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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.

Network17.224.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
17.224.0.0
Broadcast address
17.255.255.255
First usable
17.224.0.1
Last usable
17.255.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 11E00000 · Integer 299892736 to 301989887
Reverse DNS zones
224.17.in-addr.arpa
225.17.in-addr.arpa
226.17.in-addr.arpa
227.17.in-addr.arpa
228.17.in-addr.arpa
229.17.in-addr.arpa
230.17.in-addr.arpa
231.17.in-addr.arpa
232.17.in-addr.arpa
233.17.in-addr.arpa
234.17.in-addr.arpa
235.17.in-addr.arpa
236.17.in-addr.arpa
237.17.in-addr.arpa
238.17.in-addr.arpa
239.17.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010001.11100000.00000000.0000000017.224.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00010001.11100000.00000000.0000000017.224.0.0
Broadcast00010001.11111111.11111111.1111111117.255.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

17.224.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
117.224.0.0/1817.224.0.1 to 17.224.63.25417.224.63.25516,382
217.224.64.0/1817.224.64.1 to 17.224.127.25417.224.127.25516,382
317.224.128.0/1817.224.128.1 to 17.224.191.25417.224.191.25516,382
417.224.192.0/1817.224.192.1 to 17.224.255.25417.224.255.25516,382
517.225.0.0/1817.225.0.1 to 17.225.63.25417.225.63.25516,382
617.225.64.0/1817.225.64.1 to 17.225.127.25417.225.127.25516,382
717.225.128.0/1817.225.128.1 to 17.225.191.25417.225.191.25516,382
817.225.192.0/1817.225.192.1 to 17.225.255.25417.225.255.25516,382
917.226.0.0/1817.226.0.1 to 17.226.63.25417.226.63.25516,382
1017.226.64.0/1817.226.64.1 to 17.226.127.25417.226.127.25516,382
1117.226.128.0/1817.226.128.1 to 17.226.191.25417.226.191.25516,382
1217.226.192.0/1817.226.192.1 to 17.226.255.25417.226.255.25516,382
1317.227.0.0/1817.227.0.1 to 17.227.63.25417.227.63.25516,382
1417.227.64.0/1817.227.64.1 to 17.227.127.25417.227.127.25516,382
1517.227.128.0/1817.227.128.1 to 17.227.191.25417.227.191.25516,382
1617.227.192.0/1817.227.192.1 to 17.227.255.25417.227.255.25516,382
1717.228.0.0/1817.228.0.1 to 17.228.63.25417.228.63.25516,382
1817.228.64.0/1817.228.64.1 to 17.228.127.25417.228.127.25516,382
1917.228.128.0/1817.228.128.1 to 17.228.191.25417.228.191.25516,382
2017.228.192.0/1817.228.192.1 to 17.228.255.25417.228.255.25516,382
2117.229.0.0/1817.229.0.1 to 17.229.63.25417.229.63.25516,382
2217.229.64.0/1817.229.64.1 to 17.229.127.25417.229.127.25516,382
2317.229.128.0/1817.229.128.1 to 17.229.191.25417.229.191.25516,382
2417.229.192.0/1817.229.192.1 to 17.229.255.25417.229.255.25516,382
2517.230.0.0/1817.230.0.1 to 17.230.63.25417.230.63.25516,382
2617.230.64.0/1817.230.64.1 to 17.230.127.25417.230.127.25516,382
2717.230.128.0/1817.230.128.1 to 17.230.191.25417.230.191.25516,382
2817.230.192.0/1817.230.192.1 to 17.230.255.25417.230.255.25516,382
2917.231.0.0/1817.231.0.1 to 17.231.63.25417.231.63.25516,382
3017.231.64.0/1817.231.64.1 to 17.231.127.25417.231.127.25516,382
3117.231.128.0/1817.231.128.1 to 17.231.191.25417.231.191.25516,382
3217.231.192.0/1817.231.192.1 to 17.231.255.25417.231.255.25516,382
3317.232.0.0/1817.232.0.1 to 17.232.63.25417.232.63.25516,382
