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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.

Network5.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
5.0.0.0
Broadcast address
5.63.255.255
First usable
5.0.0.1
Last usable
5.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 05000000 · Integer 83886080 to 88080383
Reverse DNS zones
0.5.in-addr.arpa
1.5.in-addr.arpa
2.5.in-addr.arpa
3.5.in-addr.arpa
4.5.in-addr.arpa
5.5.in-addr.arpa
6.5.in-addr.arpa
7.5.in-addr.arpa
8.5.in-addr.arpa
9.5.in-addr.arpa
10.5.in-addr.arpa
11.5.in-addr.arpa
12.5.in-addr.arpa
13.5.in-addr.arpa
14.5.in-addr.arpa
15.5.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000101.00000000.00000000.000000005.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00000101.00000000.00000000.000000005.0.0.0
Broadcast00000101.00111111.11111111.111111115.63.255.255
Split into smaller subnets/19
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

5.0.0.0/10 makes 512 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
15.0.0.0/195.0.0.1 to 5.0.31.2545.0.31.2558,190
25.0.32.0/195.0.32.1 to 5.0.63.2545.0.63.2558,190
35.0.64.0/195.0.64.1 to 5.0.95.2545.0.95.2558,190
45.0.96.0/195.0.96.1 to 5.0.127.2545.0.127.2558,190
55.0.128.0/195.0.128.1 to 5.0.159.2545.0.159.2558,190
65.0.160.0/195.0.160.1 to 5.0.191.2545.0.191.2558,190
75.0.192.0/195.0.192.1 to 5.0.223.2545.0.223.2558,190
85.0.224.0/195.0.224.1 to 5.0.255.2545.0.255.2558,190
95.1.0.0/195.1.0.1 to 5.1.31.2545.1.31.2558,190
105.1.32.0/195.1.32.1 to 5.1.63.2545.1.63.2558,190
115.1.64.0/195.1.64.1 to 5.1.95.2545.1.95.2558,190
125.1.96.0/195.1.96.1 to 5.1.127.2545.1.127.2558,190
135.1.128.0/195.1.128.1 to 5.1.159.2545.1.159.2558,190
145.1.160.0/195.1.160.1 to 5.1.191.2545.1.191.2558,190
155.1.192.0/195.1.192.1 to 5.1.223.2545.1.223.2558,190
165.1.224.0/195.1.224.1 to 5.1.255.2545.1.255.2558,190
175.2.0.0/195.2.0.1 to 5.2.31.2545.2.31.2558,190
185.2.32.0/195.2.32.1 to 5.2.63.2545.2.63.2558,190
195.2.64.0/195.2.64.1 to 5.2.95.2545.2.95.2558,190
205.2.96.0/195.2.96.1 to 5.2.127.2545.2.127.2558,190
215.2.128.0/195.2.128.1 to 5.2.159.2545.2.159.2558,190
225.2.160.0/195.2.160.1 to 5.2.191.2545.2.191.2558,190
235.2.192.0/195.2.192.1 to 5.2.223.2545.2.223.2558,190
245.2.224.0/195.2.224.1 to 5.2.255.2545.2.255.2558,190
255.3.0.0/195.3.0.1 to 5.3.31.2545.3.31.2558,190
265.3.32.0/195.3.32.1 to 5.3.63.2545.3.63.2558,190
275.3.64.0/195.3.64.1 to 5.3.95.2545.3.95.2558,190
285.3.96.0/195.3.96.1 to 5.3.127.2545.3.127.2558,190
295.3.128.0/195.3.128.1 to 5.3.159.2545.3.159.2558,190
305.3.160.0/195.3.160.1 to 5.3.191.2545.3.191.2558,190
