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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.

Network8.78.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
8.78.0.0
Broadcast address
8.78.255.255
First usable
8.78.0.1
Last usable
8.78.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 084E0000 · Integer 139329536 to 139395071
Reverse DNS zone
78.8.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001000.01001110..00000000.000000008.78.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00001000.01001110..00000000.000000008.78.0.0
Broadcast00001000.01001110..11111111.111111118.78.255.255
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

8.78.0.0/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
18.78.0.0/288.78.0.1 to 8.78.0.148.78.0.1514
28.78.0.16/288.78.0.17 to 8.78.0.308.78.0.3114
38.78.0.32/288.78.0.33 to 8.78.0.468.78.0.4714
48.78.0.48/288.78.0.49 to 8.78.0.628.78.0.6314
58.78.0.64/288.78.0.65 to 8.78.0.788.78.0.7914
68.78.0.80/288.78.0.81 to 8.78.0.948.78.0.9514
78.78.0.96/288.78.0.97 to 8.78.0.1108.78.0.11114
88.78.0.112/288.78.0.113 to 8.78.0.1268.78.0.12714
98.78.0.128/288.78.0.129 to 8.78.0.1428.78.0.14314
108.78.0.144/288.78.0.145 to 8.78.0.1588.78.0.15914
118.78.0.160/288.78.0.161 to 8.78.0.1748.78.0.17514
128.78.0.176/288.78.0.177 to 8.78.0.1908.78.0.19114
138.78.0.192/288.78.0.193 to 8.78.0.2068.78.0.20714
148.78.0.208/288.78.0.209 to 8.78.0.2228.78.0.22314
158.78.0.224/288.78.0.225 to 8.78.0.2388.78.0.23914
168.78.0.240/288.78.0.241 to 8.78.0.2548.78.0.25514
178.78.1.0/288.78.1.1 to 8.78.1.148.78.1.1514
188.78.1.16/288.78.1.17 to 8.78.1.308.78.1.3114
198.78.1.32/288.78.1.33 to 8.78.1.468.78.1.4714
208.78.1.48/288.78.1.49 to 8.78.1.628.78.1.6314
218.78.1.64/288.78.1.65 to 8.78.1.788.78.1.7914
228.78.1.80/288.78.1.81 to 8.78.1.948.78.1.9514
238.78.1.96/288.78.1.97 to 8.78.1.1108.78.1.11114
248.78.1.112/288.78.1.113 to 8.78.1.1268.78.1.12714
258.78.1.128/288.78.1.129 to 8.78.1.1428.78.1.14314
268.78.1.144/288.78.1.145 to 8.78.1.1588.78.1.15914
278.78.1.160/288.78.1.161 to 8.78.1.1748.78.1.17514
288.78.1.176/288.78.1.177 to 8.78.1.1908.78.1.19114
298.78.1.192/288.78.1.193 to 8.78.1.2068.78.1.20714
308.78.1.208/288.78.1.209 to 8.78.1.2228.78.1.22314
318.78.1.224/288.78.1.225 to 8.78.1.2388.78.1.23914
328.78.1.240/288.78.1.241 to 8.78.1.2548.78.1.25514
338.78.2.0/288.78.2.1 to 8.78.2.148.78.2.1514
348.78.2.16/288.78.2.17 to 8.78.2.308.78.2.3114
358.78.2.32/288.78.2.33 to 8.78.2.468.78.2.4714
368.78.2.48/288.78.2.49 to 8.78.2.628.78.2.6314
378.78.2.64/288.78.2.65 to 8.78.2.788.78.2.7914
388.78.2.80/288.78.2.81 to 8.78.2.948.78.2.9514
398.78.2.96/288.78.2.97 to 8.78.2.1108.78.2.11114
408.78.2.112/288.78.2.113 to 8.78.2.1268.78.2.12714
418.78.2.128/288.78.2.129 to 8.78.2.1428.78.2.14314
428.78.2.144/288.78.2.145 to 8.78.2.1588.78.2.15914
