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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.

Network6.167.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
6.167.0.0
Broadcast address
6.167.127.255
First usable
6.167.0.1
Last usable
6.167.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 06A70000 · Integer 111607808 to 111640575
Reverse DNS zones
0.167.6.in-addr.arpa
1.167.6.in-addr.arpa
2.167.6.in-addr.arpa
3.167.6.in-addr.arpa
4.167.6.in-addr.arpa
5.167.6.in-addr.arpa
6.167.6.in-addr.arpa
7.167.6.in-addr.arpa
8.167.6.in-addr.arpa
9.167.6.in-addr.arpa
10.167.6.in-addr.arpa
11.167.6.in-addr.arpa
12.167.6.in-addr.arpa
13.167.6.in-addr.arpa
14.167.6.in-addr.arpa
15.167.6.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000110.10100111.00000000.000000006.167.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00000110.10100111.00000000.000000006.167.0.0
Broadcast00000110.10100111.01111111.111111116.167.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

6.167.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.167.0.0/286.167.0.1 to 6.167.0.146.167.0.1514
26.167.0.16/286.167.0.17 to 6.167.0.306.167.0.3114
36.167.0.32/286.167.0.33 to 6.167.0.466.167.0.4714
46.167.0.48/286.167.0.49 to 6.167.0.626.167.0.6314
56.167.0.64/286.167.0.65 to 6.167.0.786.167.0.7914
66.167.0.80/286.167.0.81 to 6.167.0.946.167.0.9514
76.167.0.96/286.167.0.97 to 6.167.0.1106.167.0.11114
86.167.0.112/286.167.0.113 to 6.167.0.1266.167.0.12714
96.167.0.128/286.167.0.129 to 6.167.0.1426.167.0.14314
106.167.0.144/286.167.0.145 to 6.167.0.1586.167.0.15914
116.167.0.160/286.167.0.161 to 6.167.0.1746.167.0.17514
126.167.0.176/286.167.0.177 to 6.167.0.1906.167.0.19114
136.167.0.192/286.167.0.193 to 6.167.0.2066.167.0.20714
146.167.0.208/286.167.0.209 to 6.167.0.2226.167.0.22314
156.167.0.224/286.167.0.225 to 6.167.0.2386.167.0.23914
166.167.0.240/286.167.0.241 to 6.167.0.2546.167.0.25514
176.167.1.0/286.167.1.1 to 6.167.1.146.167.1.1514
186.167.1.16/286.167.1.17 to 6.167.1.306.167.1.3114
196.167.1.32/286.167.1.33 to 6.167.1.466.167.1.4714
206.167.1.48/286.167.1.49 to 6.167.1.626.167.1.6314
216.167.1.64/286.167.1.65 to 6.167.1.786.167.1.7914
226.167.1.80/286.167.1.81 to 6.167.1.946.167.1.9514
236.167.1.96/286.167.1.97 to 6.167.1.1106.167.1.11114
246.167.1.112/286.167.1.113 to 6.167.1.1266.167.1.12714
256.167.1.128/286.167.1.129 to 6.167.1.1426.167.1.14314
266.167.1.144/286.167.1.145 to 6.167.1.1586.167.1.15914
276.167.1.160/286.167.1.161 to 6.167.1.1746.167.1.17514
286.167.1.176/286.167.1.177 to 6.167.1.1906.167.1.19114
296.167.1.192/286.167.1.193 to 6.167.1.2066.167.1.20714
306.167.1.208/286.167.1.209 to 6.167.1.2226.167.1.22314
316.167.1.224/286.167.1.225 to 6.167.1.2386.167.1.23914
326.167.1.240/286.167.1.241 to 6.167.1.2546.167.1.25514
336.167.2.0/286.167.2.1 to 6.167.2.146.167.2.1514
346.167.2.16/286.167.2.17 to 6.167.2.306.167.2.3114
356.167.2.32/286.167.2.33 to 6.167.2.466.167.2.4714
366.167.2.48/286.167.2.49 to 6.167.2.626.167.2.6314
376.167.2.64/286.167.2.65 to 6.167.2.786.167.2.7914
386.167.2.80/286.167.2.81 to 6.167.2.946.167.2.9514
