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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.

Network9.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
9.78.0.0
Broadcast address
9.78.127.255
First usable
9.78.0.1
Last usable
9.78.127.254
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 094E0000 · Integer 156106752 to 156139519
Reverse DNS zones
0.78.9.in-addr.arpa
1.78.9.in-addr.arpa
2.78.9.in-addr.arpa
3.78.9.in-addr.arpa
4.78.9.in-addr.arpa
5.78.9.in-addr.arpa
6.78.9.in-addr.arpa
7.78.9.in-addr.arpa
8.78.9.in-addr.arpa
9.78.9.in-addr.arpa
10.78.9.in-addr.arpa
11.78.9.in-addr.arpa
12.78.9.in-addr.arpa
13.78.9.in-addr.arpa
14.78.9.in-addr.arpa
15.78.9.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
Address00001001.01001110.00000000.000000009.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00001001.01001110.00000000.000000009.78.0.0
Broadcast00001001.01001110.01111111.111111119.78.127.255
Split into smaller subnets/29
/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)

9.78.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
19.78.0.0/299.78.0.1 to 9.78.0.69.78.0.76
29.78.0.8/299.78.0.9 to 9.78.0.149.78.0.156
39.78.0.16/299.78.0.17 to 9.78.0.229.78.0.236
49.78.0.24/299.78.0.25 to 9.78.0.309.78.0.316
59.78.0.32/299.78.0.33 to 9.78.0.389.78.0.396
69.78.0.40/299.78.0.41 to 9.78.0.469.78.0.476
79.78.0.48/299.78.0.49 to 9.78.0.549.78.0.556
89.78.0.56/299.78.0.57 to 9.78.0.629.78.0.636
99.78.0.64/299.78.0.65 to 9.78.0.709.78.0.716
109.78.0.72/299.78.0.73 to 9.78.0.789.78.0.796
119.78.0.80/299.78.0.81 to 9.78.0.869.78.0.876
129.78.0.88/299.78.0.89 to 9.78.0.949.78.0.956
139.78.0.96/299.78.0.97 to 9.78.0.1029.78.0.1036
149.78.0.104/299.78.0.105 to 9.78.0.1109.78.0.1116
159.78.0.112/299.78.0.113 to 9.78.0.1189.78.0.1196
169.78.0.120/299.78.0.121 to 9.78.0.1269.78.0.1276
179.78.0.128/299.78.0.129 to 9.78.0.1349.78.0.1356
189.78.0.136/299.78.0.137 to 9.78.0.1429.78.0.1436
199.78.0.144/299.78.0.145 to 9.78.0.1509.78.0.1516
209.78.0.152/299.78.0.153 to 9.78.0.1589.78.0.1596
219.78.0.160/299.78.0.161 to 9.78.0.1669.78.0.1676
229.78.0.168/299.78.0.169 to 9.78.0.1749.78.0.1756
239.78.0.176/299.78.0.177 to 9.78.0.1829.78.0.1836
249.78.0.184/299.78.0.185 to 9.78.0.1909.78.0.1916
259.78.0.192/299.78.0.193 to 9.78.0.1989.78.0.1996
269.78.0.200/299.78.0.201 to 9.78.0.2069.78.0.2076
279.78.0.208/299.78.0.209 to 9.78.0.2149.78.0.2156
289.78.0.216/299.78.0.217 to 9.78.0.2229.78.0.2236
299.78.0.224/299.78.0.225 to 9.78.0.2309.78.0.2316
309.78.0.232/299.78.0.233 to 9.78.0.2389.78.0.2396
319.78.0.240/299.78.0.241 to 9.78.0.2469.78.0.2476
329.78.0.248/299.78.0.249 to 9.78.0.2549.78.0.2556
339.78.1.0/299.78.1.1 to 9.78.1.69.78.1.76
349.78.1.8/299.78.1.9 to 9.78.1.149.78.1.156
359.78.1.16/299.78.1.17 to 9.78.1.229.78.1.236
