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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.

Network88.76.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
88.76.0.0
Broadcast address
88.77.255.255
First usable
88.76.0.1
Last usable
88.77.255.254
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 584C0000 · Integer 1481375744 to 1481506815
Reverse DNS zones
76.88.in-addr.arpa
77.88.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
Address01011000.01001100.00000000.0000000088.76.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01011000.01001100.00000000.0000000088.76.0.0
Broadcast01011000.01001101.11111111.1111111188.77.255.255
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)

88.76.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
188.76.0.0/2288.76.0.1 to 88.76.3.25488.76.3.2551,022
288.76.4.0/2288.76.4.1 to 88.76.7.25488.76.7.2551,022
388.76.8.0/2288.76.8.1 to 88.76.11.25488.76.11.2551,022
488.76.12.0/2288.76.12.1 to 88.76.15.25488.76.15.2551,022
588.76.16.0/2288.76.16.1 to 88.76.19.25488.76.19.2551,022
688.76.20.0/2288.76.20.1 to 88.76.23.25488.76.23.2551,022
788.76.24.0/2288.76.24.1 to 88.76.27.25488.76.27.2551,022
888.76.28.0/2288.76.28.1 to 88.76.31.25488.76.31.2551,022
988.76.32.0/2288.76.32.1 to 88.76.35.25488.76.35.2551,022
1088.76.36.0/2288.76.36.1 to 88.76.39.25488.76.39.2551,022
1188.76.40.0/2288.76.40.1 to 88.76.43.25488.76.43.2551,022
1288.76.44.0/2288.76.44.1 to 88.76.47.25488.76.47.2551,022
1388.76.48.0/2288.76.48.1 to 88.76.51.25488.76.51.2551,022
1488.76.52.0/2288.76.52.1 to 88.76.55.25488.76.55.2551,022
1588.76.56.0/2288.76.56.1 to 88.76.59.25488.76.59.2551,022
1688.76.60.0/2288.76.60.1 to 88.76.63.25488.76.63.2551,022
1788.76.64.0/2288.76.64.1 to 88.76.67.25488.76.67.2551,022
1888.76.68.0/2288.76.68.1 to 88.76.71.25488.76.71.2551,022
1988.76.72.0/2288.76.72.1 to 88.76.75.25488.76.75.2551,022
2088.76.76.0/2288.76.76.1 to 88.76.79.25488.76.79.2551,022
2188.76.80.0/2288.76.80.1 to 88.76.83.25488.76.83.2551,022
2288.76.84.0/2288.76.84.1 to 88.76.87.25488.76.87.2551,022
2388.76.88.0/2288.76.88.1 to 88.76.91.25488.76.91.2551,022
2488.76.92.0/2288.76.92.1 to 88.76.95.25488.76.95.2551,022
2588.76.96.0/2288.76.96.1 to 88.76.99.25488.76.99.2551,022
2688.76.100.0/2288.76.100.1 to 88.76.103.25488.76.103.2551,022
2788.76.104.0/2288.76.104.1 to 88.76.107.25488.76.107.2551,022
2888.76.108.0/2288.76.108.1 to 88.76.111.25488.76.111.2551,022
2988.76.112.0/2288.76.112.1 to 88.76.115.25488.76.115.2551,022
3088.76.116.0/2288.76.116.1 to 88.76.119.25488.76.119.2551,022
3188.76.120.0/2288.76.120.1 to 88.76.123.25488.76.123.2551,022
3288.76.124.0/2288.76.124.1 to 88.76.127.25488.76.127.2551,022
3388.76.128.0/2288.76.128.1 to 88.76.131.25488.76.131.2551,022
3488.76.132.0/2288.76.132.1 to 88.76.135.25488.76.135.2551,022
3588.76.136.0/2288.76.136.1 to 88.76.139.25488.76.139.2551,022
3688.76.140.0/2288.76.140.1 to 88.76.143.25488.76.143.2551,022
