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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.

Network84.3.192.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
84.3.192.0
Broadcast address
84.3.255.255
First usable
84.3.192.1
Last usable
84.3.255.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 5403C000 · Integer 1409531904 to 1409548287
Reverse DNS zones
192.3.84.in-addr.arpa
193.3.84.in-addr.arpa
194.3.84.in-addr.arpa
195.3.84.in-addr.arpa
196.3.84.in-addr.arpa
197.3.84.in-addr.arpa
198.3.84.in-addr.arpa
199.3.84.in-addr.arpa
200.3.84.in-addr.arpa
201.3.84.in-addr.arpa
202.3.84.in-addr.arpa
203.3.84.in-addr.arpa
204.3.84.in-addr.arpa
205.3.84.in-addr.arpa
206.3.84.in-addr.arpa
207.3.84.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010100.00000011.11000000.0000000084.3.192.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01010100.00000011.11000000.0000000084.3.192.0
Broadcast01010100.00000011.11111111.1111111184.3.255.255
Split into smaller subnets/25
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

84.3.192.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
184.3.192.0/2584.3.192.1 to 84.3.192.12684.3.192.127126
284.3.192.128/2584.3.192.129 to 84.3.192.25484.3.192.255126
384.3.193.0/2584.3.193.1 to 84.3.193.12684.3.193.127126
484.3.193.128/2584.3.193.129 to 84.3.193.25484.3.193.255126
584.3.194.0/2584.3.194.1 to 84.3.194.12684.3.194.127126
684.3.194.128/2584.3.194.129 to 84.3.194.25484.3.194.255126
784.3.195.0/2584.3.195.1 to 84.3.195.12684.3.195.127126
884.3.195.128/2584.3.195.129 to 84.3.195.25484.3.195.255126
984.3.196.0/2584.3.196.1 to 84.3.196.12684.3.196.127126
1084.3.196.128/2584.3.196.129 to 84.3.196.25484.3.196.255126
1184.3.197.0/2584.3.197.1 to 84.3.197.12684.3.197.127126
1284.3.197.128/2584.3.197.129 to 84.3.197.25484.3.197.255126
1384.3.198.0/2584.3.198.1 to 84.3.198.12684.3.198.127126
1484.3.198.128/2584.3.198.129 to 84.3.198.25484.3.198.255126
1584.3.199.0/2584.3.199.1 to 84.3.199.12684.3.199.127126
1684.3.199.128/2584.3.199.129 to 84.3.199.25484.3.199.255126
1784.3.200.0/2584.3.200.1 to 84.3.200.12684.3.200.127126
1884.3.200.128/2584.3.200.129 to 84.3.200.25484.3.200.255126
1984.3.201.0/2584.3.201.1 to 84.3.201.12684.3.201.127126
2084.3.201.128/2584.3.201.129 to 84.3.201.25484.3.201.255126
2184.3.202.0/2584.3.202.1 to 84.3.202.12684.3.202.127126
2284.3.202.128/2584.3.202.129 to 84.3.202.25484.3.202.255126
2384.3.203.0/2584.3.203.1 to 84.3.203.12684.3.203.127126
2484.3.203.128/2584.3.203.129 to 84.3.203.25484.3.203.255126
2584.3.204.0/2584.3.204.1 to 84.3.204.12684.3.204.127126
2684.3.204.128/2584.3.204.129 to 84.3.204.25484.3.204.255126
2784.3.205.0/2584.3.205.1 to 84.3.205.12684.3.205.127126
2884.3.205.128/2584.3.205.129 to 84.3.205.25484.3.205.255126
2984.3.206.0/2584.3.206.1 to 84.3.206.12684.3.206.127126
3084.3.206.128/2584.3.206.129 to 84.3.206.25484.3.206.255126
3184.3.207.0/2584.3.207.1 to 84.3.207.12684.3.207.127126