438.78.2.160/288.78.2.161 to 8.78.2.1748.78.2.17514
448.78.2.176/288.78.2.177 to 8.78.2.1908.78.2.19114
458.78.2.192/288.78.2.193 to 8.78.2.2068.78.2.20714
468.78.2.208/288.78.2.209 to 8.78.2.2228.78.2.22314
478.78.2.224/288.78.2.225 to 8.78.2.2388.78.2.23914
488.78.2.240/288.78.2.241 to 8.78.2.2548.78.2.25514
498.78.3.0/288.78.3.1 to 8.78.3.148.78.3.1514
508.78.3.16/288.78.3.17 to 8.78.3.308.78.3.3114
518.78.3.32/288.78.3.33 to 8.78.3.468.78.3.4714
528.78.3.48/288.78.3.49 to 8.78.3.628.78.3.6314
538.78.3.64/288.78.3.65 to 8.78.3.788.78.3.7914
548.78.3.80/288.78.3.81 to 8.78.3.948.78.3.9514
558.78.3.96/288.78.3.97 to 8.78.3.1108.78.3.11114
568.78.3.112/288.78.3.113 to 8.78.3.1268.78.3.12714
578.78.3.128/288.78.3.129 to 8.78.3.1428.78.3.14314
588.78.3.144/288.78.3.145 to 8.78.3.1588.78.3.15914
598.78.3.160/288.78.3.161 to 8.78.3.1748.78.3.17514
608.78.3.176/288.78.3.177 to 8.78.3.1908.78.3.19114
618.78.3.192/288.78.3.193 to 8.78.3.2068.78.3.20714
628.78.3.208/288.78.3.209 to 8.78.3.2228.78.3.22314
638.78.3.224/288.78.3.225 to 8.78.3.2388.78.3.23914
648.78.3.240/288.78.3.241 to 8.78.3.2548.78.3.25514
658.78.4.0/288.78.4.1 to 8.78.4.148.78.4.1514
668.78.4.16/288.78.4.17 to 8.78.4.308.78.4.3114
678.78.4.32/288.78.4.33 to 8.78.4.468.78.4.4714
688.78.4.48/288.78.4.49 to 8.78.4.628.78.4.6314
698.78.4.64/288.78.4.65 to 8.78.4.788.78.4.7914
708.78.4.80/288.78.4.81 to 8.78.4.948.78.4.9514
718.78.4.96/288.78.4.97 to 8.78.4.1108.78.4.11114
728.78.4.112/288.78.4.113 to 8.78.4.1268.78.4.12714
738.78.4.128/288.78.4.129 to 8.78.4.1428.78.4.14314
748.78.4.144/288.78.4.145 to 8.78.4.1588.78.4.15914
758.78.4.160/288.78.4.161 to 8.78.4.1748.78.4.17514
768.78.4.176/288.78.4.177 to 8.78.4.1908.78.4.19114
778.78.4.192/288.78.4.193 to 8.78.4.2068.78.4.20714
788.78.4.208/288.78.4.209 to 8.78.4.2228.78.4.22314
798.78.4.224/288.78.4.225 to 8.78.4.2388.78.4.23914
808.78.4.240/288.78.4.241 to 8.78.4.2548.78.4.25514
818.78.5.0/288.78.5.1 to 8.78.5.148.78.5.1514
828.78.5.16/288.78.5.17 to 8.78.5.308.78.5.3114
838.78.5.32/288.78.5.33 to 8.78.5.468.78.5.4714
848.78.5.48/288.78.5.49 to 8.78.5.628.78.5.6314
858.78.5.64/288.78.5.65 to 8.78.5.788.78.5.7914
868.78.5.80/288.78.5.81 to 8.78.5.948.78.5.9514
878.78.5.96/288.78.5.97 to 8.78.5.1108.78.5.11114
888.78.5.112/288.78.5.113 to 8.78.5.1268.78.5.12714
898.78.5.128/288.78.5.129 to 8.78.5.1428.78.5.14314
908.78.5.144/288.78.5.145 to 8.78.5.1588.78.5.15914
918.78.5.160/288.78.5.161 to 8.78.5.1748.78.5.17514
928.78.5.176/288.78.5.177 to 8.78.5.1908.78.5.19114
938.78.5.192/288.78.5.193 to 8.78.5.2068.78.5.20714
948.78.5.208/288.78.5.209 to 8.78.5.2228.78.5.22314
958.78.5.224/288.78.5.225 to 8.78.5.2388.78.5.23914
968.78.5.240/288.78.5.241 to 8.78.5.2548.78.5.25514
978.78.6.0/288.78.6.1 to 8.78.6.148.78.6.1514
988.78.6.16/288.78.6.17 to 8.78.6.308.78.6.3114
998.78.6.32/288.78.6.33 to 8.78.6.468.78.6.4714
