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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.

Network8.58.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
8.58.0.0
Broadcast address
8.58.63.255
First usable
8.58.0.1
Last usable
8.58.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 083A0000 · Integer 138018816 to 138035199
Reverse DNS zones
0.58.8.in-addr.arpa
1.58.8.in-addr.arpa
2.58.8.in-addr.arpa
3.58.8.in-addr.arpa
4.58.8.in-addr.arpa
5.58.8.in-addr.arpa
6.58.8.in-addr.arpa
7.58.8.in-addr.arpa
8.58.8.in-addr.arpa
9.58.8.in-addr.arpa
10.58.8.in-addr.arpa
11.58.8.in-addr.arpa
12.58.8.in-addr.arpa
13.58.8.in-addr.arpa
14.58.8.in-addr.arpa
15.58.8.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001000.00111010.00000000.000000008.58.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00001000.00111010.00000000.000000008.58.0.0
Broadcast00001000.00111010.00111111.111111118.58.63.255
Split into smaller subnets/29
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

8.58.0.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
18.58.0.0/298.58.0.1 to 8.58.0.68.58.0.76
28.58.0.8/298.58.0.9 to 8.58.0.148.58.0.156
38.58.0.16/298.58.0.17 to 8.58.0.228.58.0.236
48.58.0.24/298.58.0.25 to 8.58.0.308.58.0.316
58.58.0.32/298.58.0.33 to 8.58.0.388.58.0.396
68.58.0.40/298.58.0.41 to 8.58.0.468.58.0.476
78.58.0.48/298.58.0.49 to 8.58.0.548.58.0.556
88.58.0.56/298.58.0.57 to 8.58.0.628.58.0.636
98.58.0.64/298.58.0.65 to 8.58.0.708.58.0.716
108.58.0.72/298.58.0.73 to 8.58.0.788.58.0.796
118.58.0.80/298.58.0.81 to 8.58.0.868.58.0.876
128.58.0.88/298.58.0.89 to 8.58.0.948.58.0.956
138.58.0.96/298.58.0.97 to 8.58.0.1028.58.0.1036
148.58.0.104/298.58.0.105 to 8.58.0.1108.58.0.1116
158.58.0.112/298.58.0.113 to 8.58.0.1188.58.0.1196
168.58.0.120/298.58.0.121 to 8.58.0.1268.58.0.1276
178.58.0.128/298.58.0.129 to 8.58.0.1348.58.0.1356
188.58.0.136/298.58.0.137 to 8.58.0.1428.58.0.1436
198.58.0.144/298.58.0.145 to 8.58.0.1508.58.0.1516
208.58.0.152/298.58.0.153 to 8.58.0.1588.58.0.1596
218.58.0.160/298.58.0.161 to 8.58.0.1668.58.0.1676
228.58.0.168/298.58.0.169 to 8.58.0.1748.58.0.1756
238.58.0.176/298.58.0.177 to 8.58.0.1828.58.0.1836
248.58.0.184/298.58.0.185 to 8.58.0.1908.58.0.1916
258.58.0.192/298.58.0.193 to 8.58.0.1988.58.0.1996
268.58.0.200/298.58.0.201 to 8.58.0.2068.58.0.2076
278.58.0.208/298.58.0.209 to 8.58.0.2148.58.0.2156
288.58.0.216/298.58.0.217 to 8.58.0.2228.58.0.2236
298.58.0.224/298.58.0.225 to 8.58.0.2308.58.0.2316
308.58.0.232/298.58.0.233 to 8.58.0.2388.58.0.2396
318.58.0.240/298.58.0.241 to 8.58.0.2468.58.0.2476
328.58.0.248/298.58.0.249 to 8.58.0.2548.58.0.2556
338.58.1.0/298.58.1.1 to 8.58.1.68.58.1.76
348.58.1.8/298.58.1.9 to 8.58.1.148.58.1.156
358.58.1.16/298.58.1.17 to 8.58.1.228.58.1.236
