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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.

Network9.2.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
9.2.0.0
Broadcast address
9.2.31.255
First usable
9.2.0.1
Last usable
9.2.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 09020000 · Integer 151126016 to 151134207
Reverse DNS zones
0.2.9.in-addr.arpa
1.2.9.in-addr.arpa
2.2.9.in-addr.arpa
3.2.9.in-addr.arpa
4.2.9.in-addr.arpa
5.2.9.in-addr.arpa
6.2.9.in-addr.arpa
7.2.9.in-addr.arpa
8.2.9.in-addr.arpa
9.2.9.in-addr.arpa
10.2.9.in-addr.arpa
11.2.9.in-addr.arpa
12.2.9.in-addr.arpa
13.2.9.in-addr.arpa
14.2.9.in-addr.arpa
15.2.9.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001001.00000010.00000000.000000009.2.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00001001.00000010.00000000.000000009.2.0.0
Broadcast00001001.00000010.00011111.111111119.2.31.255
Split into smaller subnets/30
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

9.2.0.0/19 makes 2,048 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
19.2.0.0/309.2.0.1 to 9.2.0.29.2.0.32
29.2.0.4/309.2.0.5 to 9.2.0.69.2.0.72
39.2.0.8/309.2.0.9 to 9.2.0.109.2.0.112
49.2.0.12/309.2.0.13 to 9.2.0.149.2.0.152
59.2.0.16/309.2.0.17 to 9.2.0.189.2.0.192
69.2.0.20/309.2.0.21 to 9.2.0.229.2.0.232
79.2.0.24/309.2.0.25 to 9.2.0.269.2.0.272
89.2.0.28/309.2.0.29 to 9.2.0.309.2.0.312
99.2.0.32/309.2.0.33 to 9.2.0.349.2.0.352
109.2.0.36/309.2.0.37 to 9.2.0.389.2.0.392
119.2.0.40/309.2.0.41 to 9.2.0.429.2.0.432
129.2.0.44/309.2.0.45 to 9.2.0.469.2.0.472
139.2.0.48/309.2.0.49 to 9.2.0.509.2.0.512
149.2.0.52/309.2.0.53 to 9.2.0.549.2.0.552
159.2.0.56/309.2.0.57 to 9.2.0.589.2.0.592
169.2.0.60/309.2.0.61 to 9.2.0.629.2.0.632
179.2.0.64/309.2.0.65 to 9.2.0.669.2.0.672
189.2.0.68/309.2.0.69 to 9.2.0.709.2.0.712
199.2.0.72/309.2.0.73 to 9.2.0.749.2.0.752
209.2.0.76/309.2.0.77 to 9.2.0.789.2.0.792
219.2.0.80/309.2.0.81 to 9.2.0.829.2.0.832
229.2.0.84/309.2.0.85 to 9.2.0.869.2.0.872
239.2.0.88/309.2.0.89 to 9.2.0.909.2.0.912
249.2.0.92/309.2.0.93 to 9.2.0.949.2.0.952
259.2.0.96/309.2.0.97 to 9.2.0.989.2.0.992
269.2.0.100/309.2.0.101 to 9.2.0.1029.2.0.1032
279.2.0.104/309.2.0.105 to 9.2.0.1069.2.0.1072
289.2.0.108/309.2.0.109 to 9.2.0.1109.2.0.1112
299.2.0.112/309.2.0.113 to 9.2.0.1149.2.0.1152
309.2.0.116/309.2.0.117 to 9.2.0.1189.2.0.1192
319.2.0.120/309.2.0.121 to 9.2.0.1229.2.0.1232
329.2.0.124/309.2.0.125 to 9.2.0.1269.2.0.1272
339.2.0.128/309.2.0.129 to 9.2.0.1309.2.0.1312
349.2.0.132/309.2.0.133 to 9.2.0.1349.2.0.1352
359.2.0.136/309.2.0.137 to 9.2.0.1389.2.0.1392
