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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.

Network162.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
162.0.0.0
Broadcast address
163.255.255.255
First usable
162.0.0.1
Last usable
163.255.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex A2000000 · Integer 2717908992 to 2751463423
Reverse DNS zones
162.in-addr.arpa
163.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
Address10100010.00000000.00000000.00000000162.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10100010.00000000.00000000.00000000162.0.0.0
Broadcast10100011.11111111.11111111.11111111163.255.255.255
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)

162.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1162.0.0.0/14162.0.0.1 to 162.3.255.254162.3.255.255262,142
2162.4.0.0/14162.4.0.1 to 162.7.255.254162.7.255.255262,142
3162.8.0.0/14162.8.0.1 to 162.11.255.254162.11.255.255262,142
4162.12.0.0/14162.12.0.1 to 162.15.255.254162.15.255.255262,142
5162.16.0.0/14162.16.0.1 to 162.19.255.254162.19.255.255262,142
6162.20.0.0/14162.20.0.1 to 162.23.255.254162.23.255.255262,142
7162.24.0.0/14162.24.0.1 to 162.27.255.254162.27.255.255262,142
8162.28.0.0/14162.28.0.1 to 162.31.255.254162.31.255.255262,142
9162.32.0.0/14162.32.0.1 to 162.35.255.254162.35.255.255262,142
10162.36.0.0/14162.36.0.1 to 162.39.255.254162.39.255.255262,142
11162.40.0.0/14162.40.0.1 to 162.43.255.254162.43.255.255262,142
12162.44.0.0/14162.44.0.1 to 162.47.255.254162.47.255.255262,142
13162.48.0.0/14162.48.0.1 to 162.51.255.254162.51.255.255262,142
14162.52.0.0/14162.52.0.1 to 162.55.255.254162.55.255.255262,142
15162.56.0.0/14162.56.0.1 to 162.59.255.254162.59.255.255262,142
16162.60.0.0/14162.60.0.1 to 162.63.255.254162.63.255.255262,142
17162.64.0.0/14162.64.0.1 to 162.67.255.254162.67.255.255262,142
18162.68.0.0/14162.68.0.1 to 162.71.255.254162.71.255.255262,142
19162.72.0.0/14162.72.0.1 to 162.75.255.254162.75.255.255262,142
20162.76.0.0/14162.76.0.1 to 162.79.255.254162.79.255.255262,142
21162.80.0.0/14162.80.0.1 to 162.83.255.254162.83.255.255262,142
22162.84.0.0/14162.84.0.1 to 162.87.255.254162.87.255.255262,142
23162.88.0.0/14162.88.0.1 to 162.91.255.254162.91.255.255262,142
24162.92.0.0/14162.92.0.1 to 162.95.255.254162.95.255.255262,142
25162.96.0.0/14162.96.0.1 to 162.99.255.254162.99.255.255262,142
26162.100.0.0/14162.100.0.1 to 162.103.255.254162.103.255.255262,142
27162.104.0.0/14162.104.0.1 to 162.107.255.254162.107.255.255262,142
28162.108.0.0/14162.108.0.1 to 162.111.255.254162.111.255.255262,142
29162.112.0.0/14162.112.0.1 to 162.115.255.254162.115.255.255262,142
30162.116.0.0/14162.116.0.1 to 162.119.255.254162.119.255.255262,142
31162.120.0.0/14162.120.0.1 to 162.123.255.254162.123.255.255262,142
32162.124.0.0/14162.124.0.1 to 162.127.255.254162.127.255.255262,142
33162.128.0.0/14162.128.0.1 to 162.131.255.254162.131.255.255262,142
34162.132.0.0/14162.132.0.1 to 162.135.255.254162.135.255.255262,142
35162.136.0.0/14162.136.0.1 to 162.139.255.254162.139.255.255262,142
36162.140.0.0/14162.140.0.1 to 162.143.255.254162.143.255.255262,142