3788.76.144.0/2288.76.144.1 to 88.76.147.25488.76.147.2551,022
3888.76.148.0/2288.76.148.1 to 88.76.151.25488.76.151.2551,022
3988.76.152.0/2288.76.152.1 to 88.76.155.25488.76.155.2551,022
4088.76.156.0/2288.76.156.1 to 88.76.159.25488.76.159.2551,022
4188.76.160.0/2288.76.160.1 to 88.76.163.25488.76.163.2551,022
4288.76.164.0/2288.76.164.1 to 88.76.167.25488.76.167.2551,022
4388.76.168.0/2288.76.168.1 to 88.76.171.25488.76.171.2551,022
4488.76.172.0/2288.76.172.1 to 88.76.175.25488.76.175.2551,022
4588.76.176.0/2288.76.176.1 to 88.76.179.25488.76.179.2551,022
4688.76.180.0/2288.76.180.1 to 88.76.183.25488.76.183.2551,022
4788.76.184.0/2288.76.184.1 to 88.76.187.25488.76.187.2551,022
4888.76.188.0/2288.76.188.1 to 88.76.191.25488.76.191.2551,022
4988.76.192.0/2288.76.192.1 to 88.76.195.25488.76.195.2551,022
5088.76.196.0/2288.76.196.1 to 88.76.199.25488.76.199.2551,022
5188.76.200.0/2288.76.200.1 to 88.76.203.25488.76.203.2551,022
5288.76.204.0/2288.76.204.1 to 88.76.207.25488.76.207.2551,022
5388.76.208.0/2288.76.208.1 to 88.76.211.25488.76.211.2551,022
5488.76.212.0/2288.76.212.1 to 88.76.215.25488.76.215.2551,022
5588.76.216.0/2288.76.216.1 to 88.76.219.25488.76.219.2551,022
5688.76.220.0/2288.76.220.1 to 88.76.223.25488.76.223.2551,022
5788.76.224.0/2288.76.224.1 to 88.76.227.25488.76.227.2551,022
5888.76.228.0/2288.76.228.1 to 88.76.231.25488.76.231.2551,022
5988.76.232.0/2288.76.232.1 to 88.76.235.25488.76.235.2551,022
6088.76.236.0/2288.76.236.1 to 88.76.239.25488.76.239.2551,022
6188.76.240.0/2288.76.240.1 to 88.76.243.25488.76.243.2551,022
6288.76.244.0/2288.76.244.1 to 88.76.247.25488.76.247.2551,022
6388.76.248.0/2288.76.248.1 to 88.76.251.25488.76.251.2551,022
6488.76.252.0/2288.76.252.1 to 88.76.255.25488.76.255.2551,022
6588.77.0.0/2288.77.0.1 to 88.77.3.25488.77.3.2551,022
6688.77.4.0/2288.77.4.1 to 88.77.7.25488.77.7.2551,022
6788.77.8.0/2288.77.8.1 to 88.77.11.25488.77.11.2551,022
6888.77.12.0/2288.77.12.1 to 88.77.15.25488.77.15.2551,022
6988.77.16.0/2288.77.16.1 to 88.77.19.25488.77.19.2551,022
7088.77.20.0/2288.77.20.1 to 88.77.23.25488.77.23.2551,022
7188.77.24.0/2288.77.24.1 to 88.77.27.25488.77.27.2551,022
7288.77.28.0/2288.77.28.1 to 88.77.31.25488.77.31.2551,022
7388.77.32.0/2288.77.32.1 to 88.77.35.25488.77.35.2551,022
7488.77.36.0/2288.77.36.1 to 88.77.39.25488.77.39.2551,022
7588.77.40.0/2288.77.40.1 to 88.77.43.25488.77.43.2551,022
7688.77.44.0/2288.77.44.1 to 88.77.47.25488.77.47.2551,022
7788.77.48.0/2288.77.48.1 to 88.77.51.25488.77.51.2551,022
7888.77.52.0/2288.77.52.1 to 88.77.55.25488.77.55.2551,022
7988.77.56.0/2288.77.56.1 to 88.77.59.25488.77.59.2551,022
8088.77.60.0/2288.77.60.1 to 88.77.63.25488.77.63.2551,022
8188.77.64.0/2288.77.64.1 to 88.77.67.25488.77.67.2551,022
8288.77.68.0/2288.77.68.1 to 88.77.71.25488.77.71.2551,022
8388.77.72.0/2288.77.72.1 to 88.77.75.25488.77.75.2551,022
