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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.

Network4.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
4.0.0.0
Broadcast address
7.255.255.255
First usable
4.0.0.1
Last usable
7.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 04000000 · Integer 67108864 to 134217727
Reverse DNS zones
4.in-addr.arpa
5.in-addr.arpa
6.in-addr.arpa
7.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000100.00000000.00000000.000000004.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network00000100.00000000.00000000.000000004.0.0.0
Broadcast00000111.11111111.11111111.111111117.255.255.255
Split into smaller subnets/15
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

4.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.0.0.0/154.0.0.1 to 4.1.255.2544.1.255.255131,070
24.2.0.0/154.2.0.1 to 4.3.255.2544.3.255.255131,070
34.4.0.0/154.4.0.1 to 4.5.255.2544.5.255.255131,070
44.6.0.0/154.6.0.1 to 4.7.255.2544.7.255.255131,070
54.8.0.0/154.8.0.1 to 4.9.255.2544.9.255.255131,070
64.10.0.0/154.10.0.1 to 4.11.255.2544.11.255.255131,070
74.12.0.0/154.12.0.1 to 4.13.255.2544.13.255.255131,070
84.14.0.0/154.14.0.1 to 4.15.255.2544.15.255.255131,070
94.16.0.0/154.16.0.1 to 4.17.255.2544.17.255.255131,070
104.18.0.0/154.18.0.1 to 4.19.255.2544.19.255.255131,070
114.20.0.0/154.20.0.1 to 4.21.255.2544.21.255.255131,070
124.22.0.0/154.22.0.1 to 4.23.255.2544.23.255.255131,070
134.24.0.0/154.24.0.1 to 4.25.255.2544.25.255.255131,070
144.26.0.0/154.26.0.1 to 4.27.255.2544.27.255.255131,070
154.28.0.0/154.28.0.1 to 4.29.255.2544.29.255.255131,070
164.30.0.0/154.30.0.1 to 4.31.255.2544.31.255.255131,070
174.32.0.0/154.32.0.1 to 4.33.255.2544.33.255.255131,070
184.34.0.0/154.34.0.1 to 4.35.255.2544.35.255.255131,070
194.36.0.0/154.36.0.1 to 4.37.255.2544.37.255.255131,070
204.38.0.0/154.38.0.1 to 4.39.255.2544.39.255.255131,070
214.40.0.0/154.40.0.1 to 4.41.255.2544.41.255.255131,070
224.42.0.0/154.42.0.1 to 4.43.255.2544.43.255.255131,070
234.44.0.0/154.44.0.1 to 4.45.255.2544.45.255.255131,070
244.46.0.0/154.46.0.1 to 4.47.255.2544.47.255.255131,070
254.48.0.0/154.48.0.1 to 4.49.255.2544.49.255.255131,070
264.50.0.0/154.50.0.1 to 4.51.255.2544.51.255.255131,070
274.52.0.0/154.52.0.1 to 4.53.255.2544.53.255.255131,070
284.54.0.0/154.54.0.1 to 4.55.255.2544.55.255.255131,070
294.56.0.0/154.56.0.1 to 4.57.255.2544.57.255.255131,070
304.58.0.0/154.58.0.1 to 4.59.255.2544.59.255.255131,070
314.60.0.0/154.60.0.1 to 4.61.255.2544.61.255.255131,070
324.62.0.0/154.62.0.1 to 4.63.255.2544.63.255.255131,070
334.64.0.0/154.64.0.1 to 4.65.255.2544.65.255.255131,070
344.66.0.0/154.66.0.1 to 4.67.255.2544.67.255.255131,070
