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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.

Network184.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
184.0.0.0
Broadcast address
184.255.255.255
First usable
184.0.0.1
Last usable
184.255.255.254
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 B8000000 · Integer 3087007744 to 3103784959
Reverse DNS zone
184.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111000..00000000.00000000.00000000184.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10111000..00000000.00000000.00000000184.0.0.0
Broadcast10111000..11111111.11111111.11111111184.255.255.255
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)

184.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1184.0.0.0/15184.0.0.1 to 184.1.255.254184.1.255.255131,070
2184.2.0.0/15184.2.0.1 to 184.3.255.254184.3.255.255131,070
3184.4.0.0/15184.4.0.1 to 184.5.255.254184.5.255.255131,070
4184.6.0.0/15184.6.0.1 to 184.7.255.254184.7.255.255131,070
5184.8.0.0/15184.8.0.1 to 184.9.255.254184.9.255.255131,070
6184.10.0.0/15184.10.0.1 to 184.11.255.254184.11.255.255131,070
7184.12.0.0/15184.12.0.1 to 184.13.255.254184.13.255.255131,070
8184.14.0.0/15184.14.0.1 to 184.15.255.254184.15.255.255131,070
9184.16.0.0/15184.16.0.1 to 184.17.255.254184.17.255.255131,070
10184.18.0.0/15184.18.0.1 to 184.19.255.254184.19.255.255131,070
11184.20.0.0/15184.20.0.1 to 184.21.255.254184.21.255.255131,070
12184.22.0.0/15184.22.0.1 to 184.23.255.254184.23.255.255131,070
13184.24.0.0/15184.24.0.1 to 184.25.255.254184.25.255.255131,070
14184.26.0.0/15184.26.0.1 to 184.27.255.254184.27.255.255131,070
15184.28.0.0/15184.28.0.1 to 184.29.255.254184.29.255.255131,070
16184.30.0.0/15184.30.0.1 to 184.31.255.254184.31.255.255131,070
17184.32.0.0/15184.32.0.1 to 184.33.255.254184.33.255.255131,070
18184.34.0.0/15184.34.0.1 to 184.35.255.254184.35.255.255131,070
19184.36.0.0/15184.36.0.1 to 184.37.255.254184.37.255.255131,070
20184.38.0.0/15184.38.0.1 to 184.39.255.254184.39.255.255131,070
21184.40.0.0/15184.40.0.1 to 184.41.255.254184.41.255.255131,070
22184.42.0.0/15184.42.0.1 to 184.43.255.254184.43.255.255131,070
23184.44.0.0/15184.44.0.1 to 184.45.255.254184.45.255.255131,070
24184.46.0.0/15184.46.0.1 to 184.47.255.254184.47.255.255131,070
25184.48.0.0/15184.48.0.1 to 184.49.255.254184.49.255.255131,070
26184.50.0.0/15184.50.0.1 to 184.51.255.254184.51.255.255131,070
27184.52.0.0/15184.52.0.1 to 184.53.255.254184.53.255.255131,070
28184.54.0.0/15184.54.0.1 to 184.55.255.254184.55.255.255131,070
29184.56.0.0/15184.56.0.1 to 184.57.255.254184.57.255.255131,070
30184.58.0.0/15184.58.0.1 to 184.59.255.254184.59.255.255131,070
31184.60.0.0/15184.60.0.1 to 184.61.255.254184.61.255.255131,070
32184.62.0.0/15184.62.0.1 to 184.63.255.254184.63.255.255131,070
33184.64.0.0/15184.64.0.1 to 184.65.255.254184.65.255.255131,070
34184.66.0.0/15184.66.0.1 to 184.67.255.254184.67.255.255131,070
35184.68.0.0/15184.68.0.1 to 184.69.255.254184.69.255.255131,070
36184.70.0.0/15184.70.0.1 to 184.71.255.254184.71.255.255131,070
37184.72.0.0/15184.72.0.1 to 184.73.255.254184.73.255.255131,070
