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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.

Network232.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
232.0.0.0
Broadcast address
233.255.255.255
First usable
232.0.0.1
Last usable
233.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
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 3925868543
Reverse DNS zones
232.in-addr.arpa
233.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101000.00000000.00000000.00000000232.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11101000.00000000.00000000.00000000232.0.0.0
Broadcast11101001.11111111.11111111.11111111233.255.255.255
Split into smaller subnets/14
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

232.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1232.0.0.0/14232.0.0.1 to 232.3.255.254232.3.255.255262,142
2232.4.0.0/14232.4.0.1 to 232.7.255.254232.7.255.255262,142
3232.8.0.0/14232.8.0.1 to 232.11.255.254232.11.255.255262,142
4232.12.0.0/14232.12.0.1 to 232.15.255.254232.15.255.255262,142
5232.16.0.0/14232.16.0.1 to 232.19.255.254232.19.255.255262,142
6232.20.0.0/14232.20.0.1 to 232.23.255.254232.23.255.255262,142
7232.24.0.0/14232.24.0.1 to 232.27.255.254232.27.255.255262,142
8232.28.0.0/14232.28.0.1 to 232.31.255.254232.31.255.255262,142
9232.32.0.0/14232.32.0.1 to 232.35.255.254232.35.255.255262,142
10232.36.0.0/14232.36.0.1 to 232.39.255.254232.39.255.255262,142
11232.40.0.0/14232.40.0.1 to 232.43.255.254232.43.255.255262,142
12232.44.0.0/14232.44.0.1 to 232.47.255.254232.47.255.255262,142
13232.48.0.0/14232.48.0.1 to 232.51.255.254232.51.255.255262,142
14232.52.0.0/14232.52.0.1 to 232.55.255.254232.55.255.255262,142
15232.56.0.0/14232.56.0.1 to 232.59.255.254232.59.255.255262,142
16232.60.0.0/14232.60.0.1 to 232.63.255.254232.63.255.255262,142
17232.64.0.0/14232.64.0.1 to 232.67.255.254232.67.255.255262,142
18232.68.0.0/14232.68.0.1 to 232.71.255.254232.71.255.255262,142
19232.72.0.0/14232.72.0.1 to 232.75.255.254232.75.255.255262,142
20232.76.0.0/14232.76.0.1 to 232.79.255.254232.79.255.255262,142
21232.80.0.0/14232.80.0.1 to 232.83.255.254232.83.255.255262,142
22232.84.0.0/14232.84.0.1 to 232.87.255.254232.87.255.255262,142
23232.88.0.0/14232.88.0.1 to 232.91.255.254232.91.255.255262,142
24232.92.0.0/14232.92.0.1 to 232.95.255.254232.95.255.255262,142
25232.96.0.0/14232.96.0.1 to 232.99.255.254232.99.255.255262,142
26232.100.0.0/14232.100.0.1 to 232.103.255.254232.103.255.255262,142
27232.104.0.0/14232.104.0.1 to 232.107.255.254232.107.255.255262,142
28232.108.0.0/14232.108.0.1 to 232.111.255.254232.111.255.255262,142
29232.112.0.0/14232.112.0.1 to 232.115.255.254232.115.255.255262,142
30232.116.0.0/14232.116.0.1 to 232.119.255.254232.119.255.255262,142
31232.120.0.0/14232.120.0.1 to 232.123.255.254232.123.255.255262,142
32232.124.0.0/14232.124.0.1 to 232.127.255.254232.127.255.255262,142
33232.128.0.0/14232.128.0.1 to 232.131.255.254232.131.255.255262,142
34232.132.0.0/14232.132.0.1 to 232.135.255.254232.135.255.255262,142
35232.136.0.0/14232.136.0.1 to 232.139.255.254232.139.255.255262,142
36232.140.0.0/14232.140.0.1 to 232.143.255.254232.143.255.255262,142
