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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.

Network96.32.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
96.32.0.0
Broadcast address
96.47.255.255
First usable
96.32.0.1
Last usable
96.47.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 60200000 · Integer 1612709888 to 1613758463
Reverse DNS zones
32.96.in-addr.arpa
33.96.in-addr.arpa
34.96.in-addr.arpa
35.96.in-addr.arpa
36.96.in-addr.arpa
37.96.in-addr.arpa
38.96.in-addr.arpa
39.96.in-addr.arpa
40.96.in-addr.arpa
41.96.in-addr.arpa
42.96.in-addr.arpa
43.96.in-addr.arpa
44.96.in-addr.arpa
45.96.in-addr.arpa
46.96.in-addr.arpa
47.96.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100000.00100000.00000000.0000000096.32.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01100000.00100000.00000000.0000000096.32.0.0
Broadcast01100000.00101111.11111111.1111111196.47.255.255
Split into smaller subnets/19
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

96.32.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
196.32.0.0/1996.32.0.1 to 96.32.31.25496.32.31.2558,190
296.32.32.0/1996.32.32.1 to 96.32.63.25496.32.63.2558,190
396.32.64.0/1996.32.64.1 to 96.32.95.25496.32.95.2558,190
496.32.96.0/1996.32.96.1 to 96.32.127.25496.32.127.2558,190
596.32.128.0/1996.32.128.1 to 96.32.159.25496.32.159.2558,190
696.32.160.0/1996.32.160.1 to 96.32.191.25496.32.191.2558,190
796.32.192.0/1996.32.192.1 to 96.32.223.25496.32.223.2558,190
896.32.224.0/1996.32.224.1 to 96.32.255.25496.32.255.2558,190
996.33.0.0/1996.33.0.1 to 96.33.31.25496.33.31.2558,190
1096.33.32.0/1996.33.32.1 to 96.33.63.25496.33.63.2558,190
1196.33.64.0/1996.33.64.1 to 96.33.95.25496.33.95.2558,190
1296.33.96.0/1996.33.96.1 to 96.33.127.25496.33.127.2558,190
1396.33.128.0/1996.33.128.1 to 96.33.159.25496.33.159.2558,190
1496.33.160.0/1996.33.160.1 to 96.33.191.25496.33.191.2558,190
1596.33.192.0/1996.33.192.1 to 96.33.223.25496.33.223.2558,190
1696.33.224.0/1996.33.224.1 to 96.33.255.25496.33.255.2558,190
1796.34.0.0/1996.34.0.1 to 96.34.31.25496.34.31.2558,190
1896.34.32.0/1996.34.32.1 to 96.34.63.25496.34.63.2558,190
1996.34.64.0/1996.34.64.1 to 96.34.95.25496.34.95.2558,190
2096.34.96.0/1996.34.96.1 to 96.34.127.25496.34.127.2558,190
2196.34.128.0/1996.34.128.1 to 96.34.159.25496.34.159.2558,190
2296.34.160.0/1996.34.160.1 to 96.34.191.25496.34.191.2558,190
2396.34.192.0/1996.34.192.1 to 96.34.223.25496.34.223.2558,190
2496.34.224.0/1996.34.224.1 to 96.34.255.25496.34.255.2558,190
2596.35.0.0/1996.35.0.1 to 96.35.31.25496.35.31.2558,190
2696.35.32.0/1996.35.32.1 to 96.35.63.25496.35.63.2558,190
2796.35.64.0/1996.35.64.1 to 96.35.95.25496.35.95.2558,190
2896.35.96.0/1996.35.96.1 to 96.35.127.25496.35.127.2558,190
2996.35.128.0/1996.35.128.1 to 96.35.159.25496.35.159.2558,190
3096.35.160.0/1996.35.160.1 to 96.35.191.25496.35.191.2558,190
3196.35.192.0/1996.35.192.1 to 96.35.223.25496.35.223.2558,190
3296.35.224.0/1996.35.224.1 to 96.35.255.25496.35.255.2558,190
