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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.

Network48.136.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
48.136.0.0
Broadcast address
48.143.255.255
First usable
48.136.0.1
Last usable
48.143.255.254
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 30880000 · Integer 814219264 to 814743551
Reverse DNS zones
136.48.in-addr.arpa
137.48.in-addr.arpa
138.48.in-addr.arpa
139.48.in-addr.arpa
140.48.in-addr.arpa
141.48.in-addr.arpa
142.48.in-addr.arpa
143.48.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
Address00110000.10001000.00000000.0000000048.136.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00110000.10001000.00000000.0000000048.136.0.0
Broadcast00110000.10001111.11111111.1111111148.143.255.255
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)

48.136.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
148.136.0.0/2048.136.0.1 to 48.136.15.25448.136.15.2554,094
248.136.16.0/2048.136.16.1 to 48.136.31.25448.136.31.2554,094
348.136.32.0/2048.136.32.1 to 48.136.47.25448.136.47.2554,094
448.136.48.0/2048.136.48.1 to 48.136.63.25448.136.63.2554,094
548.136.64.0/2048.136.64.1 to 48.136.79.25448.136.79.2554,094
648.136.80.0/2048.136.80.1 to 48.136.95.25448.136.95.2554,094
748.136.96.0/2048.136.96.1 to 48.136.111.25448.136.111.2554,094
848.136.112.0/2048.136.112.1 to 48.136.127.25448.136.127.2554,094
948.136.128.0/2048.136.128.1 to 48.136.143.25448.136.143.2554,094
1048.136.144.0/2048.136.144.1 to 48.136.159.25448.136.159.2554,094
1148.136.160.0/2048.136.160.1 to 48.136.175.25448.136.175.2554,094
1248.136.176.0/2048.136.176.1 to 48.136.191.25448.136.191.2554,094
1348.136.192.0/2048.136.192.1 to 48.136.207.25448.136.207.2554,094
1448.136.208.0/2048.136.208.1 to 48.136.223.25448.136.223.2554,094
1548.136.224.0/2048.136.224.1 to 48.136.239.25448.136.239.2554,094
1648.136.240.0/2048.136.240.1 to 48.136.255.25448.136.255.2554,094
1748.137.0.0/2048.137.0.1 to 48.137.15.25448.137.15.2554,094
1848.137.16.0/2048.137.16.1 to 48.137.31.25448.137.31.2554,094
1948.137.32.0/2048.137.32.1 to 48.137.47.25448.137.47.2554,094
2048.137.48.0/2048.137.48.1 to 48.137.63.25448.137.63.2554,094
2148.137.64.0/2048.137.64.1 to 48.137.79.25448.137.79.2554,094
2248.137.80.0/2048.137.80.1 to 48.137.95.25448.137.95.2554,094
2348.137.96.0/2048.137.96.1 to 48.137.111.25448.137.111.2554,094
2448.137.112.0/2048.137.112.1 to 48.137.127.25448.137.127.2554,094
2548.137.128.0/2048.137.128.1 to 48.137.143.25448.137.143.2554,094
2648.137.144.0/2048.137.144.1 to 48.137.159.25448.137.159.2554,094
2748.137.160.0/2048.137.160.1 to 48.137.175.25448.137.175.2554,094
2848.137.176.0/2048.137.176.1 to 48.137.191.25448.137.191.2554,094
2948.137.192.0/2048.137.192.1 to 48.137.207.25448.137.207.2554,094
3048.137.208.0/2048.137.208.1 to 48.137.223.25448.137.223.2554,094
3148.137.224.0/2048.137.224.1 to 48.137.239.25448.137.239.2554,094
3248.137.240.0/2048.137.240.1 to 48.137.255.25448.137.255.2554,094
3348.138.0.0/2048.138.0.1 to 48.138.15.25448.138.15.2554,094
3448.138.16.0/2048.138.16.1 to 48.138.31.25448.138.31.2554,094
