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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.

Network162.232.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
162.232.0.0
Broadcast address
162.233.255.255
First usable
162.232.0.1
Last usable
162.233.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex A2E80000 · Integer 2733113344 to 2733244415
Reverse DNS zones
232.162.in-addr.arpa
233.162.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100010.11101000.00000000.00000000162.232.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100010.11101000.00000000.00000000162.232.0.0
Broadcast10100010.11101001.11111111.11111111162.233.255.255
Split into smaller subnets/22
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

162.232.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1162.232.0.0/22162.232.0.1 to 162.232.3.254162.232.3.2551,022
2162.232.4.0/22162.232.4.1 to 162.232.7.254162.232.7.2551,022
3162.232.8.0/22162.232.8.1 to 162.232.11.254162.232.11.2551,022
4162.232.12.0/22162.232.12.1 to 162.232.15.254162.232.15.2551,022
5162.232.16.0/22162.232.16.1 to 162.232.19.254162.232.19.2551,022
6162.232.20.0/22162.232.20.1 to 162.232.23.254162.232.23.2551,022
7162.232.24.0/22162.232.24.1 to 162.232.27.254162.232.27.2551,022
8162.232.28.0/22162.232.28.1 to 162.232.31.254162.232.31.2551,022
9162.232.32.0/22162.232.32.1 to 162.232.35.254162.232.35.2551,022
10162.232.36.0/22162.232.36.1 to 162.232.39.254162.232.39.2551,022
11162.232.40.0/22162.232.40.1 to 162.232.43.254162.232.43.2551,022
12162.232.44.0/22162.232.44.1 to 162.232.47.254162.232.47.2551,022
13162.232.48.0/22162.232.48.1 to 162.232.51.254162.232.51.2551,022
14162.232.52.0/22162.232.52.1 to 162.232.55.254162.232.55.2551,022
15162.232.56.0/22162.232.56.1 to 162.232.59.254162.232.59.2551,022
16162.232.60.0/22162.232.60.1 to 162.232.63.254162.232.63.2551,022
17162.232.64.0/22162.232.64.1 to 162.232.67.254162.232.67.2551,022
18162.232.68.0/22162.232.68.1 to 162.232.71.254162.232.71.2551,022
19162.232.72.0/22162.232.72.1 to 162.232.75.254162.232.75.2551,022
20162.232.76.0/22162.232.76.1 to 162.232.79.254162.232.79.2551,022
21162.232.80.0/22162.232.80.1 to 162.232.83.254162.232.83.2551,022
22162.232.84.0/22162.232.84.1 to 162.232.87.254162.232.87.2551,022
23162.232.88.0/22162.232.88.1 to 162.232.91.254162.232.91.2551,022
24162.232.92.0/22162.232.92.1 to 162.232.95.254162.232.95.2551,022
25162.232.96.0/22162.232.96.1 to 162.232.99.254162.232.99.2551,022
26162.232.100.0/22162.232.100.1 to 162.232.103.254162.232.103.2551,022
27162.232.104.0/22162.232.104.1 to 162.232.107.254162.232.107.2551,022
28162.232.108.0/22162.232.108.1 to 162.232.111.254162.232.111.2551,022
29162.232.112.0/22162.232.112.1 to 162.232.115.254162.232.115.2551,022
30162.232.116.0/22162.232.116.1 to 162.232.119.254162.232.119.2551,022
31162.232.120.0/22162.232.120.1 to 162.232.123.254162.232.123.2551,022
32162.232.124.0/22162.232.124.1 to 162.232.127.254162.232.127.2551,022
33162.232.128.0/22162.232.128.1 to 162.232.131.254162.232.131.2551,022
34162.232.132.0/22162.232.132.1 to 162.232.135.254162.232.135.2551,022
35162.232.136.0/22162.232.136.1 to 162.232.139.254162.232.139.2551,022
36162.232.140.0/22162.232.140.1 to 162.232.143.254162.232.143.2551,022
