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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.

Network63.112.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
63.112.0.0
Broadcast address
63.119.255.255
First usable
63.112.0.1
Last usable
63.119.255.254
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 3F700000 · Integer 1064304640 to 1064828927
Reverse DNS zones
112.63.in-addr.arpa
113.63.in-addr.arpa
114.63.in-addr.arpa
115.63.in-addr.arpa
116.63.in-addr.arpa
117.63.in-addr.arpa
118.63.in-addr.arpa
119.63.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
Address00111111.01110000.00000000.0000000063.112.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00111111.01110000.00000000.0000000063.112.0.0
Broadcast00111111.01110111.11111111.1111111163.119.255.255
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)

63.112.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
163.112.0.0/2063.112.0.1 to 63.112.15.25463.112.15.2554,094
263.112.16.0/2063.112.16.1 to 63.112.31.25463.112.31.2554,094
363.112.32.0/2063.112.32.1 to 63.112.47.25463.112.47.2554,094
463.112.48.0/2063.112.48.1 to 63.112.63.25463.112.63.2554,094
563.112.64.0/2063.112.64.1 to 63.112.79.25463.112.79.2554,094
663.112.80.0/2063.112.80.1 to 63.112.95.25463.112.95.2554,094
763.112.96.0/2063.112.96.1 to 63.112.111.25463.112.111.2554,094
863.112.112.0/2063.112.112.1 to 63.112.127.25463.112.127.2554,094
963.112.128.0/2063.112.128.1 to 63.112.143.25463.112.143.2554,094
1063.112.144.0/2063.112.144.1 to 63.112.159.25463.112.159.2554,094
1163.112.160.0/2063.112.160.1 to 63.112.175.25463.112.175.2554,094
1263.112.176.0/2063.112.176.1 to 63.112.191.25463.112.191.2554,094
1363.112.192.0/2063.112.192.1 to 63.112.207.25463.112.207.2554,094
1463.112.208.0/2063.112.208.1 to 63.112.223.25463.112.223.2554,094
1563.112.224.0/2063.112.224.1 to 63.112.239.25463.112.239.2554,094
1663.112.240.0/2063.112.240.1 to 63.112.255.25463.112.255.2554,094
1763.113.0.0/2063.113.0.1 to 63.113.15.25463.113.15.2554,094
1863.113.16.0/2063.113.16.1 to 63.113.31.25463.113.31.2554,094
1963.113.32.0/2063.113.32.1 to 63.113.47.25463.113.47.2554,094
2063.113.48.0/2063.113.48.1 to 63.113.63.25463.113.63.2554,094
2163.113.64.0/2063.113.64.1 to 63.113.79.25463.113.79.2554,094
2263.113.80.0/2063.113.80.1 to 63.113.95.25463.113.95.2554,094
2363.113.96.0/2063.113.96.1 to 63.113.111.25463.113.111.2554,094
2463.113.112.0/2063.113.112.1 to 63.113.127.25463.113.127.2554,094
2563.113.128.0/2063.113.128.1 to 63.113.143.25463.113.143.2554,094
2663.113.144.0/2063.113.144.1 to 63.113.159.25463.113.159.2554,094
2763.113.160.0/2063.113.160.1 to 63.113.175.25463.113.175.2554,094
2863.113.176.0/2063.113.176.1 to 63.113.191.25463.113.191.2554,094
2963.113.192.0/2063.113.192.1 to 63.113.207.25463.113.207.2554,094
3063.113.208.0/2063.113.208.1 to 63.113.223.25463.113.223.2554,094
3163.113.224.0/2063.113.224.1 to 63.113.239.25463.113.239.2554,094
3263.113.240.0/2063.113.240.1 to 63.113.255.25463.113.255.2554,094
3363.114.0.0/2063.114.0.1 to 63.114.15.25463.114.15.2554,094
3463.114.16.0/2063.114.16.1 to 63.114.31.25463.114.31.2554,094
