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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.

Network6.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
6.167.0.0
Broadcast address
6.167.255.255
First usable
6.167.0.1
Last usable
6.167.255.254
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 06A70000 · Integer 111607808 to 111673343
Reverse DNS zone
167.6.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000110.10100111..00000000.000000006.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00000110.10100111..00000000.000000006.167.0.0
Broadcast00000110.10100111..11111111.111111116.167.255.255
Split into smaller subnets/23
/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)

6.167.0.0/16 makes 128 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.167.0.0/236.167.0.1 to 6.167.1.2546.167.1.255510
26.167.2.0/236.167.2.1 to 6.167.3.2546.167.3.255510
36.167.4.0/236.167.4.1 to 6.167.5.2546.167.5.255510
46.167.6.0/236.167.6.1 to 6.167.7.2546.167.7.255510
56.167.8.0/236.167.8.1 to 6.167.9.2546.167.9.255510
66.167.10.0/236.167.10.1 to 6.167.11.2546.167.11.255510
76.167.12.0/236.167.12.1 to 6.167.13.2546.167.13.255510
86.167.14.0/236.167.14.1 to 6.167.15.2546.167.15.255510
96.167.16.0/236.167.16.1 to 6.167.17.2546.167.17.255510
106.167.18.0/236.167.18.1 to 6.167.19.2546.167.19.255510
116.167.20.0/236.167.20.1 to 6.167.21.2546.167.21.255510
126.167.22.0/236.167.22.1 to 6.167.23.2546.167.23.255510
136.167.24.0/236.167.24.1 to 6.167.25.2546.167.25.255510
146.167.26.0/236.167.26.1 to 6.167.27.2546.167.27.255510
156.167.28.0/236.167.28.1 to 6.167.29.2546.167.29.255510
166.167.30.0/236.167.30.1 to 6.167.31.2546.167.31.255510
176.167.32.0/236.167.32.1 to 6.167.33.2546.167.33.255510
186.167.34.0/236.167.34.1 to 6.167.35.2546.167.35.255510
196.167.36.0/236.167.36.1 to 6.167.37.2546.167.37.255510
206.167.38.0/236.167.38.1 to 6.167.39.2546.167.39.255510
216.167.40.0/236.167.40.1 to 6.167.41.2546.167.41.255510
226.167.42.0/236.167.42.1 to 6.167.43.2546.167.43.255510
236.167.44.0/236.167.44.1 to 6.167.45.2546.167.45.255510
246.167.46.0/236.167.46.1 to 6.167.47.2546.167.47.255510
256.167.48.0/236.167.48.1 to 6.167.49.2546.167.49.255510
266.167.50.0/236.167.50.1 to 6.167.51.2546.167.51.255510
276.167.52.0/236.167.52.1 to 6.167.53.2546.167.53.255510
286.167.54.0/236.167.54.1 to 6.167.55.2546.167.55.255510
296.167.56.0/236.167.56.1 to 6.167.57.2546.167.57.255510
306.167.58.0/236.167.58.1 to 6.167.59.2546.167.59.255510
316.167.60.0/236.167.60.1 to 6.167.61.2546.167.61.255510
326.167.62.0/236.167.62.1 to 6.167.63.2546.167.63.255510
336.167.64.0/236.167.64.1 to 6.167.65.2546.167.65.255510
346.167.66.0/236.167.66.1 to 6.167.67.2546.167.67.255510
356.167.68.0/236.167.68.1 to 6.167.69.2546.167.69.255510
366.167.70.0/236.167.70.1 to 6.167.71.2546.167.71.255510
376.167.72.0/236.167.72.1 to 6.167.73.2546.167.73.255510
386.167.74.0/236.167.74.1 to 6.167.75.2546.167.75.255510
396.167.76.0/236.167.76.1 to 6.167.77.2546.167.77.255510
406.167.78.0/236.167.78.1 to 6.167.79.2546.167.79.255510
416.167.80.0/236.167.80.1 to 6.167.81.2546.167.81.255510
426.167.82.0/236.167.82.1 to 6.167.83.2546.167.83.255510
436.167.84.0/236.167.84.1 to 6.167.85.2546.167.85.255510
446.167.86.0/236.167.86.1 to 6.167.87.2546.167.87.255510
456.167.88.0/236.167.88.1 to 6.167.89.2546.167.89.255510
466.167.90.0/236.167.90.1 to 6.167.91.2546.167.91.255510
476.167.92.0/236.167.92.1 to 6.167.93.2546.167.93.255510
486.167.94.0/236.167.94.1 to 6.167.95.2546.167.95.255510
496.167.96.0/236.167.96.1 to 6.167.97.2546.167.97.255510
506.167.98.0/236.167.98.1 to 6.167.99.2546.167.99.255510
516.167.100.0/236.167.100.1 to 6.167.101.2546.167.101.255510
526.167.102.0/236.167.102.1 to 6.167.103.2546.167.103.255510
536.167.104.0/236.167.104.1 to 6.167.105.2546.167.105.255510
546.167.106.0/236.167.106.1 to 6.167.107.2546.167.107.255510
556.167.108.0/236.167.108.1 to 6.167.109.2546.167.109.255510
566.167.110.0/236.167.110.1 to 6.167.111.2546.167.111.255510
576.167.112.0/236.167.112.1 to 6.167.113.2546.167.113.255510
586.167.114.0/236.167.114.1 to 6.167.115.2546.167.115.255510
596.167.116.0/236.167.116.1 to 6.167.117.2546.167.117.255510
606.167.118.0/236.167.118.1 to 6.167.119.2546.167.119.255510
