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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.

Network11.76.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
11.76.0.0
Broadcast address
11.77.255.255
First usable
11.76.0.1
Last usable
11.77.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 0B4C0000 · Integer 189530112 to 189661183
Reverse DNS zones
76.11.in-addr.arpa
77.11.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001011.01001100.00000000.0000000011.76.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00001011.01001100.00000000.0000000011.76.0.0
Broadcast00001011.01001101.11111111.1111111111.77.255.255
Split into smaller subnets/22
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

11.76.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
111.76.0.0/2211.76.0.1 to 11.76.3.25411.76.3.2551,022
211.76.4.0/2211.76.4.1 to 11.76.7.25411.76.7.2551,022
311.76.8.0/2211.76.8.1 to 11.76.11.25411.76.11.2551,022
411.76.12.0/2211.76.12.1 to 11.76.15.25411.76.15.2551,022
511.76.16.0/2211.76.16.1 to 11.76.19.25411.76.19.2551,022
611.76.20.0/2211.76.20.1 to 11.76.23.25411.76.23.2551,022
711.76.24.0/2211.76.24.1 to 11.76.27.25411.76.27.2551,022
811.76.28.0/2211.76.28.1 to 11.76.31.25411.76.31.2551,022
911.76.32.0/2211.76.32.1 to 11.76.35.25411.76.35.2551,022
1011.76.36.0/2211.76.36.1 to 11.76.39.25411.76.39.2551,022
1111.76.40.0/2211.76.40.1 to 11.76.43.25411.76.43.2551,022
1211.76.44.0/2211.76.44.1 to 11.76.47.25411.76.47.2551,022
1311.76.48.0/2211.76.48.1 to 11.76.51.25411.76.51.2551,022
1411.76.52.0/2211.76.52.1 to 11.76.55.25411.76.55.2551,022
1511.76.56.0/2211.76.56.1 to 11.76.59.25411.76.59.2551,022
1611.76.60.0/2211.76.60.1 to 11.76.63.25411.76.63.2551,022
1711.76.64.0/2211.76.64.1 to 11.76.67.25411.76.67.2551,022
1811.76.68.0/2211.76.68.1 to 11.76.71.25411.76.71.2551,022
1911.76.72.0/2211.76.72.1 to 11.76.75.25411.76.75.2551,022
2011.76.76.0/2211.76.76.1 to 11.76.79.25411.76.79.2551,022
2111.76.80.0/2211.76.80.1 to 11.76.83.25411.76.83.2551,022
2211.76.84.0/2211.76.84.1 to 11.76.87.25411.76.87.2551,022
2311.76.88.0/2211.76.88.1 to 11.76.91.25411.76.91.2551,022
2411.76.92.0/2211.76.92.1 to 11.76.95.25411.76.95.2551,022
2511.76.96.0/2211.76.96.1 to 11.76.99.25411.76.99.2551,022
2611.76.100.0/2211.76.100.1 to 11.76.103.25411.76.103.2551,022
2711.76.104.0/2211.76.104.1 to 11.76.107.25411.76.107.2551,022
2811.76.108.0/2211.76.108.1 to 11.76.111.25411.76.111.2551,022
2911.76.112.0/2211.76.112.1 to 11.76.115.25411.76.115.2551,022
3011.76.116.0/2211.76.116.1 to 11.76.119.25411.76.119.2551,022
3111.76.120.0/2211.76.120.1 to 11.76.123.25411.76.123.2551,022
3211.76.124.0/2211.76.124.1 to 11.76.127.25411.76.127.2551,022
3311.76.128.0/2211.76.128.1 to 11.76.131.25411.76.131.2551,022
3411.76.132.0/2211.76.132.1 to 11.76.135.25411.76.135.2551,022
3511.76.136.0/2211.76.136.1 to 11.76.139.25411.76.139.2551,022
