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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.

Network72.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
72.0.0.0
Broadcast address
72.127.255.255
First usable
72.0.0.1
Last usable
72.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 48000000 · Integer 1207959552 to 1216348159
Reverse DNS zones
0.72.in-addr.arpa
1.72.in-addr.arpa
2.72.in-addr.arpa
3.72.in-addr.arpa
4.72.in-addr.arpa
5.72.in-addr.arpa
6.72.in-addr.arpa
7.72.in-addr.arpa
8.72.in-addr.arpa
9.72.in-addr.arpa
10.72.in-addr.arpa
11.72.in-addr.arpa
12.72.in-addr.arpa
13.72.in-addr.arpa
14.72.in-addr.arpa
15.72.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001000.00000000.00000000.0000000072.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01001000.00000000.00000000.0000000072.0.0.0
Broadcast01001000.01111111.11111111.1111111172.127.255.255
Split into smaller subnets/16

72.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
172.0.0.0/1672.0.0.1 to 72.0.255.25472.0.255.25565,534
272.1.0.0/1672.1.0.1 to 72.1.255.25472.1.255.25565,534
372.2.0.0/1672.2.0.1 to 72.2.255.25472.2.255.25565,534
472.3.0.0/1672.3.0.1 to 72.3.255.25472.3.255.25565,534
572.4.0.0/1672.4.0.1 to 72.4.255.25472.4.255.25565,534
672.5.0.0/1672.5.0.1 to 72.5.255.25472.5.255.25565,534
772.6.0.0/1672.6.0.1 to 72.6.255.25472.6.255.25565,534
872.7.0.0/1672.7.0.1 to 72.7.255.25472.7.255.25565,534
972.8.0.0/1672.8.0.1 to 72.8.255.25472.8.255.25565,534
1072.9.0.0/1672.9.0.1 to 72.9.255.25472.9.255.25565,534
1172.10.0.0/1672.10.0.1 to 72.10.255.25472.10.255.25565,534
1272.11.0.0/1672.11.0.1 to 72.11.255.25472.11.255.25565,534
1372.12.0.0/1672.12.0.1 to 72.12.255.25472.12.255.25565,534
1472.13.0.0/1672.13.0.1 to 72.13.255.25472.13.255.25565,534
1572.14.0.0/1672.14.0.1 to 72.14.255.25472.14.255.25565,534
1672.15.0.0/1672.15.0.1 to 72.15.255.25472.15.255.25565,534
1772.16.0.0/1672.16.0.1 to 72.16.255.25472.16.255.25565,534
1872.17.0.0/1672.17.0.1 to 72.17.255.25472.17.255.25565,534
1972.18.0.0/1672.18.0.1 to 72.18.255.25472.18.255.25565,534
2072.19.0.0/1672.19.0.1 to 72.19.255.25472.19.255.25565,534
2172.20.0.0/1672.20.0.1 to 72.20.255.25472.20.255.25565,534
2272.21.0.0/1672.21.0.1 to 72.21.255.25472.21.255.25565,534
2372.22.0.0/1672.22.0.1 to 72.22.255.25472.22.255.25565,534
2472.23.0.0/1672.23.0.1 to 72.23.255.25472.23.255.25565,534
2572.24.0.0/1672.24.0.1 to 72.24.255.25472.24.255.25565,534
2672.25.0.0/1672.25.0.1 to 72.25.255.25472.25.255.25565,534
2772.26.0.0/1672.26.0.1 to 72.26.255.25472.26.255.25565,534
2872.27.0.0/1672.27.0.1 to 72.27.255.25472.27.255.25565,534
2972.28.0.0/1672.28.0.1 to 72.28.255.25472.28.255.25565,534
3072.29.0.0/1672.29.0.1 to 72.29.255.25472.29.255.25565,534
3172.30.0.0/1672.30.0.1 to 72.30.255.25472.30.255.25565,534
3272.31.0.0/1672.31.0.1 to 72.31.255.25472.31.255.25565,534
3372.32.0.0/1672.32.0.1 to 72.32.255.25472.32.255.25565,534
