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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.

Network167.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
167.0.0.0
Broadcast address
167.255.255.255
First usable
167.0.0.1
Last usable
167.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex A7000000 · Integer 2801795072 to 2818572287
Reverse DNS zone
167.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100111..00000000.00000000.00000000167.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10100111..00000000.00000000.00000000167.0.0.0
Broadcast10100111..11111111.11111111.11111111167.255.255.255
Split into smaller subnets/15
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

167.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1167.0.0.0/15167.0.0.1 to 167.1.255.254167.1.255.255131,070
2167.2.0.0/15167.2.0.1 to 167.3.255.254167.3.255.255131,070
3167.4.0.0/15167.4.0.1 to 167.5.255.254167.5.255.255131,070
4167.6.0.0/15167.6.0.1 to 167.7.255.254167.7.255.255131,070
5167.8.0.0/15167.8.0.1 to 167.9.255.254167.9.255.255131,070
6167.10.0.0/15167.10.0.1 to 167.11.255.254167.11.255.255131,070
7167.12.0.0/15167.12.0.1 to 167.13.255.254167.13.255.255131,070
8167.14.0.0/15167.14.0.1 to 167.15.255.254167.15.255.255131,070
9167.16.0.0/15167.16.0.1 to 167.17.255.254167.17.255.255131,070
10167.18.0.0/15167.18.0.1 to 167.19.255.254167.19.255.255131,070
11167.20.0.0/15167.20.0.1 to 167.21.255.254167.21.255.255131,070
12167.22.0.0/15167.22.0.1 to 167.23.255.254167.23.255.255131,070
13167.24.0.0/15167.24.0.1 to 167.25.255.254167.25.255.255131,070
14167.26.0.0/15167.26.0.1 to 167.27.255.254167.27.255.255131,070
15167.28.0.0/15167.28.0.1 to 167.29.255.254167.29.255.255131,070
16167.30.0.0/15167.30.0.1 to 167.31.255.254167.31.255.255131,070
17167.32.0.0/15167.32.0.1 to 167.33.255.254167.33.255.255131,070
18167.34.0.0/15167.34.0.1 to 167.35.255.254167.35.255.255131,070
19167.36.0.0/15167.36.0.1 to 167.37.255.254167.37.255.255131,070
20167.38.0.0/15167.38.0.1 to 167.39.255.254167.39.255.255131,070
21167.40.0.0/15167.40.0.1 to 167.41.255.254167.41.255.255131,070
22167.42.0.0/15167.42.0.1 to 167.43.255.254167.43.255.255131,070
23167.44.0.0/15167.44.0.1 to 167.45.255.254167.45.255.255131,070
24167.46.0.0/15167.46.0.1 to 167.47.255.254167.47.255.255131,070
25167.48.0.0/15167.48.0.1 to 167.49.255.254167.49.255.255131,070
26167.50.0.0/15167.50.0.1 to 167.51.255.254167.51.255.255131,070
27167.52.0.0/15167.52.0.1 to 167.53.255.254167.53.255.255131,070
28167.54.0.0/15167.54.0.1 to 167.55.255.254167.55.255.255131,070
29167.56.0.0/15167.56.0.1 to 167.57.255.254167.57.255.255131,070
30167.58.0.0/15167.58.0.1 to 167.59.255.254167.59.255.255131,070
31167.60.0.0/15167.60.0.1 to 167.61.255.254167.61.255.255131,070
32167.62.0.0/15167.62.0.1 to 167.63.255.254167.63.255.255131,070
33167.64.0.0/15167.64.0.1 to 167.65.255.254167.65.255.255131,070
34167.66.0.0/15167.66.0.1 to 167.67.255.254167.67.255.255131,070
35167.68.0.0/15167.68.0.1 to 167.69.255.254167.69.255.255131,070
36167.70.0.0/15167.70.0.1 to 167.71.255.254167.71.255.255131,070
37167.72.0.0/15167.72.0.1 to 167.73.255.254167.73.255.255131,070
