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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.

Network30.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
30.232.0.0
Broadcast address
30.239.255.255
First usable
30.232.0.1
Last usable
30.239.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 1EE80000 · Integer 518520832 to 519045119
Reverse DNS zones
232.30.in-addr.arpa
233.30.in-addr.arpa
234.30.in-addr.arpa
235.30.in-addr.arpa
236.30.in-addr.arpa
237.30.in-addr.arpa
238.30.in-addr.arpa
239.30.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011110.11101000.00000000.0000000030.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00011110.11101000.00000000.0000000030.232.0.0
Broadcast00011110.11101111.11111111.1111111130.239.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

30.232.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
130.232.0.0/2030.232.0.1 to 30.232.15.25430.232.15.2554,094
230.232.16.0/2030.232.16.1 to 30.232.31.25430.232.31.2554,094
330.232.32.0/2030.232.32.1 to 30.232.47.25430.232.47.2554,094
430.232.48.0/2030.232.48.1 to 30.232.63.25430.232.63.2554,094
530.232.64.0/2030.232.64.1 to 30.232.79.25430.232.79.2554,094
630.232.80.0/2030.232.80.1 to 30.232.95.25430.232.95.2554,094
730.232.96.0/2030.232.96.1 to 30.232.111.25430.232.111.2554,094
830.232.112.0/2030.232.112.1 to 30.232.127.25430.232.127.2554,094
930.232.128.0/2030.232.128.1 to 30.232.143.25430.232.143.2554,094
1030.232.144.0/2030.232.144.1 to 30.232.159.25430.232.159.2554,094
1130.232.160.0/2030.232.160.1 to 30.232.175.25430.232.175.2554,094
1230.232.176.0/2030.232.176.1 to 30.232.191.25430.232.191.2554,094
1330.232.192.0/2030.232.192.1 to 30.232.207.25430.232.207.2554,094
1430.232.208.0/2030.232.208.1 to 30.232.223.25430.232.223.2554,094
1530.232.224.0/2030.232.224.1 to 30.232.239.25430.232.239.2554,094
1630.232.240.0/2030.232.240.1 to 30.232.255.25430.232.255.2554,094
1730.233.0.0/2030.233.0.1 to 30.233.15.25430.233.15.2554,094
1830.233.16.0/2030.233.16.1 to 30.233.31.25430.233.31.2554,094
1930.233.32.0/2030.233.32.1 to 30.233.47.25430.233.47.2554,094
2030.233.48.0/2030.233.48.1 to 30.233.63.25430.233.63.2554,094
2130.233.64.0/2030.233.64.1 to 30.233.79.25430.233.79.2554,094
2230.233.80.0/2030.233.80.1 to 30.233.95.25430.233.95.2554,094
2330.233.96.0/2030.233.96.1 to 30.233.111.25430.233.111.2554,094
2430.233.112.0/2030.233.112.1 to 30.233.127.25430.233.127.2554,094
2530.233.128.0/2030.233.128.1 to 30.233.143.25430.233.143.2554,094
2630.233.144.0/2030.233.144.1 to 30.233.159.25430.233.159.2554,094
2730.233.160.0/2030.233.160.1 to 30.233.175.25430.233.175.2554,094
2830.233.176.0/2030.233.176.1 to 30.233.191.25430.233.191.2554,094
2930.233.192.0/2030.233.192.1 to 30.233.207.25430.233.207.2554,094
3030.233.208.0/2030.233.208.1 to 30.233.223.25430.233.223.2554,094
3130.233.224.0/2030.233.224.1 to 30.233.239.25430.233.239.2554,094
3230.233.240.0/2030.233.240.1 to 30.233.255.25430.233.255.2554,094
3330.234.0.0/2030.234.0.1 to 30.234.15.25430.234.15.2554,094
3430.234.16.0/2030.234.16.1 to 30.234.31.25430.234.31.2554,094