37232.144.0.0/14232.144.0.1 to 232.147.255.254232.147.255.255262,142
38232.148.0.0/14232.148.0.1 to 232.151.255.254232.151.255.255262,142
39232.152.0.0/14232.152.0.1 to 232.155.255.254232.155.255.255262,142
40232.156.0.0/14232.156.0.1 to 232.159.255.254232.159.255.255262,142
41232.160.0.0/14232.160.0.1 to 232.163.255.254232.163.255.255262,142
42232.164.0.0/14232.164.0.1 to 232.167.255.254232.167.255.255262,142
43232.168.0.0/14232.168.0.1 to 232.171.255.254232.171.255.255262,142
44232.172.0.0/14232.172.0.1 to 232.175.255.254232.175.255.255262,142
45232.176.0.0/14232.176.0.1 to 232.179.255.254232.179.255.255262,142
46232.180.0.0/14232.180.0.1 to 232.183.255.254232.183.255.255262,142
47232.184.0.0/14232.184.0.1 to 232.187.255.254232.187.255.255262,142
48232.188.0.0/14232.188.0.1 to 232.191.255.254232.191.255.255262,142
49232.192.0.0/14232.192.0.1 to 232.195.255.254232.195.255.255262,142
50232.196.0.0/14232.196.0.1 to 232.199.255.254232.199.255.255262,142
51232.200.0.0/14232.200.0.1 to 232.203.255.254232.203.255.255262,142
52232.204.0.0/14232.204.0.1 to 232.207.255.254232.207.255.255262,142
53232.208.0.0/14232.208.0.1 to 232.211.255.254232.211.255.255262,142
54232.212.0.0/14232.212.0.1 to 232.215.255.254232.215.255.255262,142
55232.216.0.0/14232.216.0.1 to 232.219.255.254232.219.255.255262,142
56232.220.0.0/14232.220.0.1 to 232.223.255.254232.223.255.255262,142
57232.224.0.0/14232.224.0.1 to 232.227.255.254232.227.255.255262,142
58232.228.0.0/14232.228.0.1 to 232.231.255.254232.231.255.255262,142
59232.232.0.0/14232.232.0.1 to 232.235.255.254232.235.255.255262,142
60232.236.0.0/14232.236.0.1 to 232.239.255.254232.239.255.255262,142
61232.240.0.0/14232.240.0.1 to 232.243.255.254232.243.255.255262,142
62232.244.0.0/14232.244.0.1 to 232.247.255.254232.247.255.255262,142
63232.248.0.0/14232.248.0.1 to 232.251.255.254232.251.255.255262,142
64232.252.0.0/14232.252.0.1 to 232.255.255.254232.255.255.255262,142
65233.0.0.0/14233.0.0.1 to 233.3.255.254233.3.255.255262,142
66233.4.0.0/14233.4.0.1 to 233.7.255.254233.7.255.255262,142
67233.8.0.0/14233.8.0.1 to 233.11.255.254233.11.255.255262,142
68233.12.0.0/14233.12.0.1 to 233.15.255.254233.15.255.255262,142
69233.16.0.0/14233.16.0.1 to 233.19.255.254233.19.255.255262,142
70233.20.0.0/14233.20.0.1 to 233.23.255.254233.23.255.255262,142
71233.24.0.0/14233.24.0.1 to 233.27.255.254233.27.255.255262,142
72233.28.0.0/14233.28.0.1 to 233.31.255.254233.31.255.255262,142
73233.32.0.0/14233.32.0.1 to 233.35.255.254233.35.255.255262,142
74233.36.0.0/14233.36.0.1 to 233.39.255.254233.39.255.255262,142
75233.40.0.0/14233.40.0.1 to 233.43.255.254233.43.255.255262,142
76233.44.0.0/14233.44.0.1 to 233.47.255.254233.47.255.255262,142
77233.48.0.0/14233.48.0.1 to 233.51.255.254233.51.255.255262,142
78233.52.0.0/14233.52.0.1 to 233.55.255.254233.55.255.255262,142
79233.56.0.0/14233.56.0.1 to 233.59.255.254233.59.255.255262,142
80233.60.0.0/14233.60.0.1 to 233.63.255.254233.63.255.255262,142
81233.64.0.0/14233.64.0.1 to 233.67.255.254233.67.255.255262,142
82233.68.0.0/14233.68.0.1 to 233.71.255.254233.71.255.255262,142
83233.72.0.0/14233.72.0.1 to 233.75.255.254233.75.255.255262,142