38167.74.0.0/15167.74.0.1 to 167.75.255.254167.75.255.255131,070
39167.76.0.0/15167.76.0.1 to 167.77.255.254167.77.255.255131,070
40167.78.0.0/15167.78.0.1 to 167.79.255.254167.79.255.255131,070
41167.80.0.0/15167.80.0.1 to 167.81.255.254167.81.255.255131,070
42167.82.0.0/15167.82.0.1 to 167.83.255.254167.83.255.255131,070
43167.84.0.0/15167.84.0.1 to 167.85.255.254167.85.255.255131,070
44167.86.0.0/15167.86.0.1 to 167.87.255.254167.87.255.255131,070
45167.88.0.0/15167.88.0.1 to 167.89.255.254167.89.255.255131,070
46167.90.0.0/15167.90.0.1 to 167.91.255.254167.91.255.255131,070
47167.92.0.0/15167.92.0.1 to 167.93.255.254167.93.255.255131,070
48167.94.0.0/15167.94.0.1 to 167.95.255.254167.95.255.255131,070
49167.96.0.0/15167.96.0.1 to 167.97.255.254167.97.255.255131,070
50167.98.0.0/15167.98.0.1 to 167.99.255.254167.99.255.255131,070
51167.100.0.0/15167.100.0.1 to 167.101.255.254167.101.255.255131,070
52167.102.0.0/15167.102.0.1 to 167.103.255.254167.103.255.255131,070
53167.104.0.0/15167.104.0.1 to 167.105.255.254167.105.255.255131,070
54167.106.0.0/15167.106.0.1 to 167.107.255.254167.107.255.255131,070
55167.108.0.0/15167.108.0.1 to 167.109.255.254167.109.255.255131,070
56167.110.0.0/15167.110.0.1 to 167.111.255.254167.111.255.255131,070
57167.112.0.0/15167.112.0.1 to 167.113.255.254167.113.255.255131,070
58167.114.0.0/15167.114.0.1 to 167.115.255.254167.115.255.255131,070
59167.116.0.0/15167.116.0.1 to 167.117.255.254167.117.255.255131,070
60167.118.0.0/15167.118.0.1 to 167.119.255.254167.119.255.255131,070
61167.120.0.0/15167.120.0.1 to 167.121.255.254167.121.255.255131,070
62167.122.0.0/15167.122.0.1 to 167.123.255.254167.123.255.255131,070
63167.124.0.0/15167.124.0.1 to 167.125.255.254167.125.255.255131,070
64167.126.0.0/15167.126.0.1 to 167.127.255.254167.127.255.255131,070
65167.128.0.0/15167.128.0.1 to 167.129.255.254167.129.255.255131,070
66167.130.0.0/15167.130.0.1 to 167.131.255.254167.131.255.255131,070
67167.132.0.0/15167.132.0.1 to 167.133.255.254167.133.255.255131,070
68167.134.0.0/15167.134.0.1 to 167.135.255.254167.135.255.255131,070
69167.136.0.0/15167.136.0.1 to 167.137.255.254167.137.255.255131,070
70167.138.0.0/15167.138.0.1 to 167.139.255.254167.139.255.255131,070
71167.140.0.0/15167.140.0.1 to 167.141.255.254167.141.255.255131,070
72167.142.0.0/15167.142.0.1 to 167.143.255.254167.143.255.255131,070
73167.144.0.0/15167.144.0.1 to 167.145.255.254167.145.255.255131,070
74167.146.0.0/15167.146.0.1 to 167.147.255.254167.147.255.255131,070
75167.148.0.0/15167.148.0.1 to 167.149.255.254167.149.255.255131,070
76167.150.0.0/15167.150.0.1 to 167.151.255.254167.151.255.255131,070
77167.152.0.0/15167.152.0.1 to 167.153.255.254167.153.255.255131,070
78167.154.0.0/15167.154.0.1 to 167.155.255.254167.155.255.255131,070
79167.156.0.0/15167.156.0.1 to 167.157.255.254167.157.255.255131,070
80167.158.0.0/15167.158.0.1 to 167.159.255.254167.159.255.255131,070
81167.160.0.0/15167.160.0.1 to 167.161.255.254167.161.255.255131,070
82167.162.0.0/15167.162.0.1 to 167.163.255.254167.163.255.255131,070
83167.164.0.0/15167.164.0.1 to 167.165.255.254167.165.255.255131,070
84167.166.0.0/15167.166.0.1 to 167.167.255.254167.167.255.255131,070