368.58.1.24/298.58.1.25 to 8.58.1.308.58.1.316
378.58.1.32/298.58.1.33 to 8.58.1.388.58.1.396
388.58.1.40/298.58.1.41 to 8.58.1.468.58.1.476
398.58.1.48/298.58.1.49 to 8.58.1.548.58.1.556
408.58.1.56/298.58.1.57 to 8.58.1.628.58.1.636
418.58.1.64/298.58.1.65 to 8.58.1.708.58.1.716
428.58.1.72/298.58.1.73 to 8.58.1.788.58.1.796
438.58.1.80/298.58.1.81 to 8.58.1.868.58.1.876
448.58.1.88/298.58.1.89 to 8.58.1.948.58.1.956
458.58.1.96/298.58.1.97 to 8.58.1.1028.58.1.1036
468.58.1.104/298.58.1.105 to 8.58.1.1108.58.1.1116
478.58.1.112/298.58.1.113 to 8.58.1.1188.58.1.1196
488.58.1.120/298.58.1.121 to 8.58.1.1268.58.1.1276
498.58.1.128/298.58.1.129 to 8.58.1.1348.58.1.1356
508.58.1.136/298.58.1.137 to 8.58.1.1428.58.1.1436
518.58.1.144/298.58.1.145 to 8.58.1.1508.58.1.1516
528.58.1.152/298.58.1.153 to 8.58.1.1588.58.1.1596
538.58.1.160/298.58.1.161 to 8.58.1.1668.58.1.1676
548.58.1.168/298.58.1.169 to 8.58.1.1748.58.1.1756
558.58.1.176/298.58.1.177 to 8.58.1.1828.58.1.1836
568.58.1.184/298.58.1.185 to 8.58.1.1908.58.1.1916
578.58.1.192/298.58.1.193 to 8.58.1.1988.58.1.1996
588.58.1.200/298.58.1.201 to 8.58.1.2068.58.1.2076
598.58.1.208/298.58.1.209 to 8.58.1.2148.58.1.2156
608.58.1.216/298.58.1.217 to 8.58.1.2228.58.1.2236
618.58.1.224/298.58.1.225 to 8.58.1.2308.58.1.2316
628.58.1.232/298.58.1.233 to 8.58.1.2388.58.1.2396
638.58.1.240/298.58.1.241 to 8.58.1.2468.58.1.2476
648.58.1.248/298.58.1.249 to 8.58.1.2548.58.1.2556
658.58.2.0/298.58.2.1 to 8.58.2.68.58.2.76
668.58.2.8/298.58.2.9 to 8.58.2.148.58.2.156
678.58.2.16/298.58.2.17 to 8.58.2.228.58.2.236
688.58.2.24/298.58.2.25 to 8.58.2.308.58.2.316
698.58.2.32/298.58.2.33 to 8.58.2.388.58.2.396
708.58.2.40/298.58.2.41 to 8.58.2.468.58.2.476
718.58.2.48/298.58.2.49 to 8.58.2.548.58.2.556
728.58.2.56/298.58.2.57 to 8.58.2.628.58.2.636
738.58.2.64/298.58.2.65 to 8.58.2.708.58.2.716
748.58.2.72/298.58.2.73 to 8.58.2.788.58.2.796
758.58.2.80/298.58.2.81 to 8.58.2.868.58.2.876
768.58.2.88/298.58.2.89 to 8.58.2.948.58.2.956
778.58.2.96/298.58.2.97 to 8.58.2.1028.58.2.1036
788.58.2.104/298.58.2.105 to 8.58.2.1108.58.2.1116
798.58.2.112/298.58.2.113 to 8.58.2.1188.58.2.1196
808.58.2.120/298.58.2.121 to 8.58.2.1268.58.2.1276
818.58.2.128/298.58.2.129 to 8.58.2.1348.58.2.1356
828.58.2.136/298.58.2.137 to 8.58.2.1428.58.2.1436
838.58.2.144/298.58.2.145 to 8.58.2.1508.58.2.1516
848.58.2.152/298.58.2.153 to 8.58.2.1588.58.2.1596
858.58.2.160/298.58.2.161 to 8.58.2.1668.58.2.1676
868.58.2.168/298.58.2.169 to 8.58.2.1748.58.2.1756
878.58.2.176/298.58.2.177 to 8.58.2.1828.58.2.1836
888.58.2.184/298.58.2.185 to 8.58.2.1908.58.2.1916
898.58.2.192/298.58.2.193 to 8.58.2.1988.58.2.1996
908.58.2.200/298.58.2.201 to 8.58.2.2068.58.2.2076
918.58.2.208/298.58.2.209 to 8.58.2.2148.58.2.2156