315.3.192.0/195.3.192.1 to 5.3.223.2545.3.223.2558,190
325.3.224.0/195.3.224.1 to 5.3.255.2545.3.255.2558,190
335.4.0.0/195.4.0.1 to 5.4.31.2545.4.31.2558,190
345.4.32.0/195.4.32.1 to 5.4.63.2545.4.63.2558,190
355.4.64.0/195.4.64.1 to 5.4.95.2545.4.95.2558,190
365.4.96.0/195.4.96.1 to 5.4.127.2545.4.127.2558,190
375.4.128.0/195.4.128.1 to 5.4.159.2545.4.159.2558,190
385.4.160.0/195.4.160.1 to 5.4.191.2545.4.191.2558,190
395.4.192.0/195.4.192.1 to 5.4.223.2545.4.223.2558,190
405.4.224.0/195.4.224.1 to 5.4.255.2545.4.255.2558,190
415.5.0.0/195.5.0.1 to 5.5.31.2545.5.31.2558,190
425.5.32.0/195.5.32.1 to 5.5.63.2545.5.63.2558,190
435.5.64.0/195.5.64.1 to 5.5.95.2545.5.95.2558,190
445.5.96.0/195.5.96.1 to 5.5.127.2545.5.127.2558,190
455.5.128.0/195.5.128.1 to 5.5.159.2545.5.159.2558,190
465.5.160.0/195.5.160.1 to 5.5.191.2545.5.191.2558,190
475.5.192.0/195.5.192.1 to 5.5.223.2545.5.223.2558,190
485.5.224.0/195.5.224.1 to 5.5.255.2545.5.255.2558,190
495.6.0.0/195.6.0.1 to 5.6.31.2545.6.31.2558,190
505.6.32.0/195.6.32.1 to 5.6.63.2545.6.63.2558,190
515.6.64.0/195.6.64.1 to 5.6.95.2545.6.95.2558,190
525.6.96.0/195.6.96.1 to 5.6.127.2545.6.127.2558,190
535.6.128.0/195.6.128.1 to 5.6.159.2545.6.159.2558,190
545.6.160.0/195.6.160.1 to 5.6.191.2545.6.191.2558,190
555.6.192.0/195.6.192.1 to 5.6.223.2545.6.223.2558,190
565.6.224.0/195.6.224.1 to 5.6.255.2545.6.255.2558,190
575.7.0.0/195.7.0.1 to 5.7.31.2545.7.31.2558,190
585.7.32.0/195.7.32.1 to 5.7.63.2545.7.63.2558,190
595.7.64.0/195.7.64.1 to 5.7.95.2545.7.95.2558,190
605.7.96.0/195.7.96.1 to 5.7.127.2545.7.127.2558,190
615.7.128.0/195.7.128.1 to 5.7.159.2545.7.159.2558,190
625.7.160.0/195.7.160.1 to 5.7.191.2545.7.191.2558,190
635.7.192.0/195.7.192.1 to 5.7.223.2545.7.223.2558,190
645.7.224.0/195.7.224.1 to 5.7.255.2545.7.255.2558,190
655.8.0.0/195.8.0.1 to 5.8.31.2545.8.31.2558,190
665.8.32.0/195.8.32.1 to 5.8.63.2545.8.63.2558,190
675.8.64.0/195.8.64.1 to 5.8.95.2545.8.95.2558,190
685.8.96.0/195.8.96.1 to 5.8.127.2545.8.127.2558,190
695.8.128.0/195.8.128.1 to 5.8.159.2545.8.159.2558,190
705.8.160.0/195.8.160.1 to 5.8.191.2545.8.191.2558,190
715.8.192.0/195.8.192.1 to 5.8.223.2545.8.223.2558,190
725.8.224.0/195.8.224.1 to 5.8.255.2545.8.255.2558,190
735.9.0.0/195.9.0.1 to 5.9.31.2545.9.31.2558,190
745.9.32.0/195.9.32.1 to 5.9.63.2545.9.63.2558,190
755.9.64.0/195.9.64.1 to 5.9.95.2545.9.95.2558,190
765.9.96.0/195.9.96.1 to 5.9.127.2545.9.127.2558,190
775.9.128.0/195.9.128.1 to 5.9.159.2545.9.159.2558,190
785.9.160.0/195.9.160.1 to 5.9.191.2545.9.191.2558,190
