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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.

Network42.65.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
42.65.0.0
Broadcast address
42.65.255.255
First usable
42.65.0.1
Last usable
42.65.255.254
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 2A410000 · Integer 708902912 to 708968447
Reverse DNS zone
65.42.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101010.01000001..00000000.0000000042.65.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00101010.01000001..00000000.0000000042.65.0.0
Broadcast00101010.01000001..11111111.1111111142.65.255.255
Split into smaller subnets/23

42.65.0.0/16 makes 128 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
142.65.0.0/2342.65.0.1 to 42.65.1.25442.65.1.255510
242.65.2.0/2342.65.2.1 to 42.65.3.25442.65.3.255510
342.65.4.0/2342.65.4.1 to 42.65.5.25442.65.5.255510
442.65.6.0/2342.65.6.1 to 42.65.7.25442.65.7.255510
542.65.8.0/2342.65.8.1 to 42.65.9.25442.65.9.255510
642.65.10.0/2342.65.10.1 to 42.65.11.25442.65.11.255510
742.65.12.0/2342.65.12.1 to 42.65.13.25442.65.13.255510
842.65.14.0/2342.65.14.1 to 42.65.15.25442.65.15.255510
942.65.16.0/2342.65.16.1 to 42.65.17.25442.65.17.255510
1042.65.18.0/2342.65.18.1 to 42.65.19.25442.65.19.255510
1142.65.20.0/2342.65.20.1 to 42.65.21.25442.65.21.255510
1242.65.22.0/2342.65.22.1 to 42.65.23.25442.65.23.255510
1342.65.24.0/2342.65.24.1 to 42.65.25.25442.65.25.255510
1442.65.26.0/2342.65.26.1 to 42.65.27.25442.65.27.255510
1542.65.28.0/2342.65.28.1 to 42.65.29.25442.65.29.255510
1642.65.30.0/2342.65.30.1 to 42.65.31.25442.65.31.255510
1742.65.32.0/2342.65.32.1 to 42.65.33.25442.65.33.255510
1842.65.34.0/2342.65.34.1 to 42.65.35.25442.65.35.255510
1942.65.36.0/2342.65.36.1 to 42.65.37.25442.65.37.255510
2042.65.38.0/2342.65.38.1 to 42.65.39.25442.65.39.255510
2142.65.40.0/2342.65.40.1 to 42.65.41.25442.65.41.255510
2242.65.42.0/2342.65.42.1 to 42.65.43.25442.65.43.255510
2342.65.44.0/2342.65.44.1 to 42.65.45.25442.65.45.255510
2442.65.46.0/2342.65.46.1 to 42.65.47.25442.65.47.255510
2542.65.48.0/2342.65.48.1 to 42.65.49.25442.65.49.255510
2642.65.50.0/2342.65.50.1 to 42.65.51.25442.65.51.255510
2742.65.52.0/2342.65.52.1 to 42.65.53.25442.65.53.255510
2842.65.54.0/2342.65.54.1 to 42.65.55.25442.65.55.255510
2942.65.56.0/2342.65.56.1 to 42.65.57.25442.65.57.255510
3042.65.58.0/2342.65.58.1 to 42.65.59.25442.65.59.255510
3142.65.60.0/2342.65.60.1 to 42.65.61.25442.65.61.255510
3242.65.62.0/2342.65.62.1 to 42.65.63.25442.65.63.255510
3342.65.64.0/2342.65.64.1 to 42.65.65.25442.65.65.255510
3442.65.66.0/2342.65.66.1 to 42.65.67.25442.65.67.255510
3542.65.68.0/2342.65.68.1 to 42.65.69.25442.65.69.255510
3642.65.70.0/2342.65.70.1 to 42.65.71.25442.65.71.255510
3742.65.72.0/2342.65.72.1 to 42.65.73.25442.65.73.255510