85167.168.0.0/15167.168.0.1 to 167.169.255.254167.169.255.255131,070
86167.170.0.0/15167.170.0.1 to 167.171.255.254167.171.255.255131,070
87167.172.0.0/15167.172.0.1 to 167.173.255.254167.173.255.255131,070
88167.174.0.0/15167.174.0.1 to 167.175.255.254167.175.255.255131,070
89167.176.0.0/15167.176.0.1 to 167.177.255.254167.177.255.255131,070
90167.178.0.0/15167.178.0.1 to 167.179.255.254167.179.255.255131,070
91167.180.0.0/15167.180.0.1 to 167.181.255.254167.181.255.255131,070
92167.182.0.0/15167.182.0.1 to 167.183.255.254167.183.255.255131,070
93167.184.0.0/15167.184.0.1 to 167.185.255.254167.185.255.255131,070
94167.186.0.0/15167.186.0.1 to 167.187.255.254167.187.255.255131,070
95167.188.0.0/15167.188.0.1 to 167.189.255.254167.189.255.255131,070
96167.190.0.0/15167.190.0.1 to 167.191.255.254167.191.255.255131,070
97167.192.0.0/15167.192.0.1 to 167.193.255.254167.193.255.255131,070
98167.194.0.0/15167.194.0.1 to 167.195.255.254167.195.255.255131,070
99167.196.0.0/15167.196.0.1 to 167.197.255.254167.197.255.255131,070
100167.198.0.0/15167.198.0.1 to 167.199.255.254167.199.255.255131,070
101167.200.0.0/15167.200.0.1 to 167.201.255.254167.201.255.255131,070
102167.202.0.0/15167.202.0.1 to 167.203.255.254167.203.255.255131,070
103167.204.0.0/15167.204.0.1 to 167.205.255.254167.205.255.255131,070
104167.206.0.0/15167.206.0.1 to 167.207.255.254167.207.255.255131,070
105167.208.0.0/15167.208.0.1 to 167.209.255.254167.209.255.255131,070
106167.210.0.0/15167.210.0.1 to 167.211.255.254167.211.255.255131,070
107167.212.0.0/15167.212.0.1 to 167.213.255.254167.213.255.255131,070
108167.214.0.0/15167.214.0.1 to 167.215.255.254167.215.255.255131,070
109167.216.0.0/15167.216.0.1 to 167.217.255.254167.217.255.255131,070
110167.218.0.0/15167.218.0.1 to 167.219.255.254167.219.255.255131,070
111167.220.0.0/15167.220.0.1 to 167.221.255.254167.221.255.255131,070
112167.222.0.0/15167.222.0.1 to 167.223.255.254167.223.255.255131,070
113167.224.0.0/15167.224.0.1 to 167.225.255.254167.225.255.255131,070
114167.226.0.0/15167.226.0.1 to 167.227.255.254167.227.255.255131,070
115167.228.0.0/15167.228.0.1 to 167.229.255.254167.229.255.255131,070
116167.230.0.0/15167.230.0.1 to 167.231.255.254167.231.255.255131,070
117167.232.0.0/15167.232.0.1 to 167.233.255.254167.233.255.255131,070
118167.234.0.0/15167.234.0.1 to 167.235.255.254167.235.255.255131,070
119167.236.0.0/15167.236.0.1 to 167.237.255.254167.237.255.255131,070
120167.238.0.0/15167.238.0.1 to 167.239.255.254167.239.255.255131,070
121167.240.0.0/15167.240.0.1 to 167.241.255.254167.241.255.255131,070
122167.242.0.0/15167.242.0.1 to 167.243.255.254167.243.255.255131,070
123167.244.0.0/15167.244.0.1 to 167.245.255.254167.245.255.255131,070
124167.246.0.0/15167.246.0.1 to 167.247.255.254167.247.255.255131,070
125167.248.0.0/15167.248.0.1 to 167.249.255.254167.249.255.255131,070
126167.250.0.0/15167.250.0.1 to 167.251.255.254167.251.255.255131,070
127167.252.0.0/15167.252.0.1 to 167.253.255.254167.253.255.255131,070
128167.254.0.0/15167.254.0.1 to 167.255.255.254167.255.255.255131,070

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.