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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.

Network232.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
232.0.0.0
Broadcast address
235.255.255.255
First usable
232.0.0.1
Last usable
235.255.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E8000000 · Integer 3892314112 to 3959422975
Reverse DNS zones
232.in-addr.arpa
233.in-addr.arpa
234.in-addr.arpa
235.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
Address11101000.00000000.00000000.00000000232.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network11101000.00000000.00000000.00000000232.0.0.0
Broadcast11101011.11111111.11111111.11111111235.255.255.255
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)

232.0.0.0/6 makes 128 subnets of /13.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1232.0.0.0/13232.0.0.1 to 232.7.255.254232.7.255.255524,286
2232.8.0.0/13232.8.0.1 to 232.15.255.254232.15.255.255524,286
3232.16.0.0/13232.16.0.1 to 232.23.255.254232.23.255.255524,286
4232.24.0.0/13232.24.0.1 to 232.31.255.254232.31.255.255524,286
5232.32.0.0/13232.32.0.1 to 232.39.255.254232.39.255.255524,286
6232.40.0.0/13232.40.0.1 to 232.47.255.254232.47.255.255524,286
7232.48.0.0/13232.48.0.1 to 232.55.255.254232.55.255.255524,286
8232.56.0.0/13232.56.0.1 to 232.63.255.254232.63.255.255524,286
9232.64.0.0/13232.64.0.1 to 232.71.255.254232.71.255.255524,286
10232.72.0.0/13232.72.0.1 to 232.79.255.254232.79.255.255524,286
11232.80.0.0/13232.80.0.1 to 232.87.255.254232.87.255.255524,286
12232.88.0.0/13232.88.0.1 to 232.95.255.254232.95.255.255524,286
13232.96.0.0/13232.96.0.1 to 232.103.255.254232.103.255.255524,286
14232.104.0.0/13232.104.0.1 to 232.111.255.254232.111.255.255524,286
15232.112.0.0/13232.112.0.1 to 232.119.255.254232.119.255.255524,286
16232.120.0.0/13232.120.0.1 to 232.127.255.254232.127.255.255524,286
17232.128.0.0/13232.128.0.1 to 232.135.255.254232.135.255.255524,286
18232.136.0.0/13232.136.0.1 to 232.143.255.254232.143.255.255524,286
19232.144.0.0/13232.144.0.1 to 232.151.255.254232.151.255.255524,286
20232.152.0.0/13232.152.0.1 to 232.159.255.254232.159.255.255524,286
21232.160.0.0/13232.160.0.1 to 232.167.255.254232.167.255.255524,286
22232.168.0.0/13232.168.0.1 to 232.175.255.254232.175.255.255524,286
23232.176.0.0/13232.176.0.1 to 232.183.255.254232.183.255.255524,286
24232.184.0.0/13232.184.0.1 to 232.191.255.254232.191.255.255524,286
25232.192.0.0/13232.192.0.1 to 232.199.255.254232.199.255.255524,286
26232.200.0.0/13232.200.0.1 to 232.207.255.254232.207.255.255524,286
27232.208.0.0/13232.208.0.1 to 232.215.255.254232.215.255.255524,286
28232.216.0.0/13232.216.0.1 to 232.223.255.254232.223.255.255524,286
29232.224.0.0/13232.224.0.1 to 232.231.255.254232.231.255.255524,286
30232.232.0.0/13232.232.0.1 to 232.239.255.254232.239.255.255524,286
31232.240.0.0/13232.240.0.1 to 232.247.255.254232.247.255.255524,286
32232.248.0.0/13232.248.0.1 to 232.255.255.254232.255.255.255524,286
33233.0.0.0/13233.0.0.1 to 233.7.255.254233.7.255.255524,286
34233.8.0.0/13233.8.0.1 to 233.15.255.254233.15.255.255524,286
35233.16.0.0/13233.16.0.1 to 233.23.255.254233.23.255.255524,286
