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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.

Network55.16.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
55.16.0.0
Broadcast address
55.16.255.255
First usable
55.16.0.1
Last usable
55.16.255.254
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 37100000 · Integer 923795456 to 923860991
Reverse DNS zone
16.55.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110111.00010000..00000000.0000000055.16.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00110111.00010000..00000000.0000000055.16.0.0
Broadcast00110111.00010000..11111111.1111111155.16.255.255
Split into smaller subnets/23

55.16.0.0/16 makes 128 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.16.0.0/2355.16.0.1 to 55.16.1.25455.16.1.255510
255.16.2.0/2355.16.2.1 to 55.16.3.25455.16.3.255510
355.16.4.0/2355.16.4.1 to 55.16.5.25455.16.5.255510
455.16.6.0/2355.16.6.1 to 55.16.7.25455.16.7.255510
555.16.8.0/2355.16.8.1 to 55.16.9.25455.16.9.255510
655.16.10.0/2355.16.10.1 to 55.16.11.25455.16.11.255510
755.16.12.0/2355.16.12.1 to 55.16.13.25455.16.13.255510
855.16.14.0/2355.16.14.1 to 55.16.15.25455.16.15.255510
955.16.16.0/2355.16.16.1 to 55.16.17.25455.16.17.255510
1055.16.18.0/2355.16.18.1 to 55.16.19.25455.16.19.255510
1155.16.20.0/2355.16.20.1 to 55.16.21.25455.16.21.255510
1255.16.22.0/2355.16.22.1 to 55.16.23.25455.16.23.255510
1355.16.24.0/2355.16.24.1 to 55.16.25.25455.16.25.255510
1455.16.26.0/2355.16.26.1 to 55.16.27.25455.16.27.255510
1555.16.28.0/2355.16.28.1 to 55.16.29.25455.16.29.255510
1655.16.30.0/2355.16.30.1 to 55.16.31.25455.16.31.255510
1755.16.32.0/2355.16.32.1 to 55.16.33.25455.16.33.255510
1855.16.34.0/2355.16.34.1 to 55.16.35.25455.16.35.255510
1955.16.36.0/2355.16.36.1 to 55.16.37.25455.16.37.255510
2055.16.38.0/2355.16.38.1 to 55.16.39.25455.16.39.255510
2155.16.40.0/2355.16.40.1 to 55.16.41.25455.16.41.255510
2255.16.42.0/2355.16.42.1 to 55.16.43.25455.16.43.255510
2355.16.44.0/2355.16.44.1 to 55.16.45.25455.16.45.255510
2455.16.46.0/2355.16.46.1 to 55.16.47.25455.16.47.255510
2555.16.48.0/2355.16.48.1 to 55.16.49.25455.16.49.255510
2655.16.50.0/2355.16.50.1 to 55.16.51.25455.16.51.255510
2755.16.52.0/2355.16.52.1 to 55.16.53.25455.16.53.255510
2855.16.54.0/2355.16.54.1 to 55.16.55.25455.16.55.255510
2955.16.56.0/2355.16.56.1 to 55.16.57.25455.16.57.255510
3055.16.58.0/2355.16.58.1 to 55.16.59.25455.16.59.255510
3155.16.60.0/2355.16.60.1 to 55.16.61.25455.16.61.255510
3255.16.62.0/2355.16.62.1 to 55.16.63.25455.16.63.255510
3355.16.64.0/2355.16.64.1 to 55.16.65.25455.16.65.255510
3455.16.66.0/2355.16.66.1 to 55.16.67.25455.16.67.255510
3555.16.68.0/2355.16.68.1 to 55.16.69.25455.16.69.255510
3655.16.70.0/2355.16.70.1 to 55.16.71.25455.16.71.255510
3755.16.72.0/2355.16.72.1 to 55.16.73.25455.16.73.255510