354.68.0.0/154.68.0.1 to 4.69.255.2544.69.255.255131,070
364.70.0.0/154.70.0.1 to 4.71.255.2544.71.255.255131,070
374.72.0.0/154.72.0.1 to 4.73.255.2544.73.255.255131,070
384.74.0.0/154.74.0.1 to 4.75.255.2544.75.255.255131,070
394.76.0.0/154.76.0.1 to 4.77.255.2544.77.255.255131,070
404.78.0.0/154.78.0.1 to 4.79.255.2544.79.255.255131,070
414.80.0.0/154.80.0.1 to 4.81.255.2544.81.255.255131,070
424.82.0.0/154.82.0.1 to 4.83.255.2544.83.255.255131,070
434.84.0.0/154.84.0.1 to 4.85.255.2544.85.255.255131,070
444.86.0.0/154.86.0.1 to 4.87.255.2544.87.255.255131,070
454.88.0.0/154.88.0.1 to 4.89.255.2544.89.255.255131,070
464.90.0.0/154.90.0.1 to 4.91.255.2544.91.255.255131,070
474.92.0.0/154.92.0.1 to 4.93.255.2544.93.255.255131,070
484.94.0.0/154.94.0.1 to 4.95.255.2544.95.255.255131,070
494.96.0.0/154.96.0.1 to 4.97.255.2544.97.255.255131,070
504.98.0.0/154.98.0.1 to 4.99.255.2544.99.255.255131,070
514.100.0.0/154.100.0.1 to 4.101.255.2544.101.255.255131,070
524.102.0.0/154.102.0.1 to 4.103.255.2544.103.255.255131,070
534.104.0.0/154.104.0.1 to 4.105.255.2544.105.255.255131,070
544.106.0.0/154.106.0.1 to 4.107.255.2544.107.255.255131,070
554.108.0.0/154.108.0.1 to 4.109.255.2544.109.255.255131,070
564.110.0.0/154.110.0.1 to 4.111.255.2544.111.255.255131,070
574.112.0.0/154.112.0.1 to 4.113.255.2544.113.255.255131,070
584.114.0.0/154.114.0.1 to 4.115.255.2544.115.255.255131,070
594.116.0.0/154.116.0.1 to 4.117.255.2544.117.255.255131,070
604.118.0.0/154.118.0.1 to 4.119.255.2544.119.255.255131,070
614.120.0.0/154.120.0.1 to 4.121.255.2544.121.255.255131,070
624.122.0.0/154.122.0.1 to 4.123.255.2544.123.255.255131,070
634.124.0.0/154.124.0.1 to 4.125.255.2544.125.255.255131,070
644.126.0.0/154.126.0.1 to 4.127.255.2544.127.255.255131,070
654.128.0.0/154.128.0.1 to 4.129.255.2544.129.255.255131,070
664.130.0.0/154.130.0.1 to 4.131.255.2544.131.255.255131,070
674.132.0.0/154.132.0.1 to 4.133.255.2544.133.255.255131,070
684.134.0.0/154.134.0.1 to 4.135.255.2544.135.255.255131,070
694.136.0.0/154.136.0.1 to 4.137.255.2544.137.255.255131,070
704.138.0.0/154.138.0.1 to 4.139.255.2544.139.255.255131,070
714.140.0.0/154.140.0.1 to 4.141.255.2544.141.255.255131,070
724.142.0.0/154.142.0.1 to 4.143.255.2544.143.255.255131,070
734.144.0.0/154.144.0.1 to 4.145.255.2544.145.255.255131,070
744.146.0.0/154.146.0.1 to 4.147.255.2544.147.255.255131,070
754.148.0.0/154.148.0.1 to 4.149.255.2544.149.255.255131,070
764.150.0.0/154.150.0.1 to 4.151.255.2544.151.255.255131,070
774.152.0.0/154.152.0.1 to 4.153.255.2544.153.255.255131,070
784.154.0.0/154.154.0.1 to 4.155.255.2544.155.255.255131,070
794.156.0.0/154.156.0.1 to 4.157.255.2544.157.255.255131,070
