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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.

Network9.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
9.0.0.0
Broadcast address
9.127.255.255
First usable
9.0.0.1
Last usable
9.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 09000000 · Integer 150994944 to 159383551
Reverse DNS zones
0.9.in-addr.arpa
1.9.in-addr.arpa
2.9.in-addr.arpa
3.9.in-addr.arpa
4.9.in-addr.arpa
5.9.in-addr.arpa
6.9.in-addr.arpa
7.9.in-addr.arpa
8.9.in-addr.arpa
9.9.in-addr.arpa
10.9.in-addr.arpa
11.9.in-addr.arpa
12.9.in-addr.arpa
13.9.in-addr.arpa
14.9.in-addr.arpa
15.9.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001001.00000000.00000000.000000009.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00001001.00000000.00000000.000000009.0.0.0
Broadcast00001001.01111111.11111111.111111119.127.255.255
Split into smaller subnets/18
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

9.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
19.0.0.0/189.0.0.1 to 9.0.63.2549.0.63.25516,382
29.0.64.0/189.0.64.1 to 9.0.127.2549.0.127.25516,382
39.0.128.0/189.0.128.1 to 9.0.191.2549.0.191.25516,382
49.0.192.0/189.0.192.1 to 9.0.255.2549.0.255.25516,382
59.1.0.0/189.1.0.1 to 9.1.63.2549.1.63.25516,382
69.1.64.0/189.1.64.1 to 9.1.127.2549.1.127.25516,382
79.1.128.0/189.1.128.1 to 9.1.191.2549.1.191.25516,382
89.1.192.0/189.1.192.1 to 9.1.255.2549.1.255.25516,382
99.2.0.0/189.2.0.1 to 9.2.63.2549.2.63.25516,382
109.2.64.0/189.2.64.1 to 9.2.127.2549.2.127.25516,382
119.2.128.0/189.2.128.1 to 9.2.191.2549.2.191.25516,382
129.2.192.0/189.2.192.1 to 9.2.255.2549.2.255.25516,382
139.3.0.0/189.3.0.1 to 9.3.63.2549.3.63.25516,382
149.3.64.0/189.3.64.1 to 9.3.127.2549.3.127.25516,382
159.3.128.0/189.3.128.1 to 9.3.191.2549.3.191.25516,382
169.3.192.0/189.3.192.1 to 9.3.255.2549.3.255.25516,382
179.4.0.0/189.4.0.1 to 9.4.63.2549.4.63.25516,382
189.4.64.0/189.4.64.1 to 9.4.127.2549.4.127.25516,382
199.4.128.0/189.4.128.1 to 9.4.191.2549.4.191.25516,382
209.4.192.0/189.4.192.1 to 9.4.255.2549.4.255.25516,382
219.5.0.0/189.5.0.1 to 9.5.63.2549.5.63.25516,382
229.5.64.0/189.5.64.1 to 9.5.127.2549.5.127.25516,382
239.5.128.0/189.5.128.1 to 9.5.191.2549.5.191.25516,382
249.5.192.0/189.5.192.1 to 9.5.255.2549.5.255.25516,382
259.6.0.0/189.6.0.1 to 9.6.63.2549.6.63.25516,382
269.6.64.0/189.6.64.1 to 9.6.127.2549.6.127.25516,382
279.6.128.0/189.6.128.1 to 9.6.191.2549.6.191.25516,382
289.6.192.0/189.6.192.1 to 9.6.255.2549.6.255.25516,382
299.7.0.0/189.7.0.1 to 9.7.63.2549.7.63.25516,382
309.7.64.0/189.7.64.1 to 9.7.127.2549.7.127.25516,382
319.7.128.0/189.7.128.1 to 9.7.191.2549.7.191.25516,382
