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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.

Network116.63.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
116.63.0.0
Broadcast address
116.63.255.255
First usable
116.63.0.1
Last usable
116.63.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 743F0000 · Integer 1950285824 to 1950351359
Reverse DNS zone
63.116.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110100.00111111..00000000.00000000116.63.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01110100.00111111..00000000.00000000116.63.0.0
Broadcast01110100.00111111..11111111.11111111116.63.255.255
Split into smaller subnets/23
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

116.63.0.0/16 makes 128 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1116.63.0.0/23116.63.0.1 to 116.63.1.254116.63.1.255510
2116.63.2.0/23116.63.2.1 to 116.63.3.254116.63.3.255510
3116.63.4.0/23116.63.4.1 to 116.63.5.254116.63.5.255510
4116.63.6.0/23116.63.6.1 to 116.63.7.254116.63.7.255510
5116.63.8.0/23116.63.8.1 to 116.63.9.254116.63.9.255510
6116.63.10.0/23116.63.10.1 to 116.63.11.254116.63.11.255510
7116.63.12.0/23116.63.12.1 to 116.63.13.254116.63.13.255510
8116.63.14.0/23116.63.14.1 to 116.63.15.254116.63.15.255510
9116.63.16.0/23116.63.16.1 to 116.63.17.254116.63.17.255510
10116.63.18.0/23116.63.18.1 to 116.63.19.254116.63.19.255510
11116.63.20.0/23116.63.20.1 to 116.63.21.254116.63.21.255510
12116.63.22.0/23116.63.22.1 to 116.63.23.254116.63.23.255510
13116.63.24.0/23116.63.24.1 to 116.63.25.254116.63.25.255510
14116.63.26.0/23116.63.26.1 to 116.63.27.254116.63.27.255510
15116.63.28.0/23116.63.28.1 to 116.63.29.254116.63.29.255510
16116.63.30.0/23116.63.30.1 to 116.63.31.254116.63.31.255510
17116.63.32.0/23116.63.32.1 to 116.63.33.254116.63.33.255510
18116.63.34.0/23116.63.34.1 to 116.63.35.254116.63.35.255510
19116.63.36.0/23116.63.36.1 to 116.63.37.254116.63.37.255510
20116.63.38.0/23116.63.38.1 to 116.63.39.254116.63.39.255510
21116.63.40.0/23116.63.40.1 to 116.63.41.254116.63.41.255510
22116.63.42.0/23116.63.42.1 to 116.63.43.254116.63.43.255510
23116.63.44.0/23116.63.44.1 to 116.63.45.254116.63.45.255510
24116.63.46.0/23116.63.46.1 to 116.63.47.254116.63.47.255510
25116.63.48.0/23116.63.48.1 to 116.63.49.254116.63.49.255510
26116.63.50.0/23116.63.50.1 to 116.63.51.254116.63.51.255510
27116.63.52.0/23116.63.52.1 to 116.63.53.254116.63.53.255510
28116.63.54.0/23116.63.54.1 to 116.63.55.254116.63.55.255510
29116.63.56.0/23116.63.56.1 to 116.63.57.254116.63.57.255510
30116.63.58.0/23116.63.58.1 to 116.63.59.254116.63.59.255510
31116.63.60.0/23116.63.60.1 to 116.63.61.254116.63.61.255510
32116.63.62.0/23116.63.62.1 to 116.63.63.254116.63.63.255510
33116.63.64.0/23116.63.64.1 to 116.63.65.254116.63.65.255510
34116.63.66.0/23116.63.66.1 to 116.63.67.254116.63.67.255510
35116.63.68.0/23116.63.68.1 to 116.63.69.254116.63.69.255510
36116.63.70.0/23116.63.70.1 to 116.63.71.254116.63.71.255510
