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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.

Network116.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
116.0.0.0
Broadcast address
117.255.255.255
First usable
116.0.0.1
Last usable
117.255.255.254
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
A (default /8)
As numbers
Hex 74000000 · Integer 1946157056 to 1979711487
Reverse DNS zones
116.in-addr.arpa
117.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
Address01110100.00000000.00000000.00000000116.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01110100.00000000.00000000.00000000116.0.0.0
Broadcast01110101.11111111.11111111.11111111117.255.255.255
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)

116.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1116.0.0.0/14116.0.0.1 to 116.3.255.254116.3.255.255262,142
2116.4.0.0/14116.4.0.1 to 116.7.255.254116.7.255.255262,142
3116.8.0.0/14116.8.0.1 to 116.11.255.254116.11.255.255262,142
4116.12.0.0/14116.12.0.1 to 116.15.255.254116.15.255.255262,142
5116.16.0.0/14116.16.0.1 to 116.19.255.254116.19.255.255262,142
6116.20.0.0/14116.20.0.1 to 116.23.255.254116.23.255.255262,142
7116.24.0.0/14116.24.0.1 to 116.27.255.254116.27.255.255262,142
8116.28.0.0/14116.28.0.1 to 116.31.255.254116.31.255.255262,142
9116.32.0.0/14116.32.0.1 to 116.35.255.254116.35.255.255262,142
10116.36.0.0/14116.36.0.1 to 116.39.255.254116.39.255.255262,142
11116.40.0.0/14116.40.0.1 to 116.43.255.254116.43.255.255262,142
12116.44.0.0/14116.44.0.1 to 116.47.255.254116.47.255.255262,142
13116.48.0.0/14116.48.0.1 to 116.51.255.254116.51.255.255262,142
14116.52.0.0/14116.52.0.1 to 116.55.255.254116.55.255.255262,142
15116.56.0.0/14116.56.0.1 to 116.59.255.254116.59.255.255262,142
16116.60.0.0/14116.60.0.1 to 116.63.255.254116.63.255.255262,142
17116.64.0.0/14116.64.0.1 to 116.67.255.254116.67.255.255262,142
18116.68.0.0/14116.68.0.1 to 116.71.255.254116.71.255.255262,142
19116.72.0.0/14116.72.0.1 to 116.75.255.254116.75.255.255262,142
20116.76.0.0/14116.76.0.1 to 116.79.255.254116.79.255.255262,142
21116.80.0.0/14116.80.0.1 to 116.83.255.254116.83.255.255262,142
22116.84.0.0/14116.84.0.1 to 116.87.255.254116.87.255.255262,142
23116.88.0.0/14116.88.0.1 to 116.91.255.254116.91.255.255262,142
24116.92.0.0/14116.92.0.1 to 116.95.255.254116.95.255.255262,142
25116.96.0.0/14116.96.0.1 to 116.99.255.254116.99.255.255262,142
26116.100.0.0/14116.100.0.1 to 116.103.255.254116.103.255.255262,142
27116.104.0.0/14116.104.0.1 to 116.107.255.254116.107.255.255262,142
28116.108.0.0/14116.108.0.1 to 116.111.255.254116.111.255.255262,142
29116.112.0.0/14116.112.0.1 to 116.115.255.254116.115.255.255262,142
30116.116.0.0/14116.116.0.1 to 116.119.255.254116.119.255.255262,142
31116.120.0.0/14116.120.0.1 to 116.123.255.254116.123.255.255262,142
32116.124.0.0/14116.124.0.1 to 116.127.255.254116.127.255.255262,142
33116.128.0.0/14116.128.0.1 to 116.131.255.254116.131.255.255262,142
34116.132.0.0/14116.132.0.1 to 116.135.255.254116.135.255.255262,142
35116.136.0.0/14116.136.0.1 to 116.139.255.254116.139.255.255262,142
36116.140.0.0/14116.140.0.1 to 116.143.255.254116.143.255.255262,142