369.78.1.24/299.78.1.25 to 9.78.1.309.78.1.316
379.78.1.32/299.78.1.33 to 9.78.1.389.78.1.396
389.78.1.40/299.78.1.41 to 9.78.1.469.78.1.476
399.78.1.48/299.78.1.49 to 9.78.1.549.78.1.556
409.78.1.56/299.78.1.57 to 9.78.1.629.78.1.636
419.78.1.64/299.78.1.65 to 9.78.1.709.78.1.716
429.78.1.72/299.78.1.73 to 9.78.1.789.78.1.796
439.78.1.80/299.78.1.81 to 9.78.1.869.78.1.876
449.78.1.88/299.78.1.89 to 9.78.1.949.78.1.956
459.78.1.96/299.78.1.97 to 9.78.1.1029.78.1.1036
469.78.1.104/299.78.1.105 to 9.78.1.1109.78.1.1116
479.78.1.112/299.78.1.113 to 9.78.1.1189.78.1.1196
489.78.1.120/299.78.1.121 to 9.78.1.1269.78.1.1276
499.78.1.128/299.78.1.129 to 9.78.1.1349.78.1.1356
509.78.1.136/299.78.1.137 to 9.78.1.1429.78.1.1436
519.78.1.144/299.78.1.145 to 9.78.1.1509.78.1.1516
529.78.1.152/299.78.1.153 to 9.78.1.1589.78.1.1596
539.78.1.160/299.78.1.161 to 9.78.1.1669.78.1.1676
549.78.1.168/299.78.1.169 to 9.78.1.1749.78.1.1756
559.78.1.176/299.78.1.177 to 9.78.1.1829.78.1.1836
569.78.1.184/299.78.1.185 to 9.78.1.1909.78.1.1916
579.78.1.192/299.78.1.193 to 9.78.1.1989.78.1.1996
589.78.1.200/299.78.1.201 to 9.78.1.2069.78.1.2076
599.78.1.208/299.78.1.209 to 9.78.1.2149.78.1.2156
609.78.1.216/299.78.1.217 to 9.78.1.2229.78.1.2236
619.78.1.224/299.78.1.225 to 9.78.1.2309.78.1.2316
629.78.1.232/299.78.1.233 to 9.78.1.2389.78.1.2396
639.78.1.240/299.78.1.241 to 9.78.1.2469.78.1.2476
649.78.1.248/299.78.1.249 to 9.78.1.2549.78.1.2556
659.78.2.0/299.78.2.1 to 9.78.2.69.78.2.76
669.78.2.8/299.78.2.9 to 9.78.2.149.78.2.156
679.78.2.16/299.78.2.17 to 9.78.2.229.78.2.236
689.78.2.24/299.78.2.25 to 9.78.2.309.78.2.316
699.78.2.32/299.78.2.33 to 9.78.2.389.78.2.396
709.78.2.40/299.78.2.41 to 9.78.2.469.78.2.476
719.78.2.48/299.78.2.49 to 9.78.2.549.78.2.556
729.78.2.56/299.78.2.57 to 9.78.2.629.78.2.636
739.78.2.64/299.78.2.65 to 9.78.2.709.78.2.716
749.78.2.72/299.78.2.73 to 9.78.2.789.78.2.796
759.78.2.80/299.78.2.81 to 9.78.2.869.78.2.876
769.78.2.88/299.78.2.89 to 9.78.2.949.78.2.956
779.78.2.96/299.78.2.97 to 9.78.2.1029.78.2.1036
789.78.2.104/299.78.2.105 to 9.78.2.1109.78.2.1116
799.78.2.112/299.78.2.113 to 9.78.2.1189.78.2.1196
809.78.2.120/299.78.2.121 to 9.78.2.1269.78.2.1276
819.78.2.128/299.78.2.129 to 9.78.2.1349.78.2.1356
829.78.2.136/299.78.2.137 to 9.78.2.1429.78.2.1436
839.78.2.144/299.78.2.145 to 9.78.2.1509.78.2.1516
849.78.2.152/299.78.2.153 to 9.78.2.1589.78.2.1596
859.78.2.160/299.78.2.161 to 9.78.2.1669.78.2.1676
869.78.2.168/299.78.2.169 to 9.78.2.1749.78.2.1756
879.78.2.176/299.78.2.177 to 9.78.2.1829.78.2.1836
889.78.2.184/299.78.2.185 to 9.78.2.1909.78.2.1916
899.78.2.192/299.78.2.193 to 9.78.2.1989.78.2.1996
909.78.2.200/299.78.2.201 to 9.78.2.2069.78.2.2076
919.78.2.208/299.78.2.209 to 9.78.2.2149.78.2.2156