928.58.2.216/298.58.2.217 to 8.58.2.2228.58.2.2236
938.58.2.224/298.58.2.225 to 8.58.2.2308.58.2.2316
948.58.2.232/298.58.2.233 to 8.58.2.2388.58.2.2396
958.58.2.240/298.58.2.241 to 8.58.2.2468.58.2.2476
968.58.2.248/298.58.2.249 to 8.58.2.2548.58.2.2556
978.58.3.0/298.58.3.1 to 8.58.3.68.58.3.76
988.58.3.8/298.58.3.9 to 8.58.3.148.58.3.156
998.58.3.16/298.58.3.17 to 8.58.3.228.58.3.236
1008.58.3.24/298.58.3.25 to 8.58.3.308.58.3.316
1018.58.3.32/298.58.3.33 to 8.58.3.388.58.3.396
1028.58.3.40/298.58.3.41 to 8.58.3.468.58.3.476
1038.58.3.48/298.58.3.49 to 8.58.3.548.58.3.556
1048.58.3.56/298.58.3.57 to 8.58.3.628.58.3.636
1058.58.3.64/298.58.3.65 to 8.58.3.708.58.3.716
1068.58.3.72/298.58.3.73 to 8.58.3.788.58.3.796
1078.58.3.80/298.58.3.81 to 8.58.3.868.58.3.876
1088.58.3.88/298.58.3.89 to 8.58.3.948.58.3.956
1098.58.3.96/298.58.3.97 to 8.58.3.1028.58.3.1036
1108.58.3.104/298.58.3.105 to 8.58.3.1108.58.3.1116
1118.58.3.112/298.58.3.113 to 8.58.3.1188.58.3.1196
1128.58.3.120/298.58.3.121 to 8.58.3.1268.58.3.1276
1138.58.3.128/298.58.3.129 to 8.58.3.1348.58.3.1356
1148.58.3.136/298.58.3.137 to 8.58.3.1428.58.3.1436
1158.58.3.144/298.58.3.145 to 8.58.3.1508.58.3.1516
1168.58.3.152/298.58.3.153 to 8.58.3.1588.58.3.1596
1178.58.3.160/298.58.3.161 to 8.58.3.1668.58.3.1676
1188.58.3.168/298.58.3.169 to 8.58.3.1748.58.3.1756
1198.58.3.176/298.58.3.177 to 8.58.3.1828.58.3.1836
1208.58.3.184/298.58.3.185 to 8.58.3.1908.58.3.1916
1218.58.3.192/298.58.3.193 to 8.58.3.1988.58.3.1996
1228.58.3.200/298.58.3.201 to 8.58.3.2068.58.3.2076
1238.58.3.208/298.58.3.209 to 8.58.3.2148.58.3.2156
1248.58.3.216/298.58.3.217 to 8.58.3.2228.58.3.2236
1258.58.3.224/298.58.3.225 to 8.58.3.2308.58.3.2316
1268.58.3.232/298.58.3.233 to 8.58.3.2388.58.3.2396
1278.58.3.240/298.58.3.241 to 8.58.3.2468.58.3.2476
1288.58.3.248/298.58.3.249 to 8.58.3.2548.58.3.2556
1298.58.4.0/298.58.4.1 to 8.58.4.68.58.4.76
1308.58.4.8/298.58.4.9 to 8.58.4.148.58.4.156
1318.58.4.16/298.58.4.17 to 8.58.4.228.58.4.236
1328.58.4.24/298.58.4.25 to 8.58.4.308.58.4.316
1338.58.4.32/298.58.4.33 to 8.58.4.388.58.4.396
1348.58.4.40/298.58.4.41 to 8.58.4.468.58.4.476
1358.58.4.48/298.58.4.49 to 8.58.4.548.58.4.556
1368.58.4.56/298.58.4.57 to 8.58.4.628.58.4.636
1378.58.4.64/298.58.4.65 to 8.58.4.708.58.4.716
1388.58.4.72/298.58.4.73 to 8.58.4.788.58.4.796
1398.58.4.80/298.58.4.81 to 8.58.4.868.58.4.876
1408.58.4.88/298.58.4.89 to 8.58.4.948.58.4.956
1418.58.4.96/298.58.4.97 to 8.58.4.1028.58.4.1036
1428.58.4.104/298.58.4.105 to 8.58.4.1108.58.4.1116
1438.58.4.112/298.58.4.113 to 8.58.4.1188.58.4.1196
1448.58.4.120/298.58.4.121 to 8.58.4.1268.58.4.1276
1458.58.4.128/298.58.4.129 to 8.58.4.1348.58.4.1356
1468.58.4.136/298.58.4.137 to 8.58.4.1428.58.4.1436
1478.58.4.144/298.58.4.145 to 8.58.4.1508.58.4.1516
