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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.

Network76.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
76.0.0.0
Broadcast address
76.255.255.255
First usable
76.0.0.1
Last usable
76.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 4C000000 · Integer 1275068416 to 1291845631
Reverse DNS zone
76.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001100..00000000.00000000.0000000076.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01001100..00000000.00000000.0000000076.0.0.0
Broadcast01001100..11111111.11111111.1111111176.255.255.255
Split into smaller subnets/15
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

76.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
176.0.0.0/1576.0.0.1 to 76.1.255.25476.1.255.255131,070
276.2.0.0/1576.2.0.1 to 76.3.255.25476.3.255.255131,070
376.4.0.0/1576.4.0.1 to 76.5.255.25476.5.255.255131,070
476.6.0.0/1576.6.0.1 to 76.7.255.25476.7.255.255131,070
576.8.0.0/1576.8.0.1 to 76.9.255.25476.9.255.255131,070
676.10.0.0/1576.10.0.1 to 76.11.255.25476.11.255.255131,070
776.12.0.0/1576.12.0.1 to 76.13.255.25476.13.255.255131,070
876.14.0.0/1576.14.0.1 to 76.15.255.25476.15.255.255131,070
976.16.0.0/1576.16.0.1 to 76.17.255.25476.17.255.255131,070
1076.18.0.0/1576.18.0.1 to 76.19.255.25476.19.255.255131,070
1176.20.0.0/1576.20.0.1 to 76.21.255.25476.21.255.255131,070
1276.22.0.0/1576.22.0.1 to 76.23.255.25476.23.255.255131,070
1376.24.0.0/1576.24.0.1 to 76.25.255.25476.25.255.255131,070
1476.26.0.0/1576.26.0.1 to 76.27.255.25476.27.255.255131,070
1576.28.0.0/1576.28.0.1 to 76.29.255.25476.29.255.255131,070
1676.30.0.0/1576.30.0.1 to 76.31.255.25476.31.255.255131,070
1776.32.0.0/1576.32.0.1 to 76.33.255.25476.33.255.255131,070
1876.34.0.0/1576.34.0.1 to 76.35.255.25476.35.255.255131,070
1976.36.0.0/1576.36.0.1 to 76.37.255.25476.37.255.255131,070
2076.38.0.0/1576.38.0.1 to 76.39.255.25476.39.255.255131,070
2176.40.0.0/1576.40.0.1 to 76.41.255.25476.41.255.255131,070
2276.42.0.0/1576.42.0.1 to 76.43.255.25476.43.255.255131,070
2376.44.0.0/1576.44.0.1 to 76.45.255.25476.45.255.255131,070
2476.46.0.0/1576.46.0.1 to 76.47.255.25476.47.255.255131,070
2576.48.0.0/1576.48.0.1 to 76.49.255.25476.49.255.255131,070
2676.50.0.0/1576.50.0.1 to 76.51.255.25476.51.255.255131,070
2776.52.0.0/1576.52.0.1 to 76.53.255.25476.53.255.255131,070
2876.54.0.0/1576.54.0.1 to 76.55.255.25476.55.255.255131,070
2976.56.0.0/1576.56.0.1 to 76.57.255.25476.57.255.255131,070
3076.58.0.0/1576.58.0.1 to 76.59.255.25476.59.255.255131,070
3176.60.0.0/1576.60.0.1 to 76.61.255.25476.61.255.255131,070
3276.62.0.0/1576.62.0.1 to 76.63.255.25476.63.255.255131,070
3376.64.0.0/1576.64.0.1 to 76.65.255.25476.65.255.255131,070
3476.66.0.0/1576.66.0.1 to 76.67.255.25476.67.255.255131,070
3576.68.0.0/1576.68.0.1 to 76.69.255.25476.69.255.255131,070
3676.70.0.0/1576.70.0.1 to 76.71.255.25476.71.255.255131,070
3776.72.0.0/1576.72.0.1 to 76.73.255.25476.73.255.255131,070
3876.74.0.0/1576.74.0.1 to 76.75.255.25476.75.255.255131,070
3976.76.0.0/1576.76.0.1 to 76.77.255.25476.77.255.255131,070
4076.78.0.0/1576.78.0.1 to 76.79.255.25476.79.255.255131,070
4176.80.0.0/1576.80.0.1 to 76.81.255.25476.81.255.255131,070
4276.82.0.0/1576.82.0.1 to 76.83.255.25476.83.255.255131,070
4376.84.0.0/1576.84.0.1 to 76.85.255.25476.85.255.255131,070