369.2.0.140/309.2.0.141 to 9.2.0.1429.2.0.1432
379.2.0.144/309.2.0.145 to 9.2.0.1469.2.0.1472
389.2.0.148/309.2.0.149 to 9.2.0.1509.2.0.1512
399.2.0.152/309.2.0.153 to 9.2.0.1549.2.0.1552
409.2.0.156/309.2.0.157 to 9.2.0.1589.2.0.1592
419.2.0.160/309.2.0.161 to 9.2.0.1629.2.0.1632
429.2.0.164/309.2.0.165 to 9.2.0.1669.2.0.1672
439.2.0.168/309.2.0.169 to 9.2.0.1709.2.0.1712
449.2.0.172/309.2.0.173 to 9.2.0.1749.2.0.1752
459.2.0.176/309.2.0.177 to 9.2.0.1789.2.0.1792
469.2.0.180/309.2.0.181 to 9.2.0.1829.2.0.1832
479.2.0.184/309.2.0.185 to 9.2.0.1869.2.0.1872
489.2.0.188/309.2.0.189 to 9.2.0.1909.2.0.1912
499.2.0.192/309.2.0.193 to 9.2.0.1949.2.0.1952
509.2.0.196/309.2.0.197 to 9.2.0.1989.2.0.1992
519.2.0.200/309.2.0.201 to 9.2.0.2029.2.0.2032
529.2.0.204/309.2.0.205 to 9.2.0.2069.2.0.2072
539.2.0.208/309.2.0.209 to 9.2.0.2109.2.0.2112
549.2.0.212/309.2.0.213 to 9.2.0.2149.2.0.2152
559.2.0.216/309.2.0.217 to 9.2.0.2189.2.0.2192
569.2.0.220/309.2.0.221 to 9.2.0.2229.2.0.2232
579.2.0.224/309.2.0.225 to 9.2.0.2269.2.0.2272
589.2.0.228/309.2.0.229 to 9.2.0.2309.2.0.2312
599.2.0.232/309.2.0.233 to 9.2.0.2349.2.0.2352
609.2.0.236/309.2.0.237 to 9.2.0.2389.2.0.2392
619.2.0.240/309.2.0.241 to 9.2.0.2429.2.0.2432
629.2.0.244/309.2.0.245 to 9.2.0.2469.2.0.2472
639.2.0.248/309.2.0.249 to 9.2.0.2509.2.0.2512
649.2.0.252/309.2.0.253 to 9.2.0.2549.2.0.2552
659.2.1.0/309.2.1.1 to 9.2.1.29.2.1.32
669.2.1.4/309.2.1.5 to 9.2.1.69.2.1.72
679.2.1.8/309.2.1.9 to 9.2.1.109.2.1.112
689.2.1.12/309.2.1.13 to 9.2.1.149.2.1.152
699.2.1.16/309.2.1.17 to 9.2.1.189.2.1.192
709.2.1.20/309.2.1.21 to 9.2.1.229.2.1.232
719.2.1.24/309.2.1.25 to 9.2.1.269.2.1.272
729.2.1.28/309.2.1.29 to 9.2.1.309.2.1.312
739.2.1.32/309.2.1.33 to 9.2.1.349.2.1.352
749.2.1.36/309.2.1.37 to 9.2.1.389.2.1.392
759.2.1.40/309.2.1.41 to 9.2.1.429.2.1.432
769.2.1.44/309.2.1.45 to 9.2.1.469.2.1.472
779.2.1.48/309.2.1.49 to 9.2.1.509.2.1.512
789.2.1.52/309.2.1.53 to 9.2.1.549.2.1.552
799.2.1.56/309.2.1.57 to 9.2.1.589.2.1.592
809.2.1.60/309.2.1.61 to 9.2.1.629.2.1.632
819.2.1.64/309.2.1.65 to 9.2.1.669.2.1.672
829.2.1.68/309.2.1.69 to 9.2.1.709.2.1.712
839.2.1.72/309.2.1.73 to 9.2.1.749.2.1.752
849.2.1.76/309.2.1.77 to 9.2.1.789.2.1.792
859.2.1.80/309.2.1.81 to 9.2.1.829.2.1.832
869.2.1.84/309.2.1.85 to 9.2.1.869.2.1.872
879.2.1.88/309.2.1.89 to 9.2.1.909.2.1.912
889.2.1.92/309.2.1.93 to 9.2.1.949.2.1.952
899.2.1.96/309.2.1.97 to 9.2.1.989.2.1.992
909.2.1.100/309.2.1.101 to 9.2.1.1029.2.1.1032
919.2.1.104/309.2.1.105 to 9.2.1.1069.2.1.1072
929.2.1.108/309.2.1.109 to 9.2.1.1109.2.1.1112