329.7.192.0/189.7.192.1 to 9.7.255.2549.7.255.25516,382
339.8.0.0/189.8.0.1 to 9.8.63.2549.8.63.25516,382
349.8.64.0/189.8.64.1 to 9.8.127.2549.8.127.25516,382
359.8.128.0/189.8.128.1 to 9.8.191.2549.8.191.25516,382
369.8.192.0/189.8.192.1 to 9.8.255.2549.8.255.25516,382
379.9.0.0/189.9.0.1 to 9.9.63.2549.9.63.25516,382
389.9.64.0/189.9.64.1 to 9.9.127.2549.9.127.25516,382
399.9.128.0/189.9.128.1 to 9.9.191.2549.9.191.25516,382
409.9.192.0/189.9.192.1 to 9.9.255.2549.9.255.25516,382
419.10.0.0/189.10.0.1 to 9.10.63.2549.10.63.25516,382
429.10.64.0/189.10.64.1 to 9.10.127.2549.10.127.25516,382
439.10.128.0/189.10.128.1 to 9.10.191.2549.10.191.25516,382
449.10.192.0/189.10.192.1 to 9.10.255.2549.10.255.25516,382
459.11.0.0/189.11.0.1 to 9.11.63.2549.11.63.25516,382
469.11.64.0/189.11.64.1 to 9.11.127.2549.11.127.25516,382
479.11.128.0/189.11.128.1 to 9.11.191.2549.11.191.25516,382
489.11.192.0/189.11.192.1 to 9.11.255.2549.11.255.25516,382
499.12.0.0/189.12.0.1 to 9.12.63.2549.12.63.25516,382
509.12.64.0/189.12.64.1 to 9.12.127.2549.12.127.25516,382
519.12.128.0/189.12.128.1 to 9.12.191.2549.12.191.25516,382
529.12.192.0/189.12.192.1 to 9.12.255.2549.12.255.25516,382
539.13.0.0/189.13.0.1 to 9.13.63.2549.13.63.25516,382
549.13.64.0/189.13.64.1 to 9.13.127.2549.13.127.25516,382
559.13.128.0/189.13.128.1 to 9.13.191.2549.13.191.25516,382
569.13.192.0/189.13.192.1 to 9.13.255.2549.13.255.25516,382
579.14.0.0/189.14.0.1 to 9.14.63.2549.14.63.25516,382
589.14.64.0/189.14.64.1 to 9.14.127.2549.14.127.25516,382
599.14.128.0/189.14.128.1 to 9.14.191.2549.14.191.25516,382
609.14.192.0/189.14.192.1 to 9.14.255.2549.14.255.25516,382
619.15.0.0/189.15.0.1 to 9.15.63.2549.15.63.25516,382
629.15.64.0/189.15.64.1 to 9.15.127.2549.15.127.25516,382
639.15.128.0/189.15.128.1 to 9.15.191.2549.15.191.25516,382
649.15.192.0/189.15.192.1 to 9.15.255.2549.15.255.25516,382
659.16.0.0/189.16.0.1 to 9.16.63.2549.16.63.25516,382
669.16.64.0/189.16.64.1 to 9.16.127.2549.16.127.25516,382
679.16.128.0/189.16.128.1 to 9.16.191.2549.16.191.25516,382
689.16.192.0/189.16.192.1 to 9.16.255.2549.16.255.25516,382
699.17.0.0/189.17.0.1 to 9.17.63.2549.17.63.25516,382
709.17.64.0/189.17.64.1 to 9.17.127.2549.17.127.25516,382
719.17.128.0/189.17.128.1 to 9.17.191.2549.17.191.25516,382
729.17.192.0/189.17.192.1 to 9.17.255.2549.17.255.25516,382
739.18.0.0/189.18.0.1 to 9.18.63.2549.18.63.25516,382
749.18.64.0/189.18.64.1 to 9.18.127.2549.18.127.25516,382
759.18.128.0/189.18.128.1 to 9.18.191.2549.18.191.25516,382
769.18.192.0/189.18.192.1 to 9.18.255.2549.18.255.25516,382
779.19.0.0/189.19.0.1 to 9.19.63.2549.19.63.25516,382