37162.144.0.0/14162.144.0.1 to 162.147.255.254162.147.255.255262,142
38162.148.0.0/14162.148.0.1 to 162.151.255.254162.151.255.255262,142
39162.152.0.0/14162.152.0.1 to 162.155.255.254162.155.255.255262,142
40162.156.0.0/14162.156.0.1 to 162.159.255.254162.159.255.255262,142
41162.160.0.0/14162.160.0.1 to 162.163.255.254162.163.255.255262,142
42162.164.0.0/14162.164.0.1 to 162.167.255.254162.167.255.255262,142
43162.168.0.0/14162.168.0.1 to 162.171.255.254162.171.255.255262,142
44162.172.0.0/14162.172.0.1 to 162.175.255.254162.175.255.255262,142
45162.176.0.0/14162.176.0.1 to 162.179.255.254162.179.255.255262,142
46162.180.0.0/14162.180.0.1 to 162.183.255.254162.183.255.255262,142
47162.184.0.0/14162.184.0.1 to 162.187.255.254162.187.255.255262,142
48162.188.0.0/14162.188.0.1 to 162.191.255.254162.191.255.255262,142
49162.192.0.0/14162.192.0.1 to 162.195.255.254162.195.255.255262,142
50162.196.0.0/14162.196.0.1 to 162.199.255.254162.199.255.255262,142
51162.200.0.0/14162.200.0.1 to 162.203.255.254162.203.255.255262,142
52162.204.0.0/14162.204.0.1 to 162.207.255.254162.207.255.255262,142
53162.208.0.0/14162.208.0.1 to 162.211.255.254162.211.255.255262,142
54162.212.0.0/14162.212.0.1 to 162.215.255.254162.215.255.255262,142
55162.216.0.0/14162.216.0.1 to 162.219.255.254162.219.255.255262,142
56162.220.0.0/14162.220.0.1 to 162.223.255.254162.223.255.255262,142
57162.224.0.0/14162.224.0.1 to 162.227.255.254162.227.255.255262,142
58162.228.0.0/14162.228.0.1 to 162.231.255.254162.231.255.255262,142
59162.232.0.0/14162.232.0.1 to 162.235.255.254162.235.255.255262,142
60162.236.0.0/14162.236.0.1 to 162.239.255.254162.239.255.255262,142
61162.240.0.0/14162.240.0.1 to 162.243.255.254162.243.255.255262,142
62162.244.0.0/14162.244.0.1 to 162.247.255.254162.247.255.255262,142
63162.248.0.0/14162.248.0.1 to 162.251.255.254162.251.255.255262,142
64162.252.0.0/14162.252.0.1 to 162.255.255.254162.255.255.255262,142
65163.0.0.0/14163.0.0.1 to 163.3.255.254163.3.255.255262,142
66163.4.0.0/14163.4.0.1 to 163.7.255.254163.7.255.255262,142
67163.8.0.0/14163.8.0.1 to 163.11.255.254163.11.255.255262,142
68163.12.0.0/14163.12.0.1 to 163.15.255.254163.15.255.255262,142
69163.16.0.0/14163.16.0.1 to 163.19.255.254163.19.255.255262,142
70163.20.0.0/14163.20.0.1 to 163.23.255.254163.23.255.255262,142
71163.24.0.0/14163.24.0.1 to 163.27.255.254163.27.255.255262,142
72163.28.0.0/14163.28.0.1 to 163.31.255.254163.31.255.255262,142
73163.32.0.0/14163.32.0.1 to 163.35.255.254163.35.255.255262,142
74163.36.0.0/14163.36.0.1 to 163.39.255.254163.39.255.255262,142
75163.40.0.0/14163.40.0.1 to 163.43.255.254163.43.255.255262,142
76163.44.0.0/14163.44.0.1 to 163.47.255.254163.47.255.255262,142
77163.48.0.0/14163.48.0.1 to 163.51.255.254163.51.255.255262,142
78163.52.0.0/14163.52.0.1 to 163.55.255.254163.55.255.255262,142
79163.56.0.0/14163.56.0.1 to 163.59.255.254163.59.255.255262,142
80163.60.0.0/14163.60.0.1 to 163.63.255.254163.63.255.255262,142
81163.64.0.0/14163.64.0.1 to 163.67.255.254163.67.255.255262,142
82163.68.0.0/14163.68.0.1 to 163.71.255.254163.71.255.255262,142
83163.72.0.0/14163.72.0.1 to 163.75.255.254163.75.255.255262,142