804.158.0.0/154.158.0.1 to 4.159.255.2544.159.255.255131,070
814.160.0.0/154.160.0.1 to 4.161.255.2544.161.255.255131,070
824.162.0.0/154.162.0.1 to 4.163.255.2544.163.255.255131,070
834.164.0.0/154.164.0.1 to 4.165.255.2544.165.255.255131,070
844.166.0.0/154.166.0.1 to 4.167.255.2544.167.255.255131,070
854.168.0.0/154.168.0.1 to 4.169.255.2544.169.255.255131,070
864.170.0.0/154.170.0.1 to 4.171.255.2544.171.255.255131,070
874.172.0.0/154.172.0.1 to 4.173.255.2544.173.255.255131,070
884.174.0.0/154.174.0.1 to 4.175.255.2544.175.255.255131,070
894.176.0.0/154.176.0.1 to 4.177.255.2544.177.255.255131,070
904.178.0.0/154.178.0.1 to 4.179.255.2544.179.255.255131,070
914.180.0.0/154.180.0.1 to 4.181.255.2544.181.255.255131,070
924.182.0.0/154.182.0.1 to 4.183.255.2544.183.255.255131,070
934.184.0.0/154.184.0.1 to 4.185.255.2544.185.255.255131,070
944.186.0.0/154.186.0.1 to 4.187.255.2544.187.255.255131,070
954.188.0.0/154.188.0.1 to 4.189.255.2544.189.255.255131,070
964.190.0.0/154.190.0.1 to 4.191.255.2544.191.255.255131,070
974.192.0.0/154.192.0.1 to 4.193.255.2544.193.255.255131,070
984.194.0.0/154.194.0.1 to 4.195.255.2544.195.255.255131,070
994.196.0.0/154.196.0.1 to 4.197.255.2544.197.255.255131,070
1004.198.0.0/154.198.0.1 to 4.199.255.2544.199.255.255131,070
1014.200.0.0/154.200.0.1 to 4.201.255.2544.201.255.255131,070
1024.202.0.0/154.202.0.1 to 4.203.255.2544.203.255.255131,070
1034.204.0.0/154.204.0.1 to 4.205.255.2544.205.255.255131,070
1044.206.0.0/154.206.0.1 to 4.207.255.2544.207.255.255131,070
1054.208.0.0/154.208.0.1 to 4.209.255.2544.209.255.255131,070
1064.210.0.0/154.210.0.1 to 4.211.255.2544.211.255.255131,070
1074.212.0.0/154.212.0.1 to 4.213.255.2544.213.255.255131,070
1084.214.0.0/154.214.0.1 to 4.215.255.2544.215.255.255131,070
1094.216.0.0/154.216.0.1 to 4.217.255.2544.217.255.255131,070
1104.218.0.0/154.218.0.1 to 4.219.255.2544.219.255.255131,070
1114.220.0.0/154.220.0.1 to 4.221.255.2544.221.255.255131,070
1124.222.0.0/154.222.0.1 to 4.223.255.2544.223.255.255131,070
1134.224.0.0/154.224.0.1 to 4.225.255.2544.225.255.255131,070
1144.226.0.0/154.226.0.1 to 4.227.255.2544.227.255.255131,070
1154.228.0.0/154.228.0.1 to 4.229.255.2544.229.255.255131,070
1164.230.0.0/154.230.0.1 to 4.231.255.2544.231.255.255131,070
1174.232.0.0/154.232.0.1 to 4.233.255.2544.233.255.255131,070
1184.234.0.0/154.234.0.1 to 4.235.255.2544.235.255.255131,070
1194.236.0.0/154.236.0.1 to 4.237.255.2544.237.255.255131,070
1204.238.0.0/154.238.0.1 to 4.239.255.2544.239.255.255131,070
1214.240.0.0/154.240.0.1 to 4.241.255.2544.241.255.255131,070
1224.242.0.0/154.242.0.1 to 4.243.255.2544.243.255.255131,070
1234.244.0.0/154.244.0.1 to 4.245.255.2544.245.255.255131,070