37116.63.72.0/23116.63.72.1 to 116.63.73.254116.63.73.255510
38116.63.74.0/23116.63.74.1 to 116.63.75.254116.63.75.255510
39116.63.76.0/23116.63.76.1 to 116.63.77.254116.63.77.255510
40116.63.78.0/23116.63.78.1 to 116.63.79.254116.63.79.255510
41116.63.80.0/23116.63.80.1 to 116.63.81.254116.63.81.255510
42116.63.82.0/23116.63.82.1 to 116.63.83.254116.63.83.255510
43116.63.84.0/23116.63.84.1 to 116.63.85.254116.63.85.255510
44116.63.86.0/23116.63.86.1 to 116.63.87.254116.63.87.255510
45116.63.88.0/23116.63.88.1 to 116.63.89.254116.63.89.255510
46116.63.90.0/23116.63.90.1 to 116.63.91.254116.63.91.255510
47116.63.92.0/23116.63.92.1 to 116.63.93.254116.63.93.255510
48116.63.94.0/23116.63.94.1 to 116.63.95.254116.63.95.255510
49116.63.96.0/23116.63.96.1 to 116.63.97.254116.63.97.255510
50116.63.98.0/23116.63.98.1 to 116.63.99.254116.63.99.255510
51116.63.100.0/23116.63.100.1 to 116.63.101.254116.63.101.255510
52116.63.102.0/23116.63.102.1 to 116.63.103.254116.63.103.255510
53116.63.104.0/23116.63.104.1 to 116.63.105.254116.63.105.255510
54116.63.106.0/23116.63.106.1 to 116.63.107.254116.63.107.255510
55116.63.108.0/23116.63.108.1 to 116.63.109.254116.63.109.255510
56116.63.110.0/23116.63.110.1 to 116.63.111.254116.63.111.255510
57116.63.112.0/23116.63.112.1 to 116.63.113.254116.63.113.255510
58116.63.114.0/23116.63.114.1 to 116.63.115.254116.63.115.255510
59116.63.116.0/23116.63.116.1 to 116.63.117.254116.63.117.255510
60116.63.118.0/23116.63.118.1 to 116.63.119.254116.63.119.255510
61116.63.120.0/23116.63.120.1 to 116.63.121.254116.63.121.255510
62116.63.122.0/23116.63.122.1 to 116.63.123.254116.63.123.255510
63116.63.124.0/23116.63.124.1 to 116.63.125.254116.63.125.255510
64116.63.126.0/23116.63.126.1 to 116.63.127.254116.63.127.255510
65116.63.128.0/23116.63.128.1 to 116.63.129.254116.63.129.255510
66116.63.130.0/23116.63.130.1 to 116.63.131.254116.63.131.255510
67116.63.132.0/23116.63.132.1 to 116.63.133.254116.63.133.255510
68116.63.134.0/23116.63.134.1 to 116.63.135.254116.63.135.255510
69116.63.136.0/23116.63.136.1 to 116.63.137.254116.63.137.255510
70116.63.138.0/23116.63.138.1 to 116.63.139.254116.63.139.255510
71116.63.140.0/23116.63.140.1 to 116.63.141.254116.63.141.255510
72116.63.142.0/23116.63.142.1 to 116.63.143.254116.63.143.255510
73116.63.144.0/23116.63.144.1 to 116.63.145.254116.63.145.255510
74116.63.146.0/23116.63.146.1 to 116.63.147.254116.63.147.255510
75116.63.148.0/23116.63.148.1 to 116.63.149.254116.63.149.255510
76116.63.150.0/23116.63.150.1 to 116.63.151.254116.63.151.255510
77116.63.152.0/23116.63.152.1 to 116.63.153.254116.63.153.255510
78116.63.154.0/23116.63.154.1 to 116.63.155.254116.63.155.255510
79116.63.156.0/23116.63.156.1 to 116.63.157.254116.63.157.255510
80116.63.158.0/23116.63.158.1 to 116.63.159.254116.63.159.255510
81116.63.160.0/23116.63.160.1 to 116.63.161.254116.63.161.255510
82116.63.162.0/23116.63.162.1 to 116.63.163.254116.63.163.255510
83116.63.164.0/23116.63.164.1 to 116.63.165.254116.63.165.255510
