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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.

Network11.167.128.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
11.167.128.0
Broadcast address
11.167.191.255
First usable
11.167.128.1
Last usable
11.167.191.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 0BA78000 · Integer 195526656 to 195543039
Reverse DNS zones
128.167.11.in-addr.arpa
129.167.11.in-addr.arpa
130.167.11.in-addr.arpa
131.167.11.in-addr.arpa
132.167.11.in-addr.arpa
133.167.11.in-addr.arpa
134.167.11.in-addr.arpa
135.167.11.in-addr.arpa
136.167.11.in-addr.arpa
137.167.11.in-addr.arpa
138.167.11.in-addr.arpa
139.167.11.in-addr.arpa
140.167.11.in-addr.arpa
141.167.11.in-addr.arpa
142.167.11.in-addr.arpa
143.167.11.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001011.10100111.10000000.0000000011.167.128.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00001011.10100111.10000000.0000000011.167.128.0
Broadcast00001011.10100111.10111111.1111111111.167.191.255
Split into smaller subnets/25
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

11.167.128.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
111.167.128.0/2511.167.128.1 to 11.167.128.12611.167.128.127126
211.167.128.128/2511.167.128.129 to 11.167.128.25411.167.128.255126
311.167.129.0/2511.167.129.1 to 11.167.129.12611.167.129.127126
411.167.129.128/2511.167.129.129 to 11.167.129.25411.167.129.255126
511.167.130.0/2511.167.130.1 to 11.167.130.12611.167.130.127126
611.167.130.128/2511.167.130.129 to 11.167.130.25411.167.130.255126
711.167.131.0/2511.167.131.1 to 11.167.131.12611.167.131.127126
811.167.131.128/2511.167.131.129 to 11.167.131.25411.167.131.255126
911.167.132.0/2511.167.132.1 to 11.167.132.12611.167.132.127126
1011.167.132.128/2511.167.132.129 to 11.167.132.25411.167.132.255126
1111.167.133.0/2511.167.133.1 to 11.167.133.12611.167.133.127126
1211.167.133.128/2511.167.133.129 to 11.167.133.25411.167.133.255126
1311.167.134.0/2511.167.134.1 to 11.167.134.12611.167.134.127126
1411.167.134.128/2511.167.134.129 to 11.167.134.25411.167.134.255126
1511.167.135.0/2511.167.135.1 to 11.167.135.12611.167.135.127126
1611.167.135.128/2511.167.135.129 to 11.167.135.25411.167.135.255126
1711.167.136.0/2511.167.136.1 to 11.167.136.12611.167.136.127126
1811.167.136.128/2511.167.136.129 to 11.167.136.25411.167.136.255126
1911.167.137.0/2511.167.137.1 to 11.167.137.12611.167.137.127126
2011.167.137.128/2511.167.137.129 to 11.167.137.25411.167.137.255126
2111.167.138.0/2511.167.138.1 to 11.167.138.12611.167.138.127126
2211.167.138.128/2511.167.138.129 to 11.167.138.25411.167.138.255126
2311.167.139.0/2511.167.139.1 to 11.167.139.12611.167.139.127126
2411.167.139.128/2511.167.139.129 to 11.167.139.25411.167.139.255126
2511.167.140.0/2511.167.140.1 to 11.167.140.12611.167.140.127126
2611.167.140.128/2511.167.140.129 to 11.167.140.25411.167.140.255126
2711.167.141.0/2511.167.141.1 to 11.167.141.12611.167.141.127126
2811.167.141.128/2511.167.141.129 to 11.167.141.25411.167.141.255126
2911.167.142.0/2511.167.142.1 to 11.167.142.12611.167.142.127126
3011.167.142.128/2511.167.142.129 to 11.167.142.25411.167.142.255126
3111.167.143.0/2511.167.143.1 to 11.167.143.12611.167.143.127126
3211.167.143.128/2511.167.143.129 to 11.167.143.25411.167.143.255126