3417.232.64.0/1817.232.64.1 to 17.232.127.25417.232.127.25516,382
3517.232.128.0/1817.232.128.1 to 17.232.191.25417.232.191.25516,382
3617.232.192.0/1817.232.192.1 to 17.232.255.25417.232.255.25516,382
3717.233.0.0/1817.233.0.1 to 17.233.63.25417.233.63.25516,382
3817.233.64.0/1817.233.64.1 to 17.233.127.25417.233.127.25516,382
3917.233.128.0/1817.233.128.1 to 17.233.191.25417.233.191.25516,382
4017.233.192.0/1817.233.192.1 to 17.233.255.25417.233.255.25516,382
4117.234.0.0/1817.234.0.1 to 17.234.63.25417.234.63.25516,382
4217.234.64.0/1817.234.64.1 to 17.234.127.25417.234.127.25516,382
4317.234.128.0/1817.234.128.1 to 17.234.191.25417.234.191.25516,382
4417.234.192.0/1817.234.192.1 to 17.234.255.25417.234.255.25516,382
4517.235.0.0/1817.235.0.1 to 17.235.63.25417.235.63.25516,382
4617.235.64.0/1817.235.64.1 to 17.235.127.25417.235.127.25516,382
4717.235.128.0/1817.235.128.1 to 17.235.191.25417.235.191.25516,382
4817.235.192.0/1817.235.192.1 to 17.235.255.25417.235.255.25516,382
4917.236.0.0/1817.236.0.1 to 17.236.63.25417.236.63.25516,382
5017.236.64.0/1817.236.64.1 to 17.236.127.25417.236.127.25516,382
5117.236.128.0/1817.236.128.1 to 17.236.191.25417.236.191.25516,382
5217.236.192.0/1817.236.192.1 to 17.236.255.25417.236.255.25516,382
5317.237.0.0/1817.237.0.1 to 17.237.63.25417.237.63.25516,382
5417.237.64.0/1817.237.64.1 to 17.237.127.25417.237.127.25516,382
5517.237.128.0/1817.237.128.1 to 17.237.191.25417.237.191.25516,382
5617.237.192.0/1817.237.192.1 to 17.237.255.25417.237.255.25516,382
5717.238.0.0/1817.238.0.1 to 17.238.63.25417.238.63.25516,382
5817.238.64.0/1817.238.64.1 to 17.238.127.25417.238.127.25516,382
5917.238.128.0/1817.238.128.1 to 17.238.191.25417.238.191.25516,382
6017.238.192.0/1817.238.192.1 to 17.238.255.25417.238.255.25516,382
6117.239.0.0/1817.239.0.1 to 17.239.63.25417.239.63.25516,382
6217.239.64.0/1817.239.64.1 to 17.239.127.25417.239.127.25516,382
6317.239.128.0/1817.239.128.1 to 17.239.191.25417.239.191.25516,382
6417.239.192.0/1817.239.192.1 to 17.239.255.25417.239.255.25516,382
6517.240.0.0/1817.240.0.1 to 17.240.63.25417.240.63.25516,382
6617.240.64.0/1817.240.64.1 to 17.240.127.25417.240.127.25516,382
6717.240.128.0/1817.240.128.1 to 17.240.191.25417.240.191.25516,382
6817.240.192.0/1817.240.192.1 to 17.240.255.25417.240.255.25516,382
6917.241.0.0/1817.241.0.1 to 17.241.63.25417.241.63.25516,382
7017.241.64.0/1817.241.64.1 to 17.241.127.25417.241.127.25516,382
7117.241.128.0/1817.241.128.1 to 17.241.191.25417.241.191.25516,382
7217.241.192.0/1817.241.192.1 to 17.241.255.25417.241.255.25516,382
7317.242.0.0/1817.242.0.1 to 17.242.63.25417.242.63.25516,382
7417.242.64.0/1817.242.64.1 to 17.242.127.25417.242.127.25516,382
7517.242.128.0/1817.242.128.1 to 17.242.191.25417.242.191.25516,382
7617.242.192.0/1817.242.192.1 to 17.242.255.25417.242.255.25516,382
7717.243.0.0/1817.243.0.1 to 17.243.63.25417.243.63.25516,382
7817.243.64.0/1817.243.64.1 to 17.243.127.25417.243.127.25516,382
7917.243.128.0/1817.243.128.1 to 17.243.191.25417.243.191.25516,382
8017.243.192.0/1817.243.192.1 to 17.243.255.25417.243.255.25516,382
8117.244.0.0/1817.244.0.1 to 17.244.63.25417.244.63.25516,382