84116.63.166.0/23116.63.166.1 to 116.63.167.254116.63.167.255510
85116.63.168.0/23116.63.168.1 to 116.63.169.254116.63.169.255510
86116.63.170.0/23116.63.170.1 to 116.63.171.254116.63.171.255510
87116.63.172.0/23116.63.172.1 to 116.63.173.254116.63.173.255510
88116.63.174.0/23116.63.174.1 to 116.63.175.254116.63.175.255510
89116.63.176.0/23116.63.176.1 to 116.63.177.254116.63.177.255510
90116.63.178.0/23116.63.178.1 to 116.63.179.254116.63.179.255510
91116.63.180.0/23116.63.180.1 to 116.63.181.254116.63.181.255510
92116.63.182.0/23116.63.182.1 to 116.63.183.254116.63.183.255510
93116.63.184.0/23116.63.184.1 to 116.63.185.254116.63.185.255510
94116.63.186.0/23116.63.186.1 to 116.63.187.254116.63.187.255510
95116.63.188.0/23116.63.188.1 to 116.63.189.254116.63.189.255510
96116.63.190.0/23116.63.190.1 to 116.63.191.254116.63.191.255510
97116.63.192.0/23116.63.192.1 to 116.63.193.254116.63.193.255510
98116.63.194.0/23116.63.194.1 to 116.63.195.254116.63.195.255510
99116.63.196.0/23116.63.196.1 to 116.63.197.254116.63.197.255510
100116.63.198.0/23116.63.198.1 to 116.63.199.254116.63.199.255510
101116.63.200.0/23116.63.200.1 to 116.63.201.254116.63.201.255510
102116.63.202.0/23116.63.202.1 to 116.63.203.254116.63.203.255510
103116.63.204.0/23116.63.204.1 to 116.63.205.254116.63.205.255510
104116.63.206.0/23116.63.206.1 to 116.63.207.254116.63.207.255510
105116.63.208.0/23116.63.208.1 to 116.63.209.254116.63.209.255510
106116.63.210.0/23116.63.210.1 to 116.63.211.254116.63.211.255510
107116.63.212.0/23116.63.212.1 to 116.63.213.254116.63.213.255510
108116.63.214.0/23116.63.214.1 to 116.63.215.254116.63.215.255510
109116.63.216.0/23116.63.216.1 to 116.63.217.254116.63.217.255510
110116.63.218.0/23116.63.218.1 to 116.63.219.254116.63.219.255510
111116.63.220.0/23116.63.220.1 to 116.63.221.254116.63.221.255510
112116.63.222.0/23116.63.222.1 to 116.63.223.254116.63.223.255510
113116.63.224.0/23116.63.224.1 to 116.63.225.254116.63.225.255510
114116.63.226.0/23116.63.226.1 to 116.63.227.254116.63.227.255510
115116.63.228.0/23116.63.228.1 to 116.63.229.254116.63.229.255510
116116.63.230.0/23116.63.230.1 to 116.63.231.254116.63.231.255510
117116.63.232.0/23116.63.232.1 to 116.63.233.254116.63.233.255510
118116.63.234.0/23116.63.234.1 to 116.63.235.254116.63.235.255510
119116.63.236.0/23116.63.236.1 to 116.63.237.254116.63.237.255510
120116.63.238.0/23116.63.238.1 to 116.63.239.254116.63.239.255510
121116.63.240.0/23116.63.240.1 to 116.63.241.254116.63.241.255510
122116.63.242.0/23116.63.242.1 to 116.63.243.254116.63.243.255510
123116.63.244.0/23116.63.244.1 to 116.63.245.254116.63.245.255510
124116.63.246.0/23116.63.246.1 to 116.63.247.254116.63.247.255510
125116.63.248.0/23116.63.248.1 to 116.63.249.254116.63.249.255510
126116.63.250.0/23116.63.250.1 to 116.63.251.254116.63.251.255510
127116.63.252.0/23116.63.252.1 to 116.63.253.254116.63.253.255510
128116.63.254.0/23116.63.254.1 to 116.63.255.254116.63.255.255510

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.