3855.16.74.0/2355.16.74.1 to 55.16.75.25455.16.75.255510
3955.16.76.0/2355.16.76.1 to 55.16.77.25455.16.77.255510
4055.16.78.0/2355.16.78.1 to 55.16.79.25455.16.79.255510
4155.16.80.0/2355.16.80.1 to 55.16.81.25455.16.81.255510
4255.16.82.0/2355.16.82.1 to 55.16.83.25455.16.83.255510
4355.16.84.0/2355.16.84.1 to 55.16.85.25455.16.85.255510
4455.16.86.0/2355.16.86.1 to 55.16.87.25455.16.87.255510
4555.16.88.0/2355.16.88.1 to 55.16.89.25455.16.89.255510
4655.16.90.0/2355.16.90.1 to 55.16.91.25455.16.91.255510
4755.16.92.0/2355.16.92.1 to 55.16.93.25455.16.93.255510
4855.16.94.0/2355.16.94.1 to 55.16.95.25455.16.95.255510
4955.16.96.0/2355.16.96.1 to 55.16.97.25455.16.97.255510
5055.16.98.0/2355.16.98.1 to 55.16.99.25455.16.99.255510
5155.16.100.0/2355.16.100.1 to 55.16.101.25455.16.101.255510
5255.16.102.0/2355.16.102.1 to 55.16.103.25455.16.103.255510
5355.16.104.0/2355.16.104.1 to 55.16.105.25455.16.105.255510
5455.16.106.0/2355.16.106.1 to 55.16.107.25455.16.107.255510
5555.16.108.0/2355.16.108.1 to 55.16.109.25455.16.109.255510
5655.16.110.0/2355.16.110.1 to 55.16.111.25455.16.111.255510
5755.16.112.0/2355.16.112.1 to 55.16.113.25455.16.113.255510
5855.16.114.0/2355.16.114.1 to 55.16.115.25455.16.115.255510
5955.16.116.0/2355.16.116.1 to 55.16.117.25455.16.117.255510
6055.16.118.0/2355.16.118.1 to 55.16.119.25455.16.119.255510
6155.16.120.0/2355.16.120.1 to 55.16.121.25455.16.121.255510
6255.16.122.0/2355.16.122.1 to 55.16.123.25455.16.123.255510
6355.16.124.0/2355.16.124.1 to 55.16.125.25455.16.125.255510
6455.16.126.0/2355.16.126.1 to 55.16.127.25455.16.127.255510
6555.16.128.0/2355.16.128.1 to 55.16.129.25455.16.129.255510
6655.16.130.0/2355.16.130.1 to 55.16.131.25455.16.131.255510
6755.16.132.0/2355.16.132.1 to 55.16.133.25455.16.133.255510
6855.16.134.0/2355.16.134.1 to 55.16.135.25455.16.135.255510
6955.16.136.0/2355.16.136.1 to 55.16.137.25455.16.137.255510
7055.16.138.0/2355.16.138.1 to 55.16.139.25455.16.139.255510
7155.16.140.0/2355.16.140.1 to 55.16.141.25455.16.141.255510
7255.16.142.0/2355.16.142.1 to 55.16.143.25455.16.143.255510
7355.16.144.0/2355.16.144.1 to 55.16.145.25455.16.145.255510
7455.16.146.0/2355.16.146.1 to 55.16.147.25455.16.147.255510
7555.16.148.0/2355.16.148.1 to 55.16.149.25455.16.149.255510
7655.16.150.0/2355.16.150.1 to 55.16.151.25455.16.151.255510
7755.16.152.0/2355.16.152.1 to 55.16.153.25455.16.153.255510
7855.16.154.0/2355.16.154.1 to 55.16.155.25455.16.155.255510
7955.16.156.0/2355.16.156.1 to 55.16.157.25455.16.157.255510
8055.16.158.0/2355.16.158.1 to 55.16.159.25455.16.159.255510
8155.16.160.0/2355.16.160.1 to 55.16.161.25455.16.161.255510
8255.16.162.0/2355.16.162.1 to 55.16.163.25455.16.163.255510
8355.16.164.0/2355.16.164.1 to 55.16.165.25455.16.165.255510