36233.24.0.0/13233.24.0.1 to 233.31.255.254233.31.255.255524,286
37233.32.0.0/13233.32.0.1 to 233.39.255.254233.39.255.255524,286
38233.40.0.0/13233.40.0.1 to 233.47.255.254233.47.255.255524,286
39233.48.0.0/13233.48.0.1 to 233.55.255.254233.55.255.255524,286
40233.56.0.0/13233.56.0.1 to 233.63.255.254233.63.255.255524,286
41233.64.0.0/13233.64.0.1 to 233.71.255.254233.71.255.255524,286
42233.72.0.0/13233.72.0.1 to 233.79.255.254233.79.255.255524,286
43233.80.0.0/13233.80.0.1 to 233.87.255.254233.87.255.255524,286
44233.88.0.0/13233.88.0.1 to 233.95.255.254233.95.255.255524,286
45233.96.0.0/13233.96.0.1 to 233.103.255.254233.103.255.255524,286
46233.104.0.0/13233.104.0.1 to 233.111.255.254233.111.255.255524,286
47233.112.0.0/13233.112.0.1 to 233.119.255.254233.119.255.255524,286
48233.120.0.0/13233.120.0.1 to 233.127.255.254233.127.255.255524,286
49233.128.0.0/13233.128.0.1 to 233.135.255.254233.135.255.255524,286
50233.136.0.0/13233.136.0.1 to 233.143.255.254233.143.255.255524,286
51233.144.0.0/13233.144.0.1 to 233.151.255.254233.151.255.255524,286
52233.152.0.0/13233.152.0.1 to 233.159.255.254233.159.255.255524,286
53233.160.0.0/13233.160.0.1 to 233.167.255.254233.167.255.255524,286
54233.168.0.0/13233.168.0.1 to 233.175.255.254233.175.255.255524,286
55233.176.0.0/13233.176.0.1 to 233.183.255.254233.183.255.255524,286
56233.184.0.0/13233.184.0.1 to 233.191.255.254233.191.255.255524,286
57233.192.0.0/13233.192.0.1 to 233.199.255.254233.199.255.255524,286
58233.200.0.0/13233.200.0.1 to 233.207.255.254233.207.255.255524,286
59233.208.0.0/13233.208.0.1 to 233.215.255.254233.215.255.255524,286
60233.216.0.0/13233.216.0.1 to 233.223.255.254233.223.255.255524,286
61233.224.0.0/13233.224.0.1 to 233.231.255.254233.231.255.255524,286
62233.232.0.0/13233.232.0.1 to 233.239.255.254233.239.255.255524,286
63233.240.0.0/13233.240.0.1 to 233.247.255.254233.247.255.255524,286
64233.248.0.0/13233.248.0.1 to 233.255.255.254233.255.255.255524,286
65234.0.0.0/13234.0.0.1 to 234.7.255.254234.7.255.255524,286
66234.8.0.0/13234.8.0.1 to 234.15.255.254234.15.255.255524,286
67234.16.0.0/13234.16.0.1 to 234.23.255.254234.23.255.255524,286
68234.24.0.0/13234.24.0.1 to 234.31.255.254234.31.255.255524,286
69234.32.0.0/13234.32.0.1 to 234.39.255.254234.39.255.255524,286
70234.40.0.0/13234.40.0.1 to 234.47.255.254234.47.255.255524,286
71234.48.0.0/13234.48.0.1 to 234.55.255.254234.55.255.255524,286
72234.56.0.0/13234.56.0.1 to 234.63.255.254234.63.255.255524,286
73234.64.0.0/13234.64.0.1 to 234.71.255.254234.71.255.255524,286
74234.72.0.0/13234.72.0.1 to 234.79.255.254234.79.255.255524,286
75234.80.0.0/13234.80.0.1 to 234.87.255.254234.87.255.255524,286
76234.88.0.0/13234.88.0.1 to 234.95.255.254234.95.255.255524,286
77234.96.0.0/13234.96.0.1 to 234.103.255.254234.103.255.255524,286
78234.104.0.0/13234.104.0.1 to 234.111.255.254234.111.255.255524,286
79234.112.0.0/13234.112.0.1 to 234.119.255.254234.119.255.255524,286
80234.120.0.0/13234.120.0.1 to 234.127.255.254234.127.255.255524,286
81234.128.0.0/13234.128.0.1 to 234.135.255.254234.135.255.255524,286
82234.136.0.0/13234.136.0.1 to 234.143.255.254234.143.255.255524,286