1008.78.6.48/288.78.6.49 to 8.78.6.628.78.6.6314
1018.78.6.64/288.78.6.65 to 8.78.6.788.78.6.7914
1028.78.6.80/288.78.6.81 to 8.78.6.948.78.6.9514
1038.78.6.96/288.78.6.97 to 8.78.6.1108.78.6.11114
1048.78.6.112/288.78.6.113 to 8.78.6.1268.78.6.12714
1058.78.6.128/288.78.6.129 to 8.78.6.1428.78.6.14314
1068.78.6.144/288.78.6.145 to 8.78.6.1588.78.6.15914
1078.78.6.160/288.78.6.161 to 8.78.6.1748.78.6.17514
1088.78.6.176/288.78.6.177 to 8.78.6.1908.78.6.19114
1098.78.6.192/288.78.6.193 to 8.78.6.2068.78.6.20714
1108.78.6.208/288.78.6.209 to 8.78.6.2228.78.6.22314
1118.78.6.224/288.78.6.225 to 8.78.6.2388.78.6.23914
1128.78.6.240/288.78.6.241 to 8.78.6.2548.78.6.25514
1138.78.7.0/288.78.7.1 to 8.78.7.148.78.7.1514
1148.78.7.16/288.78.7.17 to 8.78.7.308.78.7.3114
1158.78.7.32/288.78.7.33 to 8.78.7.468.78.7.4714
1168.78.7.48/288.78.7.49 to 8.78.7.628.78.7.6314
1178.78.7.64/288.78.7.65 to 8.78.7.788.78.7.7914
1188.78.7.80/288.78.7.81 to 8.78.7.948.78.7.9514
1198.78.7.96/288.78.7.97 to 8.78.7.1108.78.7.11114
1208.78.7.112/288.78.7.113 to 8.78.7.1268.78.7.12714
1218.78.7.128/288.78.7.129 to 8.78.7.1428.78.7.14314
1228.78.7.144/288.78.7.145 to 8.78.7.1588.78.7.15914
1238.78.7.160/288.78.7.161 to 8.78.7.1748.78.7.17514
1248.78.7.176/288.78.7.177 to 8.78.7.1908.78.7.19114
1258.78.7.192/288.78.7.193 to 8.78.7.2068.78.7.20714
1268.78.7.208/288.78.7.209 to 8.78.7.2228.78.7.22314
1278.78.7.224/288.78.7.225 to 8.78.7.2388.78.7.23914
1288.78.7.240/288.78.7.241 to 8.78.7.2548.78.7.25514
1298.78.8.0/288.78.8.1 to 8.78.8.148.78.8.1514
1308.78.8.16/288.78.8.17 to 8.78.8.308.78.8.3114
1318.78.8.32/288.78.8.33 to 8.78.8.468.78.8.4714
1328.78.8.48/288.78.8.49 to 8.78.8.628.78.8.6314
1338.78.8.64/288.78.8.65 to 8.78.8.788.78.8.7914
1348.78.8.80/288.78.8.81 to 8.78.8.948.78.8.9514
1358.78.8.96/288.78.8.97 to 8.78.8.1108.78.8.11114
1368.78.8.112/288.78.8.113 to 8.78.8.1268.78.8.12714
1378.78.8.128/288.78.8.129 to 8.78.8.1428.78.8.14314
1388.78.8.144/288.78.8.145 to 8.78.8.1588.78.8.15914
1398.78.8.160/288.78.8.161 to 8.78.8.1748.78.8.17514
1408.78.8.176/288.78.8.177 to 8.78.8.1908.78.8.19114
1418.78.8.192/288.78.8.193 to 8.78.8.2068.78.8.20714
1428.78.8.208/288.78.8.209 to 8.78.8.2228.78.8.22314
1438.78.8.224/288.78.8.225 to 8.78.8.2388.78.8.23914
1448.78.8.240/288.78.8.241 to 8.78.8.2548.78.8.25514
1458.78.9.0/288.78.9.1 to 8.78.9.148.78.9.1514
1468.78.9.16/288.78.9.17 to 8.78.9.308.78.9.3114
1478.78.9.32/288.78.9.33 to 8.78.9.468.78.9.4714
1488.78.9.48/288.78.9.49 to 8.78.9.628.78.9.6314
1498.78.9.64/288.78.9.65 to 8.78.9.788.78.9.7914
1508.78.9.80/288.78.9.81 to 8.78.9.948.78.9.9514
1518.78.9.96/288.78.9.97 to 8.78.9.1108.78.9.11114
1528.78.9.112/288.78.9.113 to 8.78.9.1268.78.9.12714
1538.78.9.128/288.78.9.129 to 8.78.9.1428.78.9.14314
1548.78.9.144/288.78.9.145 to 8.78.9.1588.78.9.15914