1244.246.0.0/154.246.0.1 to 4.247.255.2544.247.255.255131,070
1254.248.0.0/154.248.0.1 to 4.249.255.2544.249.255.255131,070
1264.250.0.0/154.250.0.1 to 4.251.255.2544.251.255.255131,070
1274.252.0.0/154.252.0.1 to 4.253.255.2544.253.255.255131,070
1284.254.0.0/154.254.0.1 to 4.255.255.2544.255.255.255131,070
1295.0.0.0/155.0.0.1 to 5.1.255.2545.1.255.255131,070
1305.2.0.0/155.2.0.1 to 5.3.255.2545.3.255.255131,070
1315.4.0.0/155.4.0.1 to 5.5.255.2545.5.255.255131,070
1325.6.0.0/155.6.0.1 to 5.7.255.2545.7.255.255131,070
1335.8.0.0/155.8.0.1 to 5.9.255.2545.9.255.255131,070
1345.10.0.0/155.10.0.1 to 5.11.255.2545.11.255.255131,070
1355.12.0.0/155.12.0.1 to 5.13.255.2545.13.255.255131,070
1365.14.0.0/155.14.0.1 to 5.15.255.2545.15.255.255131,070
1375.16.0.0/155.16.0.1 to 5.17.255.2545.17.255.255131,070
1385.18.0.0/155.18.0.1 to 5.19.255.2545.19.255.255131,070
1395.20.0.0/155.20.0.1 to 5.21.255.2545.21.255.255131,070
1405.22.0.0/155.22.0.1 to 5.23.255.2545.23.255.255131,070
1415.24.0.0/155.24.0.1 to 5.25.255.2545.25.255.255131,070
1425.26.0.0/155.26.0.1 to 5.27.255.2545.27.255.255131,070
1435.28.0.0/155.28.0.1 to 5.29.255.2545.29.255.255131,070
1445.30.0.0/155.30.0.1 to 5.31.255.2545.31.255.255131,070
1455.32.0.0/155.32.0.1 to 5.33.255.2545.33.255.255131,070
1465.34.0.0/155.34.0.1 to 5.35.255.2545.35.255.255131,070
1475.36.0.0/155.36.0.1 to 5.37.255.2545.37.255.255131,070
1485.38.0.0/155.38.0.1 to 5.39.255.2545.39.255.255131,070
1495.40.0.0/155.40.0.1 to 5.41.255.2545.41.255.255131,070
1505.42.0.0/155.42.0.1 to 5.43.255.2545.43.255.255131,070
1515.44.0.0/155.44.0.1 to 5.45.255.2545.45.255.255131,070
1525.46.0.0/155.46.0.1 to 5.47.255.2545.47.255.255131,070
1535.48.0.0/155.48.0.1 to 5.49.255.2545.49.255.255131,070
1545.50.0.0/155.50.0.1 to 5.51.255.2545.51.255.255131,070
1555.52.0.0/155.52.0.1 to 5.53.255.2545.53.255.255131,070
1565.54.0.0/155.54.0.1 to 5.55.255.2545.55.255.255131,070
1575.56.0.0/155.56.0.1 to 5.57.255.2545.57.255.255131,070
1585.58.0.0/155.58.0.1 to 5.59.255.2545.59.255.255131,070
1595.60.0.0/155.60.0.1 to 5.61.255.2545.61.255.255131,070
1605.62.0.0/155.62.0.1 to 5.63.255.2545.63.255.255131,070
1615.64.0.0/155.64.0.1 to 5.65.255.2545.65.255.255131,070
1625.66.0.0/155.66.0.1 to 5.67.255.2545.67.255.255131,070
1635.68.0.0/155.68.0.1 to 5.69.255.2545.69.255.255131,070
1645.70.0.0/155.70.0.1 to 5.71.255.2545.71.255.255131,070
1655.72.0.0/155.72.0.1 to 5.73.255.2545.73.255.255131,070
1665.74.0.0/155.74.0.1 to 5.75.255.2545.75.255.255131,070
1675.76.0.0/155.76.0.1 to 5.77.255.2545.77.255.255131,070
1685.78.0.0/155.78.0.1 to 5.79.255.2545.79.255.255131,070
1695.80.0.0/155.80.0.1 to 5.81.255.2545.81.255.255131,070