3842.65.74.0/2342.65.74.1 to 42.65.75.25442.65.75.255510
3942.65.76.0/2342.65.76.1 to 42.65.77.25442.65.77.255510
4042.65.78.0/2342.65.78.1 to 42.65.79.25442.65.79.255510
4142.65.80.0/2342.65.80.1 to 42.65.81.25442.65.81.255510
4242.65.82.0/2342.65.82.1 to 42.65.83.25442.65.83.255510
4342.65.84.0/2342.65.84.1 to 42.65.85.25442.65.85.255510
4442.65.86.0/2342.65.86.1 to 42.65.87.25442.65.87.255510
4542.65.88.0/2342.65.88.1 to 42.65.89.25442.65.89.255510
4642.65.90.0/2342.65.90.1 to 42.65.91.25442.65.91.255510
4742.65.92.0/2342.65.92.1 to 42.65.93.25442.65.93.255510
4842.65.94.0/2342.65.94.1 to 42.65.95.25442.65.95.255510
4942.65.96.0/2342.65.96.1 to 42.65.97.25442.65.97.255510
5042.65.98.0/2342.65.98.1 to 42.65.99.25442.65.99.255510
5142.65.100.0/2342.65.100.1 to 42.65.101.25442.65.101.255510
5242.65.102.0/2342.65.102.1 to 42.65.103.25442.65.103.255510
5342.65.104.0/2342.65.104.1 to 42.65.105.25442.65.105.255510
5442.65.106.0/2342.65.106.1 to 42.65.107.25442.65.107.255510
5542.65.108.0/2342.65.108.1 to 42.65.109.25442.65.109.255510
5642.65.110.0/2342.65.110.1 to 42.65.111.25442.65.111.255510
5742.65.112.0/2342.65.112.1 to 42.65.113.25442.65.113.255510
5842.65.114.0/2342.65.114.1 to 42.65.115.25442.65.115.255510
5942.65.116.0/2342.65.116.1 to 42.65.117.25442.65.117.255510
6042.65.118.0/2342.65.118.1 to 42.65.119.25442.65.119.255510
6142.65.120.0/2342.65.120.1 to 42.65.121.25442.65.121.255510
6242.65.122.0/2342.65.122.1 to 42.65.123.25442.65.123.255510
6342.65.124.0/2342.65.124.1 to 42.65.125.25442.65.125.255510
6442.65.126.0/2342.65.126.1 to 42.65.127.25442.65.127.255510
6542.65.128.0/2342.65.128.1 to 42.65.129.25442.65.129.255510
6642.65.130.0/2342.65.130.1 to 42.65.131.25442.65.131.255510
6742.65.132.0/2342.65.132.1 to 42.65.133.25442.65.133.255510
6842.65.134.0/2342.65.134.1 to 42.65.135.25442.65.135.255510
6942.65.136.0/2342.65.136.1 to 42.65.137.25442.65.137.255510
7042.65.138.0/2342.65.138.1 to 42.65.139.25442.65.139.255510
7142.65.140.0/2342.65.140.1 to 42.65.141.25442.65.141.255510
7242.65.142.0/2342.65.142.1 to 42.65.143.25442.65.143.255510
7342.65.144.0/2342.65.144.1 to 42.65.145.25442.65.145.255510
7442.65.146.0/2342.65.146.1 to 42.65.147.25442.65.147.255510
7542.65.148.0/2342.65.148.1 to 42.65.149.25442.65.149.255510
7642.65.150.0/2342.65.150.1 to 42.65.151.25442.65.151.255510
7742.65.152.0/2342.65.152.1 to 42.65.153.25442.65.153.255510
7842.65.154.0/2342.65.154.1 to 42.65.155.25442.65.155.255510
7942.65.156.0/2342.65.156.1 to 42.65.157.25442.65.157.255510
8042.65.158.0/2342.65.158.1 to 42.65.159.25442.65.159.255510
8142.65.160.0/2342.65.160.1 to 42.65.161.25442.65.161.255510
8242.65.162.0/2342.65.162.1 to 42.65.163.25442.65.163.255510
8342.65.164.0/2342.65.164.1 to 42.65.165.25442.65.165.255510