795.9.192.0/195.9.192.1 to 5.9.223.2545.9.223.2558,190
805.9.224.0/195.9.224.1 to 5.9.255.2545.9.255.2558,190
815.10.0.0/195.10.0.1 to 5.10.31.2545.10.31.2558,190
825.10.32.0/195.10.32.1 to 5.10.63.2545.10.63.2558,190
835.10.64.0/195.10.64.1 to 5.10.95.2545.10.95.2558,190
845.10.96.0/195.10.96.1 to 5.10.127.2545.10.127.2558,190
855.10.128.0/195.10.128.1 to 5.10.159.2545.10.159.2558,190
865.10.160.0/195.10.160.1 to 5.10.191.2545.10.191.2558,190
875.10.192.0/195.10.192.1 to 5.10.223.2545.10.223.2558,190
885.10.224.0/195.10.224.1 to 5.10.255.2545.10.255.2558,190
895.11.0.0/195.11.0.1 to 5.11.31.2545.11.31.2558,190
905.11.32.0/195.11.32.1 to 5.11.63.2545.11.63.2558,190
915.11.64.0/195.11.64.1 to 5.11.95.2545.11.95.2558,190
925.11.96.0/195.11.96.1 to 5.11.127.2545.11.127.2558,190
935.11.128.0/195.11.128.1 to 5.11.159.2545.11.159.2558,190
945.11.160.0/195.11.160.1 to 5.11.191.2545.11.191.2558,190
955.11.192.0/195.11.192.1 to 5.11.223.2545.11.223.2558,190
965.11.224.0/195.11.224.1 to 5.11.255.2545.11.255.2558,190
975.12.0.0/195.12.0.1 to 5.12.31.2545.12.31.2558,190
985.12.32.0/195.12.32.1 to 5.12.63.2545.12.63.2558,190
995.12.64.0/195.12.64.1 to 5.12.95.2545.12.95.2558,190
1005.12.96.0/195.12.96.1 to 5.12.127.2545.12.127.2558,190
1015.12.128.0/195.12.128.1 to 5.12.159.2545.12.159.2558,190
1025.12.160.0/195.12.160.1 to 5.12.191.2545.12.191.2558,190
1035.12.192.0/195.12.192.1 to 5.12.223.2545.12.223.2558,190
1045.12.224.0/195.12.224.1 to 5.12.255.2545.12.255.2558,190
1055.13.0.0/195.13.0.1 to 5.13.31.2545.13.31.2558,190
1065.13.32.0/195.13.32.1 to 5.13.63.2545.13.63.2558,190
1075.13.64.0/195.13.64.1 to 5.13.95.2545.13.95.2558,190
1085.13.96.0/195.13.96.1 to 5.13.127.2545.13.127.2558,190
1095.13.128.0/195.13.128.1 to 5.13.159.2545.13.159.2558,190
1105.13.160.0/195.13.160.1 to 5.13.191.2545.13.191.2558,190
1115.13.192.0/195.13.192.1 to 5.13.223.2545.13.223.2558,190
1125.13.224.0/195.13.224.1 to 5.13.255.2545.13.255.2558,190
1135.14.0.0/195.14.0.1 to 5.14.31.2545.14.31.2558,190
1145.14.32.0/195.14.32.1 to 5.14.63.2545.14.63.2558,190
1155.14.64.0/195.14.64.1 to 5.14.95.2545.14.95.2558,190
1165.14.96.0/195.14.96.1 to 5.14.127.2545.14.127.2558,190
1175.14.128.0/195.14.128.1 to 5.14.159.2545.14.159.2558,190
1185.14.160.0/195.14.160.1 to 5.14.191.2545.14.191.2558,190
1195.14.192.0/195.14.192.1 to 5.14.223.2545.14.223.2558,190
1205.14.224.0/195.14.224.1 to 5.14.255.2545.14.255.2558,190
1215.15.0.0/195.15.0.1 to 5.15.31.2545.15.31.2558,190
1225.15.32.0/195.15.32.1 to 5.15.63.2545.15.63.2558,190
1235.15.64.0/195.15.64.1 to 5.15.95.2545.15.95.2558,190