3284.3.207.128/2584.3.207.129 to 84.3.207.25484.3.207.255126
3384.3.208.0/2584.3.208.1 to 84.3.208.12684.3.208.127126
3484.3.208.128/2584.3.208.129 to 84.3.208.25484.3.208.255126
3584.3.209.0/2584.3.209.1 to 84.3.209.12684.3.209.127126
3684.3.209.128/2584.3.209.129 to 84.3.209.25484.3.209.255126
3784.3.210.0/2584.3.210.1 to 84.3.210.12684.3.210.127126
3884.3.210.128/2584.3.210.129 to 84.3.210.25484.3.210.255126
3984.3.211.0/2584.3.211.1 to 84.3.211.12684.3.211.127126
4084.3.211.128/2584.3.211.129 to 84.3.211.25484.3.211.255126
4184.3.212.0/2584.3.212.1 to 84.3.212.12684.3.212.127126
4284.3.212.128/2584.3.212.129 to 84.3.212.25484.3.212.255126
4384.3.213.0/2584.3.213.1 to 84.3.213.12684.3.213.127126
4484.3.213.128/2584.3.213.129 to 84.3.213.25484.3.213.255126
4584.3.214.0/2584.3.214.1 to 84.3.214.12684.3.214.127126
4684.3.214.128/2584.3.214.129 to 84.3.214.25484.3.214.255126
4784.3.215.0/2584.3.215.1 to 84.3.215.12684.3.215.127126
4884.3.215.128/2584.3.215.129 to 84.3.215.25484.3.215.255126
4984.3.216.0/2584.3.216.1 to 84.3.216.12684.3.216.127126
5084.3.216.128/2584.3.216.129 to 84.3.216.25484.3.216.255126
5184.3.217.0/2584.3.217.1 to 84.3.217.12684.3.217.127126
5284.3.217.128/2584.3.217.129 to 84.3.217.25484.3.217.255126
5384.3.218.0/2584.3.218.1 to 84.3.218.12684.3.218.127126
5484.3.218.128/2584.3.218.129 to 84.3.218.25484.3.218.255126
5584.3.219.0/2584.3.219.1 to 84.3.219.12684.3.219.127126
5684.3.219.128/2584.3.219.129 to 84.3.219.25484.3.219.255126
5784.3.220.0/2584.3.220.1 to 84.3.220.12684.3.220.127126
5884.3.220.128/2584.3.220.129 to 84.3.220.25484.3.220.255126
5984.3.221.0/2584.3.221.1 to 84.3.221.12684.3.221.127126
6084.3.221.128/2584.3.221.129 to 84.3.221.25484.3.221.255126
6184.3.222.0/2584.3.222.1 to 84.3.222.12684.3.222.127126
6284.3.222.128/2584.3.222.129 to 84.3.222.25484.3.222.255126
6384.3.223.0/2584.3.223.1 to 84.3.223.12684.3.223.127126
6484.3.223.128/2584.3.223.129 to 84.3.223.25484.3.223.255126
6584.3.224.0/2584.3.224.1 to 84.3.224.12684.3.224.127126
6684.3.224.128/2584.3.224.129 to 84.3.224.25484.3.224.255126
6784.3.225.0/2584.3.225.1 to 84.3.225.12684.3.225.127126
6884.3.225.128/2584.3.225.129 to 84.3.225.25484.3.225.255126
6984.3.226.0/2584.3.226.1 to 84.3.226.12684.3.226.127126
7084.3.226.128/2584.3.226.129 to 84.3.226.25484.3.226.255126
7184.3.227.0/2584.3.227.1 to 84.3.227.12684.3.227.127126
7284.3.227.128/2584.3.227.129 to 84.3.227.25484.3.227.255126
7384.3.228.0/2584.3.228.1 to 84.3.228.12684.3.228.127126
7484.3.228.128/2584.3.228.129 to 84.3.228.25484.3.228.255126
7584.3.229.0/2584.3.229.1 to 84.3.229.12684.3.229.127126
7684.3.229.128/2584.3.229.129 to 84.3.229.25484.3.229.255126
7784.3.230.0/2584.3.230.1 to 84.3.230.12684.3.230.127126
7884.3.230.128/2584.3.230.129 to 84.3.230.25484.3.230.255126
7984.3.231.0/2584.3.231.1 to 84.3.231.12684.3.231.127126
8084.3.231.128/2584.3.231.129 to 84.3.231.25484.3.231.255126
