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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.

Network182.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
182.0.0.0
Broadcast address
182.255.255.255
First usable
182.0.0.1
Last usable
182.255.255.254
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 B6000000 · Integer 3053453312 to 3070230527
Reverse DNS zone
182.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110110..00000000.00000000.00000000182.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10110110..00000000.00000000.00000000182.0.0.0
Broadcast10110110..11111111.11111111.11111111182.255.255.255
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)

182.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1182.0.0.0/15182.0.0.1 to 182.1.255.254182.1.255.255131,070
2182.2.0.0/15182.2.0.1 to 182.3.255.254182.3.255.255131,070
3182.4.0.0/15182.4.0.1 to 182.5.255.254182.5.255.255131,070
4182.6.0.0/15182.6.0.1 to 182.7.255.254182.7.255.255131,070
5182.8.0.0/15182.8.0.1 to 182.9.255.254182.9.255.255131,070
6182.10.0.0/15182.10.0.1 to 182.11.255.254182.11.255.255131,070
7182.12.0.0/15182.12.0.1 to 182.13.255.254182.13.255.255131,070
8182.14.0.0/15182.14.0.1 to 182.15.255.254182.15.255.255131,070
9182.16.0.0/15182.16.0.1 to 182.17.255.254182.17.255.255131,070
10182.18.0.0/15182.18.0.1 to 182.19.255.254182.19.255.255131,070
11182.20.0.0/15182.20.0.1 to 182.21.255.254182.21.255.255131,070
12182.22.0.0/15182.22.0.1 to 182.23.255.254182.23.255.255131,070
13182.24.0.0/15182.24.0.1 to 182.25.255.254182.25.255.255131,070
14182.26.0.0/15182.26.0.1 to 182.27.255.254182.27.255.255131,070
15182.28.0.0/15182.28.0.1 to 182.29.255.254182.29.255.255131,070
16182.30.0.0/15182.30.0.1 to 182.31.255.254182.31.255.255131,070
17182.32.0.0/15182.32.0.1 to 182.33.255.254182.33.255.255131,070
18182.34.0.0/15182.34.0.1 to 182.35.255.254182.35.255.255131,070
19182.36.0.0/15182.36.0.1 to 182.37.255.254182.37.255.255131,070
20182.38.0.0/15182.38.0.1 to 182.39.255.254182.39.255.255131,070
21182.40.0.0/15182.40.0.1 to 182.41.255.254182.41.255.255131,070
22182.42.0.0/15182.42.0.1 to 182.43.255.254182.43.255.255131,070
23182.44.0.0/15182.44.0.1 to 182.45.255.254182.45.255.255131,070
24182.46.0.0/15182.46.0.1 to 182.47.255.254182.47.255.255131,070
25182.48.0.0/15182.48.0.1 to 182.49.255.254182.49.255.255131,070
26182.50.0.0/15182.50.0.1 to 182.51.255.254182.51.255.255131,070
27182.52.0.0/15182.52.0.1 to 182.53.255.254182.53.255.255131,070
28182.54.0.0/15182.54.0.1 to 182.55.255.254182.55.255.255131,070
29182.56.0.0/15182.56.0.1 to 182.57.255.254182.57.255.255131,070
30182.58.0.0/15182.58.0.1 to 182.59.255.254182.59.255.255131,070
31182.60.0.0/15182.60.0.1 to 182.61.255.254182.61.255.255131,070
32182.62.0.0/15182.62.0.1 to 182.63.255.254182.63.255.255131,070
33182.64.0.0/15182.64.0.1 to 182.65.255.254182.65.255.255131,070
34182.66.0.0/15182.66.0.1 to 182.67.255.254182.67.255.255131,070
35182.68.0.0/15182.68.0.1 to 182.69.255.254182.69.255.255131,070
36182.70.0.0/15182.70.0.1 to 182.71.255.254182.71.255.255131,070
37182.72.0.0/15182.72.0.1 to 182.73.255.254182.73.255.255131,070