3530.234.32.0/2030.234.32.1 to 30.234.47.25430.234.47.2554,094
3630.234.48.0/2030.234.48.1 to 30.234.63.25430.234.63.2554,094
3730.234.64.0/2030.234.64.1 to 30.234.79.25430.234.79.2554,094
3830.234.80.0/2030.234.80.1 to 30.234.95.25430.234.95.2554,094
3930.234.96.0/2030.234.96.1 to 30.234.111.25430.234.111.2554,094
4030.234.112.0/2030.234.112.1 to 30.234.127.25430.234.127.2554,094
4130.234.128.0/2030.234.128.1 to 30.234.143.25430.234.143.2554,094
4230.234.144.0/2030.234.144.1 to 30.234.159.25430.234.159.2554,094
4330.234.160.0/2030.234.160.1 to 30.234.175.25430.234.175.2554,094
4430.234.176.0/2030.234.176.1 to 30.234.191.25430.234.191.2554,094
4530.234.192.0/2030.234.192.1 to 30.234.207.25430.234.207.2554,094
4630.234.208.0/2030.234.208.1 to 30.234.223.25430.234.223.2554,094
4730.234.224.0/2030.234.224.1 to 30.234.239.25430.234.239.2554,094
4830.234.240.0/2030.234.240.1 to 30.234.255.25430.234.255.2554,094
4930.235.0.0/2030.235.0.1 to 30.235.15.25430.235.15.2554,094
5030.235.16.0/2030.235.16.1 to 30.235.31.25430.235.31.2554,094
5130.235.32.0/2030.235.32.1 to 30.235.47.25430.235.47.2554,094
5230.235.48.0/2030.235.48.1 to 30.235.63.25430.235.63.2554,094
5330.235.64.0/2030.235.64.1 to 30.235.79.25430.235.79.2554,094
5430.235.80.0/2030.235.80.1 to 30.235.95.25430.235.95.2554,094
5530.235.96.0/2030.235.96.1 to 30.235.111.25430.235.111.2554,094
5630.235.112.0/2030.235.112.1 to 30.235.127.25430.235.127.2554,094
5730.235.128.0/2030.235.128.1 to 30.235.143.25430.235.143.2554,094
5830.235.144.0/2030.235.144.1 to 30.235.159.25430.235.159.2554,094
5930.235.160.0/2030.235.160.1 to 30.235.175.25430.235.175.2554,094
6030.235.176.0/2030.235.176.1 to 30.235.191.25430.235.191.2554,094
6130.235.192.0/2030.235.192.1 to 30.235.207.25430.235.207.2554,094
6230.235.208.0/2030.235.208.1 to 30.235.223.25430.235.223.2554,094
6330.235.224.0/2030.235.224.1 to 30.235.239.25430.235.239.2554,094
6430.235.240.0/2030.235.240.1 to 30.235.255.25430.235.255.2554,094
6530.236.0.0/2030.236.0.1 to 30.236.15.25430.236.15.2554,094
6630.236.16.0/2030.236.16.1 to 30.236.31.25430.236.31.2554,094
6730.236.32.0/2030.236.32.1 to 30.236.47.25430.236.47.2554,094
6830.236.48.0/2030.236.48.1 to 30.236.63.25430.236.63.2554,094
6930.236.64.0/2030.236.64.1 to 30.236.79.25430.236.79.2554,094
7030.236.80.0/2030.236.80.1 to 30.236.95.25430.236.95.2554,094
7130.236.96.0/2030.236.96.1 to 30.236.111.25430.236.111.2554,094
7230.236.112.0/2030.236.112.1 to 30.236.127.25430.236.127.2554,094
7330.236.128.0/2030.236.128.1 to 30.236.143.25430.236.143.2554,094
7430.236.144.0/2030.236.144.1 to 30.236.159.25430.236.159.2554,094
7530.236.160.0/2030.236.160.1 to 30.236.175.25430.236.175.2554,094
7630.236.176.0/2030.236.176.1 to 30.236.191.25430.236.191.2554,094
7730.236.192.0/2030.236.192.1 to 30.236.207.25430.236.207.2554,094
7830.236.208.0/2030.236.208.1 to 30.236.223.25430.236.223.2554,094
7930.236.224.0/2030.236.224.1 to 30.236.239.25430.236.239.2554,094
8030.236.240.0/2030.236.240.1 to 30.236.255.25430.236.255.2554,094
8130.237.0.0/2030.237.0.1 to 30.237.15.25430.237.15.2554,094
8230.237.16.0/2030.237.16.1 to 30.237.31.25430.237.31.2554,094