1488.58.4.152/298.58.4.153 to 8.58.4.1588.58.4.1596
1498.58.4.160/298.58.4.161 to 8.58.4.1668.58.4.1676
1508.58.4.168/298.58.4.169 to 8.58.4.1748.58.4.1756
1518.58.4.176/298.58.4.177 to 8.58.4.1828.58.4.1836
1528.58.4.184/298.58.4.185 to 8.58.4.1908.58.4.1916
1538.58.4.192/298.58.4.193 to 8.58.4.1988.58.4.1996
1548.58.4.200/298.58.4.201 to 8.58.4.2068.58.4.2076
1558.58.4.208/298.58.4.209 to 8.58.4.2148.58.4.2156
1568.58.4.216/298.58.4.217 to 8.58.4.2228.58.4.2236
1578.58.4.224/298.58.4.225 to 8.58.4.2308.58.4.2316
1588.58.4.232/298.58.4.233 to 8.58.4.2388.58.4.2396
1598.58.4.240/298.58.4.241 to 8.58.4.2468.58.4.2476
1608.58.4.248/298.58.4.249 to 8.58.4.2548.58.4.2556
1618.58.5.0/298.58.5.1 to 8.58.5.68.58.5.76
1628.58.5.8/298.58.5.9 to 8.58.5.148.58.5.156
1638.58.5.16/298.58.5.17 to 8.58.5.228.58.5.236
1648.58.5.24/298.58.5.25 to 8.58.5.308.58.5.316
1658.58.5.32/298.58.5.33 to 8.58.5.388.58.5.396
1668.58.5.40/298.58.5.41 to 8.58.5.468.58.5.476
1678.58.5.48/298.58.5.49 to 8.58.5.548.58.5.556
1688.58.5.56/298.58.5.57 to 8.58.5.628.58.5.636
1698.58.5.64/298.58.5.65 to 8.58.5.708.58.5.716
1708.58.5.72/298.58.5.73 to 8.58.5.788.58.5.796
1718.58.5.80/298.58.5.81 to 8.58.5.868.58.5.876
1728.58.5.88/298.58.5.89 to 8.58.5.948.58.5.956
1738.58.5.96/298.58.5.97 to 8.58.5.1028.58.5.1036
1748.58.5.104/298.58.5.105 to 8.58.5.1108.58.5.1116
1758.58.5.112/298.58.5.113 to 8.58.5.1188.58.5.1196
1768.58.5.120/298.58.5.121 to 8.58.5.1268.58.5.1276
1778.58.5.128/298.58.5.129 to 8.58.5.1348.58.5.1356
1788.58.5.136/298.58.5.137 to 8.58.5.1428.58.5.1436
1798.58.5.144/298.58.5.145 to 8.58.5.1508.58.5.1516
1808.58.5.152/298.58.5.153 to 8.58.5.1588.58.5.1596
1818.58.5.160/298.58.5.161 to 8.58.5.1668.58.5.1676
1828.58.5.168/298.58.5.169 to 8.58.5.1748.58.5.1756
1838.58.5.176/298.58.5.177 to 8.58.5.1828.58.5.1836
1848.58.5.184/298.58.5.185 to 8.58.5.1908.58.5.1916
1858.58.5.192/298.58.5.193 to 8.58.5.1988.58.5.1996
1868.58.5.200/298.58.5.201 to 8.58.5.2068.58.5.2076
1878.58.5.208/298.58.5.209 to 8.58.5.2148.58.5.2156
1888.58.5.216/298.58.5.217 to 8.58.5.2228.58.5.2236
1898.58.5.224/298.58.5.225 to 8.58.5.2308.58.5.2316
1908.58.5.232/298.58.5.233 to 8.58.5.2388.58.5.2396
1918.58.5.240/298.58.5.241 to 8.58.5.2468.58.5.2476
1928.58.5.248/298.58.5.249 to 8.58.5.2548.58.5.2556
1938.58.6.0/298.58.6.1 to 8.58.6.68.58.6.76
1948.58.6.8/298.58.6.9 to 8.58.6.148.58.6.156
1958.58.6.16/298.58.6.17 to 8.58.6.228.58.6.236
1968.58.6.24/298.58.6.25 to 8.58.6.308.58.6.316
1978.58.6.32/298.58.6.33 to 8.58.6.388.58.6.396
1988.58.6.40/298.58.6.41 to 8.58.6.468.58.6.476
1998.58.6.48/298.58.6.49 to 8.58.6.548.58.6.556
2008.58.6.56/298.58.6.57 to 8.58.6.628.58.6.636
2018.58.6.64/298.58.6.65 to 8.58.6.708.58.6.716
2028.58.6.72/298.58.6.73 to 8.58.6.788.58.6.796