789.19.64.0/189.19.64.1 to 9.19.127.2549.19.127.25516,382
799.19.128.0/189.19.128.1 to 9.19.191.2549.19.191.25516,382
809.19.192.0/189.19.192.1 to 9.19.255.2549.19.255.25516,382
819.20.0.0/189.20.0.1 to 9.20.63.2549.20.63.25516,382
829.20.64.0/189.20.64.1 to 9.20.127.2549.20.127.25516,382
839.20.128.0/189.20.128.1 to 9.20.191.2549.20.191.25516,382
849.20.192.0/189.20.192.1 to 9.20.255.2549.20.255.25516,382
859.21.0.0/189.21.0.1 to 9.21.63.2549.21.63.25516,382
869.21.64.0/189.21.64.1 to 9.21.127.2549.21.127.25516,382
879.21.128.0/189.21.128.1 to 9.21.191.2549.21.191.25516,382
889.21.192.0/189.21.192.1 to 9.21.255.2549.21.255.25516,382
899.22.0.0/189.22.0.1 to 9.22.63.2549.22.63.25516,382
909.22.64.0/189.22.64.1 to 9.22.127.2549.22.127.25516,382
919.22.128.0/189.22.128.1 to 9.22.191.2549.22.191.25516,382
929.22.192.0/189.22.192.1 to 9.22.255.2549.22.255.25516,382
939.23.0.0/189.23.0.1 to 9.23.63.2549.23.63.25516,382
949.23.64.0/189.23.64.1 to 9.23.127.2549.23.127.25516,382
959.23.128.0/189.23.128.1 to 9.23.191.2549.23.191.25516,382
969.23.192.0/189.23.192.1 to 9.23.255.2549.23.255.25516,382
979.24.0.0/189.24.0.1 to 9.24.63.2549.24.63.25516,382
989.24.64.0/189.24.64.1 to 9.24.127.2549.24.127.25516,382
999.24.128.0/189.24.128.1 to 9.24.191.2549.24.191.25516,382
1009.24.192.0/189.24.192.1 to 9.24.255.2549.24.255.25516,382
1019.25.0.0/189.25.0.1 to 9.25.63.2549.25.63.25516,382
1029.25.64.0/189.25.64.1 to 9.25.127.2549.25.127.25516,382
1039.25.128.0/189.25.128.1 to 9.25.191.2549.25.191.25516,382
1049.25.192.0/189.25.192.1 to 9.25.255.2549.25.255.25516,382
1059.26.0.0/189.26.0.1 to 9.26.63.2549.26.63.25516,382
1069.26.64.0/189.26.64.1 to 9.26.127.2549.26.127.25516,382
1079.26.128.0/189.26.128.1 to 9.26.191.2549.26.191.25516,382
1089.26.192.0/189.26.192.1 to 9.26.255.2549.26.255.25516,382
1099.27.0.0/189.27.0.1 to 9.27.63.2549.27.63.25516,382
1109.27.64.0/189.27.64.1 to 9.27.127.2549.27.127.25516,382
1119.27.128.0/189.27.128.1 to 9.27.191.2549.27.191.25516,382
1129.27.192.0/189.27.192.1 to 9.27.255.2549.27.255.25516,382
1139.28.0.0/189.28.0.1 to 9.28.63.2549.28.63.25516,382
1149.28.64.0/189.28.64.1 to 9.28.127.2549.28.127.25516,382
1159.28.128.0/189.28.128.1 to 9.28.191.2549.28.191.25516,382
1169.28.192.0/189.28.192.1 to 9.28.255.2549.28.255.25516,382
1179.29.0.0/189.29.0.1 to 9.29.63.2549.29.63.25516,382
1189.29.64.0/189.29.64.1 to 9.29.127.2549.29.127.25516,382
1199.29.128.0/189.29.128.1 to 9.29.191.2549.29.191.25516,382
1209.29.192.0/189.29.192.1 to 9.29.255.2549.29.255.25516,382
1219.30.0.0/189.30.0.1 to 9.30.63.2549.30.63.25516,382
1229.30.64.0/189.30.64.1 to 9.30.127.2549.30.127.25516,382