3396.36.0.0/1996.36.0.1 to 96.36.31.25496.36.31.2558,190
3496.36.32.0/1996.36.32.1 to 96.36.63.25496.36.63.2558,190
3596.36.64.0/1996.36.64.1 to 96.36.95.25496.36.95.2558,190
3696.36.96.0/1996.36.96.1 to 96.36.127.25496.36.127.2558,190
3796.36.128.0/1996.36.128.1 to 96.36.159.25496.36.159.2558,190
3896.36.160.0/1996.36.160.1 to 96.36.191.25496.36.191.2558,190
3996.36.192.0/1996.36.192.1 to 96.36.223.25496.36.223.2558,190
4096.36.224.0/1996.36.224.1 to 96.36.255.25496.36.255.2558,190
4196.37.0.0/1996.37.0.1 to 96.37.31.25496.37.31.2558,190
4296.37.32.0/1996.37.32.1 to 96.37.63.25496.37.63.2558,190
4396.37.64.0/1996.37.64.1 to 96.37.95.25496.37.95.2558,190
4496.37.96.0/1996.37.96.1 to 96.37.127.25496.37.127.2558,190
4596.37.128.0/1996.37.128.1 to 96.37.159.25496.37.159.2558,190
4696.37.160.0/1996.37.160.1 to 96.37.191.25496.37.191.2558,190
4796.37.192.0/1996.37.192.1 to 96.37.223.25496.37.223.2558,190
4896.37.224.0/1996.37.224.1 to 96.37.255.25496.37.255.2558,190
4996.38.0.0/1996.38.0.1 to 96.38.31.25496.38.31.2558,190
5096.38.32.0/1996.38.32.1 to 96.38.63.25496.38.63.2558,190
5196.38.64.0/1996.38.64.1 to 96.38.95.25496.38.95.2558,190
5296.38.96.0/1996.38.96.1 to 96.38.127.25496.38.127.2558,190
5396.38.128.0/1996.38.128.1 to 96.38.159.25496.38.159.2558,190
5496.38.160.0/1996.38.160.1 to 96.38.191.25496.38.191.2558,190
5596.38.192.0/1996.38.192.1 to 96.38.223.25496.38.223.2558,190
5696.38.224.0/1996.38.224.1 to 96.38.255.25496.38.255.2558,190
5796.39.0.0/1996.39.0.1 to 96.39.31.25496.39.31.2558,190
5896.39.32.0/1996.39.32.1 to 96.39.63.25496.39.63.2558,190
5996.39.64.0/1996.39.64.1 to 96.39.95.25496.39.95.2558,190
6096.39.96.0/1996.39.96.1 to 96.39.127.25496.39.127.2558,190
6196.39.128.0/1996.39.128.1 to 96.39.159.25496.39.159.2558,190
6296.39.160.0/1996.39.160.1 to 96.39.191.25496.39.191.2558,190
6396.39.192.0/1996.39.192.1 to 96.39.223.25496.39.223.2558,190
6496.39.224.0/1996.39.224.1 to 96.39.255.25496.39.255.2558,190
6596.40.0.0/1996.40.0.1 to 96.40.31.25496.40.31.2558,190
6696.40.32.0/1996.40.32.1 to 96.40.63.25496.40.63.2558,190
6796.40.64.0/1996.40.64.1 to 96.40.95.25496.40.95.2558,190
6896.40.96.0/1996.40.96.1 to 96.40.127.25496.40.127.2558,190
6996.40.128.0/1996.40.128.1 to 96.40.159.25496.40.159.2558,190
7096.40.160.0/1996.40.160.1 to 96.40.191.25496.40.191.2558,190
7196.40.192.0/1996.40.192.1 to 96.40.223.25496.40.223.2558,190
7296.40.224.0/1996.40.224.1 to 96.40.255.25496.40.255.2558,190
7396.41.0.0/1996.41.0.1 to 96.41.31.25496.41.31.2558,190
7496.41.32.0/1996.41.32.1 to 96.41.63.25496.41.63.2558,190
7596.41.64.0/1996.41.64.1 to 96.41.95.25496.41.95.2558,190
7696.41.96.0/1996.41.96.1 to 96.41.127.25496.41.127.2558,190
7796.41.128.0/1996.41.128.1 to 96.41.159.25496.41.159.2558,190
7896.41.160.0/1996.41.160.1 to 96.41.191.25496.41.191.2558,190
7996.41.192.0/1996.41.192.1 to 96.41.223.25496.41.223.2558,190
8096.41.224.0/1996.41.224.1 to 96.41.255.25496.41.255.2558,190
8196.42.0.0/1996.42.0.1 to 96.42.31.25496.42.31.2558,190