3311.167.144.0/2511.167.144.1 to 11.167.144.12611.167.144.127126
3411.167.144.128/2511.167.144.129 to 11.167.144.25411.167.144.255126
3511.167.145.0/2511.167.145.1 to 11.167.145.12611.167.145.127126
3611.167.145.128/2511.167.145.129 to 11.167.145.25411.167.145.255126
3711.167.146.0/2511.167.146.1 to 11.167.146.12611.167.146.127126
3811.167.146.128/2511.167.146.129 to 11.167.146.25411.167.146.255126
3911.167.147.0/2511.167.147.1 to 11.167.147.12611.167.147.127126
4011.167.147.128/2511.167.147.129 to 11.167.147.25411.167.147.255126
4111.167.148.0/2511.167.148.1 to 11.167.148.12611.167.148.127126
4211.167.148.128/2511.167.148.129 to 11.167.148.25411.167.148.255126
4311.167.149.0/2511.167.149.1 to 11.167.149.12611.167.149.127126
4411.167.149.128/2511.167.149.129 to 11.167.149.25411.167.149.255126
4511.167.150.0/2511.167.150.1 to 11.167.150.12611.167.150.127126
4611.167.150.128/2511.167.150.129 to 11.167.150.25411.167.150.255126
4711.167.151.0/2511.167.151.1 to 11.167.151.12611.167.151.127126
4811.167.151.128/2511.167.151.129 to 11.167.151.25411.167.151.255126
4911.167.152.0/2511.167.152.1 to 11.167.152.12611.167.152.127126
5011.167.152.128/2511.167.152.129 to 11.167.152.25411.167.152.255126
5111.167.153.0/2511.167.153.1 to 11.167.153.12611.167.153.127126
5211.167.153.128/2511.167.153.129 to 11.167.153.25411.167.153.255126
5311.167.154.0/2511.167.154.1 to 11.167.154.12611.167.154.127126
5411.167.154.128/2511.167.154.129 to 11.167.154.25411.167.154.255126
5511.167.155.0/2511.167.155.1 to 11.167.155.12611.167.155.127126
5611.167.155.128/2511.167.155.129 to 11.167.155.25411.167.155.255126
5711.167.156.0/2511.167.156.1 to 11.167.156.12611.167.156.127126
5811.167.156.128/2511.167.156.129 to 11.167.156.25411.167.156.255126
5911.167.157.0/2511.167.157.1 to 11.167.157.12611.167.157.127126
6011.167.157.128/2511.167.157.129 to 11.167.157.25411.167.157.255126
6111.167.158.0/2511.167.158.1 to 11.167.158.12611.167.158.127126
6211.167.158.128/2511.167.158.129 to 11.167.158.25411.167.158.255126
6311.167.159.0/2511.167.159.1 to 11.167.159.12611.167.159.127126
6411.167.159.128/2511.167.159.129 to 11.167.159.25411.167.159.255126
6511.167.160.0/2511.167.160.1 to 11.167.160.12611.167.160.127126
6611.167.160.128/2511.167.160.129 to 11.167.160.25411.167.160.255126
6711.167.161.0/2511.167.161.1 to 11.167.161.12611.167.161.127126
6811.167.161.128/2511.167.161.129 to 11.167.161.25411.167.161.255126
6911.167.162.0/2511.167.162.1 to 11.167.162.12611.167.162.127126
7011.167.162.128/2511.167.162.129 to 11.167.162.25411.167.162.255126
7111.167.163.0/2511.167.163.1 to 11.167.163.12611.167.163.127126
7211.167.163.128/2511.167.163.129 to 11.167.163.25411.167.163.255126
7311.167.164.0/2511.167.164.1 to 11.167.164.12611.167.164.127126
7411.167.164.128/2511.167.164.129 to 11.167.164.25411.167.164.255126
7511.167.165.0/2511.167.165.1 to 11.167.165.12611.167.165.127126
7611.167.165.128/2511.167.165.129 to 11.167.165.25411.167.165.255126
7711.167.166.0/2511.167.166.1 to 11.167.166.12611.167.166.127126
7811.167.166.128/2511.167.166.129 to 11.167.166.25411.167.166.255126
7911.167.167.0/2511.167.167.1 to 11.167.167.12611.167.167.127126
8011.167.167.128/2511.167.167.129 to 11.167.167.25411.167.167.255126
