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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.

Network132.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
132.0.0.0
Broadcast address
135.255.255.255
First usable
132.0.0.1
Last usable
135.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex 84000000 · Integer 2214592512 to 2281701375
Reverse DNS zones
132.in-addr.arpa
133.in-addr.arpa
134.in-addr.arpa
135.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000100.00000000.00000000.00000000132.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10000100.00000000.00000000.00000000132.0.0.0
Broadcast10000111.11111111.11111111.11111111135.255.255.255
Split into smaller subnets/13
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

132.0.0.0/6 makes 128 subnets of /13.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1132.0.0.0/13132.0.0.1 to 132.7.255.254132.7.255.255524,286
2132.8.0.0/13132.8.0.1 to 132.15.255.254132.15.255.255524,286
3132.16.0.0/13132.16.0.1 to 132.23.255.254132.23.255.255524,286
4132.24.0.0/13132.24.0.1 to 132.31.255.254132.31.255.255524,286
5132.32.0.0/13132.32.0.1 to 132.39.255.254132.39.255.255524,286
6132.40.0.0/13132.40.0.1 to 132.47.255.254132.47.255.255524,286
7132.48.0.0/13132.48.0.1 to 132.55.255.254132.55.255.255524,286
8132.56.0.0/13132.56.0.1 to 132.63.255.254132.63.255.255524,286
9132.64.0.0/13132.64.0.1 to 132.71.255.254132.71.255.255524,286
10132.72.0.0/13132.72.0.1 to 132.79.255.254132.79.255.255524,286
11132.80.0.0/13132.80.0.1 to 132.87.255.254132.87.255.255524,286
12132.88.0.0/13132.88.0.1 to 132.95.255.254132.95.255.255524,286
13132.96.0.0/13132.96.0.1 to 132.103.255.254132.103.255.255524,286
14132.104.0.0/13132.104.0.1 to 132.111.255.254132.111.255.255524,286
15132.112.0.0/13132.112.0.1 to 132.119.255.254132.119.255.255524,286
16132.120.0.0/13132.120.0.1 to 132.127.255.254132.127.255.255524,286
17132.128.0.0/13132.128.0.1 to 132.135.255.254132.135.255.255524,286
18132.136.0.0/13132.136.0.1 to 132.143.255.254132.143.255.255524,286
19132.144.0.0/13132.144.0.1 to 132.151.255.254132.151.255.255524,286
20132.152.0.0/13132.152.0.1 to 132.159.255.254132.159.255.255524,286
21132.160.0.0/13132.160.0.1 to 132.167.255.254132.167.255.255524,286
22132.168.0.0/13132.168.0.1 to 132.175.255.254132.175.255.255524,286
23132.176.0.0/13132.176.0.1 to 132.183.255.254132.183.255.255524,286
24132.184.0.0/13132.184.0.1 to 132.191.255.254132.191.255.255524,286
25132.192.0.0/13132.192.0.1 to 132.199.255.254132.199.255.255524,286
26132.200.0.0/13132.200.0.1 to 132.207.255.254132.207.255.255524,286
27132.208.0.0/13132.208.0.1 to 132.215.255.254132.215.255.255524,286
28132.216.0.0/13132.216.0.1 to 132.223.255.254132.223.255.255524,286
29132.224.0.0/13132.224.0.1 to 132.231.255.254132.231.255.255524,286
30132.232.0.0/13132.232.0.1 to 132.239.255.254132.239.255.255524,286
31132.240.0.0/13132.240.0.1 to 132.247.255.254132.247.255.255524,286
32132.248.0.0/13132.248.0.1 to 132.255.255.254132.255.255.255524,286
33133.0.0.0/13133.0.0.1 to 133.7.255.254133.7.255.255524,286
34133.8.0.0/13133.8.0.1 to 133.15.255.254133.15.255.255524,286
35133.16.0.0/13133.16.0.1 to 133.23.255.254133.23.255.255524,286