38182.74.0.0/15182.74.0.1 to 182.75.255.254182.75.255.255131,070
39182.76.0.0/15182.76.0.1 to 182.77.255.254182.77.255.255131,070
40182.78.0.0/15182.78.0.1 to 182.79.255.254182.79.255.255131,070
41182.80.0.0/15182.80.0.1 to 182.81.255.254182.81.255.255131,070
42182.82.0.0/15182.82.0.1 to 182.83.255.254182.83.255.255131,070
43182.84.0.0/15182.84.0.1 to 182.85.255.254182.85.255.255131,070
44182.86.0.0/15182.86.0.1 to 182.87.255.254182.87.255.255131,070
45182.88.0.0/15182.88.0.1 to 182.89.255.254182.89.255.255131,070
46182.90.0.0/15182.90.0.1 to 182.91.255.254182.91.255.255131,070
47182.92.0.0/15182.92.0.1 to 182.93.255.254182.93.255.255131,070
48182.94.0.0/15182.94.0.1 to 182.95.255.254182.95.255.255131,070
49182.96.0.0/15182.96.0.1 to 182.97.255.254182.97.255.255131,070
50182.98.0.0/15182.98.0.1 to 182.99.255.254182.99.255.255131,070
51182.100.0.0/15182.100.0.1 to 182.101.255.254182.101.255.255131,070
52182.102.0.0/15182.102.0.1 to 182.103.255.254182.103.255.255131,070
53182.104.0.0/15182.104.0.1 to 182.105.255.254182.105.255.255131,070
54182.106.0.0/15182.106.0.1 to 182.107.255.254182.107.255.255131,070
55182.108.0.0/15182.108.0.1 to 182.109.255.254182.109.255.255131,070
56182.110.0.0/15182.110.0.1 to 182.111.255.254182.111.255.255131,070
57182.112.0.0/15182.112.0.1 to 182.113.255.254182.113.255.255131,070
58182.114.0.0/15182.114.0.1 to 182.115.255.254182.115.255.255131,070
59182.116.0.0/15182.116.0.1 to 182.117.255.254182.117.255.255131,070
60182.118.0.0/15182.118.0.1 to 182.119.255.254182.119.255.255131,070
61182.120.0.0/15182.120.0.1 to 182.121.255.254182.121.255.255131,070
62182.122.0.0/15182.122.0.1 to 182.123.255.254182.123.255.255131,070
63182.124.0.0/15182.124.0.1 to 182.125.255.254182.125.255.255131,070
64182.126.0.0/15182.126.0.1 to 182.127.255.254182.127.255.255131,070
65182.128.0.0/15182.128.0.1 to 182.129.255.254182.129.255.255131,070
66182.130.0.0/15182.130.0.1 to 182.131.255.254182.131.255.255131,070
67182.132.0.0/15182.132.0.1 to 182.133.255.254182.133.255.255131,070
68182.134.0.0/15182.134.0.1 to 182.135.255.254182.135.255.255131,070
69182.136.0.0/15182.136.0.1 to 182.137.255.254182.137.255.255131,070
70182.138.0.0/15182.138.0.1 to 182.139.255.254182.139.255.255131,070
71182.140.0.0/15182.140.0.1 to 182.141.255.254182.141.255.255131,070
72182.142.0.0/15182.142.0.1 to 182.143.255.254182.143.255.255131,070
73182.144.0.0/15182.144.0.1 to 182.145.255.254182.145.255.255131,070
74182.146.0.0/15182.146.0.1 to 182.147.255.254182.147.255.255131,070
75182.148.0.0/15182.148.0.1 to 182.149.255.254182.149.255.255131,070
76182.150.0.0/15182.150.0.1 to 182.151.255.254182.151.255.255131,070
77182.152.0.0/15182.152.0.1 to 182.153.255.254182.153.255.255131,070
78182.154.0.0/15182.154.0.1 to 182.155.255.254182.155.255.255131,070
79182.156.0.0/15182.156.0.1 to 182.157.255.254182.157.255.255131,070
80182.158.0.0/15182.158.0.1 to 182.159.255.254182.159.255.255131,070
81182.160.0.0/15182.160.0.1 to 182.161.255.254182.161.255.255131,070
82182.162.0.0/15182.162.0.1 to 182.163.255.254182.163.255.255131,070
83182.164.0.0/15182.164.0.1 to 182.165.255.254182.165.255.255131,070
84182.166.0.0/15182.166.0.1 to 182.167.255.254182.167.255.255131,070