396.167.2.96/286.167.2.97 to 6.167.2.1106.167.2.11114
406.167.2.112/286.167.2.113 to 6.167.2.1266.167.2.12714
416.167.2.128/286.167.2.129 to 6.167.2.1426.167.2.14314
426.167.2.144/286.167.2.145 to 6.167.2.1586.167.2.15914
436.167.2.160/286.167.2.161 to 6.167.2.1746.167.2.17514
446.167.2.176/286.167.2.177 to 6.167.2.1906.167.2.19114
456.167.2.192/286.167.2.193 to 6.167.2.2066.167.2.20714
466.167.2.208/286.167.2.209 to 6.167.2.2226.167.2.22314
476.167.2.224/286.167.2.225 to 6.167.2.2386.167.2.23914
486.167.2.240/286.167.2.241 to 6.167.2.2546.167.2.25514
496.167.3.0/286.167.3.1 to 6.167.3.146.167.3.1514
506.167.3.16/286.167.3.17 to 6.167.3.306.167.3.3114
516.167.3.32/286.167.3.33 to 6.167.3.466.167.3.4714
526.167.3.48/286.167.3.49 to 6.167.3.626.167.3.6314
536.167.3.64/286.167.3.65 to 6.167.3.786.167.3.7914
546.167.3.80/286.167.3.81 to 6.167.3.946.167.3.9514
556.167.3.96/286.167.3.97 to 6.167.3.1106.167.3.11114
566.167.3.112/286.167.3.113 to 6.167.3.1266.167.3.12714
576.167.3.128/286.167.3.129 to 6.167.3.1426.167.3.14314
586.167.3.144/286.167.3.145 to 6.167.3.1586.167.3.15914
596.167.3.160/286.167.3.161 to 6.167.3.1746.167.3.17514
606.167.3.176/286.167.3.177 to 6.167.3.1906.167.3.19114
616.167.3.192/286.167.3.193 to 6.167.3.2066.167.3.20714
626.167.3.208/286.167.3.209 to 6.167.3.2226.167.3.22314
636.167.3.224/286.167.3.225 to 6.167.3.2386.167.3.23914
646.167.3.240/286.167.3.241 to 6.167.3.2546.167.3.25514
656.167.4.0/286.167.4.1 to 6.167.4.146.167.4.1514
666.167.4.16/286.167.4.17 to 6.167.4.306.167.4.3114
676.167.4.32/286.167.4.33 to 6.167.4.466.167.4.4714
686.167.4.48/286.167.4.49 to 6.167.4.626.167.4.6314
696.167.4.64/286.167.4.65 to 6.167.4.786.167.4.7914
706.167.4.80/286.167.4.81 to 6.167.4.946.167.4.9514
716.167.4.96/286.167.4.97 to 6.167.4.1106.167.4.11114
726.167.4.112/286.167.4.113 to 6.167.4.1266.167.4.12714
736.167.4.128/286.167.4.129 to 6.167.4.1426.167.4.14314
746.167.4.144/286.167.4.145 to 6.167.4.1586.167.4.15914
756.167.4.160/286.167.4.161 to 6.167.4.1746.167.4.17514
766.167.4.176/286.167.4.177 to 6.167.4.1906.167.4.19114
776.167.4.192/286.167.4.193 to 6.167.4.2066.167.4.20714
786.167.4.208/286.167.4.209 to 6.167.4.2226.167.4.22314
796.167.4.224/286.167.4.225 to 6.167.4.2386.167.4.23914
806.167.4.240/286.167.4.241 to 6.167.4.2546.167.4.25514
816.167.5.0/286.167.5.1 to 6.167.5.146.167.5.1514
826.167.5.16/286.167.5.17 to 6.167.5.306.167.5.3114
836.167.5.32/286.167.5.33 to 6.167.5.466.167.5.4714
846.167.5.48/286.167.5.49 to 6.167.5.626.167.5.6314
856.167.5.64/286.167.5.65 to 6.167.5.786.167.5.7914
866.167.5.80/286.167.5.81 to 6.167.5.946.167.5.9514
876.167.5.96/286.167.5.97 to 6.167.5.1106.167.5.11114
886.167.5.112/286.167.5.113 to 6.167.5.1266.167.5.12714
896.167.5.128/286.167.5.129 to 6.167.5.1426.167.5.14314
906.167.5.144/286.167.5.145 to 6.167.5.1586.167.5.15914
916.167.5.160/286.167.5.161 to 6.167.5.1746.167.5.17514
926.167.5.176/286.167.5.177 to 6.167.5.1906.167.5.19114
936.167.5.192/286.167.5.193 to 6.167.5.2066.167.5.20714
946.167.5.208/286.167.5.209 to 6.167.5.2226.167.5.22314
956.167.5.224/286.167.5.225 to 6.167.5.2386.167.5.23914