3472.33.0.0/1672.33.0.1 to 72.33.255.25472.33.255.25565,534
3572.34.0.0/1672.34.0.1 to 72.34.255.25472.34.255.25565,534
3672.35.0.0/1672.35.0.1 to 72.35.255.25472.35.255.25565,534
3772.36.0.0/1672.36.0.1 to 72.36.255.25472.36.255.25565,534
3872.37.0.0/1672.37.0.1 to 72.37.255.25472.37.255.25565,534
3972.38.0.0/1672.38.0.1 to 72.38.255.25472.38.255.25565,534
4072.39.0.0/1672.39.0.1 to 72.39.255.25472.39.255.25565,534
4172.40.0.0/1672.40.0.1 to 72.40.255.25472.40.255.25565,534
4272.41.0.0/1672.41.0.1 to 72.41.255.25472.41.255.25565,534
4372.42.0.0/1672.42.0.1 to 72.42.255.25472.42.255.25565,534
4472.43.0.0/1672.43.0.1 to 72.43.255.25472.43.255.25565,534
4572.44.0.0/1672.44.0.1 to 72.44.255.25472.44.255.25565,534
4672.45.0.0/1672.45.0.1 to 72.45.255.25472.45.255.25565,534
4772.46.0.0/1672.46.0.1 to 72.46.255.25472.46.255.25565,534
4872.47.0.0/1672.47.0.1 to 72.47.255.25472.47.255.25565,534
4972.48.0.0/1672.48.0.1 to 72.48.255.25472.48.255.25565,534
5072.49.0.0/1672.49.0.1 to 72.49.255.25472.49.255.25565,534
5172.50.0.0/1672.50.0.1 to 72.50.255.25472.50.255.25565,534
5272.51.0.0/1672.51.0.1 to 72.51.255.25472.51.255.25565,534
5372.52.0.0/1672.52.0.1 to 72.52.255.25472.52.255.25565,534
5472.53.0.0/1672.53.0.1 to 72.53.255.25472.53.255.25565,534
5572.54.0.0/1672.54.0.1 to 72.54.255.25472.54.255.25565,534
5672.55.0.0/1672.55.0.1 to 72.55.255.25472.55.255.25565,534
5772.56.0.0/1672.56.0.1 to 72.56.255.25472.56.255.25565,534
5872.57.0.0/1672.57.0.1 to 72.57.255.25472.57.255.25565,534
5972.58.0.0/1672.58.0.1 to 72.58.255.25472.58.255.25565,534
6072.59.0.0/1672.59.0.1 to 72.59.255.25472.59.255.25565,534
6172.60.0.0/1672.60.0.1 to 72.60.255.25472.60.255.25565,534
6272.61.0.0/1672.61.0.1 to 72.61.255.25472.61.255.25565,534
6372.62.0.0/1672.62.0.1 to 72.62.255.25472.62.255.25565,534
6472.63.0.0/1672.63.0.1 to 72.63.255.25472.63.255.25565,534
6572.64.0.0/1672.64.0.1 to 72.64.255.25472.64.255.25565,534
6672.65.0.0/1672.65.0.1 to 72.65.255.25472.65.255.25565,534
6772.66.0.0/1672.66.0.1 to 72.66.255.25472.66.255.25565,534
6872.67.0.0/1672.67.0.1 to 72.67.255.25472.67.255.25565,534
6972.68.0.0/1672.68.0.1 to 72.68.255.25472.68.255.25565,534
7072.69.0.0/1672.69.0.1 to 72.69.255.25472.69.255.25565,534
7172.70.0.0/1672.70.0.1 to 72.70.255.25472.70.255.25565,534
7272.71.0.0/1672.71.0.1 to 72.71.255.25472.71.255.25565,534
7372.72.0.0/1672.72.0.1 to 72.72.255.25472.72.255.25565,534
7472.73.0.0/1672.73.0.1 to 72.73.255.25472.73.255.25565,534
7572.74.0.0/1672.74.0.1 to 72.74.255.25472.74.255.25565,534
7672.75.0.0/1672.75.0.1 to 72.75.255.25472.75.255.25565,534
7772.76.0.0/1672.76.0.1 to 72.76.255.25472.76.255.25565,534
7872.77.0.0/1672.77.0.1 to 72.77.255.25472.77.255.25565,534
7972.78.0.0/1672.78.0.1 to 72.78.255.25472.78.255.25565,534
8072.79.0.0/1672.79.0.1 to 72.79.255.25472.79.255.25565,534
8172.80.0.0/1672.80.0.1 to 72.80.255.25472.80.255.25565,534
8272.81.0.0/1672.81.0.1 to 72.81.255.25472.81.255.25565,534
