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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.

Network187.232.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
187.232.0.0
Broadcast address
187.235.255.255
First usable
187.232.0.1
Last usable
187.235.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
B (default /16)
As numbers
Hex BBE80000 · Integer 3152543744 to 3152805887
Reverse DNS zones
232.187.in-addr.arpa
233.187.in-addr.arpa
234.187.in-addr.arpa
235.187.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111011.11101000.00000000.00000000187.232.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network10111011.11101000.00000000.00000000187.232.0.0
Broadcast10111011.11101011.11111111.11111111187.235.255.255
Split into smaller subnets/21
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

187.232.0.0/14 makes 128 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1187.232.0.0/21187.232.0.1 to 187.232.7.254187.232.7.2552,046
2187.232.8.0/21187.232.8.1 to 187.232.15.254187.232.15.2552,046
3187.232.16.0/21187.232.16.1 to 187.232.23.254187.232.23.2552,046
4187.232.24.0/21187.232.24.1 to 187.232.31.254187.232.31.2552,046
5187.232.32.0/21187.232.32.1 to 187.232.39.254187.232.39.2552,046
6187.232.40.0/21187.232.40.1 to 187.232.47.254187.232.47.2552,046
7187.232.48.0/21187.232.48.1 to 187.232.55.254187.232.55.2552,046
8187.232.56.0/21187.232.56.1 to 187.232.63.254187.232.63.2552,046
9187.232.64.0/21187.232.64.1 to 187.232.71.254187.232.71.2552,046
10187.232.72.0/21187.232.72.1 to 187.232.79.254187.232.79.2552,046
11187.232.80.0/21187.232.80.1 to 187.232.87.254187.232.87.2552,046
12187.232.88.0/21187.232.88.1 to 187.232.95.254187.232.95.2552,046
13187.232.96.0/21187.232.96.1 to 187.232.103.254187.232.103.2552,046
14187.232.104.0/21187.232.104.1 to 187.232.111.254187.232.111.2552,046
15187.232.112.0/21187.232.112.1 to 187.232.119.254187.232.119.2552,046
16187.232.120.0/21187.232.120.1 to 187.232.127.254187.232.127.2552,046
17187.232.128.0/21187.232.128.1 to 187.232.135.254187.232.135.2552,046
18187.232.136.0/21187.232.136.1 to 187.232.143.254187.232.143.2552,046
19187.232.144.0/21187.232.144.1 to 187.232.151.254187.232.151.2552,046
20187.232.152.0/21187.232.152.1 to 187.232.159.254187.232.159.2552,046
21187.232.160.0/21187.232.160.1 to 187.232.167.254187.232.167.2552,046
22187.232.168.0/21187.232.168.1 to 187.232.175.254187.232.175.2552,046
23187.232.176.0/21187.232.176.1 to 187.232.183.254187.232.183.2552,046
24187.232.184.0/21187.232.184.1 to 187.232.191.254187.232.191.2552,046
25187.232.192.0/21187.232.192.1 to 187.232.199.254187.232.199.2552,046
26187.232.200.0/21187.232.200.1 to 187.232.207.254187.232.207.2552,046
27187.232.208.0/21187.232.208.1 to 187.232.215.254187.232.215.2552,046
28187.232.216.0/21187.232.216.1 to 187.232.223.254187.232.223.2552,046
29187.232.224.0/21187.232.224.1 to 187.232.231.254187.232.231.2552,046
30187.232.232.0/21187.232.232.1 to 187.232.239.254187.232.239.2552,046
31187.232.240.0/21187.232.240.1 to 187.232.247.254187.232.247.2552,046
32187.232.248.0/21187.232.248.1 to 187.232.255.254187.232.255.2552,046
33187.233.0.0/21187.233.0.1 to 187.233.7.254187.233.7.2552,046
34187.233.8.0/21187.233.8.1 to 187.233.15.254187.233.15.2552,046
35187.233.16.0/21187.233.16.1 to 187.233.23.254187.233.23.2552,046