1558.78.9.160/288.78.9.161 to 8.78.9.1748.78.9.17514
1568.78.9.176/288.78.9.177 to 8.78.9.1908.78.9.19114
1578.78.9.192/288.78.9.193 to 8.78.9.2068.78.9.20714
1588.78.9.208/288.78.9.209 to 8.78.9.2228.78.9.22314
1598.78.9.224/288.78.9.225 to 8.78.9.2388.78.9.23914
1608.78.9.240/288.78.9.241 to 8.78.9.2548.78.9.25514
1618.78.10.0/288.78.10.1 to 8.78.10.148.78.10.1514
1628.78.10.16/288.78.10.17 to 8.78.10.308.78.10.3114
1638.78.10.32/288.78.10.33 to 8.78.10.468.78.10.4714
1648.78.10.48/288.78.10.49 to 8.78.10.628.78.10.6314
1658.78.10.64/288.78.10.65 to 8.78.10.788.78.10.7914
1668.78.10.80/288.78.10.81 to 8.78.10.948.78.10.9514
1678.78.10.96/288.78.10.97 to 8.78.10.1108.78.10.11114
1688.78.10.112/288.78.10.113 to 8.78.10.1268.78.10.12714
1698.78.10.128/288.78.10.129 to 8.78.10.1428.78.10.14314
1708.78.10.144/288.78.10.145 to 8.78.10.1588.78.10.15914
1718.78.10.160/288.78.10.161 to 8.78.10.1748.78.10.17514
1728.78.10.176/288.78.10.177 to 8.78.10.1908.78.10.19114
1738.78.10.192/288.78.10.193 to 8.78.10.2068.78.10.20714
1748.78.10.208/288.78.10.209 to 8.78.10.2228.78.10.22314
1758.78.10.224/288.78.10.225 to 8.78.10.2388.78.10.23914
1768.78.10.240/288.78.10.241 to 8.78.10.2548.78.10.25514
1778.78.11.0/288.78.11.1 to 8.78.11.148.78.11.1514
1788.78.11.16/288.78.11.17 to 8.78.11.308.78.11.3114
1798.78.11.32/288.78.11.33 to 8.78.11.468.78.11.4714
1808.78.11.48/288.78.11.49 to 8.78.11.628.78.11.6314
1818.78.11.64/288.78.11.65 to 8.78.11.788.78.11.7914
1828.78.11.80/288.78.11.81 to 8.78.11.948.78.11.9514
1838.78.11.96/288.78.11.97 to 8.78.11.1108.78.11.11114
1848.78.11.112/288.78.11.113 to 8.78.11.1268.78.11.12714
1858.78.11.128/288.78.11.129 to 8.78.11.1428.78.11.14314
1868.78.11.144/288.78.11.145 to 8.78.11.1588.78.11.15914
1878.78.11.160/288.78.11.161 to 8.78.11.1748.78.11.17514
1888.78.11.176/288.78.11.177 to 8.78.11.1908.78.11.19114
1898.78.11.192/288.78.11.193 to 8.78.11.2068.78.11.20714
1908.78.11.208/288.78.11.209 to 8.78.11.2228.78.11.22314
1918.78.11.224/288.78.11.225 to 8.78.11.2388.78.11.23914
1928.78.11.240/288.78.11.241 to 8.78.11.2548.78.11.25514
1938.78.12.0/288.78.12.1 to 8.78.12.148.78.12.1514
1948.78.12.16/288.78.12.17 to 8.78.12.308.78.12.3114
1958.78.12.32/288.78.12.33 to 8.78.12.468.78.12.4714
1968.78.12.48/288.78.12.49 to 8.78.12.628.78.12.6314
1978.78.12.64/288.78.12.65 to 8.78.12.788.78.12.7914
1988.78.12.80/288.78.12.81 to 8.78.12.948.78.12.9514
1998.78.12.96/288.78.12.97 to 8.78.12.1108.78.12.11114
2008.78.12.112/288.78.12.113 to 8.78.12.1268.78.12.12714
2018.78.12.128/288.78.12.129 to 8.78.12.1428.78.12.14314
2028.78.12.144/288.78.12.145 to 8.78.12.1588.78.12.15914
2038.78.12.160/288.78.12.161 to 8.78.12.1748.78.12.17514
2048.78.12.176/288.78.12.177 to 8.78.12.1908.78.12.19114
2058.78.12.192/288.78.12.193 to 8.78.12.2068.78.12.20714
2068.78.12.208/288.78.12.209 to 8.78.12.2228.78.12.22314