37116.144.0.0/14116.144.0.1 to 116.147.255.254116.147.255.255262,142
38116.148.0.0/14116.148.0.1 to 116.151.255.254116.151.255.255262,142
39116.152.0.0/14116.152.0.1 to 116.155.255.254116.155.255.255262,142
40116.156.0.0/14116.156.0.1 to 116.159.255.254116.159.255.255262,142
41116.160.0.0/14116.160.0.1 to 116.163.255.254116.163.255.255262,142
42116.164.0.0/14116.164.0.1 to 116.167.255.254116.167.255.255262,142
43116.168.0.0/14116.168.0.1 to 116.171.255.254116.171.255.255262,142
44116.172.0.0/14116.172.0.1 to 116.175.255.254116.175.255.255262,142
45116.176.0.0/14116.176.0.1 to 116.179.255.254116.179.255.255262,142
46116.180.0.0/14116.180.0.1 to 116.183.255.254116.183.255.255262,142
47116.184.0.0/14116.184.0.1 to 116.187.255.254116.187.255.255262,142
48116.188.0.0/14116.188.0.1 to 116.191.255.254116.191.255.255262,142
49116.192.0.0/14116.192.0.1 to 116.195.255.254116.195.255.255262,142
50116.196.0.0/14116.196.0.1 to 116.199.255.254116.199.255.255262,142
51116.200.0.0/14116.200.0.1 to 116.203.255.254116.203.255.255262,142
52116.204.0.0/14116.204.0.1 to 116.207.255.254116.207.255.255262,142
53116.208.0.0/14116.208.0.1 to 116.211.255.254116.211.255.255262,142
54116.212.0.0/14116.212.0.1 to 116.215.255.254116.215.255.255262,142
55116.216.0.0/14116.216.0.1 to 116.219.255.254116.219.255.255262,142
56116.220.0.0/14116.220.0.1 to 116.223.255.254116.223.255.255262,142
57116.224.0.0/14116.224.0.1 to 116.227.255.254116.227.255.255262,142
58116.228.0.0/14116.228.0.1 to 116.231.255.254116.231.255.255262,142
59116.232.0.0/14116.232.0.1 to 116.235.255.254116.235.255.255262,142
60116.236.0.0/14116.236.0.1 to 116.239.255.254116.239.255.255262,142
61116.240.0.0/14116.240.0.1 to 116.243.255.254116.243.255.255262,142
62116.244.0.0/14116.244.0.1 to 116.247.255.254116.247.255.255262,142
63116.248.0.0/14116.248.0.1 to 116.251.255.254116.251.255.255262,142
64116.252.0.0/14116.252.0.1 to 116.255.255.254116.255.255.255262,142
65117.0.0.0/14117.0.0.1 to 117.3.255.254117.3.255.255262,142
66117.4.0.0/14117.4.0.1 to 117.7.255.254117.7.255.255262,142
67117.8.0.0/14117.8.0.1 to 117.11.255.254117.11.255.255262,142
68117.12.0.0/14117.12.0.1 to 117.15.255.254117.15.255.255262,142
69117.16.0.0/14117.16.0.1 to 117.19.255.254117.19.255.255262,142
70117.20.0.0/14117.20.0.1 to 117.23.255.254117.23.255.255262,142
71117.24.0.0/14117.24.0.1 to 117.27.255.254117.27.255.255262,142
72117.28.0.0/14117.28.0.1 to 117.31.255.254117.31.255.255262,142
73117.32.0.0/14117.32.0.1 to 117.35.255.254117.35.255.255262,142
74117.36.0.0/14117.36.0.1 to 117.39.255.254117.39.255.255262,142
75117.40.0.0/14117.40.0.1 to 117.43.255.254117.43.255.255262,142
76117.44.0.0/14117.44.0.1 to 117.47.255.254117.47.255.255262,142
77117.48.0.0/14117.48.0.1 to 117.51.255.254117.51.255.255262,142
78117.52.0.0/14117.52.0.1 to 117.55.255.254117.55.255.255262,142
79117.56.0.0/14117.56.0.1 to 117.59.255.254117.59.255.255262,142
80117.60.0.0/14117.60.0.1 to 117.63.255.254117.63.255.255262,142
81117.64.0.0/14117.64.0.1 to 117.67.255.254117.67.255.255262,142
82117.68.0.0/14117.68.0.1 to 117.71.255.254117.71.255.255262,142
83117.72.0.0/14117.72.0.1 to 117.75.255.254117.75.255.255262,142
