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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.

Network32.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
32.167.0.0
Broadcast address
32.167.255.255
First usable
32.167.0.1
Last usable
32.167.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 20A70000 · Integer 547815424 to 547880959
Reverse DNS zone
167.32.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100000.10100111..00000000.0000000032.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00100000.10100111..00000000.0000000032.167.0.0
Broadcast00100000.10100111..11111111.1111111132.167.255.255
Split into smaller subnets/22
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

32.167.0.0/16 makes 64 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
132.167.0.0/2232.167.0.1 to 32.167.3.25432.167.3.2551,022
232.167.4.0/2232.167.4.1 to 32.167.7.25432.167.7.2551,022
332.167.8.0/2232.167.8.1 to 32.167.11.25432.167.11.2551,022
432.167.12.0/2232.167.12.1 to 32.167.15.25432.167.15.2551,022
532.167.16.0/2232.167.16.1 to 32.167.19.25432.167.19.2551,022
632.167.20.0/2232.167.20.1 to 32.167.23.25432.167.23.2551,022
732.167.24.0/2232.167.24.1 to 32.167.27.25432.167.27.2551,022
832.167.28.0/2232.167.28.1 to 32.167.31.25432.167.31.2551,022
932.167.32.0/2232.167.32.1 to 32.167.35.25432.167.35.2551,022
1032.167.36.0/2232.167.36.1 to 32.167.39.25432.167.39.2551,022
1132.167.40.0/2232.167.40.1 to 32.167.43.25432.167.43.2551,022
1232.167.44.0/2232.167.44.1 to 32.167.47.25432.167.47.2551,022
1332.167.48.0/2232.167.48.1 to 32.167.51.25432.167.51.2551,022
1432.167.52.0/2232.167.52.1 to 32.167.55.25432.167.55.2551,022
1532.167.56.0/2232.167.56.1 to 32.167.59.25432.167.59.2551,022
1632.167.60.0/2232.167.60.1 to 32.167.63.25432.167.63.2551,022
1732.167.64.0/2232.167.64.1 to 32.167.67.25432.167.67.2551,022
1832.167.68.0/2232.167.68.1 to 32.167.71.25432.167.71.2551,022
1932.167.72.0/2232.167.72.1 to 32.167.75.25432.167.75.2551,022
2032.167.76.0/2232.167.76.1 to 32.167.79.25432.167.79.2551,022
2132.167.80.0/2232.167.80.1 to 32.167.83.25432.167.83.2551,022
2232.167.84.0/2232.167.84.1 to 32.167.87.25432.167.87.2551,022
2332.167.88.0/2232.167.88.1 to 32.167.91.25432.167.91.2551,022
2432.167.92.0/2232.167.92.1 to 32.167.95.25432.167.95.2551,022
2532.167.96.0/2232.167.96.1 to 32.167.99.25432.167.99.2551,022
2632.167.100.0/2232.167.100.1 to 32.167.103.25432.167.103.2551,022
2732.167.104.0/2232.167.104.1 to 32.167.107.25432.167.107.2551,022
2832.167.108.0/2232.167.108.1 to 32.167.111.25432.167.111.2551,022
2932.167.112.0/2232.167.112.1 to 32.167.115.25432.167.115.2551,022
3032.167.116.0/2232.167.116.1 to 32.167.119.25432.167.119.2551,022
3132.167.120.0/2232.167.120.1 to 32.167.123.25432.167.123.2551,022
3232.167.124.0/2232.167.124.1 to 32.167.127.25432.167.127.2551,022
3332.167.128.0/2232.167.128.1 to 32.167.131.25432.167.131.2551,022
3432.167.132.0/2232.167.132.1 to 32.167.135.25432.167.135.2551,022
3532.167.136.0/2232.167.136.1 to 32.167.139.25432.167.139.2551,022
3632.167.140.0/2232.167.140.1 to 32.167.143.25432.167.143.2551,022
3732.167.144.0/2232.167.144.1 to 32.167.147.25432.167.147.2551,022
3832.167.148.0/2232.167.148.1 to 32.167.151.25432.167.151.2551,022
3932.167.152.0/2232.167.152.1 to 32.167.155.25432.167.155.2551,022
4032.167.156.0/2232.167.156.1 to 32.167.159.25432.167.159.2551,022
4132.167.160.0/2232.167.160.1 to 32.167.163.25432.167.163.2551,022
4232.167.164.0/2232.167.164.1 to 32.167.167.25432.167.167.2551,022
4332.167.168.0/2232.167.168.1 to 32.167.171.25432.167.171.2551,022
4432.167.172.0/2232.167.172.1 to 32.167.175.25432.167.175.2551,022
4532.167.176.0/2232.167.176.1 to 32.167.179.25432.167.179.2551,022
4632.167.180.0/2232.167.180.1 to 32.167.183.25432.167.183.2551,022
4732.167.184.0/2232.167.184.1 to 32.167.187.25432.167.187.2551,022
4832.167.188.0/2232.167.188.1 to 32.167.191.25432.167.191.2551,022
4932.167.192.0/2232.167.192.1 to 32.167.195.25432.167.195.2551,022
5032.167.196.0/2232.167.196.1 to 32.167.199.25432.167.199.2551,022
5132.167.200.0/2232.167.200.1 to 32.167.203.25432.167.203.2551,022
5232.167.204.0/2232.167.204.1 to 32.167.207.25432.167.207.2551,022
5332.167.208.0/2232.167.208.1 to 32.167.211.25432.167.211.2551,022
5432.167.212.0/2232.167.212.1 to 32.167.215.25432.167.215.2551,022
5532.167.216.0/2232.167.216.1 to 32.167.219.25432.167.219.2551,022
5632.167.220.0/2232.167.220.1 to 32.167.223.25432.167.223.2551,022
5732.167.224.0/2232.167.224.1 to 32.167.227.25432.167.227.2551,022
5832.167.228.0/2232.167.228.1 to 32.167.231.25432.167.231.2551,022
5932.167.232.0/2232.167.232.1 to 32.167.235.25432.167.235.2551,022
6032.167.236.0/2232.167.236.1 to 32.167.239.25432.167.239.2551,022
6132.167.240.0/2232.167.240.1 to 32.167.243.25432.167.243.2551,022
6232.167.244.0/2232.167.244.1 to 32.167.247.25432.167.247.2551,022
6332.167.248.0/2232.167.248.1 to 32.167.251.25432.167.251.2551,022
6432.167.252.0/2232.167.252.1 to 32.167.255.25432.167.255.2551,022

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.