2078.78.12.224/288.78.12.225 to 8.78.12.2388.78.12.23914
2088.78.12.240/288.78.12.241 to 8.78.12.2548.78.12.25514
2098.78.13.0/288.78.13.1 to 8.78.13.148.78.13.1514
2108.78.13.16/288.78.13.17 to 8.78.13.308.78.13.3114
2118.78.13.32/288.78.13.33 to 8.78.13.468.78.13.4714
2128.78.13.48/288.78.13.49 to 8.78.13.628.78.13.6314
2138.78.13.64/288.78.13.65 to 8.78.13.788.78.13.7914
2148.78.13.80/288.78.13.81 to 8.78.13.948.78.13.9514
2158.78.13.96/288.78.13.97 to 8.78.13.1108.78.13.11114
2168.78.13.112/288.78.13.113 to 8.78.13.1268.78.13.12714
2178.78.13.128/288.78.13.129 to 8.78.13.1428.78.13.14314
2188.78.13.144/288.78.13.145 to 8.78.13.1588.78.13.15914
2198.78.13.160/288.78.13.161 to 8.78.13.1748.78.13.17514
2208.78.13.176/288.78.13.177 to 8.78.13.1908.78.13.19114
2218.78.13.192/288.78.13.193 to 8.78.13.2068.78.13.20714
2228.78.13.208/288.78.13.209 to 8.78.13.2228.78.13.22314
2238.78.13.224/288.78.13.225 to 8.78.13.2388.78.13.23914
2248.78.13.240/288.78.13.241 to 8.78.13.2548.78.13.25514
2258.78.14.0/288.78.14.1 to 8.78.14.148.78.14.1514
2268.78.14.16/288.78.14.17 to 8.78.14.308.78.14.3114
2278.78.14.32/288.78.14.33 to 8.78.14.468.78.14.4714
2288.78.14.48/288.78.14.49 to 8.78.14.628.78.14.6314
2298.78.14.64/288.78.14.65 to 8.78.14.788.78.14.7914
2308.78.14.80/288.78.14.81 to 8.78.14.948.78.14.9514
2318.78.14.96/288.78.14.97 to 8.78.14.1108.78.14.11114
2328.78.14.112/288.78.14.113 to 8.78.14.1268.78.14.12714
2338.78.14.128/288.78.14.129 to 8.78.14.1428.78.14.14314
2348.78.14.144/288.78.14.145 to 8.78.14.1588.78.14.15914
2358.78.14.160/288.78.14.161 to 8.78.14.1748.78.14.17514
2368.78.14.176/288.78.14.177 to 8.78.14.1908.78.14.19114
2378.78.14.192/288.78.14.193 to 8.78.14.2068.78.14.20714
2388.78.14.208/288.78.14.209 to 8.78.14.2228.78.14.22314
2398.78.14.224/288.78.14.225 to 8.78.14.2388.78.14.23914
2408.78.14.240/288.78.14.241 to 8.78.14.2548.78.14.25514
2418.78.15.0/288.78.15.1 to 8.78.15.148.78.15.1514
2428.78.15.16/288.78.15.17 to 8.78.15.308.78.15.3114
2438.78.15.32/288.78.15.33 to 8.78.15.468.78.15.4714
2448.78.15.48/288.78.15.49 to 8.78.15.628.78.15.6314
2458.78.15.64/288.78.15.65 to 8.78.15.788.78.15.7914
2468.78.15.80/288.78.15.81 to 8.78.15.948.78.15.9514
2478.78.15.96/288.78.15.97 to 8.78.15.1108.78.15.11114
2488.78.15.112/288.78.15.113 to 8.78.15.1268.78.15.12714
2498.78.15.128/288.78.15.129 to 8.78.15.1428.78.15.14314
2508.78.15.144/288.78.15.145 to 8.78.15.1588.78.15.15914
2518.78.15.160/288.78.15.161 to 8.78.15.1748.78.15.17514
2528.78.15.176/288.78.15.177 to 8.78.15.1908.78.15.19114
2538.78.15.192/288.78.15.193 to 8.78.15.2068.78.15.20714
2548.78.15.208/288.78.15.209 to 8.78.15.2228.78.15.22314
2558.78.15.224/288.78.15.225 to 8.78.15.2388.78.15.23914
2568.78.15.240/288.78.15.241 to 8.78.15.2548.78.15.25514

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.