8455.16.166.0/2355.16.166.1 to 55.16.167.25455.16.167.255510
8555.16.168.0/2355.16.168.1 to 55.16.169.25455.16.169.255510
8655.16.170.0/2355.16.170.1 to 55.16.171.25455.16.171.255510
8755.16.172.0/2355.16.172.1 to 55.16.173.25455.16.173.255510
8855.16.174.0/2355.16.174.1 to 55.16.175.25455.16.175.255510
8955.16.176.0/2355.16.176.1 to 55.16.177.25455.16.177.255510
9055.16.178.0/2355.16.178.1 to 55.16.179.25455.16.179.255510
9155.16.180.0/2355.16.180.1 to 55.16.181.25455.16.181.255510
9255.16.182.0/2355.16.182.1 to 55.16.183.25455.16.183.255510
9355.16.184.0/2355.16.184.1 to 55.16.185.25455.16.185.255510
9455.16.186.0/2355.16.186.1 to 55.16.187.25455.16.187.255510
9555.16.188.0/2355.16.188.1 to 55.16.189.25455.16.189.255510
9655.16.190.0/2355.16.190.1 to 55.16.191.25455.16.191.255510
9755.16.192.0/2355.16.192.1 to 55.16.193.25455.16.193.255510
9855.16.194.0/2355.16.194.1 to 55.16.195.25455.16.195.255510
9955.16.196.0/2355.16.196.1 to 55.16.197.25455.16.197.255510
10055.16.198.0/2355.16.198.1 to 55.16.199.25455.16.199.255510
10155.16.200.0/2355.16.200.1 to 55.16.201.25455.16.201.255510
10255.16.202.0/2355.16.202.1 to 55.16.203.25455.16.203.255510
10355.16.204.0/2355.16.204.1 to 55.16.205.25455.16.205.255510
10455.16.206.0/2355.16.206.1 to 55.16.207.25455.16.207.255510
10555.16.208.0/2355.16.208.1 to 55.16.209.25455.16.209.255510
10655.16.210.0/2355.16.210.1 to 55.16.211.25455.16.211.255510
10755.16.212.0/2355.16.212.1 to 55.16.213.25455.16.213.255510
10855.16.214.0/2355.16.214.1 to 55.16.215.25455.16.215.255510
10955.16.216.0/2355.16.216.1 to 55.16.217.25455.16.217.255510
11055.16.218.0/2355.16.218.1 to 55.16.219.25455.16.219.255510
11155.16.220.0/2355.16.220.1 to 55.16.221.25455.16.221.255510
11255.16.222.0/2355.16.222.1 to 55.16.223.25455.16.223.255510
11355.16.224.0/2355.16.224.1 to 55.16.225.25455.16.225.255510
11455.16.226.0/2355.16.226.1 to 55.16.227.25455.16.227.255510
11555.16.228.0/2355.16.228.1 to 55.16.229.25455.16.229.255510
11655.16.230.0/2355.16.230.1 to 55.16.231.25455.16.231.255510
11755.16.232.0/2355.16.232.1 to 55.16.233.25455.16.233.255510
11855.16.234.0/2355.16.234.1 to 55.16.235.25455.16.235.255510
11955.16.236.0/2355.16.236.1 to 55.16.237.25455.16.237.255510
12055.16.238.0/2355.16.238.1 to 55.16.239.25455.16.239.255510
12155.16.240.0/2355.16.240.1 to 55.16.241.25455.16.241.255510
12255.16.242.0/2355.16.242.1 to 55.16.243.25455.16.243.255510
12355.16.244.0/2355.16.244.1 to 55.16.245.25455.16.245.255510
12455.16.246.0/2355.16.246.1 to 55.16.247.25455.16.247.255510
12555.16.248.0/2355.16.248.1 to 55.16.249.25455.16.249.255510
12655.16.250.0/2355.16.250.1 to 55.16.251.25455.16.251.255510
12755.16.252.0/2355.16.252.1 to 55.16.253.25455.16.253.255510
12855.16.254.0/2355.16.254.1 to 55.16.255.25455.16.255.255510

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