38184.74.0.0/15184.74.0.1 to 184.75.255.254184.75.255.255131,070
39184.76.0.0/15184.76.0.1 to 184.77.255.254184.77.255.255131,070
40184.78.0.0/15184.78.0.1 to 184.79.255.254184.79.255.255131,070
41184.80.0.0/15184.80.0.1 to 184.81.255.254184.81.255.255131,070
42184.82.0.0/15184.82.0.1 to 184.83.255.254184.83.255.255131,070
43184.84.0.0/15184.84.0.1 to 184.85.255.254184.85.255.255131,070
44184.86.0.0/15184.86.0.1 to 184.87.255.254184.87.255.255131,070
45184.88.0.0/15184.88.0.1 to 184.89.255.254184.89.255.255131,070
46184.90.0.0/15184.90.0.1 to 184.91.255.254184.91.255.255131,070
47184.92.0.0/15184.92.0.1 to 184.93.255.254184.93.255.255131,070
48184.94.0.0/15184.94.0.1 to 184.95.255.254184.95.255.255131,070
49184.96.0.0/15184.96.0.1 to 184.97.255.254184.97.255.255131,070
50184.98.0.0/15184.98.0.1 to 184.99.255.254184.99.255.255131,070
51184.100.0.0/15184.100.0.1 to 184.101.255.254184.101.255.255131,070
52184.102.0.0/15184.102.0.1 to 184.103.255.254184.103.255.255131,070
53184.104.0.0/15184.104.0.1 to 184.105.255.254184.105.255.255131,070
54184.106.0.0/15184.106.0.1 to 184.107.255.254184.107.255.255131,070
55184.108.0.0/15184.108.0.1 to 184.109.255.254184.109.255.255131,070
56184.110.0.0/15184.110.0.1 to 184.111.255.254184.111.255.255131,070
57184.112.0.0/15184.112.0.1 to 184.113.255.254184.113.255.255131,070
58184.114.0.0/15184.114.0.1 to 184.115.255.254184.115.255.255131,070
59184.116.0.0/15184.116.0.1 to 184.117.255.254184.117.255.255131,070
60184.118.0.0/15184.118.0.1 to 184.119.255.254184.119.255.255131,070
61184.120.0.0/15184.120.0.1 to 184.121.255.254184.121.255.255131,070
62184.122.0.0/15184.122.0.1 to 184.123.255.254184.123.255.255131,070
63184.124.0.0/15184.124.0.1 to 184.125.255.254184.125.255.255131,070
64184.126.0.0/15184.126.0.1 to 184.127.255.254184.127.255.255131,070
65184.128.0.0/15184.128.0.1 to 184.129.255.254184.129.255.255131,070
66184.130.0.0/15184.130.0.1 to 184.131.255.254184.131.255.255131,070
67184.132.0.0/15184.132.0.1 to 184.133.255.254184.133.255.255131,070
68184.134.0.0/15184.134.0.1 to 184.135.255.254184.135.255.255131,070
69184.136.0.0/15184.136.0.1 to 184.137.255.254184.137.255.255131,070
70184.138.0.0/15184.138.0.1 to 184.139.255.254184.139.255.255131,070
71184.140.0.0/15184.140.0.1 to 184.141.255.254184.141.255.255131,070
72184.142.0.0/15184.142.0.1 to 184.143.255.254184.143.255.255131,070
73184.144.0.0/15184.144.0.1 to 184.145.255.254184.145.255.255131,070
74184.146.0.0/15184.146.0.1 to 184.147.255.254184.147.255.255131,070
75184.148.0.0/15184.148.0.1 to 184.149.255.254184.149.255.255131,070
76184.150.0.0/15184.150.0.1 to 184.151.255.254184.151.255.255131,070
77184.152.0.0/15184.152.0.1 to 184.153.255.254184.153.255.255131,070
78184.154.0.0/15184.154.0.1 to 184.155.255.254184.155.255.255131,070
79184.156.0.0/15184.156.0.1 to 184.157.255.254184.157.255.255131,070
80184.158.0.0/15184.158.0.1 to 184.159.255.254184.159.255.255131,070
81184.160.0.0/15184.160.0.1 to 184.161.255.254184.161.255.255131,070
82184.162.0.0/15184.162.0.1 to 184.163.255.254184.163.255.255131,070
83184.164.0.0/15184.164.0.1 to 184.165.255.254184.165.255.255131,070
84184.166.0.0/15184.166.0.1 to 184.167.255.254184.167.255.255131,070