36187.233.24.0/21187.233.24.1 to 187.233.31.254187.233.31.2552,046
37187.233.32.0/21187.233.32.1 to 187.233.39.254187.233.39.2552,046
38187.233.40.0/21187.233.40.1 to 187.233.47.254187.233.47.2552,046
39187.233.48.0/21187.233.48.1 to 187.233.55.254187.233.55.2552,046
40187.233.56.0/21187.233.56.1 to 187.233.63.254187.233.63.2552,046
41187.233.64.0/21187.233.64.1 to 187.233.71.254187.233.71.2552,046
42187.233.72.0/21187.233.72.1 to 187.233.79.254187.233.79.2552,046
43187.233.80.0/21187.233.80.1 to 187.233.87.254187.233.87.2552,046
44187.233.88.0/21187.233.88.1 to 187.233.95.254187.233.95.2552,046
45187.233.96.0/21187.233.96.1 to 187.233.103.254187.233.103.2552,046
46187.233.104.0/21187.233.104.1 to 187.233.111.254187.233.111.2552,046
47187.233.112.0/21187.233.112.1 to 187.233.119.254187.233.119.2552,046
48187.233.120.0/21187.233.120.1 to 187.233.127.254187.233.127.2552,046
49187.233.128.0/21187.233.128.1 to 187.233.135.254187.233.135.2552,046
50187.233.136.0/21187.233.136.1 to 187.233.143.254187.233.143.2552,046
51187.233.144.0/21187.233.144.1 to 187.233.151.254187.233.151.2552,046
52187.233.152.0/21187.233.152.1 to 187.233.159.254187.233.159.2552,046
53187.233.160.0/21187.233.160.1 to 187.233.167.254187.233.167.2552,046
54187.233.168.0/21187.233.168.1 to 187.233.175.254187.233.175.2552,046
55187.233.176.0/21187.233.176.1 to 187.233.183.254187.233.183.2552,046
56187.233.184.0/21187.233.184.1 to 187.233.191.254187.233.191.2552,046
57187.233.192.0/21187.233.192.1 to 187.233.199.254187.233.199.2552,046
58187.233.200.0/21187.233.200.1 to 187.233.207.254187.233.207.2552,046
59187.233.208.0/21187.233.208.1 to 187.233.215.254187.233.215.2552,046
60187.233.216.0/21187.233.216.1 to 187.233.223.254187.233.223.2552,046
61187.233.224.0/21187.233.224.1 to 187.233.231.254187.233.231.2552,046
62187.233.232.0/21187.233.232.1 to 187.233.239.254187.233.239.2552,046
63187.233.240.0/21187.233.240.1 to 187.233.247.254187.233.247.2552,046
64187.233.248.0/21187.233.248.1 to 187.233.255.254187.233.255.2552,046
65187.234.0.0/21187.234.0.1 to 187.234.7.254187.234.7.2552,046
66187.234.8.0/21187.234.8.1 to 187.234.15.254187.234.15.2552,046
67187.234.16.0/21187.234.16.1 to 187.234.23.254187.234.23.2552,046
68187.234.24.0/21187.234.24.1 to 187.234.31.254187.234.31.2552,046
69187.234.32.0/21187.234.32.1 to 187.234.39.254187.234.39.2552,046
70187.234.40.0/21187.234.40.1 to 187.234.47.254187.234.47.2552,046
71187.234.48.0/21187.234.48.1 to 187.234.55.254187.234.55.2552,046
72187.234.56.0/21187.234.56.1 to 187.234.63.254187.234.63.2552,046
73187.234.64.0/21187.234.64.1 to 187.234.71.254187.234.71.2552,046
74187.234.72.0/21187.234.72.1 to 187.234.79.254187.234.79.2552,046
75187.234.80.0/21187.234.80.1 to 187.234.87.254187.234.87.2552,046
76187.234.88.0/21187.234.88.1 to 187.234.95.254187.234.95.2552,046
77187.234.96.0/21187.234.96.1 to 187.234.103.254187.234.103.2552,046
78187.234.104.0/21187.234.104.1 to 187.234.111.254187.234.111.2552,046
79187.234.112.0/21187.234.112.1 to 187.234.119.254187.234.119.2552,046
80187.234.120.0/21187.234.120.1 to 187.234.127.254187.234.127.2552,046
81187.234.128.0/21187.234.128.1 to 187.234.135.254187.234.135.2552,046
82187.234.136.0/21187.234.136.1 to 187.234.143.254187.234.143.2552,046