966.167.5.240/286.167.5.241 to 6.167.5.2546.167.5.25514
976.167.6.0/286.167.6.1 to 6.167.6.146.167.6.1514
986.167.6.16/286.167.6.17 to 6.167.6.306.167.6.3114
996.167.6.32/286.167.6.33 to 6.167.6.466.167.6.4714
1006.167.6.48/286.167.6.49 to 6.167.6.626.167.6.6314
1016.167.6.64/286.167.6.65 to 6.167.6.786.167.6.7914
1026.167.6.80/286.167.6.81 to 6.167.6.946.167.6.9514
1036.167.6.96/286.167.6.97 to 6.167.6.1106.167.6.11114
1046.167.6.112/286.167.6.113 to 6.167.6.1266.167.6.12714
1056.167.6.128/286.167.6.129 to 6.167.6.1426.167.6.14314
1066.167.6.144/286.167.6.145 to 6.167.6.1586.167.6.15914
1076.167.6.160/286.167.6.161 to 6.167.6.1746.167.6.17514
1086.167.6.176/286.167.6.177 to 6.167.6.1906.167.6.19114
1096.167.6.192/286.167.6.193 to 6.167.6.2066.167.6.20714
1106.167.6.208/286.167.6.209 to 6.167.6.2226.167.6.22314
1116.167.6.224/286.167.6.225 to 6.167.6.2386.167.6.23914
1126.167.6.240/286.167.6.241 to 6.167.6.2546.167.6.25514
1136.167.7.0/286.167.7.1 to 6.167.7.146.167.7.1514
1146.167.7.16/286.167.7.17 to 6.167.7.306.167.7.3114
1156.167.7.32/286.167.7.33 to 6.167.7.466.167.7.4714
1166.167.7.48/286.167.7.49 to 6.167.7.626.167.7.6314
1176.167.7.64/286.167.7.65 to 6.167.7.786.167.7.7914
1186.167.7.80/286.167.7.81 to 6.167.7.946.167.7.9514
1196.167.7.96/286.167.7.97 to 6.167.7.1106.167.7.11114
1206.167.7.112/286.167.7.113 to 6.167.7.1266.167.7.12714
1216.167.7.128/286.167.7.129 to 6.167.7.1426.167.7.14314
1226.167.7.144/286.167.7.145 to 6.167.7.1586.167.7.15914
1236.167.7.160/286.167.7.161 to 6.167.7.1746.167.7.17514
1246.167.7.176/286.167.7.177 to 6.167.7.1906.167.7.19114
1256.167.7.192/286.167.7.193 to 6.167.7.2066.167.7.20714
1266.167.7.208/286.167.7.209 to 6.167.7.2226.167.7.22314
1276.167.7.224/286.167.7.225 to 6.167.7.2386.167.7.23914
1286.167.7.240/286.167.7.241 to 6.167.7.2546.167.7.25514
1296.167.8.0/286.167.8.1 to 6.167.8.146.167.8.1514
1306.167.8.16/286.167.8.17 to 6.167.8.306.167.8.3114
1316.167.8.32/286.167.8.33 to 6.167.8.466.167.8.4714
1326.167.8.48/286.167.8.49 to 6.167.8.626.167.8.6314
1336.167.8.64/286.167.8.65 to 6.167.8.786.167.8.7914
1346.167.8.80/286.167.8.81 to 6.167.8.946.167.8.9514
1356.167.8.96/286.167.8.97 to 6.167.8.1106.167.8.11114
1366.167.8.112/286.167.8.113 to 6.167.8.1266.167.8.12714
1376.167.8.128/286.167.8.129 to 6.167.8.1426.167.8.14314
1386.167.8.144/286.167.8.145 to 6.167.8.1586.167.8.15914
1396.167.8.160/286.167.8.161 to 6.167.8.1746.167.8.17514
1406.167.8.176/286.167.8.177 to 6.167.8.1906.167.8.19114
1416.167.8.192/286.167.8.193 to 6.167.8.2066.167.8.20714
1426.167.8.208/286.167.8.209 to 6.167.8.2226.167.8.22314
1436.167.8.224/286.167.8.225 to 6.167.8.2386.167.8.23914
1446.167.8.240/286.167.8.241 to 6.167.8.2546.167.8.25514
1456.167.9.0/286.167.9.1 to 6.167.9.146.167.9.1514
1466.167.9.16/286.167.9.17 to 6.167.9.306.167.9.3114
1476.167.9.32/286.167.9.33 to 6.167.9.466.167.9.4714
1486.167.9.48/286.167.9.49 to 6.167.9.626.167.9.6314
1496.167.9.64/286.167.9.65 to 6.167.9.786.167.9.7914
1506.167.9.80/286.167.9.81 to 6.167.9.946.167.9.9514
1516.167.9.96/286.167.9.97 to 6.167.9.1106.167.9.11114
1526.167.9.112/286.167.9.113 to 6.167.9.1266.167.9.12714