84233.76.0.0/14233.76.0.1 to 233.79.255.254233.79.255.255262,142
85233.80.0.0/14233.80.0.1 to 233.83.255.254233.83.255.255262,142
86233.84.0.0/14233.84.0.1 to 233.87.255.254233.87.255.255262,142
87233.88.0.0/14233.88.0.1 to 233.91.255.254233.91.255.255262,142
88233.92.0.0/14233.92.0.1 to 233.95.255.254233.95.255.255262,142
89233.96.0.0/14233.96.0.1 to 233.99.255.254233.99.255.255262,142
90233.100.0.0/14233.100.0.1 to 233.103.255.254233.103.255.255262,142
91233.104.0.0/14233.104.0.1 to 233.107.255.254233.107.255.255262,142
92233.108.0.0/14233.108.0.1 to 233.111.255.254233.111.255.255262,142
93233.112.0.0/14233.112.0.1 to 233.115.255.254233.115.255.255262,142
94233.116.0.0/14233.116.0.1 to 233.119.255.254233.119.255.255262,142
95233.120.0.0/14233.120.0.1 to 233.123.255.254233.123.255.255262,142
96233.124.0.0/14233.124.0.1 to 233.127.255.254233.127.255.255262,142
97233.128.0.0/14233.128.0.1 to 233.131.255.254233.131.255.255262,142
98233.132.0.0/14233.132.0.1 to 233.135.255.254233.135.255.255262,142
99233.136.0.0/14233.136.0.1 to 233.139.255.254233.139.255.255262,142
100233.140.0.0/14233.140.0.1 to 233.143.255.254233.143.255.255262,142
101233.144.0.0/14233.144.0.1 to 233.147.255.254233.147.255.255262,142
102233.148.0.0/14233.148.0.1 to 233.151.255.254233.151.255.255262,142
103233.152.0.0/14233.152.0.1 to 233.155.255.254233.155.255.255262,142
104233.156.0.0/14233.156.0.1 to 233.159.255.254233.159.255.255262,142
105233.160.0.0/14233.160.0.1 to 233.163.255.254233.163.255.255262,142
106233.164.0.0/14233.164.0.1 to 233.167.255.254233.167.255.255262,142
107233.168.0.0/14233.168.0.1 to 233.171.255.254233.171.255.255262,142
108233.172.0.0/14233.172.0.1 to 233.175.255.254233.175.255.255262,142
109233.176.0.0/14233.176.0.1 to 233.179.255.254233.179.255.255262,142
110233.180.0.0/14233.180.0.1 to 233.183.255.254233.183.255.255262,142
111233.184.0.0/14233.184.0.1 to 233.187.255.254233.187.255.255262,142
112233.188.0.0/14233.188.0.1 to 233.191.255.254233.191.255.255262,142
113233.192.0.0/14233.192.0.1 to 233.195.255.254233.195.255.255262,142
114233.196.0.0/14233.196.0.1 to 233.199.255.254233.199.255.255262,142
115233.200.0.0/14233.200.0.1 to 233.203.255.254233.203.255.255262,142
116233.204.0.0/14233.204.0.1 to 233.207.255.254233.207.255.255262,142
117233.208.0.0/14233.208.0.1 to 233.211.255.254233.211.255.255262,142
118233.212.0.0/14233.212.0.1 to 233.215.255.254233.215.255.255262,142
119233.216.0.0/14233.216.0.1 to 233.219.255.254233.219.255.255262,142
120233.220.0.0/14233.220.0.1 to 233.223.255.254233.223.255.255262,142
121233.224.0.0/14233.224.0.1 to 233.227.255.254233.227.255.255262,142
122233.228.0.0/14233.228.0.1 to 233.231.255.254233.231.255.255262,142
123233.232.0.0/14233.232.0.1 to 233.235.255.254233.235.255.255262,142
124233.236.0.0/14233.236.0.1 to 233.239.255.254233.239.255.255262,142
125233.240.0.0/14233.240.0.1 to 233.243.255.254233.243.255.255262,142
126233.244.0.0/14233.244.0.1 to 233.247.255.254233.247.255.255262,142
127233.248.0.0/14233.248.0.1 to 233.251.255.254233.251.255.255262,142
128233.252.0.0/14233.252.0.1 to 233.255.255.254233.255.255.255262,142

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.