36133.24.0.0/13133.24.0.1 to 133.31.255.254133.31.255.255524,286
37133.32.0.0/13133.32.0.1 to 133.39.255.254133.39.255.255524,286
38133.40.0.0/13133.40.0.1 to 133.47.255.254133.47.255.255524,286
39133.48.0.0/13133.48.0.1 to 133.55.255.254133.55.255.255524,286
40133.56.0.0/13133.56.0.1 to 133.63.255.254133.63.255.255524,286
41133.64.0.0/13133.64.0.1 to 133.71.255.254133.71.255.255524,286
42133.72.0.0/13133.72.0.1 to 133.79.255.254133.79.255.255524,286
43133.80.0.0/13133.80.0.1 to 133.87.255.254133.87.255.255524,286
44133.88.0.0/13133.88.0.1 to 133.95.255.254133.95.255.255524,286
45133.96.0.0/13133.96.0.1 to 133.103.255.254133.103.255.255524,286
46133.104.0.0/13133.104.0.1 to 133.111.255.254133.111.255.255524,286
47133.112.0.0/13133.112.0.1 to 133.119.255.254133.119.255.255524,286
48133.120.0.0/13133.120.0.1 to 133.127.255.254133.127.255.255524,286
49133.128.0.0/13133.128.0.1 to 133.135.255.254133.135.255.255524,286
50133.136.0.0/13133.136.0.1 to 133.143.255.254133.143.255.255524,286
51133.144.0.0/13133.144.0.1 to 133.151.255.254133.151.255.255524,286
52133.152.0.0/13133.152.0.1 to 133.159.255.254133.159.255.255524,286
53133.160.0.0/13133.160.0.1 to 133.167.255.254133.167.255.255524,286
54133.168.0.0/13133.168.0.1 to 133.175.255.254133.175.255.255524,286
55133.176.0.0/13133.176.0.1 to 133.183.255.254133.183.255.255524,286
56133.184.0.0/13133.184.0.1 to 133.191.255.254133.191.255.255524,286
57133.192.0.0/13133.192.0.1 to 133.199.255.254133.199.255.255524,286
58133.200.0.0/13133.200.0.1 to 133.207.255.254133.207.255.255524,286
59133.208.0.0/13133.208.0.1 to 133.215.255.254133.215.255.255524,286
60133.216.0.0/13133.216.0.1 to 133.223.255.254133.223.255.255524,286
61133.224.0.0/13133.224.0.1 to 133.231.255.254133.231.255.255524,286
62133.232.0.0/13133.232.0.1 to 133.239.255.254133.239.255.255524,286
63133.240.0.0/13133.240.0.1 to 133.247.255.254133.247.255.255524,286
64133.248.0.0/13133.248.0.1 to 133.255.255.254133.255.255.255524,286
65134.0.0.0/13134.0.0.1 to 134.7.255.254134.7.255.255524,286
66134.8.0.0/13134.8.0.1 to 134.15.255.254134.15.255.255524,286
67134.16.0.0/13134.16.0.1 to 134.23.255.254134.23.255.255524,286
68134.24.0.0/13134.24.0.1 to 134.31.255.254134.31.255.255524,286
69134.32.0.0/13134.32.0.1 to 134.39.255.254134.39.255.255524,286
70134.40.0.0/13134.40.0.1 to 134.47.255.254134.47.255.255524,286
71134.48.0.0/13134.48.0.1 to 134.55.255.254134.55.255.255524,286
72134.56.0.0/13134.56.0.1 to 134.63.255.254134.63.255.255524,286
73134.64.0.0/13134.64.0.1 to 134.71.255.254134.71.255.255524,286
74134.72.0.0/13134.72.0.1 to 134.79.255.254134.79.255.255524,286
75134.80.0.0/13134.80.0.1 to 134.87.255.254134.87.255.255524,286
76134.88.0.0/13134.88.0.1 to 134.95.255.254134.95.255.255524,286
77134.96.0.0/13134.96.0.1 to 134.103.255.254134.103.255.255524,286
78134.104.0.0/13134.104.0.1 to 134.111.255.254134.111.255.255524,286
79134.112.0.0/13134.112.0.1 to 134.119.255.254134.119.255.255524,286
80134.120.0.0/13134.120.0.1 to 134.127.255.254134.127.255.255524,286
81134.128.0.0/13134.128.0.1 to 134.135.255.254134.135.255.255524,286
82134.136.0.0/13134.136.0.1 to 134.143.255.254134.143.255.255524,286