1239.30.128.0/189.30.128.1 to 9.30.191.2549.30.191.25516,382
1249.30.192.0/189.30.192.1 to 9.30.255.2549.30.255.25516,382
1259.31.0.0/189.31.0.1 to 9.31.63.2549.31.63.25516,382
1269.31.64.0/189.31.64.1 to 9.31.127.2549.31.127.25516,382
1279.31.128.0/189.31.128.1 to 9.31.191.2549.31.191.25516,382
1289.31.192.0/189.31.192.1 to 9.31.255.2549.31.255.25516,382
1299.32.0.0/189.32.0.1 to 9.32.63.2549.32.63.25516,382
1309.32.64.0/189.32.64.1 to 9.32.127.2549.32.127.25516,382
1319.32.128.0/189.32.128.1 to 9.32.191.2549.32.191.25516,382
1329.32.192.0/189.32.192.1 to 9.32.255.2549.32.255.25516,382
1339.33.0.0/189.33.0.1 to 9.33.63.2549.33.63.25516,382
1349.33.64.0/189.33.64.1 to 9.33.127.2549.33.127.25516,382
1359.33.128.0/189.33.128.1 to 9.33.191.2549.33.191.25516,382
1369.33.192.0/189.33.192.1 to 9.33.255.2549.33.255.25516,382
1379.34.0.0/189.34.0.1 to 9.34.63.2549.34.63.25516,382
1389.34.64.0/189.34.64.1 to 9.34.127.2549.34.127.25516,382
1399.34.128.0/189.34.128.1 to 9.34.191.2549.34.191.25516,382
1409.34.192.0/189.34.192.1 to 9.34.255.2549.34.255.25516,382
1419.35.0.0/189.35.0.1 to 9.35.63.2549.35.63.25516,382
1429.35.64.0/189.35.64.1 to 9.35.127.2549.35.127.25516,382
1439.35.128.0/189.35.128.1 to 9.35.191.2549.35.191.25516,382
1449.35.192.0/189.35.192.1 to 9.35.255.2549.35.255.25516,382
1459.36.0.0/189.36.0.1 to 9.36.63.2549.36.63.25516,382
1469.36.64.0/189.36.64.1 to 9.36.127.2549.36.127.25516,382
1479.36.128.0/189.36.128.1 to 9.36.191.2549.36.191.25516,382
1489.36.192.0/189.36.192.1 to 9.36.255.2549.36.255.25516,382
1499.37.0.0/189.37.0.1 to 9.37.63.2549.37.63.25516,382
1509.37.64.0/189.37.64.1 to 9.37.127.2549.37.127.25516,382
1519.37.128.0/189.37.128.1 to 9.37.191.2549.37.191.25516,382
1529.37.192.0/189.37.192.1 to 9.37.255.2549.37.255.25516,382
1539.38.0.0/189.38.0.1 to 9.38.63.2549.38.63.25516,382
1549.38.64.0/189.38.64.1 to 9.38.127.2549.38.127.25516,382
1559.38.128.0/189.38.128.1 to 9.38.191.2549.38.191.25516,382
1569.38.192.0/189.38.192.1 to 9.38.255.2549.38.255.25516,382
1579.39.0.0/189.39.0.1 to 9.39.63.2549.39.63.25516,382
1589.39.64.0/189.39.64.1 to 9.39.127.2549.39.127.25516,382
1599.39.128.0/189.39.128.1 to 9.39.191.2549.39.191.25516,382
1609.39.192.0/189.39.192.1 to 9.39.255.2549.39.255.25516,382
1619.40.0.0/189.40.0.1 to 9.40.63.2549.40.63.25516,382
1629.40.64.0/189.40.64.1 to 9.40.127.2549.40.127.25516,382
1639.40.128.0/189.40.128.1 to 9.40.191.2549.40.191.25516,382
1649.40.192.0/189.40.192.1 to 9.40.255.2549.40.255.25516,382
1659.41.0.0/189.41.0.1 to 9.41.63.2549.41.63.25516,382
1669.41.64.0/189.41.64.1 to 9.41.127.2549.41.127.25516,382
1679.41.128.0/189.41.128.1 to 9.41.191.2549.41.191.25516,382