37162.232.144.0/22162.232.144.1 to 162.232.147.254162.232.147.2551,022
38162.232.148.0/22162.232.148.1 to 162.232.151.254162.232.151.2551,022
39162.232.152.0/22162.232.152.1 to 162.232.155.254162.232.155.2551,022
40162.232.156.0/22162.232.156.1 to 162.232.159.254162.232.159.2551,022
41162.232.160.0/22162.232.160.1 to 162.232.163.254162.232.163.2551,022
42162.232.164.0/22162.232.164.1 to 162.232.167.254162.232.167.2551,022
43162.232.168.0/22162.232.168.1 to 162.232.171.254162.232.171.2551,022
44162.232.172.0/22162.232.172.1 to 162.232.175.254162.232.175.2551,022
45162.232.176.0/22162.232.176.1 to 162.232.179.254162.232.179.2551,022
46162.232.180.0/22162.232.180.1 to 162.232.183.254162.232.183.2551,022
47162.232.184.0/22162.232.184.1 to 162.232.187.254162.232.187.2551,022
48162.232.188.0/22162.232.188.1 to 162.232.191.254162.232.191.2551,022
49162.232.192.0/22162.232.192.1 to 162.232.195.254162.232.195.2551,022
50162.232.196.0/22162.232.196.1 to 162.232.199.254162.232.199.2551,022
51162.232.200.0/22162.232.200.1 to 162.232.203.254162.232.203.2551,022
52162.232.204.0/22162.232.204.1 to 162.232.207.254162.232.207.2551,022
53162.232.208.0/22162.232.208.1 to 162.232.211.254162.232.211.2551,022
54162.232.212.0/22162.232.212.1 to 162.232.215.254162.232.215.2551,022
55162.232.216.0/22162.232.216.1 to 162.232.219.254162.232.219.2551,022
56162.232.220.0/22162.232.220.1 to 162.232.223.254162.232.223.2551,022
57162.232.224.0/22162.232.224.1 to 162.232.227.254162.232.227.2551,022
58162.232.228.0/22162.232.228.1 to 162.232.231.254162.232.231.2551,022
59162.232.232.0/22162.232.232.1 to 162.232.235.254162.232.235.2551,022
60162.232.236.0/22162.232.236.1 to 162.232.239.254162.232.239.2551,022
61162.232.240.0/22162.232.240.1 to 162.232.243.254162.232.243.2551,022
62162.232.244.0/22162.232.244.1 to 162.232.247.254162.232.247.2551,022
63162.232.248.0/22162.232.248.1 to 162.232.251.254162.232.251.2551,022
64162.232.252.0/22162.232.252.1 to 162.232.255.254162.232.255.2551,022
65162.233.0.0/22162.233.0.1 to 162.233.3.254162.233.3.2551,022
66162.233.4.0/22162.233.4.1 to 162.233.7.254162.233.7.2551,022
67162.233.8.0/22162.233.8.1 to 162.233.11.254162.233.11.2551,022
68162.233.12.0/22162.233.12.1 to 162.233.15.254162.233.15.2551,022
69162.233.16.0/22162.233.16.1 to 162.233.19.254162.233.19.2551,022
70162.233.20.0/22162.233.20.1 to 162.233.23.254162.233.23.2551,022
71162.233.24.0/22162.233.24.1 to 162.233.27.254162.233.27.2551,022
72162.233.28.0/22162.233.28.1 to 162.233.31.254162.233.31.2551,022
73162.233.32.0/22162.233.32.1 to 162.233.35.254162.233.35.2551,022
74162.233.36.0/22162.233.36.1 to 162.233.39.254162.233.39.2551,022
75162.233.40.0/22162.233.40.1 to 162.233.43.254162.233.43.2551,022
76162.233.44.0/22162.233.44.1 to 162.233.47.254162.233.47.2551,022
77162.233.48.0/22162.233.48.1 to 162.233.51.254162.233.51.2551,022
78162.233.52.0/22162.233.52.1 to 162.233.55.254162.233.55.2551,022
79162.233.56.0/22162.233.56.1 to 162.233.59.254162.233.59.2551,022
80162.233.60.0/22162.233.60.1 to 162.233.63.254162.233.63.2551,022
81162.233.64.0/22162.233.64.1 to 162.233.67.254162.233.67.2551,022
82162.233.68.0/22162.233.68.1 to 162.233.71.254162.233.71.2551,022
83162.233.72.0/22162.233.72.1 to 162.233.75.254162.233.75.2551,022