929.78.2.216/299.78.2.217 to 9.78.2.2229.78.2.2236
939.78.2.224/299.78.2.225 to 9.78.2.2309.78.2.2316
949.78.2.232/299.78.2.233 to 9.78.2.2389.78.2.2396
959.78.2.240/299.78.2.241 to 9.78.2.2469.78.2.2476
969.78.2.248/299.78.2.249 to 9.78.2.2549.78.2.2556
979.78.3.0/299.78.3.1 to 9.78.3.69.78.3.76
989.78.3.8/299.78.3.9 to 9.78.3.149.78.3.156
999.78.3.16/299.78.3.17 to 9.78.3.229.78.3.236
1009.78.3.24/299.78.3.25 to 9.78.3.309.78.3.316
1019.78.3.32/299.78.3.33 to 9.78.3.389.78.3.396
1029.78.3.40/299.78.3.41 to 9.78.3.469.78.3.476
1039.78.3.48/299.78.3.49 to 9.78.3.549.78.3.556
1049.78.3.56/299.78.3.57 to 9.78.3.629.78.3.636
1059.78.3.64/299.78.3.65 to 9.78.3.709.78.3.716
1069.78.3.72/299.78.3.73 to 9.78.3.789.78.3.796
1079.78.3.80/299.78.3.81 to 9.78.3.869.78.3.876
1089.78.3.88/299.78.3.89 to 9.78.3.949.78.3.956
1099.78.3.96/299.78.3.97 to 9.78.3.1029.78.3.1036
1109.78.3.104/299.78.3.105 to 9.78.3.1109.78.3.1116
1119.78.3.112/299.78.3.113 to 9.78.3.1189.78.3.1196
1129.78.3.120/299.78.3.121 to 9.78.3.1269.78.3.1276
1139.78.3.128/299.78.3.129 to 9.78.3.1349.78.3.1356
1149.78.3.136/299.78.3.137 to 9.78.3.1429.78.3.1436
1159.78.3.144/299.78.3.145 to 9.78.3.1509.78.3.1516
1169.78.3.152/299.78.3.153 to 9.78.3.1589.78.3.1596
1179.78.3.160/299.78.3.161 to 9.78.3.1669.78.3.1676
1189.78.3.168/299.78.3.169 to 9.78.3.1749.78.3.1756
1199.78.3.176/299.78.3.177 to 9.78.3.1829.78.3.1836
1209.78.3.184/299.78.3.185 to 9.78.3.1909.78.3.1916
1219.78.3.192/299.78.3.193 to 9.78.3.1989.78.3.1996
1229.78.3.200/299.78.3.201 to 9.78.3.2069.78.3.2076
1239.78.3.208/299.78.3.209 to 9.78.3.2149.78.3.2156
1249.78.3.216/299.78.3.217 to 9.78.3.2229.78.3.2236
1259.78.3.224/299.78.3.225 to 9.78.3.2309.78.3.2316
1269.78.3.232/299.78.3.233 to 9.78.3.2389.78.3.2396
1279.78.3.240/299.78.3.241 to 9.78.3.2469.78.3.2476
1289.78.3.248/299.78.3.249 to 9.78.3.2549.78.3.2556
1299.78.4.0/299.78.4.1 to 9.78.4.69.78.4.76
1309.78.4.8/299.78.4.9 to 9.78.4.149.78.4.156
1319.78.4.16/299.78.4.17 to 9.78.4.229.78.4.236
1329.78.4.24/299.78.4.25 to 9.78.4.309.78.4.316
1339.78.4.32/299.78.4.33 to 9.78.4.389.78.4.396
1349.78.4.40/299.78.4.41 to 9.78.4.469.78.4.476
1359.78.4.48/299.78.4.49 to 9.78.4.549.78.4.556
1369.78.4.56/299.78.4.57 to 9.78.4.629.78.4.636
1379.78.4.64/299.78.4.65 to 9.78.4.709.78.4.716
1389.78.4.72/299.78.4.73 to 9.78.4.789.78.4.796
1399.78.4.80/299.78.4.81 to 9.78.4.869.78.4.876
1409.78.4.88/299.78.4.89 to 9.78.4.949.78.4.956
1419.78.4.96/299.78.4.97 to 9.78.4.1029.78.4.1036
1429.78.4.104/299.78.4.105 to 9.78.4.1109.78.4.1116
1439.78.4.112/299.78.4.113 to 9.78.4.1189.78.4.1196
1449.78.4.120/299.78.4.121 to 9.78.4.1269.78.4.1276
1459.78.4.128/299.78.4.129 to 9.78.4.1349.78.4.1356
1469.78.4.136/299.78.4.137 to 9.78.4.1429.78.4.1436
1479.78.4.144/299.78.4.145 to 9.78.4.1509.78.4.1516
