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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.

Network83.192.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
83.192.0.0
Broadcast address
83.207.255.255
First usable
83.192.0.1
Last usable
83.207.255.254
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 53C00000 · Integer 1405091840 to 1406140415
Reverse DNS zones
192.83.in-addr.arpa
193.83.in-addr.arpa
194.83.in-addr.arpa
195.83.in-addr.arpa
196.83.in-addr.arpa
197.83.in-addr.arpa
198.83.in-addr.arpa
199.83.in-addr.arpa
200.83.in-addr.arpa
201.83.in-addr.arpa
202.83.in-addr.arpa
203.83.in-addr.arpa
204.83.in-addr.arpa
205.83.in-addr.arpa
206.83.in-addr.arpa
207.83.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
Address01010011.11000000.00000000.0000000083.192.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01010011.11000000.00000000.0000000083.192.0.0
Broadcast01010011.11001111.11111111.1111111183.207.255.255
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)

83.192.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
183.192.0.0/1983.192.0.1 to 83.192.31.25483.192.31.2558,190
283.192.32.0/1983.192.32.1 to 83.192.63.25483.192.63.2558,190
383.192.64.0/1983.192.64.1 to 83.192.95.25483.192.95.2558,190
483.192.96.0/1983.192.96.1 to 83.192.127.25483.192.127.2558,190
583.192.128.0/1983.192.128.1 to 83.192.159.25483.192.159.2558,190
683.192.160.0/1983.192.160.1 to 83.192.191.25483.192.191.2558,190
783.192.192.0/1983.192.192.1 to 83.192.223.25483.192.223.2558,190
883.192.224.0/1983.192.224.1 to 83.192.255.25483.192.255.2558,190
983.193.0.0/1983.193.0.1 to 83.193.31.25483.193.31.2558,190
1083.193.32.0/1983.193.32.1 to 83.193.63.25483.193.63.2558,190
1183.193.64.0/1983.193.64.1 to 83.193.95.25483.193.95.2558,190
1283.193.96.0/1983.193.96.1 to 83.193.127.25483.193.127.2558,190
1383.193.128.0/1983.193.128.1 to 83.193.159.25483.193.159.2558,190
1483.193.160.0/1983.193.160.1 to 83.193.191.25483.193.191.2558,190
1583.193.192.0/1983.193.192.1 to 83.193.223.25483.193.223.2558,190
1683.193.224.0/1983.193.224.1 to 83.193.255.25483.193.255.2558,190
1783.194.0.0/1983.194.0.1 to 83.194.31.25483.194.31.2558,190
1883.194.32.0/1983.194.32.1 to 83.194.63.25483.194.63.2558,190
1983.194.64.0/1983.194.64.1 to 83.194.95.25483.194.95.2558,190
2083.194.96.0/1983.194.96.1 to 83.194.127.25483.194.127.2558,190
2183.194.128.0/1983.194.128.1 to 83.194.159.25483.194.159.2558,190
2283.194.160.0/1983.194.160.1 to 83.194.191.25483.194.191.2558,190
2383.194.192.0/1983.194.192.1 to 83.194.223.25483.194.223.2558,190
2483.194.224.0/1983.194.224.1 to 83.194.255.25483.194.255.2558,190
2583.195.0.0/1983.195.0.1 to 83.195.31.25483.195.31.2558,190
2683.195.32.0/1983.195.32.1 to 83.195.63.25483.195.63.2558,190
2783.195.64.0/1983.195.64.1 to 83.195.95.25483.195.95.2558,190
2883.195.96.0/1983.195.96.1 to 83.195.127.25483.195.127.2558,190
2983.195.128.0/1983.195.128.1 to 83.195.159.25483.195.159.2558,190
3083.195.160.0/1983.195.160.1 to 83.195.191.25483.195.191.2558,190
3183.195.192.0/1983.195.192.1 to 83.195.223.25483.195.223.2558,190
3283.195.224.0/1983.195.224.1 to 83.195.255.25483.195.255.2558,190