939.2.1.112/309.2.1.113 to 9.2.1.1149.2.1.1152
949.2.1.116/309.2.1.117 to 9.2.1.1189.2.1.1192
959.2.1.120/309.2.1.121 to 9.2.1.1229.2.1.1232
969.2.1.124/309.2.1.125 to 9.2.1.1269.2.1.1272
979.2.1.128/309.2.1.129 to 9.2.1.1309.2.1.1312
989.2.1.132/309.2.1.133 to 9.2.1.1349.2.1.1352
999.2.1.136/309.2.1.137 to 9.2.1.1389.2.1.1392
1009.2.1.140/309.2.1.141 to 9.2.1.1429.2.1.1432
1019.2.1.144/309.2.1.145 to 9.2.1.1469.2.1.1472
1029.2.1.148/309.2.1.149 to 9.2.1.1509.2.1.1512
1039.2.1.152/309.2.1.153 to 9.2.1.1549.2.1.1552
1049.2.1.156/309.2.1.157 to 9.2.1.1589.2.1.1592
1059.2.1.160/309.2.1.161 to 9.2.1.1629.2.1.1632
1069.2.1.164/309.2.1.165 to 9.2.1.1669.2.1.1672
1079.2.1.168/309.2.1.169 to 9.2.1.1709.2.1.1712
1089.2.1.172/309.2.1.173 to 9.2.1.1749.2.1.1752
1099.2.1.176/309.2.1.177 to 9.2.1.1789.2.1.1792
1109.2.1.180/309.2.1.181 to 9.2.1.1829.2.1.1832
1119.2.1.184/309.2.1.185 to 9.2.1.1869.2.1.1872
1129.2.1.188/309.2.1.189 to 9.2.1.1909.2.1.1912
1139.2.1.192/309.2.1.193 to 9.2.1.1949.2.1.1952
1149.2.1.196/309.2.1.197 to 9.2.1.1989.2.1.1992
1159.2.1.200/309.2.1.201 to 9.2.1.2029.2.1.2032
1169.2.1.204/309.2.1.205 to 9.2.1.2069.2.1.2072
1179.2.1.208/309.2.1.209 to 9.2.1.2109.2.1.2112
1189.2.1.212/309.2.1.213 to 9.2.1.2149.2.1.2152
1199.2.1.216/309.2.1.217 to 9.2.1.2189.2.1.2192
1209.2.1.220/309.2.1.221 to 9.2.1.2229.2.1.2232
1219.2.1.224/309.2.1.225 to 9.2.1.2269.2.1.2272
1229.2.1.228/309.2.1.229 to 9.2.1.2309.2.1.2312
1239.2.1.232/309.2.1.233 to 9.2.1.2349.2.1.2352
1249.2.1.236/309.2.1.237 to 9.2.1.2389.2.1.2392
1259.2.1.240/309.2.1.241 to 9.2.1.2429.2.1.2432
1269.2.1.244/309.2.1.245 to 9.2.1.2469.2.1.2472
1279.2.1.248/309.2.1.249 to 9.2.1.2509.2.1.2512
1289.2.1.252/309.2.1.253 to 9.2.1.2549.2.1.2552
1299.2.2.0/309.2.2.1 to 9.2.2.29.2.2.32
1309.2.2.4/309.2.2.5 to 9.2.2.69.2.2.72
1319.2.2.8/309.2.2.9 to 9.2.2.109.2.2.112
1329.2.2.12/309.2.2.13 to 9.2.2.149.2.2.152
1339.2.2.16/309.2.2.17 to 9.2.2.189.2.2.192
1349.2.2.20/309.2.2.21 to 9.2.2.229.2.2.232
1359.2.2.24/309.2.2.25 to 9.2.2.269.2.2.272
1369.2.2.28/309.2.2.29 to 9.2.2.309.2.2.312
1379.2.2.32/309.2.2.33 to 9.2.2.349.2.2.352
1389.2.2.36/309.2.2.37 to 9.2.2.389.2.2.392
1399.2.2.40/309.2.2.41 to 9.2.2.429.2.2.432
1409.2.2.44/309.2.2.45 to 9.2.2.469.2.2.472
1419.2.2.48/309.2.2.49 to 9.2.2.509.2.2.512
1429.2.2.52/309.2.2.53 to 9.2.2.549.2.2.552
1439.2.2.56/309.2.2.57 to 9.2.2.589.2.2.592
1449.2.2.60/309.2.2.61 to 9.2.2.629.2.2.632
1459.2.2.64/309.2.2.65 to 9.2.2.669.2.2.672
1469.2.2.68/309.2.2.69 to 9.2.2.709.2.2.712
1479.2.2.72/309.2.2.73 to 9.2.2.749.2.2.752