1689.41.192.0/189.41.192.1 to 9.41.255.2549.41.255.25516,382
1699.42.0.0/189.42.0.1 to 9.42.63.2549.42.63.25516,382
1709.42.64.0/189.42.64.1 to 9.42.127.2549.42.127.25516,382
1719.42.128.0/189.42.128.1 to 9.42.191.2549.42.191.25516,382
1729.42.192.0/189.42.192.1 to 9.42.255.2549.42.255.25516,382
1739.43.0.0/189.43.0.1 to 9.43.63.2549.43.63.25516,382
1749.43.64.0/189.43.64.1 to 9.43.127.2549.43.127.25516,382
1759.43.128.0/189.43.128.1 to 9.43.191.2549.43.191.25516,382
1769.43.192.0/189.43.192.1 to 9.43.255.2549.43.255.25516,382
1779.44.0.0/189.44.0.1 to 9.44.63.2549.44.63.25516,382
1789.44.64.0/189.44.64.1 to 9.44.127.2549.44.127.25516,382
1799.44.128.0/189.44.128.1 to 9.44.191.2549.44.191.25516,382
1809.44.192.0/189.44.192.1 to 9.44.255.2549.44.255.25516,382
1819.45.0.0/189.45.0.1 to 9.45.63.2549.45.63.25516,382
1829.45.64.0/189.45.64.1 to 9.45.127.2549.45.127.25516,382
1839.45.128.0/189.45.128.1 to 9.45.191.2549.45.191.25516,382
1849.45.192.0/189.45.192.1 to 9.45.255.2549.45.255.25516,382
1859.46.0.0/189.46.0.1 to 9.46.63.2549.46.63.25516,382
1869.46.64.0/189.46.64.1 to 9.46.127.2549.46.127.25516,382
1879.46.128.0/189.46.128.1 to 9.46.191.2549.46.191.25516,382
1889.46.192.0/189.46.192.1 to 9.46.255.2549.46.255.25516,382
1899.47.0.0/189.47.0.1 to 9.47.63.2549.47.63.25516,382
1909.47.64.0/189.47.64.1 to 9.47.127.2549.47.127.25516,382
1919.47.128.0/189.47.128.1 to 9.47.191.2549.47.191.25516,382
1929.47.192.0/189.47.192.1 to 9.47.255.2549.47.255.25516,382
1939.48.0.0/189.48.0.1 to 9.48.63.2549.48.63.25516,382
1949.48.64.0/189.48.64.1 to 9.48.127.2549.48.127.25516,382
1959.48.128.0/189.48.128.1 to 9.48.191.2549.48.191.25516,382
1969.48.192.0/189.48.192.1 to 9.48.255.2549.48.255.25516,382
1979.49.0.0/189.49.0.1 to 9.49.63.2549.49.63.25516,382
1989.49.64.0/189.49.64.1 to 9.49.127.2549.49.127.25516,382
1999.49.128.0/189.49.128.1 to 9.49.191.2549.49.191.25516,382
2009.49.192.0/189.49.192.1 to 9.49.255.2549.49.255.25516,382
2019.50.0.0/189.50.0.1 to 9.50.63.2549.50.63.25516,382
2029.50.64.0/189.50.64.1 to 9.50.127.2549.50.127.25516,382
2039.50.128.0/189.50.128.1 to 9.50.191.2549.50.191.25516,382
2049.50.192.0/189.50.192.1 to 9.50.255.2549.50.255.25516,382
2059.51.0.0/189.51.0.1 to 9.51.63.2549.51.63.25516,382
2069.51.64.0/189.51.64.1 to 9.51.127.2549.51.127.25516,382
2079.51.128.0/189.51.128.1 to 9.51.191.2549.51.191.25516,382
2089.51.192.0/189.51.192.1 to 9.51.255.2549.51.255.25516,382
2099.52.0.0/189.52.0.1 to 9.52.63.2549.52.63.25516,382
2109.52.64.0/189.52.64.1 to 9.52.127.2549.52.127.25516,382
2119.52.128.0/189.52.128.1 to 9.52.191.2549.52.191.25516,382
2129.52.192.0/189.52.192.1 to 9.52.255.2549.52.255.25516,382