1245.15.96.0/195.15.96.1 to 5.15.127.2545.15.127.2558,190
1255.15.128.0/195.15.128.1 to 5.15.159.2545.15.159.2558,190
1265.15.160.0/195.15.160.1 to 5.15.191.2545.15.191.2558,190
1275.15.192.0/195.15.192.1 to 5.15.223.2545.15.223.2558,190
1285.15.224.0/195.15.224.1 to 5.15.255.2545.15.255.2558,190
1295.16.0.0/195.16.0.1 to 5.16.31.2545.16.31.2558,190
1305.16.32.0/195.16.32.1 to 5.16.63.2545.16.63.2558,190
1315.16.64.0/195.16.64.1 to 5.16.95.2545.16.95.2558,190
1325.16.96.0/195.16.96.1 to 5.16.127.2545.16.127.2558,190
1335.16.128.0/195.16.128.1 to 5.16.159.2545.16.159.2558,190
1345.16.160.0/195.16.160.1 to 5.16.191.2545.16.191.2558,190
1355.16.192.0/195.16.192.1 to 5.16.223.2545.16.223.2558,190
1365.16.224.0/195.16.224.1 to 5.16.255.2545.16.255.2558,190
1375.17.0.0/195.17.0.1 to 5.17.31.2545.17.31.2558,190
1385.17.32.0/195.17.32.1 to 5.17.63.2545.17.63.2558,190
1395.17.64.0/195.17.64.1 to 5.17.95.2545.17.95.2558,190
1405.17.96.0/195.17.96.1 to 5.17.127.2545.17.127.2558,190
1415.17.128.0/195.17.128.1 to 5.17.159.2545.17.159.2558,190
1425.17.160.0/195.17.160.1 to 5.17.191.2545.17.191.2558,190
1435.17.192.0/195.17.192.1 to 5.17.223.2545.17.223.2558,190
1445.17.224.0/195.17.224.1 to 5.17.255.2545.17.255.2558,190
1455.18.0.0/195.18.0.1 to 5.18.31.2545.18.31.2558,190
1465.18.32.0/195.18.32.1 to 5.18.63.2545.18.63.2558,190
1475.18.64.0/195.18.64.1 to 5.18.95.2545.18.95.2558,190
1485.18.96.0/195.18.96.1 to 5.18.127.2545.18.127.2558,190
1495.18.128.0/195.18.128.1 to 5.18.159.2545.18.159.2558,190
1505.18.160.0/195.18.160.1 to 5.18.191.2545.18.191.2558,190
1515.18.192.0/195.18.192.1 to 5.18.223.2545.18.223.2558,190
1525.18.224.0/195.18.224.1 to 5.18.255.2545.18.255.2558,190
1535.19.0.0/195.19.0.1 to 5.19.31.2545.19.31.2558,190
1545.19.32.0/195.19.32.1 to 5.19.63.2545.19.63.2558,190
1555.19.64.0/195.19.64.1 to 5.19.95.2545.19.95.2558,190
1565.19.96.0/195.19.96.1 to 5.19.127.2545.19.127.2558,190
1575.19.128.0/195.19.128.1 to 5.19.159.2545.19.159.2558,190
1585.19.160.0/195.19.160.1 to 5.19.191.2545.19.191.2558,190
1595.19.192.0/195.19.192.1 to 5.19.223.2545.19.223.2558,190
1605.19.224.0/195.19.224.1 to 5.19.255.2545.19.255.2558,190
1615.20.0.0/195.20.0.1 to 5.20.31.2545.20.31.2558,190
1625.20.32.0/195.20.32.1 to 5.20.63.2545.20.63.2558,190
1635.20.64.0/195.20.64.1 to 5.20.95.2545.20.95.2558,190
1645.20.96.0/195.20.96.1 to 5.20.127.2545.20.127.2558,190
1655.20.128.0/195.20.128.1 to 5.20.159.2545.20.159.2558,190
1665.20.160.0/195.20.160.1 to 5.20.191.2545.20.191.2558,190
1675.20.192.0/195.20.192.1 to 5.20.223.2545.20.223.2558,190
1685.20.224.0/195.20.224.1 to 5.20.255.2545.20.255.2558,190