1489.78.4.152/299.78.4.153 to 9.78.4.1589.78.4.1596
1499.78.4.160/299.78.4.161 to 9.78.4.1669.78.4.1676
1509.78.4.168/299.78.4.169 to 9.78.4.1749.78.4.1756
1519.78.4.176/299.78.4.177 to 9.78.4.1829.78.4.1836
1529.78.4.184/299.78.4.185 to 9.78.4.1909.78.4.1916
1539.78.4.192/299.78.4.193 to 9.78.4.1989.78.4.1996
1549.78.4.200/299.78.4.201 to 9.78.4.2069.78.4.2076
1559.78.4.208/299.78.4.209 to 9.78.4.2149.78.4.2156
1569.78.4.216/299.78.4.217 to 9.78.4.2229.78.4.2236
1579.78.4.224/299.78.4.225 to 9.78.4.2309.78.4.2316
1589.78.4.232/299.78.4.233 to 9.78.4.2389.78.4.2396
1599.78.4.240/299.78.4.241 to 9.78.4.2469.78.4.2476
1609.78.4.248/299.78.4.249 to 9.78.4.2549.78.4.2556
1619.78.5.0/299.78.5.1 to 9.78.5.69.78.5.76
1629.78.5.8/299.78.5.9 to 9.78.5.149.78.5.156
1639.78.5.16/299.78.5.17 to 9.78.5.229.78.5.236
1649.78.5.24/299.78.5.25 to 9.78.5.309.78.5.316
1659.78.5.32/299.78.5.33 to 9.78.5.389.78.5.396
1669.78.5.40/299.78.5.41 to 9.78.5.469.78.5.476
1679.78.5.48/299.78.5.49 to 9.78.5.549.78.5.556
1689.78.5.56/299.78.5.57 to 9.78.5.629.78.5.636
1699.78.5.64/299.78.5.65 to 9.78.5.709.78.5.716
1709.78.5.72/299.78.5.73 to 9.78.5.789.78.5.796
1719.78.5.80/299.78.5.81 to 9.78.5.869.78.5.876
1729.78.5.88/299.78.5.89 to 9.78.5.949.78.5.956
1739.78.5.96/299.78.5.97 to 9.78.5.1029.78.5.1036
1749.78.5.104/299.78.5.105 to 9.78.5.1109.78.5.1116
1759.78.5.112/299.78.5.113 to 9.78.5.1189.78.5.1196
1769.78.5.120/299.78.5.121 to 9.78.5.1269.78.5.1276
1779.78.5.128/299.78.5.129 to 9.78.5.1349.78.5.1356
1789.78.5.136/299.78.5.137 to 9.78.5.1429.78.5.1436
1799.78.5.144/299.78.5.145 to 9.78.5.1509.78.5.1516
1809.78.5.152/299.78.5.153 to 9.78.5.1589.78.5.1596
1819.78.5.160/299.78.5.161 to 9.78.5.1669.78.5.1676
1829.78.5.168/299.78.5.169 to 9.78.5.1749.78.5.1756
1839.78.5.176/299.78.5.177 to 9.78.5.1829.78.5.1836
1849.78.5.184/299.78.5.185 to 9.78.5.1909.78.5.1916
1859.78.5.192/299.78.5.193 to 9.78.5.1989.78.5.1996
1869.78.5.200/299.78.5.201 to 9.78.5.2069.78.5.2076
1879.78.5.208/299.78.5.209 to 9.78.5.2149.78.5.2156
1889.78.5.216/299.78.5.217 to 9.78.5.2229.78.5.2236
1899.78.5.224/299.78.5.225 to 9.78.5.2309.78.5.2316
1909.78.5.232/299.78.5.233 to 9.78.5.2389.78.5.2396
1919.78.5.240/299.78.5.241 to 9.78.5.2469.78.5.2476
1929.78.5.248/299.78.5.249 to 9.78.5.2549.78.5.2556
1939.78.6.0/299.78.6.1 to 9.78.6.69.78.6.76
1949.78.6.8/299.78.6.9 to 9.78.6.149.78.6.156
1959.78.6.16/299.78.6.17 to 9.78.6.229.78.6.236
1969.78.6.24/299.78.6.25 to 9.78.6.309.78.6.316
1979.78.6.32/299.78.6.33 to 9.78.6.389.78.6.396
1989.78.6.40/299.78.6.41 to 9.78.6.469.78.6.476
1999.78.6.48/299.78.6.49 to 9.78.6.549.78.6.556
2009.78.6.56/299.78.6.57 to 9.78.6.629.78.6.636
2019.78.6.64/299.78.6.65 to 9.78.6.709.78.6.716
2029.78.6.72/299.78.6.73 to 9.78.6.789.78.6.796