83187.234.144.0/21187.234.144.1 to 187.234.151.254187.234.151.2552,046
84187.234.152.0/21187.234.152.1 to 187.234.159.254187.234.159.2552,046
85187.234.160.0/21187.234.160.1 to 187.234.167.254187.234.167.2552,046
86187.234.168.0/21187.234.168.1 to 187.234.175.254187.234.175.2552,046
87187.234.176.0/21187.234.176.1 to 187.234.183.254187.234.183.2552,046
88187.234.184.0/21187.234.184.1 to 187.234.191.254187.234.191.2552,046
89187.234.192.0/21187.234.192.1 to 187.234.199.254187.234.199.2552,046
90187.234.200.0/21187.234.200.1 to 187.234.207.254187.234.207.2552,046
91187.234.208.0/21187.234.208.1 to 187.234.215.254187.234.215.2552,046
92187.234.216.0/21187.234.216.1 to 187.234.223.254187.234.223.2552,046
93187.234.224.0/21187.234.224.1 to 187.234.231.254187.234.231.2552,046
94187.234.232.0/21187.234.232.1 to 187.234.239.254187.234.239.2552,046
95187.234.240.0/21187.234.240.1 to 187.234.247.254187.234.247.2552,046
96187.234.248.0/21187.234.248.1 to 187.234.255.254187.234.255.2552,046
97187.235.0.0/21187.235.0.1 to 187.235.7.254187.235.7.2552,046
98187.235.8.0/21187.235.8.1 to 187.235.15.254187.235.15.2552,046
99187.235.16.0/21187.235.16.1 to 187.235.23.254187.235.23.2552,046
100187.235.24.0/21187.235.24.1 to 187.235.31.254187.235.31.2552,046
101187.235.32.0/21187.235.32.1 to 187.235.39.254187.235.39.2552,046
102187.235.40.0/21187.235.40.1 to 187.235.47.254187.235.47.2552,046
103187.235.48.0/21187.235.48.1 to 187.235.55.254187.235.55.2552,046
104187.235.56.0/21187.235.56.1 to 187.235.63.254187.235.63.2552,046
105187.235.64.0/21187.235.64.1 to 187.235.71.254187.235.71.2552,046
106187.235.72.0/21187.235.72.1 to 187.235.79.254187.235.79.2552,046
107187.235.80.0/21187.235.80.1 to 187.235.87.254187.235.87.2552,046
108187.235.88.0/21187.235.88.1 to 187.235.95.254187.235.95.2552,046
109187.235.96.0/21187.235.96.1 to 187.235.103.254187.235.103.2552,046
110187.235.104.0/21187.235.104.1 to 187.235.111.254187.235.111.2552,046
111187.235.112.0/21187.235.112.1 to 187.235.119.254187.235.119.2552,046
112187.235.120.0/21187.235.120.1 to 187.235.127.254187.235.127.2552,046
113187.235.128.0/21187.235.128.1 to 187.235.135.254187.235.135.2552,046
114187.235.136.0/21187.235.136.1 to 187.235.143.254187.235.143.2552,046
115187.235.144.0/21187.235.144.1 to 187.235.151.254187.235.151.2552,046
116187.235.152.0/21187.235.152.1 to 187.235.159.254187.235.159.2552,046
117187.235.160.0/21187.235.160.1 to 187.235.167.254187.235.167.2552,046
118187.235.168.0/21187.235.168.1 to 187.235.175.254187.235.175.2552,046
119187.235.176.0/21187.235.176.1 to 187.235.183.254187.235.183.2552,046
120187.235.184.0/21187.235.184.1 to 187.235.191.254187.235.191.2552,046
121187.235.192.0/21187.235.192.1 to 187.235.199.254187.235.199.2552,046
122187.235.200.0/21187.235.200.1 to 187.235.207.254187.235.207.2552,046
123187.235.208.0/21187.235.208.1 to 187.235.215.254187.235.215.2552,046
124187.235.216.0/21187.235.216.1 to 187.235.223.254187.235.223.2552,046
125187.235.224.0/21187.235.224.1 to 187.235.231.254187.235.231.2552,046
126187.235.232.0/21187.235.232.1 to 187.235.239.254187.235.239.2552,046
127187.235.240.0/21187.235.240.1 to 187.235.247.254187.235.247.2552,046
128187.235.248.0/21187.235.248.1 to 187.235.255.254187.235.255.2552,046

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.