8372.82.0.0/1672.82.0.1 to 72.82.255.25472.82.255.25565,534
8472.83.0.0/1672.83.0.1 to 72.83.255.25472.83.255.25565,534
8572.84.0.0/1672.84.0.1 to 72.84.255.25472.84.255.25565,534
8672.85.0.0/1672.85.0.1 to 72.85.255.25472.85.255.25565,534
8772.86.0.0/1672.86.0.1 to 72.86.255.25472.86.255.25565,534
8872.87.0.0/1672.87.0.1 to 72.87.255.25472.87.255.25565,534
8972.88.0.0/1672.88.0.1 to 72.88.255.25472.88.255.25565,534
9072.89.0.0/1672.89.0.1 to 72.89.255.25472.89.255.25565,534
9172.90.0.0/1672.90.0.1 to 72.90.255.25472.90.255.25565,534
9272.91.0.0/1672.91.0.1 to 72.91.255.25472.91.255.25565,534
9372.92.0.0/1672.92.0.1 to 72.92.255.25472.92.255.25565,534
9472.93.0.0/1672.93.0.1 to 72.93.255.25472.93.255.25565,534
9572.94.0.0/1672.94.0.1 to 72.94.255.25472.94.255.25565,534
9672.95.0.0/1672.95.0.1 to 72.95.255.25472.95.255.25565,534
9772.96.0.0/1672.96.0.1 to 72.96.255.25472.96.255.25565,534
9872.97.0.0/1672.97.0.1 to 72.97.255.25472.97.255.25565,534
9972.98.0.0/1672.98.0.1 to 72.98.255.25472.98.255.25565,534
10072.99.0.0/1672.99.0.1 to 72.99.255.25472.99.255.25565,534
10172.100.0.0/1672.100.0.1 to 72.100.255.25472.100.255.25565,534
10272.101.0.0/1672.101.0.1 to 72.101.255.25472.101.255.25565,534
10372.102.0.0/1672.102.0.1 to 72.102.255.25472.102.255.25565,534
10472.103.0.0/1672.103.0.1 to 72.103.255.25472.103.255.25565,534
10572.104.0.0/1672.104.0.1 to 72.104.255.25472.104.255.25565,534
10672.105.0.0/1672.105.0.1 to 72.105.255.25472.105.255.25565,534
10772.106.0.0/1672.106.0.1 to 72.106.255.25472.106.255.25565,534
10872.107.0.0/1672.107.0.1 to 72.107.255.25472.107.255.25565,534
10972.108.0.0/1672.108.0.1 to 72.108.255.25472.108.255.25565,534
11072.109.0.0/1672.109.0.1 to 72.109.255.25472.109.255.25565,534
11172.110.0.0/1672.110.0.1 to 72.110.255.25472.110.255.25565,534
11272.111.0.0/1672.111.0.1 to 72.111.255.25472.111.255.25565,534
11372.112.0.0/1672.112.0.1 to 72.112.255.25472.112.255.25565,534
11472.113.0.0/1672.113.0.1 to 72.113.255.25472.113.255.25565,534
11572.114.0.0/1672.114.0.1 to 72.114.255.25472.114.255.25565,534
11672.115.0.0/1672.115.0.1 to 72.115.255.25472.115.255.25565,534
11772.116.0.0/1672.116.0.1 to 72.116.255.25472.116.255.25565,534
11872.117.0.0/1672.117.0.1 to 72.117.255.25472.117.255.25565,534
11972.118.0.0/1672.118.0.1 to 72.118.255.25472.118.255.25565,534
12072.119.0.0/1672.119.0.1 to 72.119.255.25472.119.255.25565,534
12172.120.0.0/1672.120.0.1 to 72.120.255.25472.120.255.25565,534
12272.121.0.0/1672.121.0.1 to 72.121.255.25472.121.255.25565,534
12372.122.0.0/1672.122.0.1 to 72.122.255.25472.122.255.25565,534
12472.123.0.0/1672.123.0.1 to 72.123.255.25472.123.255.25565,534
12572.124.0.0/1672.124.0.1 to 72.124.255.25472.124.255.25565,534
12672.125.0.0/1672.125.0.1 to 72.125.255.25472.125.255.25565,534
12772.126.0.0/1672.126.0.1 to 72.126.255.25472.126.255.25565,534
12872.127.0.0/1672.127.0.1 to 72.127.255.25472.127.255.25565,534

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