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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.

Network16.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
16.232.0.0
Broadcast address
16.239.255.255
First usable
16.232.0.1
Last usable
16.239.255.254
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 10E80000 · Integer 283639808 to 284164095
Reverse DNS zones
232.16.in-addr.arpa
233.16.in-addr.arpa
234.16.in-addr.arpa
235.16.in-addr.arpa
236.16.in-addr.arpa
237.16.in-addr.arpa
238.16.in-addr.arpa
239.16.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
Address00010000.11101000.00000000.0000000016.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00010000.11101000.00000000.0000000016.232.0.0
Broadcast00010000.11101111.11111111.1111111116.239.255.255
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)

16.232.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.232.0.0/2016.232.0.1 to 16.232.15.25416.232.15.2554,094
216.232.16.0/2016.232.16.1 to 16.232.31.25416.232.31.2554,094
316.232.32.0/2016.232.32.1 to 16.232.47.25416.232.47.2554,094
416.232.48.0/2016.232.48.1 to 16.232.63.25416.232.63.2554,094
516.232.64.0/2016.232.64.1 to 16.232.79.25416.232.79.2554,094
616.232.80.0/2016.232.80.1 to 16.232.95.25416.232.95.2554,094
716.232.96.0/2016.232.96.1 to 16.232.111.25416.232.111.2554,094
816.232.112.0/2016.232.112.1 to 16.232.127.25416.232.127.2554,094
916.232.128.0/2016.232.128.1 to 16.232.143.25416.232.143.2554,094
1016.232.144.0/2016.232.144.1 to 16.232.159.25416.232.159.2554,094
1116.232.160.0/2016.232.160.1 to 16.232.175.25416.232.175.2554,094
1216.232.176.0/2016.232.176.1 to 16.232.191.25416.232.191.2554,094
1316.232.192.0/2016.232.192.1 to 16.232.207.25416.232.207.2554,094
1416.232.208.0/2016.232.208.1 to 16.232.223.25416.232.223.2554,094
1516.232.224.0/2016.232.224.1 to 16.232.239.25416.232.239.2554,094
1616.232.240.0/2016.232.240.1 to 16.232.255.25416.232.255.2554,094
1716.233.0.0/2016.233.0.1 to 16.233.15.25416.233.15.2554,094
1816.233.16.0/2016.233.16.1 to 16.233.31.25416.233.31.2554,094
1916.233.32.0/2016.233.32.1 to 16.233.47.25416.233.47.2554,094
2016.233.48.0/2016.233.48.1 to 16.233.63.25416.233.63.2554,094
2116.233.64.0/2016.233.64.1 to 16.233.79.25416.233.79.2554,094
2216.233.80.0/2016.233.80.1 to 16.233.95.25416.233.95.2554,094
2316.233.96.0/2016.233.96.1 to 16.233.111.25416.233.111.2554,094
2416.233.112.0/2016.233.112.1 to 16.233.127.25416.233.127.2554,094
2516.233.128.0/2016.233.128.1 to 16.233.143.25416.233.143.2554,094
2616.233.144.0/2016.233.144.1 to 16.233.159.25416.233.159.2554,094
2716.233.160.0/2016.233.160.1 to 16.233.175.25416.233.175.2554,094
2816.233.176.0/2016.233.176.1 to 16.233.191.25416.233.191.2554,094
2916.233.192.0/2016.233.192.1 to 16.233.207.25416.233.207.2554,094
3016.233.208.0/2016.233.208.1 to 16.233.223.25416.233.223.2554,094
3116.233.224.0/2016.233.224.1 to 16.233.239.25416.233.239.2554,094
3216.233.240.0/2016.233.240.1 to 16.233.255.25416.233.255.2554,094
3316.234.0.0/2016.234.0.1 to 16.234.15.25416.234.15.2554,094
3416.234.16.0/2016.234.16.1 to 16.234.31.25416.234.31.2554,094