2139.53.0.0/189.53.0.1 to 9.53.63.2549.53.63.25516,382
2149.53.64.0/189.53.64.1 to 9.53.127.2549.53.127.25516,382
2159.53.128.0/189.53.128.1 to 9.53.191.2549.53.191.25516,382
2169.53.192.0/189.53.192.1 to 9.53.255.2549.53.255.25516,382
2179.54.0.0/189.54.0.1 to 9.54.63.2549.54.63.25516,382
2189.54.64.0/189.54.64.1 to 9.54.127.2549.54.127.25516,382
2199.54.128.0/189.54.128.1 to 9.54.191.2549.54.191.25516,382
2209.54.192.0/189.54.192.1 to 9.54.255.2549.54.255.25516,382
2219.55.0.0/189.55.0.1 to 9.55.63.2549.55.63.25516,382
2229.55.64.0/189.55.64.1 to 9.55.127.2549.55.127.25516,382
2239.55.128.0/189.55.128.1 to 9.55.191.2549.55.191.25516,382
2249.55.192.0/189.55.192.1 to 9.55.255.2549.55.255.25516,382
2259.56.0.0/189.56.0.1 to 9.56.63.2549.56.63.25516,382
2269.56.64.0/189.56.64.1 to 9.56.127.2549.56.127.25516,382
2279.56.128.0/189.56.128.1 to 9.56.191.2549.56.191.25516,382
2289.56.192.0/189.56.192.1 to 9.56.255.2549.56.255.25516,382
2299.57.0.0/189.57.0.1 to 9.57.63.2549.57.63.25516,382
2309.57.64.0/189.57.64.1 to 9.57.127.2549.57.127.25516,382
2319.57.128.0/189.57.128.1 to 9.57.191.2549.57.191.25516,382
2329.57.192.0/189.57.192.1 to 9.57.255.2549.57.255.25516,382
2339.58.0.0/189.58.0.1 to 9.58.63.2549.58.63.25516,382
2349.58.64.0/189.58.64.1 to 9.58.127.2549.58.127.25516,382
2359.58.128.0/189.58.128.1 to 9.58.191.2549.58.191.25516,382
2369.58.192.0/189.58.192.1 to 9.58.255.2549.58.255.25516,382
2379.59.0.0/189.59.0.1 to 9.59.63.2549.59.63.25516,382
2389.59.64.0/189.59.64.1 to 9.59.127.2549.59.127.25516,382
2399.59.128.0/189.59.128.1 to 9.59.191.2549.59.191.25516,382
2409.59.192.0/189.59.192.1 to 9.59.255.2549.59.255.25516,382
2419.60.0.0/189.60.0.1 to 9.60.63.2549.60.63.25516,382
2429.60.64.0/189.60.64.1 to 9.60.127.2549.60.127.25516,382
2439.60.128.0/189.60.128.1 to 9.60.191.2549.60.191.25516,382
2449.60.192.0/189.60.192.1 to 9.60.255.2549.60.255.25516,382
2459.61.0.0/189.61.0.1 to 9.61.63.2549.61.63.25516,382
2469.61.64.0/189.61.64.1 to 9.61.127.2549.61.127.25516,382
2479.61.128.0/189.61.128.1 to 9.61.191.2549.61.191.25516,382
2489.61.192.0/189.61.192.1 to 9.61.255.2549.61.255.25516,382
2499.62.0.0/189.62.0.1 to 9.62.63.2549.62.63.25516,382
2509.62.64.0/189.62.64.1 to 9.62.127.2549.62.127.25516,382
2519.62.128.0/189.62.128.1 to 9.62.191.2549.62.191.25516,382
2529.62.192.0/189.62.192.1 to 9.62.255.2549.62.255.25516,382
2539.63.0.0/189.63.0.1 to 9.63.63.2549.63.63.25516,382
2549.63.64.0/189.63.64.1 to 9.63.127.2549.63.127.25516,382
2559.63.128.0/189.63.128.1 to 9.63.191.2549.63.191.25516,382
2569.63.192.0/189.63.192.1 to 9.63.255.2549.63.255.25516,382

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.