2038.58.6.80/298.58.6.81 to 8.58.6.868.58.6.876
2048.58.6.88/298.58.6.89 to 8.58.6.948.58.6.956
2058.58.6.96/298.58.6.97 to 8.58.6.1028.58.6.1036
2068.58.6.104/298.58.6.105 to 8.58.6.1108.58.6.1116
2078.58.6.112/298.58.6.113 to 8.58.6.1188.58.6.1196
2088.58.6.120/298.58.6.121 to 8.58.6.1268.58.6.1276
2098.58.6.128/298.58.6.129 to 8.58.6.1348.58.6.1356
2108.58.6.136/298.58.6.137 to 8.58.6.1428.58.6.1436
2118.58.6.144/298.58.6.145 to 8.58.6.1508.58.6.1516
2128.58.6.152/298.58.6.153 to 8.58.6.1588.58.6.1596
2138.58.6.160/298.58.6.161 to 8.58.6.1668.58.6.1676
2148.58.6.168/298.58.6.169 to 8.58.6.1748.58.6.1756
2158.58.6.176/298.58.6.177 to 8.58.6.1828.58.6.1836
2168.58.6.184/298.58.6.185 to 8.58.6.1908.58.6.1916
2178.58.6.192/298.58.6.193 to 8.58.6.1988.58.6.1996
2188.58.6.200/298.58.6.201 to 8.58.6.2068.58.6.2076
2198.58.6.208/298.58.6.209 to 8.58.6.2148.58.6.2156
2208.58.6.216/298.58.6.217 to 8.58.6.2228.58.6.2236
2218.58.6.224/298.58.6.225 to 8.58.6.2308.58.6.2316
2228.58.6.232/298.58.6.233 to 8.58.6.2388.58.6.2396
2238.58.6.240/298.58.6.241 to 8.58.6.2468.58.6.2476
2248.58.6.248/298.58.6.249 to 8.58.6.2548.58.6.2556
2258.58.7.0/298.58.7.1 to 8.58.7.68.58.7.76
2268.58.7.8/298.58.7.9 to 8.58.7.148.58.7.156
2278.58.7.16/298.58.7.17 to 8.58.7.228.58.7.236
2288.58.7.24/298.58.7.25 to 8.58.7.308.58.7.316
2298.58.7.32/298.58.7.33 to 8.58.7.388.58.7.396
2308.58.7.40/298.58.7.41 to 8.58.7.468.58.7.476
2318.58.7.48/298.58.7.49 to 8.58.7.548.58.7.556
2328.58.7.56/298.58.7.57 to 8.58.7.628.58.7.636
2338.58.7.64/298.58.7.65 to 8.58.7.708.58.7.716
2348.58.7.72/298.58.7.73 to 8.58.7.788.58.7.796
2358.58.7.80/298.58.7.81 to 8.58.7.868.58.7.876
2368.58.7.88/298.58.7.89 to 8.58.7.948.58.7.956
2378.58.7.96/298.58.7.97 to 8.58.7.1028.58.7.1036
2388.58.7.104/298.58.7.105 to 8.58.7.1108.58.7.1116
2398.58.7.112/298.58.7.113 to 8.58.7.1188.58.7.1196
2408.58.7.120/298.58.7.121 to 8.58.7.1268.58.7.1276
2418.58.7.128/298.58.7.129 to 8.58.7.1348.58.7.1356
2428.58.7.136/298.58.7.137 to 8.58.7.1428.58.7.1436
2438.58.7.144/298.58.7.145 to 8.58.7.1508.58.7.1516
2448.58.7.152/298.58.7.153 to 8.58.7.1588.58.7.1596
2458.58.7.160/298.58.7.161 to 8.58.7.1668.58.7.1676
2468.58.7.168/298.58.7.169 to 8.58.7.1748.58.7.1756
2478.58.7.176/298.58.7.177 to 8.58.7.1828.58.7.1836
2488.58.7.184/298.58.7.185 to 8.58.7.1908.58.7.1916
2498.58.7.192/298.58.7.193 to 8.58.7.1988.58.7.1996
2508.58.7.200/298.58.7.201 to 8.58.7.2068.58.7.2076
2518.58.7.208/298.58.7.209 to 8.58.7.2148.58.7.2156
2528.58.7.216/298.58.7.217 to 8.58.7.2228.58.7.2236
2538.58.7.224/298.58.7.225 to 8.58.7.2308.58.7.2316
2548.58.7.232/298.58.7.233 to 8.58.7.2388.58.7.2396
2558.58.7.240/298.58.7.241 to 8.58.7.2468.58.7.2476
2568.58.7.248/298.58.7.249 to 8.58.7.2548.58.7.2556

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.