84163.76.0.0/14163.76.0.1 to 163.79.255.254163.79.255.255262,142
85163.80.0.0/14163.80.0.1 to 163.83.255.254163.83.255.255262,142
86163.84.0.0/14163.84.0.1 to 163.87.255.254163.87.255.255262,142
87163.88.0.0/14163.88.0.1 to 163.91.255.254163.91.255.255262,142
88163.92.0.0/14163.92.0.1 to 163.95.255.254163.95.255.255262,142
89163.96.0.0/14163.96.0.1 to 163.99.255.254163.99.255.255262,142
90163.100.0.0/14163.100.0.1 to 163.103.255.254163.103.255.255262,142
91163.104.0.0/14163.104.0.1 to 163.107.255.254163.107.255.255262,142
92163.108.0.0/14163.108.0.1 to 163.111.255.254163.111.255.255262,142
93163.112.0.0/14163.112.0.1 to 163.115.255.254163.115.255.255262,142
94163.116.0.0/14163.116.0.1 to 163.119.255.254163.119.255.255262,142
95163.120.0.0/14163.120.0.1 to 163.123.255.254163.123.255.255262,142
96163.124.0.0/14163.124.0.1 to 163.127.255.254163.127.255.255262,142
97163.128.0.0/14163.128.0.1 to 163.131.255.254163.131.255.255262,142
98163.132.0.0/14163.132.0.1 to 163.135.255.254163.135.255.255262,142
99163.136.0.0/14163.136.0.1 to 163.139.255.254163.139.255.255262,142
100163.140.0.0/14163.140.0.1 to 163.143.255.254163.143.255.255262,142
101163.144.0.0/14163.144.0.1 to 163.147.255.254163.147.255.255262,142
102163.148.0.0/14163.148.0.1 to 163.151.255.254163.151.255.255262,142
103163.152.0.0/14163.152.0.1 to 163.155.255.254163.155.255.255262,142
104163.156.0.0/14163.156.0.1 to 163.159.255.254163.159.255.255262,142
105163.160.0.0/14163.160.0.1 to 163.163.255.254163.163.255.255262,142
106163.164.0.0/14163.164.0.1 to 163.167.255.254163.167.255.255262,142
107163.168.0.0/14163.168.0.1 to 163.171.255.254163.171.255.255262,142
108163.172.0.0/14163.172.0.1 to 163.175.255.254163.175.255.255262,142
109163.176.0.0/14163.176.0.1 to 163.179.255.254163.179.255.255262,142
110163.180.0.0/14163.180.0.1 to 163.183.255.254163.183.255.255262,142
111163.184.0.0/14163.184.0.1 to 163.187.255.254163.187.255.255262,142
112163.188.0.0/14163.188.0.1 to 163.191.255.254163.191.255.255262,142
113163.192.0.0/14163.192.0.1 to 163.195.255.254163.195.255.255262,142
114163.196.0.0/14163.196.0.1 to 163.199.255.254163.199.255.255262,142
115163.200.0.0/14163.200.0.1 to 163.203.255.254163.203.255.255262,142
116163.204.0.0/14163.204.0.1 to 163.207.255.254163.207.255.255262,142
117163.208.0.0/14163.208.0.1 to 163.211.255.254163.211.255.255262,142
118163.212.0.0/14163.212.0.1 to 163.215.255.254163.215.255.255262,142
119163.216.0.0/14163.216.0.1 to 163.219.255.254163.219.255.255262,142
120163.220.0.0/14163.220.0.1 to 163.223.255.254163.223.255.255262,142
121163.224.0.0/14163.224.0.1 to 163.227.255.254163.227.255.255262,142
122163.228.0.0/14163.228.0.1 to 163.231.255.254163.231.255.255262,142
123163.232.0.0/14163.232.0.1 to 163.235.255.254163.235.255.255262,142
124163.236.0.0/14163.236.0.1 to 163.239.255.254163.239.255.255262,142
125163.240.0.0/14163.240.0.1 to 163.243.255.254163.243.255.255262,142
126163.244.0.0/14163.244.0.1 to 163.247.255.254163.247.255.255262,142
127163.248.0.0/14163.248.0.1 to 163.251.255.254163.251.255.255262,142
128163.252.0.0/14163.252.0.1 to 163.255.255.254163.255.255.255262,142

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.