84162.233.76.0/22162.233.76.1 to 162.233.79.254162.233.79.2551,022
85162.233.80.0/22162.233.80.1 to 162.233.83.254162.233.83.2551,022
86162.233.84.0/22162.233.84.1 to 162.233.87.254162.233.87.2551,022
87162.233.88.0/22162.233.88.1 to 162.233.91.254162.233.91.2551,022
88162.233.92.0/22162.233.92.1 to 162.233.95.254162.233.95.2551,022
89162.233.96.0/22162.233.96.1 to 162.233.99.254162.233.99.2551,022
90162.233.100.0/22162.233.100.1 to 162.233.103.254162.233.103.2551,022
91162.233.104.0/22162.233.104.1 to 162.233.107.254162.233.107.2551,022
92162.233.108.0/22162.233.108.1 to 162.233.111.254162.233.111.2551,022
93162.233.112.0/22162.233.112.1 to 162.233.115.254162.233.115.2551,022
94162.233.116.0/22162.233.116.1 to 162.233.119.254162.233.119.2551,022
95162.233.120.0/22162.233.120.1 to 162.233.123.254162.233.123.2551,022
96162.233.124.0/22162.233.124.1 to 162.233.127.254162.233.127.2551,022
97162.233.128.0/22162.233.128.1 to 162.233.131.254162.233.131.2551,022
98162.233.132.0/22162.233.132.1 to 162.233.135.254162.233.135.2551,022
99162.233.136.0/22162.233.136.1 to 162.233.139.254162.233.139.2551,022
100162.233.140.0/22162.233.140.1 to 162.233.143.254162.233.143.2551,022
101162.233.144.0/22162.233.144.1 to 162.233.147.254162.233.147.2551,022
102162.233.148.0/22162.233.148.1 to 162.233.151.254162.233.151.2551,022
103162.233.152.0/22162.233.152.1 to 162.233.155.254162.233.155.2551,022
104162.233.156.0/22162.233.156.1 to 162.233.159.254162.233.159.2551,022
105162.233.160.0/22162.233.160.1 to 162.233.163.254162.233.163.2551,022
106162.233.164.0/22162.233.164.1 to 162.233.167.254162.233.167.2551,022
107162.233.168.0/22162.233.168.1 to 162.233.171.254162.233.171.2551,022
108162.233.172.0/22162.233.172.1 to 162.233.175.254162.233.175.2551,022
109162.233.176.0/22162.233.176.1 to 162.233.179.254162.233.179.2551,022
110162.233.180.0/22162.233.180.1 to 162.233.183.254162.233.183.2551,022
111162.233.184.0/22162.233.184.1 to 162.233.187.254162.233.187.2551,022
112162.233.188.0/22162.233.188.1 to 162.233.191.254162.233.191.2551,022
113162.233.192.0/22162.233.192.1 to 162.233.195.254162.233.195.2551,022
114162.233.196.0/22162.233.196.1 to 162.233.199.254162.233.199.2551,022
115162.233.200.0/22162.233.200.1 to 162.233.203.254162.233.203.2551,022
116162.233.204.0/22162.233.204.1 to 162.233.207.254162.233.207.2551,022
117162.233.208.0/22162.233.208.1 to 162.233.211.254162.233.211.2551,022
118162.233.212.0/22162.233.212.1 to 162.233.215.254162.233.215.2551,022
119162.233.216.0/22162.233.216.1 to 162.233.219.254162.233.219.2551,022
120162.233.220.0/22162.233.220.1 to 162.233.223.254162.233.223.2551,022
121162.233.224.0/22162.233.224.1 to 162.233.227.254162.233.227.2551,022
122162.233.228.0/22162.233.228.1 to 162.233.231.254162.233.231.2551,022
123162.233.232.0/22162.233.232.1 to 162.233.235.254162.233.235.2551,022
124162.233.236.0/22162.233.236.1 to 162.233.239.254162.233.239.2551,022
125162.233.240.0/22162.233.240.1 to 162.233.243.254162.233.243.2551,022
126162.233.244.0/22162.233.244.1 to 162.233.247.254162.233.247.2551,022
127162.233.248.0/22162.233.248.1 to 162.233.251.254162.233.251.2551,022
128162.233.252.0/22162.233.252.1 to 162.233.255.254162.233.255.2551,022

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.