8330.237.32.0/2030.237.32.1 to 30.237.47.25430.237.47.2554,094
8430.237.48.0/2030.237.48.1 to 30.237.63.25430.237.63.2554,094
8530.237.64.0/2030.237.64.1 to 30.237.79.25430.237.79.2554,094
8630.237.80.0/2030.237.80.1 to 30.237.95.25430.237.95.2554,094
8730.237.96.0/2030.237.96.1 to 30.237.111.25430.237.111.2554,094
8830.237.112.0/2030.237.112.1 to 30.237.127.25430.237.127.2554,094
8930.237.128.0/2030.237.128.1 to 30.237.143.25430.237.143.2554,094
9030.237.144.0/2030.237.144.1 to 30.237.159.25430.237.159.2554,094
9130.237.160.0/2030.237.160.1 to 30.237.175.25430.237.175.2554,094
9230.237.176.0/2030.237.176.1 to 30.237.191.25430.237.191.2554,094
9330.237.192.0/2030.237.192.1 to 30.237.207.25430.237.207.2554,094
9430.237.208.0/2030.237.208.1 to 30.237.223.25430.237.223.2554,094
9530.237.224.0/2030.237.224.1 to 30.237.239.25430.237.239.2554,094
9630.237.240.0/2030.237.240.1 to 30.237.255.25430.237.255.2554,094
9730.238.0.0/2030.238.0.1 to 30.238.15.25430.238.15.2554,094
9830.238.16.0/2030.238.16.1 to 30.238.31.25430.238.31.2554,094
9930.238.32.0/2030.238.32.1 to 30.238.47.25430.238.47.2554,094
10030.238.48.0/2030.238.48.1 to 30.238.63.25430.238.63.2554,094
10130.238.64.0/2030.238.64.1 to 30.238.79.25430.238.79.2554,094
10230.238.80.0/2030.238.80.1 to 30.238.95.25430.238.95.2554,094
10330.238.96.0/2030.238.96.1 to 30.238.111.25430.238.111.2554,094
10430.238.112.0/2030.238.112.1 to 30.238.127.25430.238.127.2554,094
10530.238.128.0/2030.238.128.1 to 30.238.143.25430.238.143.2554,094
10630.238.144.0/2030.238.144.1 to 30.238.159.25430.238.159.2554,094
10730.238.160.0/2030.238.160.1 to 30.238.175.25430.238.175.2554,094
10830.238.176.0/2030.238.176.1 to 30.238.191.25430.238.191.2554,094
10930.238.192.0/2030.238.192.1 to 30.238.207.25430.238.207.2554,094
11030.238.208.0/2030.238.208.1 to 30.238.223.25430.238.223.2554,094
11130.238.224.0/2030.238.224.1 to 30.238.239.25430.238.239.2554,094
11230.238.240.0/2030.238.240.1 to 30.238.255.25430.238.255.2554,094
11330.239.0.0/2030.239.0.1 to 30.239.15.25430.239.15.2554,094
11430.239.16.0/2030.239.16.1 to 30.239.31.25430.239.31.2554,094
11530.239.32.0/2030.239.32.1 to 30.239.47.25430.239.47.2554,094
11630.239.48.0/2030.239.48.1 to 30.239.63.25430.239.63.2554,094
11730.239.64.0/2030.239.64.1 to 30.239.79.25430.239.79.2554,094
11830.239.80.0/2030.239.80.1 to 30.239.95.25430.239.95.2554,094
11930.239.96.0/2030.239.96.1 to 30.239.111.25430.239.111.2554,094
12030.239.112.0/2030.239.112.1 to 30.239.127.25430.239.127.2554,094
12130.239.128.0/2030.239.128.1 to 30.239.143.25430.239.143.2554,094
12230.239.144.0/2030.239.144.1 to 30.239.159.25430.239.159.2554,094
12330.239.160.0/2030.239.160.1 to 30.239.175.25430.239.175.2554,094
12430.239.176.0/2030.239.176.1 to 30.239.191.25430.239.191.2554,094
12530.239.192.0/2030.239.192.1 to 30.239.207.25430.239.207.2554,094
12630.239.208.0/2030.239.208.1 to 30.239.223.25430.239.223.2554,094
12730.239.224.0/2030.239.224.1 to 30.239.239.25430.239.239.2554,094
12830.239.240.0/2030.239.240.1 to 30.239.255.25430.239.255.2554,094

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.