1695.21.0.0/195.21.0.1 to 5.21.31.2545.21.31.2558,190
1705.21.32.0/195.21.32.1 to 5.21.63.2545.21.63.2558,190
1715.21.64.0/195.21.64.1 to 5.21.95.2545.21.95.2558,190
1725.21.96.0/195.21.96.1 to 5.21.127.2545.21.127.2558,190
1735.21.128.0/195.21.128.1 to 5.21.159.2545.21.159.2558,190
1745.21.160.0/195.21.160.1 to 5.21.191.2545.21.191.2558,190
1755.21.192.0/195.21.192.1 to 5.21.223.2545.21.223.2558,190
1765.21.224.0/195.21.224.1 to 5.21.255.2545.21.255.2558,190
1775.22.0.0/195.22.0.1 to 5.22.31.2545.22.31.2558,190
1785.22.32.0/195.22.32.1 to 5.22.63.2545.22.63.2558,190
1795.22.64.0/195.22.64.1 to 5.22.95.2545.22.95.2558,190
1805.22.96.0/195.22.96.1 to 5.22.127.2545.22.127.2558,190
1815.22.128.0/195.22.128.1 to 5.22.159.2545.22.159.2558,190
1825.22.160.0/195.22.160.1 to 5.22.191.2545.22.191.2558,190
1835.22.192.0/195.22.192.1 to 5.22.223.2545.22.223.2558,190
1845.22.224.0/195.22.224.1 to 5.22.255.2545.22.255.2558,190
1855.23.0.0/195.23.0.1 to 5.23.31.2545.23.31.2558,190
1865.23.32.0/195.23.32.1 to 5.23.63.2545.23.63.2558,190
1875.23.64.0/195.23.64.1 to 5.23.95.2545.23.95.2558,190
1885.23.96.0/195.23.96.1 to 5.23.127.2545.23.127.2558,190
1895.23.128.0/195.23.128.1 to 5.23.159.2545.23.159.2558,190
1905.23.160.0/195.23.160.1 to 5.23.191.2545.23.191.2558,190
1915.23.192.0/195.23.192.1 to 5.23.223.2545.23.223.2558,190
1925.23.224.0/195.23.224.1 to 5.23.255.2545.23.255.2558,190
1935.24.0.0/195.24.0.1 to 5.24.31.2545.24.31.2558,190
1945.24.32.0/195.24.32.1 to 5.24.63.2545.24.63.2558,190
1955.24.64.0/195.24.64.1 to 5.24.95.2545.24.95.2558,190
1965.24.96.0/195.24.96.1 to 5.24.127.2545.24.127.2558,190
1975.24.128.0/195.24.128.1 to 5.24.159.2545.24.159.2558,190
1985.24.160.0/195.24.160.1 to 5.24.191.2545.24.191.2558,190
1995.24.192.0/195.24.192.1 to 5.24.223.2545.24.223.2558,190
2005.24.224.0/195.24.224.1 to 5.24.255.2545.24.255.2558,190
2015.25.0.0/195.25.0.1 to 5.25.31.2545.25.31.2558,190
2025.25.32.0/195.25.32.1 to 5.25.63.2545.25.63.2558,190
2035.25.64.0/195.25.64.1 to 5.25.95.2545.25.95.2558,190
2045.25.96.0/195.25.96.1 to 5.25.127.2545.25.127.2558,190
2055.25.128.0/195.25.128.1 to 5.25.159.2545.25.159.2558,190
2065.25.160.0/195.25.160.1 to 5.25.191.2545.25.191.2558,190
2075.25.192.0/195.25.192.1 to 5.25.223.2545.25.223.2558,190
2085.25.224.0/195.25.224.1 to 5.25.255.2545.25.255.2558,190
2095.26.0.0/195.26.0.1 to 5.26.31.2545.26.31.2558,190
2105.26.32.0/195.26.32.1 to 5.26.63.2545.26.63.2558,190
2115.26.64.0/195.26.64.1 to 5.26.95.2545.26.95.2558,190
2125.26.96.0/195.26.96.1 to 5.26.127.2545.26.127.2558,190
2135.26.128.0/195.26.128.1 to 5.26.159.2545.26.159.2558,190