8111.167.168.0/2511.167.168.1 to 11.167.168.12611.167.168.127126
8211.167.168.128/2511.167.168.129 to 11.167.168.25411.167.168.255126
8311.167.169.0/2511.167.169.1 to 11.167.169.12611.167.169.127126
8411.167.169.128/2511.167.169.129 to 11.167.169.25411.167.169.255126
8511.167.170.0/2511.167.170.1 to 11.167.170.12611.167.170.127126
8611.167.170.128/2511.167.170.129 to 11.167.170.25411.167.170.255126
8711.167.171.0/2511.167.171.1 to 11.167.171.12611.167.171.127126
8811.167.171.128/2511.167.171.129 to 11.167.171.25411.167.171.255126
8911.167.172.0/2511.167.172.1 to 11.167.172.12611.167.172.127126
9011.167.172.128/2511.167.172.129 to 11.167.172.25411.167.172.255126
9111.167.173.0/2511.167.173.1 to 11.167.173.12611.167.173.127126
9211.167.173.128/2511.167.173.129 to 11.167.173.25411.167.173.255126
9311.167.174.0/2511.167.174.1 to 11.167.174.12611.167.174.127126
9411.167.174.128/2511.167.174.129 to 11.167.174.25411.167.174.255126
9511.167.175.0/2511.167.175.1 to 11.167.175.12611.167.175.127126
9611.167.175.128/2511.167.175.129 to 11.167.175.25411.167.175.255126
9711.167.176.0/2511.167.176.1 to 11.167.176.12611.167.176.127126
9811.167.176.128/2511.167.176.129 to 11.167.176.25411.167.176.255126
9911.167.177.0/2511.167.177.1 to 11.167.177.12611.167.177.127126
10011.167.177.128/2511.167.177.129 to 11.167.177.25411.167.177.255126
10111.167.178.0/2511.167.178.1 to 11.167.178.12611.167.178.127126
10211.167.178.128/2511.167.178.129 to 11.167.178.25411.167.178.255126
10311.167.179.0/2511.167.179.1 to 11.167.179.12611.167.179.127126
10411.167.179.128/2511.167.179.129 to 11.167.179.25411.167.179.255126
10511.167.180.0/2511.167.180.1 to 11.167.180.12611.167.180.127126
10611.167.180.128/2511.167.180.129 to 11.167.180.25411.167.180.255126
10711.167.181.0/2511.167.181.1 to 11.167.181.12611.167.181.127126
10811.167.181.128/2511.167.181.129 to 11.167.181.25411.167.181.255126
10911.167.182.0/2511.167.182.1 to 11.167.182.12611.167.182.127126
11011.167.182.128/2511.167.182.129 to 11.167.182.25411.167.182.255126
11111.167.183.0/2511.167.183.1 to 11.167.183.12611.167.183.127126
11211.167.183.128/2511.167.183.129 to 11.167.183.25411.167.183.255126
11311.167.184.0/2511.167.184.1 to 11.167.184.12611.167.184.127126
11411.167.184.128/2511.167.184.129 to 11.167.184.25411.167.184.255126
11511.167.185.0/2511.167.185.1 to 11.167.185.12611.167.185.127126
11611.167.185.128/2511.167.185.129 to 11.167.185.25411.167.185.255126
11711.167.186.0/2511.167.186.1 to 11.167.186.12611.167.186.127126
11811.167.186.128/2511.167.186.129 to 11.167.186.25411.167.186.255126
11911.167.187.0/2511.167.187.1 to 11.167.187.12611.167.187.127126
12011.167.187.128/2511.167.187.129 to 11.167.187.25411.167.187.255126
12111.167.188.0/2511.167.188.1 to 11.167.188.12611.167.188.127126
12211.167.188.128/2511.167.188.129 to 11.167.188.25411.167.188.255126
12311.167.189.0/2511.167.189.1 to 11.167.189.12611.167.189.127126
12411.167.189.128/2511.167.189.129 to 11.167.189.25411.167.189.255126
12511.167.190.0/2511.167.190.1 to 11.167.190.12611.167.190.127126
12611.167.190.128/2511.167.190.129 to 11.167.190.25411.167.190.255126
12711.167.191.0/2511.167.191.1 to 11.167.191.12611.167.191.127126
12811.167.191.128/2511.167.191.129 to 11.167.191.25411.167.191.255126

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.