83234.144.0.0/13234.144.0.1 to 234.151.255.254234.151.255.255524,286
84234.152.0.0/13234.152.0.1 to 234.159.255.254234.159.255.255524,286
85234.160.0.0/13234.160.0.1 to 234.167.255.254234.167.255.255524,286
86234.168.0.0/13234.168.0.1 to 234.175.255.254234.175.255.255524,286
87234.176.0.0/13234.176.0.1 to 234.183.255.254234.183.255.255524,286
88234.184.0.0/13234.184.0.1 to 234.191.255.254234.191.255.255524,286
89234.192.0.0/13234.192.0.1 to 234.199.255.254234.199.255.255524,286
90234.200.0.0/13234.200.0.1 to 234.207.255.254234.207.255.255524,286
91234.208.0.0/13234.208.0.1 to 234.215.255.254234.215.255.255524,286
92234.216.0.0/13234.216.0.1 to 234.223.255.254234.223.255.255524,286
93234.224.0.0/13234.224.0.1 to 234.231.255.254234.231.255.255524,286
94234.232.0.0/13234.232.0.1 to 234.239.255.254234.239.255.255524,286
95234.240.0.0/13234.240.0.1 to 234.247.255.254234.247.255.255524,286
96234.248.0.0/13234.248.0.1 to 234.255.255.254234.255.255.255524,286
97235.0.0.0/13235.0.0.1 to 235.7.255.254235.7.255.255524,286
98235.8.0.0/13235.8.0.1 to 235.15.255.254235.15.255.255524,286
99235.16.0.0/13235.16.0.1 to 235.23.255.254235.23.255.255524,286
100235.24.0.0/13235.24.0.1 to 235.31.255.254235.31.255.255524,286
101235.32.0.0/13235.32.0.1 to 235.39.255.254235.39.255.255524,286
102235.40.0.0/13235.40.0.1 to 235.47.255.254235.47.255.255524,286
103235.48.0.0/13235.48.0.1 to 235.55.255.254235.55.255.255524,286
104235.56.0.0/13235.56.0.1 to 235.63.255.254235.63.255.255524,286
105235.64.0.0/13235.64.0.1 to 235.71.255.254235.71.255.255524,286
106235.72.0.0/13235.72.0.1 to 235.79.255.254235.79.255.255524,286
107235.80.0.0/13235.80.0.1 to 235.87.255.254235.87.255.255524,286
108235.88.0.0/13235.88.0.1 to 235.95.255.254235.95.255.255524,286
109235.96.0.0/13235.96.0.1 to 235.103.255.254235.103.255.255524,286
110235.104.0.0/13235.104.0.1 to 235.111.255.254235.111.255.255524,286
111235.112.0.0/13235.112.0.1 to 235.119.255.254235.119.255.255524,286
112235.120.0.0/13235.120.0.1 to 235.127.255.254235.127.255.255524,286
113235.128.0.0/13235.128.0.1 to 235.135.255.254235.135.255.255524,286
114235.136.0.0/13235.136.0.1 to 235.143.255.254235.143.255.255524,286
115235.144.0.0/13235.144.0.1 to 235.151.255.254235.151.255.255524,286
116235.152.0.0/13235.152.0.1 to 235.159.255.254235.159.255.255524,286
117235.160.0.0/13235.160.0.1 to 235.167.255.254235.167.255.255524,286
118235.168.0.0/13235.168.0.1 to 235.175.255.254235.175.255.255524,286
119235.176.0.0/13235.176.0.1 to 235.183.255.254235.183.255.255524,286
120235.184.0.0/13235.184.0.1 to 235.191.255.254235.191.255.255524,286
121235.192.0.0/13235.192.0.1 to 235.199.255.254235.199.255.255524,286
122235.200.0.0/13235.200.0.1 to 235.207.255.254235.207.255.255524,286
123235.208.0.0/13235.208.0.1 to 235.215.255.254235.215.255.255524,286
124235.216.0.0/13235.216.0.1 to 235.223.255.254235.223.255.255524,286
125235.224.0.0/13235.224.0.1 to 235.231.255.254235.231.255.255524,286
126235.232.0.0/13235.232.0.1 to 235.239.255.254235.239.255.255524,286
127235.240.0.0/13235.240.0.1 to 235.247.255.254235.247.255.255524,286
128235.248.0.0/13235.248.0.1 to 235.255.255.254235.255.255.255524,286

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.