3563.114.32.0/2063.114.32.1 to 63.114.47.25463.114.47.2554,094
3663.114.48.0/2063.114.48.1 to 63.114.63.25463.114.63.2554,094
3763.114.64.0/2063.114.64.1 to 63.114.79.25463.114.79.2554,094
3863.114.80.0/2063.114.80.1 to 63.114.95.25463.114.95.2554,094
3963.114.96.0/2063.114.96.1 to 63.114.111.25463.114.111.2554,094
4063.114.112.0/2063.114.112.1 to 63.114.127.25463.114.127.2554,094
4163.114.128.0/2063.114.128.1 to 63.114.143.25463.114.143.2554,094
4263.114.144.0/2063.114.144.1 to 63.114.159.25463.114.159.2554,094
4363.114.160.0/2063.114.160.1 to 63.114.175.25463.114.175.2554,094
4463.114.176.0/2063.114.176.1 to 63.114.191.25463.114.191.2554,094
4563.114.192.0/2063.114.192.1 to 63.114.207.25463.114.207.2554,094
4663.114.208.0/2063.114.208.1 to 63.114.223.25463.114.223.2554,094
4763.114.224.0/2063.114.224.1 to 63.114.239.25463.114.239.2554,094
4863.114.240.0/2063.114.240.1 to 63.114.255.25463.114.255.2554,094
4963.115.0.0/2063.115.0.1 to 63.115.15.25463.115.15.2554,094
5063.115.16.0/2063.115.16.1 to 63.115.31.25463.115.31.2554,094
5163.115.32.0/2063.115.32.1 to 63.115.47.25463.115.47.2554,094
5263.115.48.0/2063.115.48.1 to 63.115.63.25463.115.63.2554,094
5363.115.64.0/2063.115.64.1 to 63.115.79.25463.115.79.2554,094
5463.115.80.0/2063.115.80.1 to 63.115.95.25463.115.95.2554,094
5563.115.96.0/2063.115.96.1 to 63.115.111.25463.115.111.2554,094
5663.115.112.0/2063.115.112.1 to 63.115.127.25463.115.127.2554,094
5763.115.128.0/2063.115.128.1 to 63.115.143.25463.115.143.2554,094
5863.115.144.0/2063.115.144.1 to 63.115.159.25463.115.159.2554,094
5963.115.160.0/2063.115.160.1 to 63.115.175.25463.115.175.2554,094
6063.115.176.0/2063.115.176.1 to 63.115.191.25463.115.191.2554,094
6163.115.192.0/2063.115.192.1 to 63.115.207.25463.115.207.2554,094
6263.115.208.0/2063.115.208.1 to 63.115.223.25463.115.223.2554,094
6363.115.224.0/2063.115.224.1 to 63.115.239.25463.115.239.2554,094
6463.115.240.0/2063.115.240.1 to 63.115.255.25463.115.255.2554,094
6563.116.0.0/2063.116.0.1 to 63.116.15.25463.116.15.2554,094
6663.116.16.0/2063.116.16.1 to 63.116.31.25463.116.31.2554,094
6763.116.32.0/2063.116.32.1 to 63.116.47.25463.116.47.2554,094
6863.116.48.0/2063.116.48.1 to 63.116.63.25463.116.63.2554,094
6963.116.64.0/2063.116.64.1 to 63.116.79.25463.116.79.2554,094
7063.116.80.0/2063.116.80.1 to 63.116.95.25463.116.95.2554,094
7163.116.96.0/2063.116.96.1 to 63.116.111.25463.116.111.2554,094
7263.116.112.0/2063.116.112.1 to 63.116.127.25463.116.127.2554,094
7363.116.128.0/2063.116.128.1 to 63.116.143.25463.116.143.2554,094
7463.116.144.0/2063.116.144.1 to 63.116.159.25463.116.159.2554,094
7563.116.160.0/2063.116.160.1 to 63.116.175.25463.116.175.2554,094
7663.116.176.0/2063.116.176.1 to 63.116.191.25463.116.191.2554,094
7763.116.192.0/2063.116.192.1 to 63.116.207.25463.116.207.2554,094
7863.116.208.0/2063.116.208.1 to 63.116.223.25463.116.223.2554,094
7963.116.224.0/2063.116.224.1 to 63.116.239.25463.116.239.2554,094
8063.116.240.0/2063.116.240.1 to 63.116.255.25463.116.255.2554,094
8163.117.0.0/2063.117.0.1 to 63.117.15.25463.117.15.2554,094
8263.117.16.0/2063.117.16.1 to 63.117.31.25463.117.31.2554,094