3548.138.32.0/2048.138.32.1 to 48.138.47.25448.138.47.2554,094
3648.138.48.0/2048.138.48.1 to 48.138.63.25448.138.63.2554,094
3748.138.64.0/2048.138.64.1 to 48.138.79.25448.138.79.2554,094
3848.138.80.0/2048.138.80.1 to 48.138.95.25448.138.95.2554,094
3948.138.96.0/2048.138.96.1 to 48.138.111.25448.138.111.2554,094
4048.138.112.0/2048.138.112.1 to 48.138.127.25448.138.127.2554,094
4148.138.128.0/2048.138.128.1 to 48.138.143.25448.138.143.2554,094
4248.138.144.0/2048.138.144.1 to 48.138.159.25448.138.159.2554,094
4348.138.160.0/2048.138.160.1 to 48.138.175.25448.138.175.2554,094
4448.138.176.0/2048.138.176.1 to 48.138.191.25448.138.191.2554,094
4548.138.192.0/2048.138.192.1 to 48.138.207.25448.138.207.2554,094
4648.138.208.0/2048.138.208.1 to 48.138.223.25448.138.223.2554,094
4748.138.224.0/2048.138.224.1 to 48.138.239.25448.138.239.2554,094
4848.138.240.0/2048.138.240.1 to 48.138.255.25448.138.255.2554,094
4948.139.0.0/2048.139.0.1 to 48.139.15.25448.139.15.2554,094
5048.139.16.0/2048.139.16.1 to 48.139.31.25448.139.31.2554,094
5148.139.32.0/2048.139.32.1 to 48.139.47.25448.139.47.2554,094
5248.139.48.0/2048.139.48.1 to 48.139.63.25448.139.63.2554,094
5348.139.64.0/2048.139.64.1 to 48.139.79.25448.139.79.2554,094
5448.139.80.0/2048.139.80.1 to 48.139.95.25448.139.95.2554,094
5548.139.96.0/2048.139.96.1 to 48.139.111.25448.139.111.2554,094
5648.139.112.0/2048.139.112.1 to 48.139.127.25448.139.127.2554,094
5748.139.128.0/2048.139.128.1 to 48.139.143.25448.139.143.2554,094
5848.139.144.0/2048.139.144.1 to 48.139.159.25448.139.159.2554,094
5948.139.160.0/2048.139.160.1 to 48.139.175.25448.139.175.2554,094
6048.139.176.0/2048.139.176.1 to 48.139.191.25448.139.191.2554,094
6148.139.192.0/2048.139.192.1 to 48.139.207.25448.139.207.2554,094
6248.139.208.0/2048.139.208.1 to 48.139.223.25448.139.223.2554,094
6348.139.224.0/2048.139.224.1 to 48.139.239.25448.139.239.2554,094
6448.139.240.0/2048.139.240.1 to 48.139.255.25448.139.255.2554,094
6548.140.0.0/2048.140.0.1 to 48.140.15.25448.140.15.2554,094
6648.140.16.0/2048.140.16.1 to 48.140.31.25448.140.31.2554,094
6748.140.32.0/2048.140.32.1 to 48.140.47.25448.140.47.2554,094
6848.140.48.0/2048.140.48.1 to 48.140.63.25448.140.63.2554,094
6948.140.64.0/2048.140.64.1 to 48.140.79.25448.140.79.2554,094
7048.140.80.0/2048.140.80.1 to 48.140.95.25448.140.95.2554,094
7148.140.96.0/2048.140.96.1 to 48.140.111.25448.140.111.2554,094
7248.140.112.0/2048.140.112.1 to 48.140.127.25448.140.127.2554,094
7348.140.128.0/2048.140.128.1 to 48.140.143.25448.140.143.2554,094
7448.140.144.0/2048.140.144.1 to 48.140.159.25448.140.159.2554,094
7548.140.160.0/2048.140.160.1 to 48.140.175.25448.140.175.2554,094
7648.140.176.0/2048.140.176.1 to 48.140.191.25448.140.191.2554,094
7748.140.192.0/2048.140.192.1 to 48.140.207.25448.140.207.2554,094
7848.140.208.0/2048.140.208.1 to 48.140.223.25448.140.223.2554,094
7948.140.224.0/2048.140.224.1 to 48.140.239.25448.140.239.2554,094
8048.140.240.0/2048.140.240.1 to 48.140.255.25448.140.255.2554,094
8148.141.0.0/2048.141.0.1 to 48.141.15.25448.141.15.2554,094
8248.141.16.0/2048.141.16.1 to 48.141.31.25448.141.31.2554,094