1536.167.9.128/286.167.9.129 to 6.167.9.1426.167.9.14314
1546.167.9.144/286.167.9.145 to 6.167.9.1586.167.9.15914
1556.167.9.160/286.167.9.161 to 6.167.9.1746.167.9.17514
1566.167.9.176/286.167.9.177 to 6.167.9.1906.167.9.19114
1576.167.9.192/286.167.9.193 to 6.167.9.2066.167.9.20714
1586.167.9.208/286.167.9.209 to 6.167.9.2226.167.9.22314
1596.167.9.224/286.167.9.225 to 6.167.9.2386.167.9.23914
1606.167.9.240/286.167.9.241 to 6.167.9.2546.167.9.25514
1616.167.10.0/286.167.10.1 to 6.167.10.146.167.10.1514
1626.167.10.16/286.167.10.17 to 6.167.10.306.167.10.3114
1636.167.10.32/286.167.10.33 to 6.167.10.466.167.10.4714
1646.167.10.48/286.167.10.49 to 6.167.10.626.167.10.6314
1656.167.10.64/286.167.10.65 to 6.167.10.786.167.10.7914
1666.167.10.80/286.167.10.81 to 6.167.10.946.167.10.9514
1676.167.10.96/286.167.10.97 to 6.167.10.1106.167.10.11114
1686.167.10.112/286.167.10.113 to 6.167.10.1266.167.10.12714
1696.167.10.128/286.167.10.129 to 6.167.10.1426.167.10.14314
1706.167.10.144/286.167.10.145 to 6.167.10.1586.167.10.15914
1716.167.10.160/286.167.10.161 to 6.167.10.1746.167.10.17514
1726.167.10.176/286.167.10.177 to 6.167.10.1906.167.10.19114
1736.167.10.192/286.167.10.193 to 6.167.10.2066.167.10.20714
1746.167.10.208/286.167.10.209 to 6.167.10.2226.167.10.22314
1756.167.10.224/286.167.10.225 to 6.167.10.2386.167.10.23914
1766.167.10.240/286.167.10.241 to 6.167.10.2546.167.10.25514
1776.167.11.0/286.167.11.1 to 6.167.11.146.167.11.1514
1786.167.11.16/286.167.11.17 to 6.167.11.306.167.11.3114
1796.167.11.32/286.167.11.33 to 6.167.11.466.167.11.4714
1806.167.11.48/286.167.11.49 to 6.167.11.626.167.11.6314
1816.167.11.64/286.167.11.65 to 6.167.11.786.167.11.7914
1826.167.11.80/286.167.11.81 to 6.167.11.946.167.11.9514
1836.167.11.96/286.167.11.97 to 6.167.11.1106.167.11.11114
1846.167.11.112/286.167.11.113 to 6.167.11.1266.167.11.12714
1856.167.11.128/286.167.11.129 to 6.167.11.1426.167.11.14314
1866.167.11.144/286.167.11.145 to 6.167.11.1586.167.11.15914
1876.167.11.160/286.167.11.161 to 6.167.11.1746.167.11.17514
1886.167.11.176/286.167.11.177 to 6.167.11.1906.167.11.19114
1896.167.11.192/286.167.11.193 to 6.167.11.2066.167.11.20714
1906.167.11.208/286.167.11.209 to 6.167.11.2226.167.11.22314
1916.167.11.224/286.167.11.225 to 6.167.11.2386.167.11.23914
1926.167.11.240/286.167.11.241 to 6.167.11.2546.167.11.25514
1936.167.12.0/286.167.12.1 to 6.167.12.146.167.12.1514
1946.167.12.16/286.167.12.17 to 6.167.12.306.167.12.3114
1956.167.12.32/286.167.12.33 to 6.167.12.466.167.12.4714
1966.167.12.48/286.167.12.49 to 6.167.12.626.167.12.6314
1976.167.12.64/286.167.12.65 to 6.167.12.786.167.12.7914
1986.167.12.80/286.167.12.81 to 6.167.12.946.167.12.9514
1996.167.12.96/286.167.12.97 to 6.167.12.1106.167.12.11114
2006.167.12.112/286.167.12.113 to 6.167.12.1266.167.12.12714
2016.167.12.128/286.167.12.129 to 6.167.12.1426.167.12.14314
2026.167.12.144/286.167.12.145 to 6.167.12.1586.167.12.15914
2036.167.12.160/286.167.12.161 to 6.167.12.1746.167.12.17514
2046.167.12.176/286.167.12.177 to 6.167.12.1906.167.12.19114
2056.167.12.192/286.167.12.193 to 6.167.12.2066.167.12.20714