3383.196.0.0/1983.196.0.1 to 83.196.31.25483.196.31.2558,190
3483.196.32.0/1983.196.32.1 to 83.196.63.25483.196.63.2558,190
3583.196.64.0/1983.196.64.1 to 83.196.95.25483.196.95.2558,190
3683.196.96.0/1983.196.96.1 to 83.196.127.25483.196.127.2558,190
3783.196.128.0/1983.196.128.1 to 83.196.159.25483.196.159.2558,190
3883.196.160.0/1983.196.160.1 to 83.196.191.25483.196.191.2558,190
3983.196.192.0/1983.196.192.1 to 83.196.223.25483.196.223.2558,190
4083.196.224.0/1983.196.224.1 to 83.196.255.25483.196.255.2558,190
4183.197.0.0/1983.197.0.1 to 83.197.31.25483.197.31.2558,190
4283.197.32.0/1983.197.32.1 to 83.197.63.25483.197.63.2558,190
4383.197.64.0/1983.197.64.1 to 83.197.95.25483.197.95.2558,190
4483.197.96.0/1983.197.96.1 to 83.197.127.25483.197.127.2558,190
4583.197.128.0/1983.197.128.1 to 83.197.159.25483.197.159.2558,190
4683.197.160.0/1983.197.160.1 to 83.197.191.25483.197.191.2558,190
4783.197.192.0/1983.197.192.1 to 83.197.223.25483.197.223.2558,190
4883.197.224.0/1983.197.224.1 to 83.197.255.25483.197.255.2558,190
4983.198.0.0/1983.198.0.1 to 83.198.31.25483.198.31.2558,190
5083.198.32.0/1983.198.32.1 to 83.198.63.25483.198.63.2558,190
5183.198.64.0/1983.198.64.1 to 83.198.95.25483.198.95.2558,190
5283.198.96.0/1983.198.96.1 to 83.198.127.25483.198.127.2558,190
5383.198.128.0/1983.198.128.1 to 83.198.159.25483.198.159.2558,190
5483.198.160.0/1983.198.160.1 to 83.198.191.25483.198.191.2558,190
5583.198.192.0/1983.198.192.1 to 83.198.223.25483.198.223.2558,190
5683.198.224.0/1983.198.224.1 to 83.198.255.25483.198.255.2558,190
5783.199.0.0/1983.199.0.1 to 83.199.31.25483.199.31.2558,190
5883.199.32.0/1983.199.32.1 to 83.199.63.25483.199.63.2558,190
5983.199.64.0/1983.199.64.1 to 83.199.95.25483.199.95.2558,190
6083.199.96.0/1983.199.96.1 to 83.199.127.25483.199.127.2558,190
6183.199.128.0/1983.199.128.1 to 83.199.159.25483.199.159.2558,190
6283.199.160.0/1983.199.160.1 to 83.199.191.25483.199.191.2558,190
6383.199.192.0/1983.199.192.1 to 83.199.223.25483.199.223.2558,190
6483.199.224.0/1983.199.224.1 to 83.199.255.25483.199.255.2558,190
6583.200.0.0/1983.200.0.1 to 83.200.31.25483.200.31.2558,190
6683.200.32.0/1983.200.32.1 to 83.200.63.25483.200.63.2558,190
6783.200.64.0/1983.200.64.1 to 83.200.95.25483.200.95.2558,190
6883.200.96.0/1983.200.96.1 to 83.200.127.25483.200.127.2558,190
6983.200.128.0/1983.200.128.1 to 83.200.159.25483.200.159.2558,190
7083.200.160.0/1983.200.160.1 to 83.200.191.25483.200.191.2558,190
7183.200.192.0/1983.200.192.1 to 83.200.223.25483.200.223.2558,190
7283.200.224.0/1983.200.224.1 to 83.200.255.25483.200.255.2558,190
7383.201.0.0/1983.201.0.1 to 83.201.31.25483.201.31.2558,190
7483.201.32.0/1983.201.32.1 to 83.201.63.25483.201.63.2558,190
7583.201.64.0/1983.201.64.1 to 83.201.95.25483.201.95.2558,190
7683.201.96.0/1983.201.96.1 to 83.201.127.25483.201.127.2558,190
7783.201.128.0/1983.201.128.1 to 83.201.159.25483.201.159.2558,190
7883.201.160.0/1983.201.160.1 to 83.201.191.25483.201.191.2558,190
7983.201.192.0/1983.201.192.1 to 83.201.223.25483.201.223.2558,190
8083.201.224.0/1983.201.224.1 to 83.201.255.25483.201.255.2558,190
8183.202.0.0/1983.202.0.1 to 83.202.31.25483.202.31.2558,190