1489.2.2.76/309.2.2.77 to 9.2.2.789.2.2.792
1499.2.2.80/309.2.2.81 to 9.2.2.829.2.2.832
1509.2.2.84/309.2.2.85 to 9.2.2.869.2.2.872
1519.2.2.88/309.2.2.89 to 9.2.2.909.2.2.912
1529.2.2.92/309.2.2.93 to 9.2.2.949.2.2.952
1539.2.2.96/309.2.2.97 to 9.2.2.989.2.2.992
1549.2.2.100/309.2.2.101 to 9.2.2.1029.2.2.1032
1559.2.2.104/309.2.2.105 to 9.2.2.1069.2.2.1072
1569.2.2.108/309.2.2.109 to 9.2.2.1109.2.2.1112
1579.2.2.112/309.2.2.113 to 9.2.2.1149.2.2.1152
1589.2.2.116/309.2.2.117 to 9.2.2.1189.2.2.1192
1599.2.2.120/309.2.2.121 to 9.2.2.1229.2.2.1232
1609.2.2.124/309.2.2.125 to 9.2.2.1269.2.2.1272
1619.2.2.128/309.2.2.129 to 9.2.2.1309.2.2.1312
1629.2.2.132/309.2.2.133 to 9.2.2.1349.2.2.1352
1639.2.2.136/309.2.2.137 to 9.2.2.1389.2.2.1392
1649.2.2.140/309.2.2.141 to 9.2.2.1429.2.2.1432
1659.2.2.144/309.2.2.145 to 9.2.2.1469.2.2.1472
1669.2.2.148/309.2.2.149 to 9.2.2.1509.2.2.1512
1679.2.2.152/309.2.2.153 to 9.2.2.1549.2.2.1552
1689.2.2.156/309.2.2.157 to 9.2.2.1589.2.2.1592
1699.2.2.160/309.2.2.161 to 9.2.2.1629.2.2.1632
1709.2.2.164/309.2.2.165 to 9.2.2.1669.2.2.1672
1719.2.2.168/309.2.2.169 to 9.2.2.1709.2.2.1712
1729.2.2.172/309.2.2.173 to 9.2.2.1749.2.2.1752
1739.2.2.176/309.2.2.177 to 9.2.2.1789.2.2.1792
1749.2.2.180/309.2.2.181 to 9.2.2.1829.2.2.1832
1759.2.2.184/309.2.2.185 to 9.2.2.1869.2.2.1872
1769.2.2.188/309.2.2.189 to 9.2.2.1909.2.2.1912
1779.2.2.192/309.2.2.193 to 9.2.2.1949.2.2.1952
1789.2.2.196/309.2.2.197 to 9.2.2.1989.2.2.1992
1799.2.2.200/309.2.2.201 to 9.2.2.2029.2.2.2032
1809.2.2.204/309.2.2.205 to 9.2.2.2069.2.2.2072
1819.2.2.208/309.2.2.209 to 9.2.2.2109.2.2.2112
1829.2.2.212/309.2.2.213 to 9.2.2.2149.2.2.2152
1839.2.2.216/309.2.2.217 to 9.2.2.2189.2.2.2192
1849.2.2.220/309.2.2.221 to 9.2.2.2229.2.2.2232
1859.2.2.224/309.2.2.225 to 9.2.2.2269.2.2.2272
1869.2.2.228/309.2.2.229 to 9.2.2.2309.2.2.2312
1879.2.2.232/309.2.2.233 to 9.2.2.2349.2.2.2352
1889.2.2.236/309.2.2.237 to 9.2.2.2389.2.2.2392
1899.2.2.240/309.2.2.241 to 9.2.2.2429.2.2.2432
1909.2.2.244/309.2.2.245 to 9.2.2.2469.2.2.2472
1919.2.2.248/309.2.2.249 to 9.2.2.2509.2.2.2512
1929.2.2.252/309.2.2.253 to 9.2.2.2549.2.2.2552
1939.2.3.0/309.2.3.1 to 9.2.3.29.2.3.32
1949.2.3.4/309.2.3.5 to 9.2.3.69.2.3.72
1959.2.3.8/309.2.3.9 to 9.2.3.109.2.3.112
1969.2.3.12/309.2.3.13 to 9.2.3.149.2.3.152
1979.2.3.16/309.2.3.17 to 9.2.3.189.2.3.192
1989.2.3.20/309.2.3.21 to 9.2.3.229.2.3.232
1999.2.3.24/309.2.3.25 to 9.2.3.269.2.3.272
2009.2.3.28/309.2.3.29 to 9.2.3.309.2.3.312
2019.2.3.32/309.2.3.33 to 9.2.3.349.2.3.352
2029.2.3.36/309.2.3.37 to 9.2.3.389.2.3.392