85184.168.0.0/15184.168.0.1 to 184.169.255.254184.169.255.255131,070
86184.170.0.0/15184.170.0.1 to 184.171.255.254184.171.255.255131,070
87184.172.0.0/15184.172.0.1 to 184.173.255.254184.173.255.255131,070
88184.174.0.0/15184.174.0.1 to 184.175.255.254184.175.255.255131,070
89184.176.0.0/15184.176.0.1 to 184.177.255.254184.177.255.255131,070
90184.178.0.0/15184.178.0.1 to 184.179.255.254184.179.255.255131,070
91184.180.0.0/15184.180.0.1 to 184.181.255.254184.181.255.255131,070
92184.182.0.0/15184.182.0.1 to 184.183.255.254184.183.255.255131,070
93184.184.0.0/15184.184.0.1 to 184.185.255.254184.185.255.255131,070
94184.186.0.0/15184.186.0.1 to 184.187.255.254184.187.255.255131,070
95184.188.0.0/15184.188.0.1 to 184.189.255.254184.189.255.255131,070
96184.190.0.0/15184.190.0.1 to 184.191.255.254184.191.255.255131,070
97184.192.0.0/15184.192.0.1 to 184.193.255.254184.193.255.255131,070
98184.194.0.0/15184.194.0.1 to 184.195.255.254184.195.255.255131,070
99184.196.0.0/15184.196.0.1 to 184.197.255.254184.197.255.255131,070
100184.198.0.0/15184.198.0.1 to 184.199.255.254184.199.255.255131,070
101184.200.0.0/15184.200.0.1 to 184.201.255.254184.201.255.255131,070
102184.202.0.0/15184.202.0.1 to 184.203.255.254184.203.255.255131,070
103184.204.0.0/15184.204.0.1 to 184.205.255.254184.205.255.255131,070
104184.206.0.0/15184.206.0.1 to 184.207.255.254184.207.255.255131,070
105184.208.0.0/15184.208.0.1 to 184.209.255.254184.209.255.255131,070
106184.210.0.0/15184.210.0.1 to 184.211.255.254184.211.255.255131,070
107184.212.0.0/15184.212.0.1 to 184.213.255.254184.213.255.255131,070
108184.214.0.0/15184.214.0.1 to 184.215.255.254184.215.255.255131,070
109184.216.0.0/15184.216.0.1 to 184.217.255.254184.217.255.255131,070
110184.218.0.0/15184.218.0.1 to 184.219.255.254184.219.255.255131,070
111184.220.0.0/15184.220.0.1 to 184.221.255.254184.221.255.255131,070
112184.222.0.0/15184.222.0.1 to 184.223.255.254184.223.255.255131,070
113184.224.0.0/15184.224.0.1 to 184.225.255.254184.225.255.255131,070
114184.226.0.0/15184.226.0.1 to 184.227.255.254184.227.255.255131,070
115184.228.0.0/15184.228.0.1 to 184.229.255.254184.229.255.255131,070
116184.230.0.0/15184.230.0.1 to 184.231.255.254184.231.255.255131,070
117184.232.0.0/15184.232.0.1 to 184.233.255.254184.233.255.255131,070
118184.234.0.0/15184.234.0.1 to 184.235.255.254184.235.255.255131,070
119184.236.0.0/15184.236.0.1 to 184.237.255.254184.237.255.255131,070
120184.238.0.0/15184.238.0.1 to 184.239.255.254184.239.255.255131,070
121184.240.0.0/15184.240.0.1 to 184.241.255.254184.241.255.255131,070
122184.242.0.0/15184.242.0.1 to 184.243.255.254184.243.255.255131,070
123184.244.0.0/15184.244.0.1 to 184.245.255.254184.245.255.255131,070
124184.246.0.0/15184.246.0.1 to 184.247.255.254184.247.255.255131,070
125184.248.0.0/15184.248.0.1 to 184.249.255.254184.249.255.255131,070
126184.250.0.0/15184.250.0.1 to 184.251.255.254184.251.255.255131,070
127184.252.0.0/15184.252.0.1 to 184.253.255.254184.253.255.255131,070
128184.254.0.0/15184.254.0.1 to 184.255.255.254184.255.255.255131,070

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.