8363.117.32.0/2063.117.32.1 to 63.117.47.25463.117.47.2554,094
8463.117.48.0/2063.117.48.1 to 63.117.63.25463.117.63.2554,094
8563.117.64.0/2063.117.64.1 to 63.117.79.25463.117.79.2554,094
8663.117.80.0/2063.117.80.1 to 63.117.95.25463.117.95.2554,094
8763.117.96.0/2063.117.96.1 to 63.117.111.25463.117.111.2554,094
8863.117.112.0/2063.117.112.1 to 63.117.127.25463.117.127.2554,094
8963.117.128.0/2063.117.128.1 to 63.117.143.25463.117.143.2554,094
9063.117.144.0/2063.117.144.1 to 63.117.159.25463.117.159.2554,094
9163.117.160.0/2063.117.160.1 to 63.117.175.25463.117.175.2554,094
9263.117.176.0/2063.117.176.1 to 63.117.191.25463.117.191.2554,094
9363.117.192.0/2063.117.192.1 to 63.117.207.25463.117.207.2554,094
9463.117.208.0/2063.117.208.1 to 63.117.223.25463.117.223.2554,094
9563.117.224.0/2063.117.224.1 to 63.117.239.25463.117.239.2554,094
9663.117.240.0/2063.117.240.1 to 63.117.255.25463.117.255.2554,094
9763.118.0.0/2063.118.0.1 to 63.118.15.25463.118.15.2554,094
9863.118.16.0/2063.118.16.1 to 63.118.31.25463.118.31.2554,094
9963.118.32.0/2063.118.32.1 to 63.118.47.25463.118.47.2554,094
10063.118.48.0/2063.118.48.1 to 63.118.63.25463.118.63.2554,094
10163.118.64.0/2063.118.64.1 to 63.118.79.25463.118.79.2554,094
10263.118.80.0/2063.118.80.1 to 63.118.95.25463.118.95.2554,094
10363.118.96.0/2063.118.96.1 to 63.118.111.25463.118.111.2554,094
10463.118.112.0/2063.118.112.1 to 63.118.127.25463.118.127.2554,094
10563.118.128.0/2063.118.128.1 to 63.118.143.25463.118.143.2554,094
10663.118.144.0/2063.118.144.1 to 63.118.159.25463.118.159.2554,094
10763.118.160.0/2063.118.160.1 to 63.118.175.25463.118.175.2554,094
10863.118.176.0/2063.118.176.1 to 63.118.191.25463.118.191.2554,094
10963.118.192.0/2063.118.192.1 to 63.118.207.25463.118.207.2554,094
11063.118.208.0/2063.118.208.1 to 63.118.223.25463.118.223.2554,094
11163.118.224.0/2063.118.224.1 to 63.118.239.25463.118.239.2554,094
11263.118.240.0/2063.118.240.1 to 63.118.255.25463.118.255.2554,094
11363.119.0.0/2063.119.0.1 to 63.119.15.25463.119.15.2554,094
11463.119.16.0/2063.119.16.1 to 63.119.31.25463.119.31.2554,094
11563.119.32.0/2063.119.32.1 to 63.119.47.25463.119.47.2554,094
11663.119.48.0/2063.119.48.1 to 63.119.63.25463.119.63.2554,094
11763.119.64.0/2063.119.64.1 to 63.119.79.25463.119.79.2554,094
11863.119.80.0/2063.119.80.1 to 63.119.95.25463.119.95.2554,094
11963.119.96.0/2063.119.96.1 to 63.119.111.25463.119.111.2554,094
12063.119.112.0/2063.119.112.1 to 63.119.127.25463.119.127.2554,094
12163.119.128.0/2063.119.128.1 to 63.119.143.25463.119.143.2554,094
12263.119.144.0/2063.119.144.1 to 63.119.159.25463.119.159.2554,094
12363.119.160.0/2063.119.160.1 to 63.119.175.25463.119.175.2554,094
12463.119.176.0/2063.119.176.1 to 63.119.191.25463.119.191.2554,094
12563.119.192.0/2063.119.192.1 to 63.119.207.25463.119.207.2554,094
12663.119.208.0/2063.119.208.1 to 63.119.223.25463.119.223.2554,094
12763.119.224.0/2063.119.224.1 to 63.119.239.25463.119.239.2554,094
12863.119.240.0/2063.119.240.1 to 63.119.255.25463.119.255.2554,094

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.