8488.77.76.0/2288.77.76.1 to 88.77.79.25488.77.79.2551,022
8588.77.80.0/2288.77.80.1 to 88.77.83.25488.77.83.2551,022
8688.77.84.0/2288.77.84.1 to 88.77.87.25488.77.87.2551,022
8788.77.88.0/2288.77.88.1 to 88.77.91.25488.77.91.2551,022
8888.77.92.0/2288.77.92.1 to 88.77.95.25488.77.95.2551,022
8988.77.96.0/2288.77.96.1 to 88.77.99.25488.77.99.2551,022
9088.77.100.0/2288.77.100.1 to 88.77.103.25488.77.103.2551,022
9188.77.104.0/2288.77.104.1 to 88.77.107.25488.77.107.2551,022
9288.77.108.0/2288.77.108.1 to 88.77.111.25488.77.111.2551,022
9388.77.112.0/2288.77.112.1 to 88.77.115.25488.77.115.2551,022
9488.77.116.0/2288.77.116.1 to 88.77.119.25488.77.119.2551,022
9588.77.120.0/2288.77.120.1 to 88.77.123.25488.77.123.2551,022
9688.77.124.0/2288.77.124.1 to 88.77.127.25488.77.127.2551,022
9788.77.128.0/2288.77.128.1 to 88.77.131.25488.77.131.2551,022
9888.77.132.0/2288.77.132.1 to 88.77.135.25488.77.135.2551,022
9988.77.136.0/2288.77.136.1 to 88.77.139.25488.77.139.2551,022
10088.77.140.0/2288.77.140.1 to 88.77.143.25488.77.143.2551,022
10188.77.144.0/2288.77.144.1 to 88.77.147.25488.77.147.2551,022
10288.77.148.0/2288.77.148.1 to 88.77.151.25488.77.151.2551,022
10388.77.152.0/2288.77.152.1 to 88.77.155.25488.77.155.2551,022
10488.77.156.0/2288.77.156.1 to 88.77.159.25488.77.159.2551,022
10588.77.160.0/2288.77.160.1 to 88.77.163.25488.77.163.2551,022
10688.77.164.0/2288.77.164.1 to 88.77.167.25488.77.167.2551,022
10788.77.168.0/2288.77.168.1 to 88.77.171.25488.77.171.2551,022
10888.77.172.0/2288.77.172.1 to 88.77.175.25488.77.175.2551,022
10988.77.176.0/2288.77.176.1 to 88.77.179.25488.77.179.2551,022
11088.77.180.0/2288.77.180.1 to 88.77.183.25488.77.183.2551,022
11188.77.184.0/2288.77.184.1 to 88.77.187.25488.77.187.2551,022
11288.77.188.0/2288.77.188.1 to 88.77.191.25488.77.191.2551,022
11388.77.192.0/2288.77.192.1 to 88.77.195.25488.77.195.2551,022
11488.77.196.0/2288.77.196.1 to 88.77.199.25488.77.199.2551,022
11588.77.200.0/2288.77.200.1 to 88.77.203.25488.77.203.2551,022
11688.77.204.0/2288.77.204.1 to 88.77.207.25488.77.207.2551,022
11788.77.208.0/2288.77.208.1 to 88.77.211.25488.77.211.2551,022
11888.77.212.0/2288.77.212.1 to 88.77.215.25488.77.215.2551,022
11988.77.216.0/2288.77.216.1 to 88.77.219.25488.77.219.2551,022
12088.77.220.0/2288.77.220.1 to 88.77.223.25488.77.223.2551,022
12188.77.224.0/2288.77.224.1 to 88.77.227.25488.77.227.2551,022
12288.77.228.0/2288.77.228.1 to 88.77.231.25488.77.231.2551,022
12388.77.232.0/2288.77.232.1 to 88.77.235.25488.77.235.2551,022
12488.77.236.0/2288.77.236.1 to 88.77.239.25488.77.239.2551,022
12588.77.240.0/2288.77.240.1 to 88.77.243.25488.77.243.2551,022
12688.77.244.0/2288.77.244.1 to 88.77.247.25488.77.247.2551,022
12788.77.248.0/2288.77.248.1 to 88.77.251.25488.77.251.2551,022
12888.77.252.0/2288.77.252.1 to 88.77.255.25488.77.255.2551,022

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.