3611.76.140.0/2211.76.140.1 to 11.76.143.25411.76.143.2551,022
3711.76.144.0/2211.76.144.1 to 11.76.147.25411.76.147.2551,022
3811.76.148.0/2211.76.148.1 to 11.76.151.25411.76.151.2551,022
3911.76.152.0/2211.76.152.1 to 11.76.155.25411.76.155.2551,022
4011.76.156.0/2211.76.156.1 to 11.76.159.25411.76.159.2551,022
4111.76.160.0/2211.76.160.1 to 11.76.163.25411.76.163.2551,022
4211.76.164.0/2211.76.164.1 to 11.76.167.25411.76.167.2551,022
4311.76.168.0/2211.76.168.1 to 11.76.171.25411.76.171.2551,022
4411.76.172.0/2211.76.172.1 to 11.76.175.25411.76.175.2551,022
4511.76.176.0/2211.76.176.1 to 11.76.179.25411.76.179.2551,022
4611.76.180.0/2211.76.180.1 to 11.76.183.25411.76.183.2551,022
4711.76.184.0/2211.76.184.1 to 11.76.187.25411.76.187.2551,022
4811.76.188.0/2211.76.188.1 to 11.76.191.25411.76.191.2551,022
4911.76.192.0/2211.76.192.1 to 11.76.195.25411.76.195.2551,022
5011.76.196.0/2211.76.196.1 to 11.76.199.25411.76.199.2551,022
5111.76.200.0/2211.76.200.1 to 11.76.203.25411.76.203.2551,022
5211.76.204.0/2211.76.204.1 to 11.76.207.25411.76.207.2551,022
5311.76.208.0/2211.76.208.1 to 11.76.211.25411.76.211.2551,022
5411.76.212.0/2211.76.212.1 to 11.76.215.25411.76.215.2551,022
5511.76.216.0/2211.76.216.1 to 11.76.219.25411.76.219.2551,022
5611.76.220.0/2211.76.220.1 to 11.76.223.25411.76.223.2551,022
5711.76.224.0/2211.76.224.1 to 11.76.227.25411.76.227.2551,022
5811.76.228.0/2211.76.228.1 to 11.76.231.25411.76.231.2551,022
5911.76.232.0/2211.76.232.1 to 11.76.235.25411.76.235.2551,022
6011.76.236.0/2211.76.236.1 to 11.76.239.25411.76.239.2551,022
6111.76.240.0/2211.76.240.1 to 11.76.243.25411.76.243.2551,022
6211.76.244.0/2211.76.244.1 to 11.76.247.25411.76.247.2551,022
6311.76.248.0/2211.76.248.1 to 11.76.251.25411.76.251.2551,022
6411.76.252.0/2211.76.252.1 to 11.76.255.25411.76.255.2551,022
6511.77.0.0/2211.77.0.1 to 11.77.3.25411.77.3.2551,022
6611.77.4.0/2211.77.4.1 to 11.77.7.25411.77.7.2551,022
6711.77.8.0/2211.77.8.1 to 11.77.11.25411.77.11.2551,022
6811.77.12.0/2211.77.12.1 to 11.77.15.25411.77.15.2551,022
6911.77.16.0/2211.77.16.1 to 11.77.19.25411.77.19.2551,022
7011.77.20.0/2211.77.20.1 to 11.77.23.25411.77.23.2551,022
7111.77.24.0/2211.77.24.1 to 11.77.27.25411.77.27.2551,022
7211.77.28.0/2211.77.28.1 to 11.77.31.25411.77.31.2551,022
7311.77.32.0/2211.77.32.1 to 11.77.35.25411.77.35.2551,022
7411.77.36.0/2211.77.36.1 to 11.77.39.25411.77.39.2551,022
7511.77.40.0/2211.77.40.1 to 11.77.43.25411.77.43.2551,022
7611.77.44.0/2211.77.44.1 to 11.77.47.25411.77.47.2551,022
7711.77.48.0/2211.77.48.1 to 11.77.51.25411.77.51.2551,022
7811.77.52.0/2211.77.52.1 to 11.77.55.25411.77.55.2551,022
7911.77.56.0/2211.77.56.1 to 11.77.59.25411.77.59.2551,022
8011.77.60.0/2211.77.60.1 to 11.77.63.25411.77.63.2551,022
8111.77.64.0/2211.77.64.1 to 11.77.67.25411.77.67.2551,022
8211.77.68.0/2211.77.68.1 to 11.77.71.25411.77.71.2551,022
8311.77.72.0/2211.77.72.1 to 11.77.75.25411.77.75.2551,022