8283.202.32.0/1983.202.32.1 to 83.202.63.25483.202.63.2558,190
8383.202.64.0/1983.202.64.1 to 83.202.95.25483.202.95.2558,190
8483.202.96.0/1983.202.96.1 to 83.202.127.25483.202.127.2558,190
8583.202.128.0/1983.202.128.1 to 83.202.159.25483.202.159.2558,190
8683.202.160.0/1983.202.160.1 to 83.202.191.25483.202.191.2558,190
8783.202.192.0/1983.202.192.1 to 83.202.223.25483.202.223.2558,190
8883.202.224.0/1983.202.224.1 to 83.202.255.25483.202.255.2558,190
8983.203.0.0/1983.203.0.1 to 83.203.31.25483.203.31.2558,190
9083.203.32.0/1983.203.32.1 to 83.203.63.25483.203.63.2558,190
9183.203.64.0/1983.203.64.1 to 83.203.95.25483.203.95.2558,190
9283.203.96.0/1983.203.96.1 to 83.203.127.25483.203.127.2558,190
9383.203.128.0/1983.203.128.1 to 83.203.159.25483.203.159.2558,190
9483.203.160.0/1983.203.160.1 to 83.203.191.25483.203.191.2558,190
9583.203.192.0/1983.203.192.1 to 83.203.223.25483.203.223.2558,190
9683.203.224.0/1983.203.224.1 to 83.203.255.25483.203.255.2558,190
9783.204.0.0/1983.204.0.1 to 83.204.31.25483.204.31.2558,190
9883.204.32.0/1983.204.32.1 to 83.204.63.25483.204.63.2558,190
9983.204.64.0/1983.204.64.1 to 83.204.95.25483.204.95.2558,190
10083.204.96.0/1983.204.96.1 to 83.204.127.25483.204.127.2558,190
10183.204.128.0/1983.204.128.1 to 83.204.159.25483.204.159.2558,190
10283.204.160.0/1983.204.160.1 to 83.204.191.25483.204.191.2558,190
10383.204.192.0/1983.204.192.1 to 83.204.223.25483.204.223.2558,190
10483.204.224.0/1983.204.224.1 to 83.204.255.25483.204.255.2558,190
10583.205.0.0/1983.205.0.1 to 83.205.31.25483.205.31.2558,190
10683.205.32.0/1983.205.32.1 to 83.205.63.25483.205.63.2558,190
10783.205.64.0/1983.205.64.1 to 83.205.95.25483.205.95.2558,190
10883.205.96.0/1983.205.96.1 to 83.205.127.25483.205.127.2558,190
10983.205.128.0/1983.205.128.1 to 83.205.159.25483.205.159.2558,190
11083.205.160.0/1983.205.160.1 to 83.205.191.25483.205.191.2558,190
11183.205.192.0/1983.205.192.1 to 83.205.223.25483.205.223.2558,190
11283.205.224.0/1983.205.224.1 to 83.205.255.25483.205.255.2558,190
11383.206.0.0/1983.206.0.1 to 83.206.31.25483.206.31.2558,190
11483.206.32.0/1983.206.32.1 to 83.206.63.25483.206.63.2558,190
11583.206.64.0/1983.206.64.1 to 83.206.95.25483.206.95.2558,190
11683.206.96.0/1983.206.96.1 to 83.206.127.25483.206.127.2558,190
11783.206.128.0/1983.206.128.1 to 83.206.159.25483.206.159.2558,190
11883.206.160.0/1983.206.160.1 to 83.206.191.25483.206.191.2558,190
11983.206.192.0/1983.206.192.1 to 83.206.223.25483.206.223.2558,190
12083.206.224.0/1983.206.224.1 to 83.206.255.25483.206.255.2558,190
12183.207.0.0/1983.207.0.1 to 83.207.31.25483.207.31.2558,190
12283.207.32.0/1983.207.32.1 to 83.207.63.25483.207.63.2558,190
12383.207.64.0/1983.207.64.1 to 83.207.95.25483.207.95.2558,190
12483.207.96.0/1983.207.96.1 to 83.207.127.25483.207.127.2558,190
12583.207.128.0/1983.207.128.1 to 83.207.159.25483.207.159.2558,190
12683.207.160.0/1983.207.160.1 to 83.207.191.25483.207.191.2558,190
12783.207.192.0/1983.207.192.1 to 83.207.223.25483.207.223.2558,190
12883.207.224.0/1983.207.224.1 to 83.207.255.25483.207.255.2558,190

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.