8348.141.32.0/2048.141.32.1 to 48.141.47.25448.141.47.2554,094
8448.141.48.0/2048.141.48.1 to 48.141.63.25448.141.63.2554,094
8548.141.64.0/2048.141.64.1 to 48.141.79.25448.141.79.2554,094
8648.141.80.0/2048.141.80.1 to 48.141.95.25448.141.95.2554,094
8748.141.96.0/2048.141.96.1 to 48.141.111.25448.141.111.2554,094
8848.141.112.0/2048.141.112.1 to 48.141.127.25448.141.127.2554,094
8948.141.128.0/2048.141.128.1 to 48.141.143.25448.141.143.2554,094
9048.141.144.0/2048.141.144.1 to 48.141.159.25448.141.159.2554,094
9148.141.160.0/2048.141.160.1 to 48.141.175.25448.141.175.2554,094
9248.141.176.0/2048.141.176.1 to 48.141.191.25448.141.191.2554,094
9348.141.192.0/2048.141.192.1 to 48.141.207.25448.141.207.2554,094
9448.141.208.0/2048.141.208.1 to 48.141.223.25448.141.223.2554,094
9548.141.224.0/2048.141.224.1 to 48.141.239.25448.141.239.2554,094
9648.141.240.0/2048.141.240.1 to 48.141.255.25448.141.255.2554,094
9748.142.0.0/2048.142.0.1 to 48.142.15.25448.142.15.2554,094
9848.142.16.0/2048.142.16.1 to 48.142.31.25448.142.31.2554,094
9948.142.32.0/2048.142.32.1 to 48.142.47.25448.142.47.2554,094
10048.142.48.0/2048.142.48.1 to 48.142.63.25448.142.63.2554,094
10148.142.64.0/2048.142.64.1 to 48.142.79.25448.142.79.2554,094
10248.142.80.0/2048.142.80.1 to 48.142.95.25448.142.95.2554,094
10348.142.96.0/2048.142.96.1 to 48.142.111.25448.142.111.2554,094
10448.142.112.0/2048.142.112.1 to 48.142.127.25448.142.127.2554,094
10548.142.128.0/2048.142.128.1 to 48.142.143.25448.142.143.2554,094
10648.142.144.0/2048.142.144.1 to 48.142.159.25448.142.159.2554,094
10748.142.160.0/2048.142.160.1 to 48.142.175.25448.142.175.2554,094
10848.142.176.0/2048.142.176.1 to 48.142.191.25448.142.191.2554,094
10948.142.192.0/2048.142.192.1 to 48.142.207.25448.142.207.2554,094
11048.142.208.0/2048.142.208.1 to 48.142.223.25448.142.223.2554,094
11148.142.224.0/2048.142.224.1 to 48.142.239.25448.142.239.2554,094
11248.142.240.0/2048.142.240.1 to 48.142.255.25448.142.255.2554,094
11348.143.0.0/2048.143.0.1 to 48.143.15.25448.143.15.2554,094
11448.143.16.0/2048.143.16.1 to 48.143.31.25448.143.31.2554,094
11548.143.32.0/2048.143.32.1 to 48.143.47.25448.143.47.2554,094
11648.143.48.0/2048.143.48.1 to 48.143.63.25448.143.63.2554,094
11748.143.64.0/2048.143.64.1 to 48.143.79.25448.143.79.2554,094
11848.143.80.0/2048.143.80.1 to 48.143.95.25448.143.95.2554,094
11948.143.96.0/2048.143.96.1 to 48.143.111.25448.143.111.2554,094
12048.143.112.0/2048.143.112.1 to 48.143.127.25448.143.127.2554,094
12148.143.128.0/2048.143.128.1 to 48.143.143.25448.143.143.2554,094
12248.143.144.0/2048.143.144.1 to 48.143.159.25448.143.159.2554,094
12348.143.160.0/2048.143.160.1 to 48.143.175.25448.143.175.2554,094
12448.143.176.0/2048.143.176.1 to 48.143.191.25448.143.191.2554,094
12548.143.192.0/2048.143.192.1 to 48.143.207.25448.143.207.2554,094
12648.143.208.0/2048.143.208.1 to 48.143.223.25448.143.223.2554,094
12748.143.224.0/2048.143.224.1 to 48.143.239.25448.143.239.2554,094
12848.143.240.0/2048.143.240.1 to 48.143.255.25448.143.255.2554,094

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.