8217.244.64.0/1817.244.64.1 to 17.244.127.25417.244.127.25516,382
8317.244.128.0/1817.244.128.1 to 17.244.191.25417.244.191.25516,382
8417.244.192.0/1817.244.192.1 to 17.244.255.25417.244.255.25516,382
8517.245.0.0/1817.245.0.1 to 17.245.63.25417.245.63.25516,382
8617.245.64.0/1817.245.64.1 to 17.245.127.25417.245.127.25516,382
8717.245.128.0/1817.245.128.1 to 17.245.191.25417.245.191.25516,382
8817.245.192.0/1817.245.192.1 to 17.245.255.25417.245.255.25516,382
8917.246.0.0/1817.246.0.1 to 17.246.63.25417.246.63.25516,382
9017.246.64.0/1817.246.64.1 to 17.246.127.25417.246.127.25516,382
9117.246.128.0/1817.246.128.1 to 17.246.191.25417.246.191.25516,382
9217.246.192.0/1817.246.192.1 to 17.246.255.25417.246.255.25516,382
9317.247.0.0/1817.247.0.1 to 17.247.63.25417.247.63.25516,382
9417.247.64.0/1817.247.64.1 to 17.247.127.25417.247.127.25516,382
9517.247.128.0/1817.247.128.1 to 17.247.191.25417.247.191.25516,382
9617.247.192.0/1817.247.192.1 to 17.247.255.25417.247.255.25516,382
9717.248.0.0/1817.248.0.1 to 17.248.63.25417.248.63.25516,382
9817.248.64.0/1817.248.64.1 to 17.248.127.25417.248.127.25516,382
9917.248.128.0/1817.248.128.1 to 17.248.191.25417.248.191.25516,382
10017.248.192.0/1817.248.192.1 to 17.248.255.25417.248.255.25516,382
10117.249.0.0/1817.249.0.1 to 17.249.63.25417.249.63.25516,382
10217.249.64.0/1817.249.64.1 to 17.249.127.25417.249.127.25516,382
10317.249.128.0/1817.249.128.1 to 17.249.191.25417.249.191.25516,382
10417.249.192.0/1817.249.192.1 to 17.249.255.25417.249.255.25516,382
10517.250.0.0/1817.250.0.1 to 17.250.63.25417.250.63.25516,382
10617.250.64.0/1817.250.64.1 to 17.250.127.25417.250.127.25516,382
10717.250.128.0/1817.250.128.1 to 17.250.191.25417.250.191.25516,382
10817.250.192.0/1817.250.192.1 to 17.250.255.25417.250.255.25516,382
10917.251.0.0/1817.251.0.1 to 17.251.63.25417.251.63.25516,382
11017.251.64.0/1817.251.64.1 to 17.251.127.25417.251.127.25516,382
11117.251.128.0/1817.251.128.1 to 17.251.191.25417.251.191.25516,382
11217.251.192.0/1817.251.192.1 to 17.251.255.25417.251.255.25516,382
11317.252.0.0/1817.252.0.1 to 17.252.63.25417.252.63.25516,382
11417.252.64.0/1817.252.64.1 to 17.252.127.25417.252.127.25516,382
11517.252.128.0/1817.252.128.1 to 17.252.191.25417.252.191.25516,382
11617.252.192.0/1817.252.192.1 to 17.252.255.25417.252.255.25516,382
11717.253.0.0/1817.253.0.1 to 17.253.63.25417.253.63.25516,382
11817.253.64.0/1817.253.64.1 to 17.253.127.25417.253.127.25516,382
11917.253.128.0/1817.253.128.1 to 17.253.191.25417.253.191.25516,382
12017.253.192.0/1817.253.192.1 to 17.253.255.25417.253.255.25516,382
12117.254.0.0/1817.254.0.1 to 17.254.63.25417.254.63.25516,382
12217.254.64.0/1817.254.64.1 to 17.254.127.25417.254.127.25516,382
12317.254.128.0/1817.254.128.1 to 17.254.191.25417.254.191.25516,382
12417.254.192.0/1817.254.192.1 to 17.254.255.25417.254.255.25516,382
12517.255.0.0/1817.255.0.1 to 17.255.63.25417.255.63.25516,382
12617.255.64.0/1817.255.64.1 to 17.255.127.25417.255.127.25516,382
12717.255.128.0/1817.255.128.1 to 17.255.191.25417.255.191.25516,382
12817.255.192.0/1817.255.192.1 to 17.255.255.25417.255.255.25516,382

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.