2551,022
2054.19.48.0/224.19.48.1 to 4.19.51.2544.19.51.2551,022
2064.19.52.0/224.19.52.1 to 4.19.55.2544.19.55.2551,022
2074.19.56.0/224.19.56.1 to 4.19.59.2544.19.59.2551,022
2084.19.60.0/224.19.60.1 to 4.19.63.2544.19.63.2551,022
2094.19.64.0/224.19.64.1 to 4.19.67.2544.19.67.2551,022
2104.19.68.0/224.19.68.1 to 4.19.71.2544.19.71.2551,022
2114.19.72.0/224.19.72.1 to 4.19.75.2544.19.75.2551,022
2124.19.76.0/224.19.76.1 to 4.19.79.2544.19.79.2551,022
2134.19.80.0/224.19.80.1 to 4.19.83.2544.19.83.2551,022
2144.19.84.0/224.19.84.1 to 4.19.87.2544.19.87.2551,022
2154.19.88.0/224.19.88.1 to 4.19.91.2544.19.91.2551,022
2164.19.92.0/224.19.92.1 to 4.19.95.2544.19.95.2551,022
2174.19.96.0/224.19.96.1 to 4.19.99.2544.19.99.2551,022
2184.19.100.0/224.19.100.1 to 4.19.103.2544.19.103.2551,022
2194.19.104.0/224.19.104.1 to 4.19.107.2544.19.107.2551,022
2204.19.108.0/224.19.108.1 to 4.19.111.2544.19.111.2551,022
2214.19.112.0/224.19.112.1 to 4.19.115.2544.19.115.2551,022
2224.19.116.0/224.19.116.1 to 4.19.119.2544.19.119.2551,022
2234.19.120.0/224.19.120.1 to 4.19.123.2544.19.123.2551,022
2244.19.124.0/224.19.124.1 to 4.19.127.2544.19.127.2551,022
2254.19.128.0/224.19.128.1 to 4.19.131.2544.19.131.2551,022
2264.19.132.0/224.19.132.1 to 4.19.135.2544.19.135.2551,022
2274.19.136.0/224.19.136.1 to 4.19.139.2544.19.139.2551,022
2284.19.140.0/224.19.140.1 to 4.19.143.2544.19.143.2551,022
2294.19.144.0/224.19.144.1 to 4.19.147.2544.19.147.2551,022
2304.19.148.0/224.19.148.1 to 4.19.151.2544.19.151.2551,022
2314.19.152.0/224.19.152.1 to 4.19.155.2544.19.155.2551,022
2324.19.156.0/224.19.156.1 to 4.19.159.2544.19.159.2551,022
2334.19.160.0/224.19.160.1 to 4.19.163.2544.19.163.2551,022
2344.19.164.0/224.19.164.1 to 4.19.167.2544.19.167.2551,022
2354.19.168.0/224.19.168.1 to 4.19.171.2544.19.171.2551,022
2364.19.172.0/224.19.172.1 to 4.19.175.2544.19.175.2551,022
2374.19.176.0/224.19.176.1 to 4.19.179.2544.19.179.2551,022
2384.19.180.0/224.19.180.1 to 4.19.183.2544.19.183.2551,022
2394.19.184.0/224.19.184.1 to 4.19.187.2544.19.187.2551,022
2404.19.188.0/224.19.188.1 to 4.19.191.2544.19.191.2551,022
2414.19.192.0/224.19.192.1 to 4.19.195.2544.19.195.2551,022
2424.19.196.0/224.19.196.1 to 4.19.199.2544.19.199.2551,022
2434.19.200.0/224.19.200.1 to 4.19.203.2544.19.203.2551,022
2444.19.204.0/224.19.204.1 to 4.19.207.2544.19.207.2551,022
2454.19.208.0/224.19.208.1 to 4.19.211.2544.19.211.2551,022
2464.19.212.0/224.19.212.1 to 4.19.215.2544.19.215.2551,022
2474.19.216.0/224.19.216.1 to 4.19.219.2544.19.219.2551,022
2484.19.220.0/224.19.220.1 to 4.19.223.2544.19.223.2551,022
2494.19.224.0/224.19.224.1 to 4.19.227.2544.19.227.2551,022
2504.19.228.0/224.19.228.1 to 4.19.231.2544.19.231.2551,022
2514.19.232.0/224.19.232.1 to 4.19.235.2544.19.235.2551,022
2524.19.236.0/224.19.236.1 to 4.19.239.2544.19.239.2551,022
2534.19.240.0/224.19.240.1 to 4.19.243.2544.19.243.2551,022
2544.19.244.0/224.19.244.1 to 4.19.247.2544.19.247.2551,022
2554.19.248.0/224.19.248.1 to 4.19.251.2544.19.251.2551,022
2564.19.252.0/224.19.252.1 to 4.19.255.2544.19.255.2551,022

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.