3516.234.32.0/2016.234.32.1 to 16.234.47.25416.234.47.2554,094
3616.234.48.0/2016.234.48.1 to 16.234.63.25416.234.63.2554,094
3716.234.64.0/2016.234.64.1 to 16.234.79.25416.234.79.2554,094
3816.234.80.0/2016.234.80.1 to 16.234.95.25416.234.95.2554,094
3916.234.96.0/2016.234.96.1 to 16.234.111.25416.234.111.2554,094
4016.234.112.0/2016.234.112.1 to 16.234.127.25416.234.127.2554,094
4116.234.128.0/2016.234.128.1 to 16.234.143.25416.234.143.2554,094
4216.234.144.0/2016.234.144.1 to 16.234.159.25416.234.159.2554,094
4316.234.160.0/2016.234.160.1 to 16.234.175.25416.234.175.2554,094
4416.234.176.0/2016.234.176.1 to 16.234.191.25416.234.191.2554,094
4516.234.192.0/2016.234.192.1 to 16.234.207.25416.234.207.2554,094
4616.234.208.0/2016.234.208.1 to 16.234.223.25416.234.223.2554,094
4716.234.224.0/2016.234.224.1 to 16.234.239.25416.234.239.2554,094
4816.234.240.0/2016.234.240.1 to 16.234.255.25416.234.255.2554,094
4916.235.0.0/2016.235.0.1 to 16.235.15.25416.235.15.2554,094
5016.235.16.0/2016.235.16.1 to 16.235.31.25416.235.31.2554,094
5116.235.32.0/2016.235.32.1 to 16.235.47.25416.235.47.2554,094
5216.235.48.0/2016.235.48.1 to 16.235.63.25416.235.63.2554,094
5316.235.64.0/2016.235.64.1 to 16.235.79.25416.235.79.2554,094
5416.235.80.0/2016.235.80.1 to 16.235.95.25416.235.95.2554,094
5516.235.96.0/2016.235.96.1 to 16.235.111.25416.235.111.2554,094
5616.235.112.0/2016.235.112.1 to 16.235.127.25416.235.127.2554,094
5716.235.128.0/2016.235.128.1 to 16.235.143.25416.235.143.2554,094
5816.235.144.0/2016.235.144.1 to 16.235.159.25416.235.159.2554,094
5916.235.160.0/2016.235.160.1 to 16.235.175.25416.235.175.2554,094
6016.235.176.0/2016.235.176.1 to 16.235.191.25416.235.191.2554,094
6116.235.192.0/2016.235.192.1 to 16.235.207.25416.235.207.2554,094
6216.235.208.0/2016.235.208.1 to 16.235.223.25416.235.223.2554,094
6316.235.224.0/2016.235.224.1 to 16.235.239.25416.235.239.2554,094
6416.235.240.0/2016.235.240.1 to 16.235.255.25416.235.255.2554,094
6516.236.0.0/2016.236.0.1 to 16.236.15.25416.236.15.2554,094
6616.236.16.0/2016.236.16.1 to 16.236.31.25416.236.31.2554,094
6716.236.32.0/2016.236.32.1 to 16.236.47.25416.236.47.2554,094
6816.236.48.0/2016.236.48.1 to 16.236.63.25416.236.63.2554,094
6916.236.64.0/2016.236.64.1 to 16.236.79.25416.236.79.2554,094
7016.236.80.0/2016.236.80.1 to 16.236.95.25416.236.95.2554,094
7116.236.96.0/2016.236.96.1 to 16.236.111.25416.236.111.2554,094
7216.236.112.0/2016.236.112.1 to 16.236.127.25416.236.127.2554,094
7316.236.128.0/2016.236.128.1 to 16.236.143.25416.236.143.2554,094
7416.236.144.0/2016.236.144.1 to 16.236.159.25416.236.159.2554,094
7516.236.160.0/2016.236.160.1 to 16.236.175.25416.236.175.2554,094
7616.236.176.0/2016.236.176.1 to 16.236.191.25416.236.191.2554,094
7716.236.192.0/2016.236.192.1 to 16.236.207.25416.236.207.2554,094
7816.236.208.0/2016.236.208.1 to 16.236.223.25416.236.223.2554,094
7916.236.224.0/2016.236.224.1 to 16.236.239.25416.236.239.2554,094
8016.236.240.0/2016.236.240.1 to 16.236.255.25416.236.255.2554,094
8116.237.0.0/2016.237.0.1 to 16.237.15.25416.237.15.2554,094
8216.237.16.0/2016.237.16.1 to 16.237.31.25416.237.31.2554,094