1705.82.0.0/155.82.0.1 to 5.83.255.2545.83.255.255131,070
1715.84.0.0/155.84.0.1 to 5.85.255.2545.85.255.255131,070
1725.86.0.0/155.86.0.1 to 5.87.255.2545.87.255.255131,070
1735.88.0.0/155.88.0.1 to 5.89.255.2545.89.255.255131,070
1745.90.0.0/155.90.0.1 to 5.91.255.2545.91.255.255131,070
1755.92.0.0/155.92.0.1 to 5.93.255.2545.93.255.255131,070
1765.94.0.0/155.94.0.1 to 5.95.255.2545.95.255.255131,070
1775.96.0.0/155.96.0.1 to 5.97.255.2545.97.255.255131,070
1785.98.0.0/155.98.0.1 to 5.99.255.2545.99.255.255131,070
1795.100.0.0/155.100.0.1 to 5.101.255.2545.101.255.255131,070
1805.102.0.0/155.102.0.1 to 5.103.255.2545.103.255.255131,070
1815.104.0.0/155.104.0.1 to 5.105.255.2545.105.255.255131,070
1825.106.0.0/155.106.0.1 to 5.107.255.2545.107.255.255131,070
1835.108.0.0/155.108.0.1 to 5.109.255.2545.109.255.255131,070
1845.110.0.0/155.110.0.1 to 5.111.255.2545.111.255.255131,070
1855.112.0.0/155.112.0.1 to 5.113.255.2545.113.255.255131,070
1865.114.0.0/155.114.0.1 to 5.115.255.2545.115.255.255131,070
1875.116.0.0/155.116.0.1 to 5.117.255.2545.117.255.255131,070
1885.118.0.0/155.118.0.1 to 5.119.255.2545.119.255.255131,070
1895.120.0.0/155.120.0.1 to 5.121.255.2545.121.255.255131,070
1905.122.0.0/155.122.0.1 to 5.123.255.2545.123.255.255131,070
1915.124.0.0/155.124.0.1 to 5.125.255.2545.125.255.255131,070
1925.126.0.0/155.126.0.1 to 5.127.255.2545.127.255.255131,070
1935.128.0.0/155.128.0.1 to 5.129.255.2545.129.255.255131,070
1945.130.0.0/155.130.0.1 to 5.131.255.2545.131.255.255131,070
1955.132.0.0/155.132.0.1 to 5.133.255.2545.133.255.255131,070
1965.134.0.0/155.134.0.1 to 5.135.255.2545.135.255.255131,070
1975.136.0.0/155.136.0.1 to 5.137.255.2545.137.255.255131,070
1985.138.0.0/155.138.0.1 to 5.139.255.2545.139.255.255131,070
1995.140.0.0/155.140.0.1 to 5.141.255.2545.141.255.255131,070
2005.142.0.0/155.142.0.1 to 5.143.255.2545.143.255.255131,070
2015.144.0.0/155.144.0.1 to 5.145.255.2545.145.255.255131,070
2025.146.0.0/155.146.0.1 to 5.147.255.2545.147.255.255131,070
2035.148.0.0/155.148.0.1 to 5.149.255.2545.149.255.255131,070
2045.150.0.0/155.150.0.1 to 5.151.255.2545.151.255.255131,070
2055.152.0.0/155.152.0.1 to 5.153.255.2545.153.255.255131,070
2065.154.0.0/155.154.0.1 to 5.155.255.2545.155.255.255131,070
2075.156.0.0/155.156.0.1 to 5.157.255.2545.157.255.255131,070
2085.158.0.0/155.158.0.1 to 5.159.255.2545.159.255.255131,070
2095.160.0.0/155.160.0.1 to 5.161.255.2545.161.255.255131,070
2105.162.0.0/155.162.0.1 to 5.163.255.2545.163.255.255131,070
2115.164.0.0/155.164.0.1 to 5.165.255.2545.165.255.255131,070
2125.166.0.0/155.166.0.1 to 5.167.255.2545.167.255.255131,070
2135.168.0.0/155.168.0.1 to 5.169.255.2545.169.255.255131,070