616.167.120.0/236.167.120.1 to 6.167.121.2546.167.121.255510
626.167.122.0/236.167.122.1 to 6.167.123.2546.167.123.255510
636.167.124.0/236.167.124.1 to 6.167.125.2546.167.125.255510
646.167.126.0/236.167.126.1 to 6.167.127.2546.167.127.255510
656.167.128.0/236.167.128.1 to 6.167.129.2546.167.129.255510
666.167.130.0/236.167.130.1 to 6.167.131.2546.167.131.255510
676.167.132.0/236.167.132.1 to 6.167.133.2546.167.133.255510
686.167.134.0/236.167.134.1 to 6.167.135.2546.167.135.255510
696.167.136.0/236.167.136.1 to 6.167.137.2546.167.137.255510
706.167.138.0/236.167.138.1 to 6.167.139.2546.167.139.255510
716.167.140.0/236.167.140.1 to 6.167.141.2546.167.141.255510
726.167.142.0/236.167.142.1 to 6.167.143.2546.167.143.255510
736.167.144.0/236.167.144.1 to 6.167.145.2546.167.145.255510
746.167.146.0/236.167.146.1 to 6.167.147.2546.167.147.255510
756.167.148.0/236.167.148.1 to 6.167.149.2546.167.149.255510
766.167.150.0/236.167.150.1 to 6.167.151.2546.167.151.255510
776.167.152.0/236.167.152.1 to 6.167.153.2546.167.153.255510
786.167.154.0/236.167.154.1 to 6.167.155.2546.167.155.255510
796.167.156.0/236.167.156.1 to 6.167.157.2546.167.157.255510
806.167.158.0/236.167.158.1 to 6.167.159.2546.167.159.255510
816.167.160.0/236.167.160.1 to 6.167.161.2546.167.161.255510
826.167.162.0/236.167.162.1 to 6.167.163.2546.167.163.255510
836.167.164.0/236.167.164.1 to 6.167.165.2546.167.165.255510
846.167.166.0/236.167.166.1 to 6.167.167.2546.167.167.255510
856.167.168.0/236.167.168.1 to 6.167.169.2546.167.169.255510
866.167.170.0/236.167.170.1 to 6.167.171.2546.167.171.255510
876.167.172.0/236.167.172.1 to 6.167.173.2546.167.173.255510
886.167.174.0/236.167.174.1 to 6.167.175.2546.167.175.255510
896.167.176.0/236.167.176.1 to 6.167.177.2546.167.177.255510
906.167.178.0/236.167.178.1 to 6.167.179.2546.167.179.255510
916.167.180.0/236.167.180.1 to 6.167.181.2546.167.181.255510
926.167.182.0/236.167.182.1 to 6.167.183.2546.167.183.255510
936.167.184.0/236.167.184.1 to 6.167.185.2546.167.185.255510
946.167.186.0/236.167.186.1 to 6.167.187.2546.167.187.255510
956.167.188.0/236.167.188.1 to 6.167.189.2546.167.189.255510
966.167.190.0/236.167.190.1 to 6.167.191.2546.167.191.255510
976.167.192.0/236.167.192.1 to 6.167.193.2546.167.193.255510
986.167.194.0/236.167.194.1 to 6.167.195.2546.167.195.255510
996.167.196.0/236.167.196.1 to 6.167.197.2546.167.197.255510
1006.167.198.0/236.167.198.1 to 6.167.199.2546.167.199.255510
1016.167.200.0/236.167.200.1 to 6.167.201.2546.167.201.255510
1026.167.202.0/236.167.202.1 to 6.167.203.2546.167.203.255510
1036.167.204.0/236.167.204.1 to 6.167.205.2546.167.205.255510
1046.167.206.0/236.167.206.1 to 6.167.207.2546.167.207.255510
1056.167.208.0/236.167.208.1 to 6.167.209.2546.167.209.255510
1066.167.210.0/236.167.210.1 to 6.167.211.2546.167.211.255510
1076.167.212.0/236.167.212.1 to 6.167.213.2546.167.213.255510
1086.167.214.0/236.167.214.1 to 6.167.215.2546.167.215.255510
1096.167.216.0/236.167.216.1 to 6.167.217.2546.167.217.255510
1106.167.218.0/236.167.218.1 to 6.167.219.2546.167.219.255510
1116.167.220.0/236.167.220.1 to 6.167.221.2546.167.221.255510
1126.167.222.0/236.167.222.1 to 6.167.223.2546.167.223.255510
1136.167.224.0/236.167.224.1 to 6.167.225.2546.167.225.255510
1146.167.226.0/236.167.226.1 to 6.167.227.2546.167.227.255510
1156.167.228.0/236.167.228.1 to 6.167.229.2546.167.229.255510
1166.167.230.0/236.167.230.1 to 6.167.231.2546.167.231.255510
1176.167.232.0/236.167.232.1 to 6.167.233.2546.167.233.255510
1186.167.234.0/236.167.234.1 to 6.167.235.2546.167.235.255510
1196.167.236.0/236.167.236.1 to 6.167.237.2546.167.237.255510
1206.167.238.0/236.167.238.1 to 6.167.239.2546.167.239.255510
1216.167.240.0/236.167.240.1 to 6.167.241.2546.167.241.255510
1226.167.242.0/236.167.242.1 to 6.167.243.2546.167.243.255510
1236.167.244.0/236.167.244.1 to 6.167.245.2546.167.245.255510
1246.167.246.0/236.167.246.1 to 6.167.247.2546.167.247.255510
1256.167.248.0/236.167.248.1 to 6.167.249.2546.167.249.255510
1266.167.250.0/236.167.250.1 to 6.167.251.2546.167.251.255510
1276.167.252.0/236.167.252.1 to 6.167.253.2546.167.253.255510
1286.167.254.0/236.167.254.1 to 6.167.255.2546.167.255.255510

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.