2039.78.6.80/299.78.6.81 to 9.78.6.869.78.6.876
2049.78.6.88/299.78.6.89 to 9.78.6.949.78.6.956
2059.78.6.96/299.78.6.97 to 9.78.6.1029.78.6.1036
2069.78.6.104/299.78.6.105 to 9.78.6.1109.78.6.1116
2079.78.6.112/299.78.6.113 to 9.78.6.1189.78.6.1196
2089.78.6.120/299.78.6.121 to 9.78.6.1269.78.6.1276
2099.78.6.128/299.78.6.129 to 9.78.6.1349.78.6.1356
2109.78.6.136/299.78.6.137 to 9.78.6.1429.78.6.1436
2119.78.6.144/299.78.6.145 to 9.78.6.1509.78.6.1516
2129.78.6.152/299.78.6.153 to 9.78.6.1589.78.6.1596
2139.78.6.160/299.78.6.161 to 9.78.6.1669.78.6.1676
2149.78.6.168/299.78.6.169 to 9.78.6.1749.78.6.1756
2159.78.6.176/299.78.6.177 to 9.78.6.1829.78.6.1836
2169.78.6.184/299.78.6.185 to 9.78.6.1909.78.6.1916
2179.78.6.192/299.78.6.193 to 9.78.6.1989.78.6.1996
2189.78.6.200/299.78.6.201 to 9.78.6.2069.78.6.2076
2199.78.6.208/299.78.6.209 to 9.78.6.2149.78.6.2156
2209.78.6.216/299.78.6.217 to 9.78.6.2229.78.6.2236
2219.78.6.224/299.78.6.225 to 9.78.6.2309.78.6.2316
2229.78.6.232/299.78.6.233 to 9.78.6.2389.78.6.2396
2239.78.6.240/299.78.6.241 to 9.78.6.2469.78.6.2476
2249.78.6.248/299.78.6.249 to 9.78.6.2549.78.6.2556
2259.78.7.0/299.78.7.1 to 9.78.7.69.78.7.76
2269.78.7.8/299.78.7.9 to 9.78.7.149.78.7.156
2279.78.7.16/299.78.7.17 to 9.78.7.229.78.7.236
2289.78.7.24/299.78.7.25 to 9.78.7.309.78.7.316
2299.78.7.32/299.78.7.33 to 9.78.7.389.78.7.396
2309.78.7.40/299.78.7.41 to 9.78.7.469.78.7.476
2319.78.7.48/299.78.7.49 to 9.78.7.549.78.7.556
2329.78.7.56/299.78.7.57 to 9.78.7.629.78.7.636
2339.78.7.64/299.78.7.65 to 9.78.7.709.78.7.716
2349.78.7.72/299.78.7.73 to 9.78.7.789.78.7.796
2359.78.7.80/299.78.7.81 to 9.78.7.869.78.7.876
2369.78.7.88/299.78.7.89 to 9.78.7.949.78.7.956
2379.78.7.96/299.78.7.97 to 9.78.7.1029.78.7.1036
2389.78.7.104/299.78.7.105 to 9.78.7.1109.78.7.1116
2399.78.7.112/299.78.7.113 to 9.78.7.1189.78.7.1196
2409.78.7.120/299.78.7.121 to 9.78.7.1269.78.7.1276
2419.78.7.128/299.78.7.129 to 9.78.7.1349.78.7.1356
2429.78.7.136/299.78.7.137 to 9.78.7.1429.78.7.1436
2439.78.7.144/299.78.7.145 to 9.78.7.1509.78.7.1516
2449.78.7.152/299.78.7.153 to 9.78.7.1589.78.7.1596
2459.78.7.160/299.78.7.161 to 9.78.7.1669.78.7.1676
2469.78.7.168/299.78.7.169 to 9.78.7.1749.78.7.1756
2479.78.7.176/299.78.7.177 to 9.78.7.1829.78.7.1836
2489.78.7.184/299.78.7.185 to 9.78.7.1909.78.7.1916
2499.78.7.192/299.78.7.193 to 9.78.7.1989.78.7.1996
2509.78.7.200/299.78.7.201 to 9.78.7.2069.78.7.2076
2519.78.7.208/299.78.7.209 to 9.78.7.2149.78.7.2156
2529.78.7.216/299.78.7.217 to 9.78.7.2229.78.7.2236
2539.78.7.224/299.78.7.225 to 9.78.7.2309.78.7.2316
2549.78.7.232/299.78.7.233 to 9.78.7.2389.78.7.2396
2559.78.7.240/299.78.7.241 to 9.78.7.2469.78.7.2476
2569.78.7.248/299.78.7.249 to 9.78.7.2549.78.7.2556

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.