8184.3.232.0/2584.3.232.1 to 84.3.232.12684.3.232.127126
8284.3.232.128/2584.3.232.129 to 84.3.232.25484.3.232.255126
8384.3.233.0/2584.3.233.1 to 84.3.233.12684.3.233.127126
8484.3.233.128/2584.3.233.129 to 84.3.233.25484.3.233.255126
8584.3.234.0/2584.3.234.1 to 84.3.234.12684.3.234.127126
8684.3.234.128/2584.3.234.129 to 84.3.234.25484.3.234.255126
8784.3.235.0/2584.3.235.1 to 84.3.235.12684.3.235.127126
8884.3.235.128/2584.3.235.129 to 84.3.235.25484.3.235.255126
8984.3.236.0/2584.3.236.1 to 84.3.236.12684.3.236.127126
9084.3.236.128/2584.3.236.129 to 84.3.236.25484.3.236.255126
9184.3.237.0/2584.3.237.1 to 84.3.237.12684.3.237.127126
9284.3.237.128/2584.3.237.129 to 84.3.237.25484.3.237.255126
9384.3.238.0/2584.3.238.1 to 84.3.238.12684.3.238.127126
9484.3.238.128/2584.3.238.129 to 84.3.238.25484.3.238.255126
9584.3.239.0/2584.3.239.1 to 84.3.239.12684.3.239.127126
9684.3.239.128/2584.3.239.129 to 84.3.239.25484.3.239.255126
9784.3.240.0/2584.3.240.1 to 84.3.240.12684.3.240.127126
9884.3.240.128/2584.3.240.129 to 84.3.240.25484.3.240.255126
9984.3.241.0/2584.3.241.1 to 84.3.241.12684.3.241.127126
10084.3.241.128/2584.3.241.129 to 84.3.241.25484.3.241.255126
10184.3.242.0/2584.3.242.1 to 84.3.242.12684.3.242.127126
10284.3.242.128/2584.3.242.129 to 84.3.242.25484.3.242.255126
10384.3.243.0/2584.3.243.1 to 84.3.243.12684.3.243.127126
10484.3.243.128/2584.3.243.129 to 84.3.243.25484.3.243.255126
10584.3.244.0/2584.3.244.1 to 84.3.244.12684.3.244.127126
10684.3.244.128/2584.3.244.129 to 84.3.244.25484.3.244.255126
10784.3.245.0/2584.3.245.1 to 84.3.245.12684.3.245.127126
10884.3.245.128/2584.3.245.129 to 84.3.245.25484.3.245.255126
10984.3.246.0/2584.3.246.1 to 84.3.246.12684.3.246.127126
11084.3.246.128/2584.3.246.129 to 84.3.246.25484.3.246.255126
11184.3.247.0/2584.3.247.1 to 84.3.247.12684.3.247.127126
11284.3.247.128/2584.3.247.129 to 84.3.247.25484.3.247.255126
11384.3.248.0/2584.3.248.1 to 84.3.248.12684.3.248.127126
11484.3.248.128/2584.3.248.129 to 84.3.248.25484.3.248.255126
11584.3.249.0/2584.3.249.1 to 84.3.249.12684.3.249.127126
11684.3.249.128/2584.3.249.129 to 84.3.249.25484.3.249.255126
11784.3.250.0/2584.3.250.1 to 84.3.250.12684.3.250.127126
11884.3.250.128/2584.3.250.129 to 84.3.250.25484.3.250.255126
11984.3.251.0/2584.3.251.1 to 84.3.251.12684.3.251.127126
12084.3.251.128/2584.3.251.129 to 84.3.251.25484.3.251.255126
12184.3.252.0/2584.3.252.1 to 84.3.252.12684.3.252.127126
12284.3.252.128/2584.3.252.129 to 84.3.252.25484.3.252.255126
12384.3.253.0/2584.3.253.1 to 84.3.253.12684.3.253.127126
12484.3.253.128/2584.3.253.129 to 84.3.253.25484.3.253.255126
12584.3.254.0/2584.3.254.1 to 84.3.254.12684.3.254.127126
12684.3.254.128/2584.3.254.129 to 84.3.254.25484.3.254.255126
12784.3.255.0/2584.3.255.1 to 84.3.255.12684.3.255.127126
12884.3.255.128/2584.3.255.129 to 84.3.255.25484.3.255.255126

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.