2039.2.3.40/309.2.3.41 to 9.2.3.429.2.3.432
2049.2.3.44/309.2.3.45 to 9.2.3.469.2.3.472
2059.2.3.48/309.2.3.49 to 9.2.3.509.2.3.512
2069.2.3.52/309.2.3.53 to 9.2.3.549.2.3.552
2079.2.3.56/309.2.3.57 to 9.2.3.589.2.3.592
2089.2.3.60/309.2.3.61 to 9.2.3.629.2.3.632
2099.2.3.64/309.2.3.65 to 9.2.3.669.2.3.672
2109.2.3.68/309.2.3.69 to 9.2.3.709.2.3.712
2119.2.3.72/309.2.3.73 to 9.2.3.749.2.3.752
2129.2.3.76/309.2.3.77 to 9.2.3.789.2.3.792
2139.2.3.80/309.2.3.81 to 9.2.3.829.2.3.832
2149.2.3.84/309.2.3.85 to 9.2.3.869.2.3.872
2159.2.3.88/309.2.3.89 to 9.2.3.909.2.3.912
2169.2.3.92/309.2.3.93 to 9.2.3.949.2.3.952
2179.2.3.96/309.2.3.97 to 9.2.3.989.2.3.992
2189.2.3.100/309.2.3.101 to 9.2.3.1029.2.3.1032
2199.2.3.104/309.2.3.105 to 9.2.3.1069.2.3.1072
2209.2.3.108/309.2.3.109 to 9.2.3.1109.2.3.1112
2219.2.3.112/309.2.3.113 to 9.2.3.1149.2.3.1152
2229.2.3.116/309.2.3.117 to 9.2.3.1189.2.3.1192
2239.2.3.120/309.2.3.121 to 9.2.3.1229.2.3.1232
2249.2.3.124/309.2.3.125 to 9.2.3.1269.2.3.1272
2259.2.3.128/309.2.3.129 to 9.2.3.1309.2.3.1312
2269.2.3.132/309.2.3.133 to 9.2.3.1349.2.3.1352
2279.2.3.136/309.2.3.137 to 9.2.3.1389.2.3.1392
2289.2.3.140/309.2.3.141 to 9.2.3.1429.2.3.1432
2299.2.3.144/309.2.3.145 to 9.2.3.1469.2.3.1472
2309.2.3.148/309.2.3.149 to 9.2.3.1509.2.3.1512
2319.2.3.152/309.2.3.153 to 9.2.3.1549.2.3.1552
2329.2.3.156/309.2.3.157 to 9.2.3.1589.2.3.1592
2339.2.3.160/309.2.3.161 to 9.2.3.1629.2.3.1632
2349.2.3.164/309.2.3.165 to 9.2.3.1669.2.3.1672
2359.2.3.168/309.2.3.169 to 9.2.3.1709.2.3.1712
2369.2.3.172/309.2.3.173 to 9.2.3.1749.2.3.1752
2379.2.3.176/309.2.3.177 to 9.2.3.1789.2.3.1792
2389.2.3.180/309.2.3.181 to 9.2.3.1829.2.3.1832
2399.2.3.184/309.2.3.185 to 9.2.3.1869.2.3.1872
2409.2.3.188/309.2.3.189 to 9.2.3.1909.2.3.1912
2419.2.3.192/309.2.3.193 to 9.2.3.1949.2.3.1952
2429.2.3.196/309.2.3.197 to 9.2.3.1989.2.3.1992
2439.2.3.200/309.2.3.201 to 9.2.3.2029.2.3.2032
2449.2.3.204/309.2.3.205 to 9.2.3.2069.2.3.2072
2459.2.3.208/309.2.3.209 to 9.2.3.2109.2.3.2112
2469.2.3.212/309.2.3.213 to 9.2.3.2149.2.3.2152
2479.2.3.216/309.2.3.217 to 9.2.3.2189.2.3.2192
2489.2.3.220/309.2.3.221 to 9.2.3.2229.2.3.2232
2499.2.3.224/309.2.3.225 to 9.2.3.2269.2.3.2272
2509.2.3.228/309.2.3.229 to 9.2.3.2309.2.3.2312
2519.2.3.232/309.2.3.233 to 9.2.3.2349.2.3.2352
2529.2.3.236/309.2.3.237 to 9.2.3.2389.2.3.2392
2539.2.3.240/309.2.3.241 to 9.2.3.2429.2.3.2432
2549.2.3.244/309.2.3.245 to 9.2.3.2469.2.3.2472
2559.2.3.248/309.2.3.249 to 9.2.3.2509.2.3.2512
2569.2.3.252/309.2.3.253 to 9.2.3.2549.2.3.2552

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.