8296.42.32.0/1996.42.32.1 to 96.42.63.25496.42.63.2558,190
8396.42.64.0/1996.42.64.1 to 96.42.95.25496.42.95.2558,190
8496.42.96.0/1996.42.96.1 to 96.42.127.25496.42.127.2558,190
8596.42.128.0/1996.42.128.1 to 96.42.159.25496.42.159.2558,190
8696.42.160.0/1996.42.160.1 to 96.42.191.25496.42.191.2558,190
8796.42.192.0/1996.42.192.1 to 96.42.223.25496.42.223.2558,190
8896.42.224.0/1996.42.224.1 to 96.42.255.25496.42.255.2558,190
8996.43.0.0/1996.43.0.1 to 96.43.31.25496.43.31.2558,190
9096.43.32.0/1996.43.32.1 to 96.43.63.25496.43.63.2558,190
9196.43.64.0/1996.43.64.1 to 96.43.95.25496.43.95.2558,190
9296.43.96.0/1996.43.96.1 to 96.43.127.25496.43.127.2558,190
9396.43.128.0/1996.43.128.1 to 96.43.159.25496.43.159.2558,190
9496.43.160.0/1996.43.160.1 to 96.43.191.25496.43.191.2558,190
9596.43.192.0/1996.43.192.1 to 96.43.223.25496.43.223.2558,190
9696.43.224.0/1996.43.224.1 to 96.43.255.25496.43.255.2558,190
9796.44.0.0/1996.44.0.1 to 96.44.31.25496.44.31.2558,190
9896.44.32.0/1996.44.32.1 to 96.44.63.25496.44.63.2558,190
9996.44.64.0/1996.44.64.1 to 96.44.95.25496.44.95.2558,190
10096.44.96.0/1996.44.96.1 to 96.44.127.25496.44.127.2558,190
10196.44.128.0/1996.44.128.1 to 96.44.159.25496.44.159.2558,190
10296.44.160.0/1996.44.160.1 to 96.44.191.25496.44.191.2558,190
10396.44.192.0/1996.44.192.1 to 96.44.223.25496.44.223.2558,190
10496.44.224.0/1996.44.224.1 to 96.44.255.25496.44.255.2558,190
10596.45.0.0/1996.45.0.1 to 96.45.31.25496.45.31.2558,190
10696.45.32.0/1996.45.32.1 to 96.45.63.25496.45.63.2558,190
10796.45.64.0/1996.45.64.1 to 96.45.95.25496.45.95.2558,190
10896.45.96.0/1996.45.96.1 to 96.45.127.25496.45.127.2558,190
10996.45.128.0/1996.45.128.1 to 96.45.159.25496.45.159.2558,190
11096.45.160.0/1996.45.160.1 to 96.45.191.25496.45.191.2558,190
11196.45.192.0/1996.45.192.1 to 96.45.223.25496.45.223.2558,190
11296.45.224.0/1996.45.224.1 to 96.45.255.25496.45.255.2558,190
11396.46.0.0/1996.46.0.1 to 96.46.31.25496.46.31.2558,190
11496.46.32.0/1996.46.32.1 to 96.46.63.25496.46.63.2558,190
11596.46.64.0/1996.46.64.1 to 96.46.95.25496.46.95.2558,190
11696.46.96.0/1996.46.96.1 to 96.46.127.25496.46.127.2558,190
11796.46.128.0/1996.46.128.1 to 96.46.159.25496.46.159.2558,190
11896.46.160.0/1996.46.160.1 to 96.46.191.25496.46.191.2558,190
11996.46.192.0/1996.46.192.1 to 96.46.223.25496.46.223.2558,190
12096.46.224.0/1996.46.224.1 to 96.46.255.25496.46.255.2558,190
12196.47.0.0/1996.47.0.1 to 96.47.31.25496.47.31.2558,190
12296.47.32.0/1996.47.32.1 to 96.47.63.25496.47.63.2558,190
12396.47.64.0/1996.47.64.1 to 96.47.95.25496.47.95.2558,190
12496.47.96.0/1996.47.96.1 to 96.47.127.25496.47.127.2558,190
12596.47.128.0/1996.47.128.1 to 96.47.159.25496.47.159.2558,190
12696.47.160.0/1996.47.160.1 to 96.47.191.25496.47.191.2558,190
12796.47.192.0/1996.47.192.1 to 96.47.223.25496.47.223.2558,190
12896.47.224.0/1996.47.224.1 to 96.47.255.25496.47.255.2558,190

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.