2145.170.0.0/155.170.0.1 to 5.171.255.2545.171.255.255131,070
2155.172.0.0/155.172.0.1 to 5.173.255.2545.173.255.255131,070
2165.174.0.0/155.174.0.1 to 5.175.255.2545.175.255.255131,070
2175.176.0.0/155.176.0.1 to 5.177.255.2545.177.255.255131,070
2185.178.0.0/155.178.0.1 to 5.179.255.2545.179.255.255131,070
2195.180.0.0/155.180.0.1 to 5.181.255.2545.181.255.255131,070
2205.182.0.0/155.182.0.1 to 5.183.255.2545.183.255.255131,070
2215.184.0.0/155.184.0.1 to 5.185.255.2545.185.255.255131,070
2225.186.0.0/155.186.0.1 to 5.187.255.2545.187.255.255131,070
2235.188.0.0/155.188.0.1 to 5.189.255.2545.189.255.255131,070
2245.190.0.0/155.190.0.1 to 5.191.255.2545.191.255.255131,070
2255.192.0.0/155.192.0.1 to 5.193.255.2545.193.255.255131,070
2265.194.0.0/155.194.0.1 to 5.195.255.2545.195.255.255131,070
2275.196.0.0/155.196.0.1 to 5.197.255.2545.197.255.255131,070
2285.198.0.0/155.198.0.1 to 5.199.255.2545.199.255.255131,070
2295.200.0.0/155.200.0.1 to 5.201.255.2545.201.255.255131,070
2305.202.0.0/155.202.0.1 to 5.203.255.2545.203.255.255131,070
2315.204.0.0/155.204.0.1 to 5.205.255.2545.205.255.255131,070
2325.206.0.0/155.206.0.1 to 5.207.255.2545.207.255.255131,070
2335.208.0.0/155.208.0.1 to 5.209.255.2545.209.255.255131,070
2345.210.0.0/155.210.0.1 to 5.211.255.2545.211.255.255131,070
2355.212.0.0/155.212.0.1 to 5.213.255.2545.213.255.255131,070
2365.214.0.0/155.214.0.1 to 5.215.255.2545.215.255.255131,070
2375.216.0.0/155.216.0.1 to 5.217.255.2545.217.255.255131,070
2385.218.0.0/155.218.0.1 to 5.219.255.2545.219.255.255131,070
2395.220.0.0/155.220.0.1 to 5.221.255.2545.221.255.255131,070
2405.222.0.0/155.222.0.1 to 5.223.255.2545.223.255.255131,070
2415.224.0.0/155.224.0.1 to 5.225.255.2545.225.255.255131,070
2425.226.0.0/155.226.0.1 to 5.227.255.2545.227.255.255131,070
2435.228.0.0/155.228.0.1 to 5.229.255.2545.229.255.255131,070
2445.230.0.0/155.230.0.1 to 5.231.255.2545.231.255.255131,070
2455.232.0.0/155.232.0.1 to 5.233.255.2545.233.255.255131,070
2465.234.0.0/155.234.0.1 to 5.235.255.2545.235.255.255131,070
2475.236.0.0/155.236.0.1 to 5.237.255.2545.237.255.255131,070
2485.238.0.0/155.238.0.1 to 5.239.255.2545.239.255.255131,070
2495.240.0.0/155.240.0.1 to 5.241.255.2545.241.255.255131,070
2505.242.0.0/155.242.0.1 to 5.243.255.2545.243.255.255131,070
2515.244.0.0/155.244.0.1 to 5.245.255.2545.245.255.255131,070
2525.246.0.0/155.246.0.1 to 5.247.255.2545.247.255.255131,070
2535.248.0.0/155.248.0.1 to 5.249.255.2545.249.255.255131,070
2545.250.0.0/155.250.0.1 to 5.251.255.2545.251.255.255131,070
2555.252.0.0/155.252.0.1 to 5.253.255.2545.253.255.255131,070
2565.254.0.0/155.254.0.1 to 5.255.255.2545.255.255.255131,070

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.