84117.76.0.0/14117.76.0.1 to 117.79.255.254117.79.255.255262,142
85117.80.0.0/14117.80.0.1 to 117.83.255.254117.83.255.255262,142
86117.84.0.0/14117.84.0.1 to 117.87.255.254117.87.255.255262,142
87117.88.0.0/14117.88.0.1 to 117.91.255.254117.91.255.255262,142
88117.92.0.0/14117.92.0.1 to 117.95.255.254117.95.255.255262,142
89117.96.0.0/14117.96.0.1 to 117.99.255.254117.99.255.255262,142
90117.100.0.0/14117.100.0.1 to 117.103.255.254117.103.255.255262,142
91117.104.0.0/14117.104.0.1 to 117.107.255.254117.107.255.255262,142
92117.108.0.0/14117.108.0.1 to 117.111.255.254117.111.255.255262,142
93117.112.0.0/14117.112.0.1 to 117.115.255.254117.115.255.255262,142
94117.116.0.0/14117.116.0.1 to 117.119.255.254117.119.255.255262,142
95117.120.0.0/14117.120.0.1 to 117.123.255.254117.123.255.255262,142
96117.124.0.0/14117.124.0.1 to 117.127.255.254117.127.255.255262,142
97117.128.0.0/14117.128.0.1 to 117.131.255.254117.131.255.255262,142
98117.132.0.0/14117.132.0.1 to 117.135.255.254117.135.255.255262,142
99117.136.0.0/14117.136.0.1 to 117.139.255.254117.139.255.255262,142
100117.140.0.0/14117.140.0.1 to 117.143.255.254117.143.255.255262,142
101117.144.0.0/14117.144.0.1 to 117.147.255.254117.147.255.255262,142
102117.148.0.0/14117.148.0.1 to 117.151.255.254117.151.255.255262,142
103117.152.0.0/14117.152.0.1 to 117.155.255.254117.155.255.255262,142
104117.156.0.0/14117.156.0.1 to 117.159.255.254117.159.255.255262,142
105117.160.0.0/14117.160.0.1 to 117.163.255.254117.163.255.255262,142
106117.164.0.0/14117.164.0.1 to 117.167.255.254117.167.255.255262,142
107117.168.0.0/14117.168.0.1 to 117.171.255.254117.171.255.255262,142
108117.172.0.0/14117.172.0.1 to 117.175.255.254117.175.255.255262,142
109117.176.0.0/14117.176.0.1 to 117.179.255.254117.179.255.255262,142
110117.180.0.0/14117.180.0.1 to 117.183.255.254117.183.255.255262,142
111117.184.0.0/14117.184.0.1 to 117.187.255.254117.187.255.255262,142
112117.188.0.0/14117.188.0.1 to 117.191.255.254117.191.255.255262,142
113117.192.0.0/14117.192.0.1 to 117.195.255.254117.195.255.255262,142
114117.196.0.0/14117.196.0.1 to 117.199.255.254117.199.255.255262,142
115117.200.0.0/14117.200.0.1 to 117.203.255.254117.203.255.255262,142
116117.204.0.0/14117.204.0.1 to 117.207.255.254117.207.255.255262,142
117117.208.0.0/14117.208.0.1 to 117.211.255.254117.211.255.255262,142
118117.212.0.0/14117.212.0.1 to 117.215.255.254117.215.255.255262,142
119117.216.0.0/14117.216.0.1 to 117.219.255.254117.219.255.255262,142
120117.220.0.0/14117.220.0.1 to 117.223.255.254117.223.255.255262,142
121117.224.0.0/14117.224.0.1 to 117.227.255.254117.227.255.255262,142
122117.228.0.0/14117.228.0.1 to 117.231.255.254117.231.255.255262,142
123117.232.0.0/14117.232.0.1 to 117.235.255.254117.235.255.255262,142
124117.236.0.0/14117.236.0.1 to 117.239.255.254117.239.255.255262,142
125117.240.0.0/14117.240.0.1 to 117.243.255.254117.243.255.255262,142
126117.244.0.0/14117.244.0.1 to 117.247.255.254117.247.255.255262,142
127117.248.0.0/14117.248.0.1 to 117.251.255.254117.251.255.255262,142
128117.252.0.0/14117.252.0.1 to 117.255.255.254117.255.255.255262,142

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.