2145.26.160.0/195.26.160.1 to 5.26.191.2545.26.191.2558,190
2155.26.192.0/195.26.192.1 to 5.26.223.2545.26.223.2558,190
2165.26.224.0/195.26.224.1 to 5.26.255.2545.26.255.2558,190
2175.27.0.0/195.27.0.1 to 5.27.31.2545.27.31.2558,190
2185.27.32.0/195.27.32.1 to 5.27.63.2545.27.63.2558,190
2195.27.64.0/195.27.64.1 to 5.27.95.2545.27.95.2558,190
2205.27.96.0/195.27.96.1 to 5.27.127.2545.27.127.2558,190
2215.27.128.0/195.27.128.1 to 5.27.159.2545.27.159.2558,190
2225.27.160.0/195.27.160.1 to 5.27.191.2545.27.191.2558,190
2235.27.192.0/195.27.192.1 to 5.27.223.2545.27.223.2558,190
2245.27.224.0/195.27.224.1 to 5.27.255.2545.27.255.2558,190
2255.28.0.0/195.28.0.1 to 5.28.31.2545.28.31.2558,190
2265.28.32.0/195.28.32.1 to 5.28.63.2545.28.63.2558,190
2275.28.64.0/195.28.64.1 to 5.28.95.2545.28.95.2558,190
2285.28.96.0/195.28.96.1 to 5.28.127.2545.28.127.2558,190
2295.28.128.0/195.28.128.1 to 5.28.159.2545.28.159.2558,190
2305.28.160.0/195.28.160.1 to 5.28.191.2545.28.191.2558,190
2315.28.192.0/195.28.192.1 to 5.28.223.2545.28.223.2558,190
2325.28.224.0/195.28.224.1 to 5.28.255.2545.28.255.2558,190
2335.29.0.0/195.29.0.1 to 5.29.31.2545.29.31.2558,190
2345.29.32.0/195.29.32.1 to 5.29.63.2545.29.63.2558,190
2355.29.64.0/195.29.64.1 to 5.29.95.2545.29.95.2558,190
2365.29.96.0/195.29.96.1 to 5.29.127.2545.29.127.2558,190
2375.29.128.0/195.29.128.1 to 5.29.159.2545.29.159.2558,190
2385.29.160.0/195.29.160.1 to 5.29.191.2545.29.191.2558,190
2395.29.192.0/195.29.192.1 to 5.29.223.2545.29.223.2558,190
2405.29.224.0/195.29.224.1 to 5.29.255.2545.29.255.2558,190
2415.30.0.0/195.30.0.1 to 5.30.31.2545.30.31.2558,190
2425.30.32.0/195.30.32.1 to 5.30.63.2545.30.63.2558,190
2435.30.64.0/195.30.64.1 to 5.30.95.2545.30.95.2558,190
2445.30.96.0/195.30.96.1 to 5.30.127.2545.30.127.2558,190
2455.30.128.0/195.30.128.1 to 5.30.159.2545.30.159.2558,190
2465.30.160.0/195.30.160.1 to 5.30.191.2545.30.191.2558,190
2475.30.192.0/195.30.192.1 to 5.30.223.2545.30.223.2558,190
2485.30.224.0/195.30.224.1 to 5.30.255.2545.30.255.2558,190
2495.31.0.0/195.31.0.1 to 5.31.31.2545.31.31.2558,190
2505.31.32.0/195.31.32.1 to 5.31.63.2545.31.63.2558,190
2515.31.64.0/195.31.64.1 to 5.31.95.2545.31.95.2558,190
2525.31.96.0/195.31.96.1 to 5.31.127.2545.31.127.2558,190
2535.31.128.0/195.31.128.1 to 5.31.159.2545.31.159.2558,190
2545.31.160.0/195.31.160.1 to 5.31.191.2545.31.191.2558,190
2555.31.192.0/195.31.192.1 to 5.31.223.2545.31.223.2558,190
2565.31.224.0/195.31.224.1 to 5.31.255.2545.31.255.2558,190

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.