8442.65.166.0/2342.65.166.1 to 42.65.167.25442.65.167.255510
8542.65.168.0/2342.65.168.1 to 42.65.169.25442.65.169.255510
8642.65.170.0/2342.65.170.1 to 42.65.171.25442.65.171.255510
8742.65.172.0/2342.65.172.1 to 42.65.173.25442.65.173.255510
8842.65.174.0/2342.65.174.1 to 42.65.175.25442.65.175.255510
8942.65.176.0/2342.65.176.1 to 42.65.177.25442.65.177.255510
9042.65.178.0/2342.65.178.1 to 42.65.179.25442.65.179.255510
9142.65.180.0/2342.65.180.1 to 42.65.181.25442.65.181.255510
9242.65.182.0/2342.65.182.1 to 42.65.183.25442.65.183.255510
9342.65.184.0/2342.65.184.1 to 42.65.185.25442.65.185.255510
9442.65.186.0/2342.65.186.1 to 42.65.187.25442.65.187.255510
9542.65.188.0/2342.65.188.1 to 42.65.189.25442.65.189.255510
9642.65.190.0/2342.65.190.1 to 42.65.191.25442.65.191.255510
9742.65.192.0/2342.65.192.1 to 42.65.193.25442.65.193.255510
9842.65.194.0/2342.65.194.1 to 42.65.195.25442.65.195.255510
9942.65.196.0/2342.65.196.1 to 42.65.197.25442.65.197.255510
10042.65.198.0/2342.65.198.1 to 42.65.199.25442.65.199.255510
10142.65.200.0/2342.65.200.1 to 42.65.201.25442.65.201.255510
10242.65.202.0/2342.65.202.1 to 42.65.203.25442.65.203.255510
10342.65.204.0/2342.65.204.1 to 42.65.205.25442.65.205.255510
10442.65.206.0/2342.65.206.1 to 42.65.207.25442.65.207.255510
10542.65.208.0/2342.65.208.1 to 42.65.209.25442.65.209.255510
10642.65.210.0/2342.65.210.1 to 42.65.211.25442.65.211.255510
10742.65.212.0/2342.65.212.1 to 42.65.213.25442.65.213.255510
10842.65.214.0/2342.65.214.1 to 42.65.215.25442.65.215.255510
10942.65.216.0/2342.65.216.1 to 42.65.217.25442.65.217.255510
11042.65.218.0/2342.65.218.1 to 42.65.219.25442.65.219.255510
11142.65.220.0/2342.65.220.1 to 42.65.221.25442.65.221.255510
11242.65.222.0/2342.65.222.1 to 42.65.223.25442.65.223.255510
11342.65.224.0/2342.65.224.1 to 42.65.225.25442.65.225.255510
11442.65.226.0/2342.65.226.1 to 42.65.227.25442.65.227.255510
11542.65.228.0/2342.65.228.1 to 42.65.229.25442.65.229.255510
11642.65.230.0/2342.65.230.1 to 42.65.231.25442.65.231.255510
11742.65.232.0/2342.65.232.1 to 42.65.233.25442.65.233.255510
11842.65.234.0/2342.65.234.1 to 42.65.235.25442.65.235.255510
11942.65.236.0/2342.65.236.1 to 42.65.237.25442.65.237.255510
12042.65.238.0/2342.65.238.1 to 42.65.239.25442.65.239.255510
12142.65.240.0/2342.65.240.1 to 42.65.241.25442.65.241.255510
12242.65.242.0/2342.65.242.1 to 42.65.243.25442.65.243.255510
12342.65.244.0/2342.65.244.1 to 42.65.245.25442.65.245.255510
12442.65.246.0/2342.65.246.1 to 42.65.247.25442.65.247.255510
12542.65.248.0/2342.65.248.1 to 42.65.249.25442.65.249.255510
12642.65.250.0/2342.65.250.1 to 42.65.251.25442.65.251.255510
12742.65.252.0/2342.65.252.1 to 42.65.253.25442.65.253.255510
12842.65.254.0/2342.65.254.1 to 42.65.255.25442.65.255.255510

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