8411.77.76.0/2211.77.76.1 to 11.77.79.25411.77.79.2551,022
8511.77.80.0/2211.77.80.1 to 11.77.83.25411.77.83.2551,022
8611.77.84.0/2211.77.84.1 to 11.77.87.25411.77.87.2551,022
8711.77.88.0/2211.77.88.1 to 11.77.91.25411.77.91.2551,022
8811.77.92.0/2211.77.92.1 to 11.77.95.25411.77.95.2551,022
8911.77.96.0/2211.77.96.1 to 11.77.99.25411.77.99.2551,022
9011.77.100.0/2211.77.100.1 to 11.77.103.25411.77.103.2551,022
9111.77.104.0/2211.77.104.1 to 11.77.107.25411.77.107.2551,022
9211.77.108.0/2211.77.108.1 to 11.77.111.25411.77.111.2551,022
9311.77.112.0/2211.77.112.1 to 11.77.115.25411.77.115.2551,022
9411.77.116.0/2211.77.116.1 to 11.77.119.25411.77.119.2551,022
9511.77.120.0/2211.77.120.1 to 11.77.123.25411.77.123.2551,022
9611.77.124.0/2211.77.124.1 to 11.77.127.25411.77.127.2551,022
9711.77.128.0/2211.77.128.1 to 11.77.131.25411.77.131.2551,022
9811.77.132.0/2211.77.132.1 to 11.77.135.25411.77.135.2551,022
9911.77.136.0/2211.77.136.1 to 11.77.139.25411.77.139.2551,022
10011.77.140.0/2211.77.140.1 to 11.77.143.25411.77.143.2551,022
10111.77.144.0/2211.77.144.1 to 11.77.147.25411.77.147.2551,022
10211.77.148.0/2211.77.148.1 to 11.77.151.25411.77.151.2551,022
10311.77.152.0/2211.77.152.1 to 11.77.155.25411.77.155.2551,022
10411.77.156.0/2211.77.156.1 to 11.77.159.25411.77.159.2551,022
10511.77.160.0/2211.77.160.1 to 11.77.163.25411.77.163.2551,022
10611.77.164.0/2211.77.164.1 to 11.77.167.25411.77.167.2551,022
10711.77.168.0/2211.77.168.1 to 11.77.171.25411.77.171.2551,022
10811.77.172.0/2211.77.172.1 to 11.77.175.25411.77.175.2551,022
10911.77.176.0/2211.77.176.1 to 11.77.179.25411.77.179.2551,022
11011.77.180.0/2211.77.180.1 to 11.77.183.25411.77.183.2551,022
11111.77.184.0/2211.77.184.1 to 11.77.187.25411.77.187.2551,022
11211.77.188.0/2211.77.188.1 to 11.77.191.25411.77.191.2551,022
11311.77.192.0/2211.77.192.1 to 11.77.195.25411.77.195.2551,022
11411.77.196.0/2211.77.196.1 to 11.77.199.25411.77.199.2551,022
11511.77.200.0/2211.77.200.1 to 11.77.203.25411.77.203.2551,022
11611.77.204.0/2211.77.204.1 to 11.77.207.25411.77.207.2551,022
11711.77.208.0/2211.77.208.1 to 11.77.211.25411.77.211.2551,022
11811.77.212.0/2211.77.212.1 to 11.77.215.25411.77.215.2551,022
11911.77.216.0/2211.77.216.1 to 11.77.219.25411.77.219.2551,022
12011.77.220.0/2211.77.220.1 to 11.77.223.25411.77.223.2551,022
12111.77.224.0/2211.77.224.1 to 11.77.227.25411.77.227.2551,022
12211.77.228.0/2211.77.228.1 to 11.77.231.25411.77.231.2551,022
12311.77.232.0/2211.77.232.1 to 11.77.235.25411.77.235.2551,022
12411.77.236.0/2211.77.236.1 to 11.77.239.25411.77.239.2551,022
12511.77.240.0/2211.77.240.1 to 11.77.243.25411.77.243.2551,022
12611.77.244.0/2211.77.244.1 to 11.77.247.25411.77.247.2551,022
12711.77.248.0/2211.77.248.1 to 11.77.251.25411.77.251.2551,022
12811.77.252.0/2211.77.252.1 to 11.77.255.25411.77.255.2551,022

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.