8316.237.32.0/2016.237.32.1 to 16.237.47.25416.237.47.2554,094
8416.237.48.0/2016.237.48.1 to 16.237.63.25416.237.63.2554,094
8516.237.64.0/2016.237.64.1 to 16.237.79.25416.237.79.2554,094
8616.237.80.0/2016.237.80.1 to 16.237.95.25416.237.95.2554,094
8716.237.96.0/2016.237.96.1 to 16.237.111.25416.237.111.2554,094
8816.237.112.0/2016.237.112.1 to 16.237.127.25416.237.127.2554,094
8916.237.128.0/2016.237.128.1 to 16.237.143.25416.237.143.2554,094
9016.237.144.0/2016.237.144.1 to 16.237.159.25416.237.159.2554,094
9116.237.160.0/2016.237.160.1 to 16.237.175.25416.237.175.2554,094
9216.237.176.0/2016.237.176.1 to 16.237.191.25416.237.191.2554,094
9316.237.192.0/2016.237.192.1 to 16.237.207.25416.237.207.2554,094
9416.237.208.0/2016.237.208.1 to 16.237.223.25416.237.223.2554,094
9516.237.224.0/2016.237.224.1 to 16.237.239.25416.237.239.2554,094
9616.237.240.0/2016.237.240.1 to 16.237.255.25416.237.255.2554,094
9716.238.0.0/2016.238.0.1 to 16.238.15.25416.238.15.2554,094
9816.238.16.0/2016.238.16.1 to 16.238.31.25416.238.31.2554,094
9916.238.32.0/2016.238.32.1 to 16.238.47.25416.238.47.2554,094
10016.238.48.0/2016.238.48.1 to 16.238.63.25416.238.63.2554,094
10116.238.64.0/2016.238.64.1 to 16.238.79.25416.238.79.2554,094
10216.238.80.0/2016.238.80.1 to 16.238.95.25416.238.95.2554,094
10316.238.96.0/2016.238.96.1 to 16.238.111.25416.238.111.2554,094
10416.238.112.0/2016.238.112.1 to 16.238.127.25416.238.127.2554,094
10516.238.128.0/2016.238.128.1 to 16.238.143.25416.238.143.2554,094
10616.238.144.0/2016.238.144.1 to 16.238.159.25416.238.159.2554,094
10716.238.160.0/2016.238.160.1 to 16.238.175.25416.238.175.2554,094
10816.238.176.0/2016.238.176.1 to 16.238.191.25416.238.191.2554,094
10916.238.192.0/2016.238.192.1 to 16.238.207.25416.238.207.2554,094
11016.238.208.0/2016.238.208.1 to 16.238.223.25416.238.223.2554,094
11116.238.224.0/2016.238.224.1 to 16.238.239.25416.238.239.2554,094
11216.238.240.0/2016.238.240.1 to 16.238.255.25416.238.255.2554,094
11316.239.0.0/2016.239.0.1 to 16.239.15.25416.239.15.2554,094
11416.239.16.0/2016.239.16.1 to 16.239.31.25416.239.31.2554,094
11516.239.32.0/2016.239.32.1 to 16.239.47.25416.239.47.2554,094
11616.239.48.0/2016.239.48.1 to 16.239.63.25416.239.63.2554,094
11716.239.64.0/2016.239.64.1 to 16.239.79.25416.239.79.2554,094
11816.239.80.0/2016.239.80.1 to 16.239.95.25416.239.95.2554,094
11916.239.96.0/2016.239.96.1 to 16.239.111.25416.239.111.2554,094
12016.239.112.0/2016.239.112.1 to 16.239.127.25416.239.127.2554,094
12116.239.128.0/2016.239.128.1 to 16.239.143.25416.239.143.2554,094
12216.239.144.0/2016.239.144.1 to 16.239.159.25416.239.159.2554,094
12316.239.160.0/2016.239.160.1 to 16.239.175.25416.239.175.2554,094
12416.239.176.0/2016.239.176.1 to 16.239.191.25416.239.191.2554,094
12516.239.192.0/2016.239.192.1 to 16.239.207.25416.239.207.2554,094
12616.239.208.0/2016.239.208.1 to 16.239.223.25416.239.223.2554,094
12716.239.224.0/2016.239.224.1 to 16.239.239.25416.239.239.2554,094
12816.239.240.0/2016.239.240.1 to 16.239.255.25416.239.255.2554,094

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.