83134.144.0.0/13134.144.0.1 to 134.151.255.254134.151.255.255524,286
84134.152.0.0/13134.152.0.1 to 134.159.255.254134.159.255.255524,286
85134.160.0.0/13134.160.0.1 to 134.167.255.254134.167.255.255524,286
86134.168.0.0/13134.168.0.1 to 134.175.255.254134.175.255.255524,286
87134.176.0.0/13134.176.0.1 to 134.183.255.254134.183.255.255524,286
88134.184.0.0/13134.184.0.1 to 134.191.255.254134.191.255.255524,286
89134.192.0.0/13134.192.0.1 to 134.199.255.254134.199.255.255524,286
90134.200.0.0/13134.200.0.1 to 134.207.255.254134.207.255.255524,286
91134.208.0.0/13134.208.0.1 to 134.215.255.254134.215.255.255524,286
92134.216.0.0/13134.216.0.1 to 134.223.255.254134.223.255.255524,286
93134.224.0.0/13134.224.0.1 to 134.231.255.254134.231.255.255524,286
94134.232.0.0/13134.232.0.1 to 134.239.255.254134.239.255.255524,286
95134.240.0.0/13134.240.0.1 to 134.247.255.254134.247.255.255524,286
96134.248.0.0/13134.248.0.1 to 134.255.255.254134.255.255.255524,286
97135.0.0.0/13135.0.0.1 to 135.7.255.254135.7.255.255524,286
98135.8.0.0/13135.8.0.1 to 135.15.255.254135.15.255.255524,286
99135.16.0.0/13135.16.0.1 to 135.23.255.254135.23.255.255524,286
100135.24.0.0/13135.24.0.1 to 135.31.255.254135.31.255.255524,286
101135.32.0.0/13135.32.0.1 to 135.39.255.254135.39.255.255524,286
102135.40.0.0/13135.40.0.1 to 135.47.255.254135.47.255.255524,286
103135.48.0.0/13135.48.0.1 to 135.55.255.254135.55.255.255524,286
104135.56.0.0/13135.56.0.1 to 135.63.255.254135.63.255.255524,286
105135.64.0.0/13135.64.0.1 to 135.71.255.254135.71.255.255524,286
106135.72.0.0/13135.72.0.1 to 135.79.255.254135.79.255.255524,286
107135.80.0.0/13135.80.0.1 to 135.87.255.254135.87.255.255524,286
108135.88.0.0/13135.88.0.1 to 135.95.255.254135.95.255.255524,286
109135.96.0.0/13135.96.0.1 to 135.103.255.254135.103.255.255524,286
110135.104.0.0/13135.104.0.1 to 135.111.255.254135.111.255.255524,286
111135.112.0.0/13135.112.0.1 to 135.119.255.254135.119.255.255524,286
112135.120.0.0/13135.120.0.1 to 135.127.255.254135.127.255.255524,286
113135.128.0.0/13135.128.0.1 to 135.135.255.254135.135.255.255524,286
114135.136.0.0/13135.136.0.1 to 135.143.255.254135.143.255.255524,286
115135.144.0.0/13135.144.0.1 to 135.151.255.254135.151.255.255524,286
116135.152.0.0/13135.152.0.1 to 135.159.255.254135.159.255.255524,286
117135.160.0.0/13135.160.0.1 to 135.167.255.254135.167.255.255524,286
118135.168.0.0/13135.168.0.1 to 135.175.255.254135.175.255.255524,286
119135.176.0.0/13135.176.0.1 to 135.183.255.254135.183.255.255524,286
120135.184.0.0/13135.184.0.1 to 135.191.255.254135.191.255.255524,286
121135.192.0.0/13135.192.0.1 to 135.199.255.254135.199.255.255524,286
122135.200.0.0/13135.200.0.1 to 135.207.255.254135.207.255.255524,286
123135.208.0.0/13135.208.0.1 to 135.215.255.254135.215.255.255524,286
124135.216.0.0/13135.216.0.1 to 135.223.255.254135.223.255.255524,286
125135.224.0.0/13135.224.0.1 to 135.231.255.254135.231.255.255524,286
126135.232.0.0/13135.232.0.1 to 135.239.255.254135.239.255.255524,286
127135.240.0.0/13135.240.0.1 to 135.247.255.254135.247.255.255524,286
128135.248.0.0/13135.248.0.1 to 135.255.255.254135.255.255.255524,286

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.