85182.168.0.0/15182.168.0.1 to 182.169.255.254182.169.255.255131,070
86182.170.0.0/15182.170.0.1 to 182.171.255.254182.171.255.255131,070
87182.172.0.0/15182.172.0.1 to 182.173.255.254182.173.255.255131,070
88182.174.0.0/15182.174.0.1 to 182.175.255.254182.175.255.255131,070
89182.176.0.0/15182.176.0.1 to 182.177.255.254182.177.255.255131,070
90182.178.0.0/15182.178.0.1 to 182.179.255.254182.179.255.255131,070
91182.180.0.0/15182.180.0.1 to 182.181.255.254182.181.255.255131,070
92182.182.0.0/15182.182.0.1 to 182.183.255.254182.183.255.255131,070
93182.184.0.0/15182.184.0.1 to 182.185.255.254182.185.255.255131,070
94182.186.0.0/15182.186.0.1 to 182.187.255.254182.187.255.255131,070
95182.188.0.0/15182.188.0.1 to 182.189.255.254182.189.255.255131,070
96182.190.0.0/15182.190.0.1 to 182.191.255.254182.191.255.255131,070
97182.192.0.0/15182.192.0.1 to 182.193.255.254182.193.255.255131,070
98182.194.0.0/15182.194.0.1 to 182.195.255.254182.195.255.255131,070
99182.196.0.0/15182.196.0.1 to 182.197.255.254182.197.255.255131,070
100182.198.0.0/15182.198.0.1 to 182.199.255.254182.199.255.255131,070
101182.200.0.0/15182.200.0.1 to 182.201.255.254182.201.255.255131,070
102182.202.0.0/15182.202.0.1 to 182.203.255.254182.203.255.255131,070
103182.204.0.0/15182.204.0.1 to 182.205.255.254182.205.255.255131,070
104182.206.0.0/15182.206.0.1 to 182.207.255.254182.207.255.255131,070
105182.208.0.0/15182.208.0.1 to 182.209.255.254182.209.255.255131,070
106182.210.0.0/15182.210.0.1 to 182.211.255.254182.211.255.255131,070
107182.212.0.0/15182.212.0.1 to 182.213.255.254182.213.255.255131,070
108182.214.0.0/15182.214.0.1 to 182.215.255.254182.215.255.255131,070
109182.216.0.0/15182.216.0.1 to 182.217.255.254182.217.255.255131,070
110182.218.0.0/15182.218.0.1 to 182.219.255.254182.219.255.255131,070
111182.220.0.0/15182.220.0.1 to 182.221.255.254182.221.255.255131,070
112182.222.0.0/15182.222.0.1 to 182.223.255.254182.223.255.255131,070
113182.224.0.0/15182.224.0.1 to 182.225.255.254182.225.255.255131,070
114182.226.0.0/15182.226.0.1 to 182.227.255.254182.227.255.255131,070
115182.228.0.0/15182.228.0.1 to 182.229.255.254182.229.255.255131,070
116182.230.0.0/15182.230.0.1 to 182.231.255.254182.231.255.255131,070
117182.232.0.0/15182.232.0.1 to 182.233.255.254182.233.255.255131,070
118182.234.0.0/15182.234.0.1 to 182.235.255.254182.235.255.255131,070
119182.236.0.0/15182.236.0.1 to 182.237.255.254182.237.255.255131,070
120182.238.0.0/15182.238.0.1 to 182.239.255.254182.239.255.255131,070
121182.240.0.0/15182.240.0.1 to 182.241.255.254182.241.255.255131,070
122182.242.0.0/15182.242.0.1 to 182.243.255.254182.243.255.255131,070
123182.244.0.0/15182.244.0.1 to 182.245.255.254182.245.255.255131,070
124182.246.0.0/15182.246.0.1 to 182.247.255.254182.247.255.255131,070
125182.248.0.0/15182.248.0.1 to 182.249.255.254182.249.255.255131,070
126182.250.0.0/15182.250.0.1 to 182.251.255.254182.251.255.255131,070
127182.252.0.0/15182.252.0.1 to 182.253.255.254182.253.255.255131,070
128182.254.0.0/15182.254.0.1 to 182.255.255.254182.255.255.255131,070

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.