2066.167.12.208/286.167.12.209 to 6.167.12.2226.167.12.22314
2076.167.12.224/286.167.12.225 to 6.167.12.2386.167.12.23914
2086.167.12.240/286.167.12.241 to 6.167.12.2546.167.12.25514
2096.167.13.0/286.167.13.1 to 6.167.13.146.167.13.1514
2106.167.13.16/286.167.13.17 to 6.167.13.306.167.13.3114
2116.167.13.32/286.167.13.33 to 6.167.13.466.167.13.4714
2126.167.13.48/286.167.13.49 to 6.167.13.626.167.13.6314
2136.167.13.64/286.167.13.65 to 6.167.13.786.167.13.7914
2146.167.13.80/286.167.13.81 to 6.167.13.946.167.13.9514
2156.167.13.96/286.167.13.97 to 6.167.13.1106.167.13.11114
2166.167.13.112/286.167.13.113 to 6.167.13.1266.167.13.12714
2176.167.13.128/286.167.13.129 to 6.167.13.1426.167.13.14314
2186.167.13.144/286.167.13.145 to 6.167.13.1586.167.13.15914
2196.167.13.160/286.167.13.161 to 6.167.13.1746.167.13.17514
2206.167.13.176/286.167.13.177 to 6.167.13.1906.167.13.19114
2216.167.13.192/286.167.13.193 to 6.167.13.2066.167.13.20714
2226.167.13.208/286.167.13.209 to 6.167.13.2226.167.13.22314
2236.167.13.224/286.167.13.225 to 6.167.13.2386.167.13.23914
2246.167.13.240/286.167.13.241 to 6.167.13.2546.167.13.25514
2256.167.14.0/286.167.14.1 to 6.167.14.146.167.14.1514
2266.167.14.16/286.167.14.17 to 6.167.14.306.167.14.3114
2276.167.14.32/286.167.14.33 to 6.167.14.466.167.14.4714
2286.167.14.48/286.167.14.49 to 6.167.14.626.167.14.6314
2296.167.14.64/286.167.14.65 to 6.167.14.786.167.14.7914
2306.167.14.80/286.167.14.81 to 6.167.14.946.167.14.9514
2316.167.14.96/286.167.14.97 to 6.167.14.1106.167.14.11114
2326.167.14.112/286.167.14.113 to 6.167.14.1266.167.14.12714
2336.167.14.128/286.167.14.129 to 6.167.14.1426.167.14.14314
2346.167.14.144/286.167.14.145 to 6.167.14.1586.167.14.15914
2356.167.14.160/286.167.14.161 to 6.167.14.1746.167.14.17514
2366.167.14.176/286.167.14.177 to 6.167.14.1906.167.14.19114
2376.167.14.192/286.167.14.193 to 6.167.14.2066.167.14.20714
2386.167.14.208/286.167.14.209 to 6.167.14.2226.167.14.22314
2396.167.14.224/286.167.14.225 to 6.167.14.2386.167.14.23914
2406.167.14.240/286.167.14.241 to 6.167.14.2546.167.14.25514
2416.167.15.0/286.167.15.1 to 6.167.15.146.167.15.1514
2426.167.15.16/286.167.15.17 to 6.167.15.306.167.15.3114
2436.167.15.32/286.167.15.33 to 6.167.15.466.167.15.4714
2446.167.15.48/286.167.15.49 to 6.167.15.626.167.15.6314
2456.167.15.64/286.167.15.65 to 6.167.15.786.167.15.7914
2466.167.15.80/286.167.15.81 to 6.167.15.946.167.15.9514
2476.167.15.96/286.167.15.97 to 6.167.15.1106.167.15.11114
2486.167.15.112/286.167.15.113 to 6.167.15.1266.167.15.12714
2496.167.15.128/286.167.15.129 to 6.167.15.1426.167.15.14314
2506.167.15.144/286.167.15.145 to 6.167.15.1586.167.15.15914
2516.167.15.160/286.167.15.161 to 6.167.15.1746.167.15.17514
2526.167.15.176/286.167.15.177 to 6.167.15.1906.167.15.19114
2536.167.15.192/286.167.15.193 to 6.167.15.2066.167.15.20714
2546.167.15.208/286.167.15.209 to 6.167.15.2226.167.15.22314
2556.167.15.224/286.167.15.225 to 6.167.15.2386.167.15.23914
2566.167.15.240/286.167.15.241 to 6.167.15.2546.167.15.25514

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.