4476.86.0.0/1576.86.0.1 to 76.87.255.25476.87.255.255131,070
4576.88.0.0/1576.88.0.1 to 76.89.255.25476.89.255.255131,070
4676.90.0.0/1576.90.0.1 to 76.91.255.25476.91.255.255131,070
4776.92.0.0/1576.92.0.1 to 76.93.255.25476.93.255.255131,070
4876.94.0.0/1576.94.0.1 to 76.95.255.25476.95.255.255131,070
4976.96.0.0/1576.96.0.1 to 76.97.255.25476.97.255.255131,070
5076.98.0.0/1576.98.0.1 to 76.99.255.25476.99.255.255131,070
5176.100.0.0/1576.100.0.1 to 76.101.255.25476.101.255.255131,070
5276.102.0.0/1576.102.0.1 to 76.103.255.25476.103.255.255131,070
5376.104.0.0/1576.104.0.1 to 76.105.255.25476.105.255.255131,070
5476.106.0.0/1576.106.0.1 to 76.107.255.25476.107.255.255131,070
5576.108.0.0/1576.108.0.1 to 76.109.255.25476.109.255.255131,070
5676.110.0.0/1576.110.0.1 to 76.111.255.25476.111.255.255131,070
5776.112.0.0/1576.112.0.1 to 76.113.255.25476.113.255.255131,070
5876.114.0.0/1576.114.0.1 to 76.115.255.25476.115.255.255131,070
5976.116.0.0/1576.116.0.1 to 76.117.255.25476.117.255.255131,070
6076.118.0.0/1576.118.0.1 to 76.119.255.25476.119.255.255131,070
6176.120.0.0/1576.120.0.1 to 76.121.255.25476.121.255.255131,070
6276.122.0.0/1576.122.0.1 to 76.123.255.25476.123.255.255131,070
6376.124.0.0/1576.124.0.1 to 76.125.255.25476.125.255.255131,070
6476.126.0.0/1576.126.0.1 to 76.127.255.25476.127.255.255131,070
6576.128.0.0/1576.128.0.1 to 76.129.255.25476.129.255.255131,070
6676.130.0.0/1576.130.0.1 to 76.131.255.25476.131.255.255131,070
6776.132.0.0/1576.132.0.1 to 76.133.255.25476.133.255.255131,070
6876.134.0.0/1576.134.0.1 to 76.135.255.25476.135.255.255131,070
6976.136.0.0/1576.136.0.1 to 76.137.255.25476.137.255.255131,070
7076.138.0.0/1576.138.0.1 to 76.139.255.25476.139.255.255131,070
7176.140.0.0/1576.140.0.1 to 76.141.255.25476.141.255.255131,070
7276.142.0.0/1576.142.0.1 to 76.143.255.25476.143.255.255131,070
7376.144.0.0/1576.144.0.1 to 76.145.255.25476.145.255.255131,070
7476.146.0.0/1576.146.0.1 to 76.147.255.25476.147.255.255131,070
7576.148.0.0/1576.148.0.1 to 76.149.255.25476.149.255.255131,070
7676.150.0.0/1576.150.0.1 to 76.151.255.25476.151.255.255131,070
7776.152.0.0/1576.152.0.1 to 76.153.255.25476.153.255.255131,070
7876.154.0.0/1576.154.0.1 to 76.155.255.25476.155.255.255131,070
7976.156.0.0/1576.156.0.1 to 76.157.255.25476.157.255.255131,070
8076.158.0.0/1576.158.0.1 to 76.159.255.25476.159.255.255131,070
8176.160.0.0/1576.160.0.1 to 76.161.255.25476.161.255.255131,070
8276.162.0.0/1576.162.0.1 to 76.163.255.25476.163.255.255131,070
8376.164.0.0/1576.164.0.1 to 76.165.255.25476.165.255.255131,070
8476.166.0.0/1576.166.0.1 to 76.167.255.25476.167.255.255131,070
8576.168.0.0/1576.168.0.1 to 76.169.255.25476.169.255.255131,070
8676.170.0.0/1576.170.0.1 to 76.171.255.25476.171.255.255131,070
8776.172.0.0/1576.172.0.1 to 76.173.255.25476.173.255.255131,070
8876.174.0.0/1576.174.0.1 to 76.175.255.25476.175.255.255131,070
8976.176.0.0/1576.176.0.1 to 76.177.255.25476.177.255.255131,070
9076.178.0.0/1576.178.0.1 to 76.179.255.25476.179.255.255131,070
9176.180.0.0/1576.180.0.1 to 76.181.255.25476.181.255.255131,070
9276.182.0.0/1576.182.0.1 to 76.183.255.25476.183.255.255131,070
9376.184.0.0/1576.184.0.1 to 76.185.255.25476.185.255.255131,070
9476.186.0.0/1576.186.0.1 to 76.187.255.25476.187.255.255131,070
9576.188.0.0/1576.188.0.1 to 76.189.255.25476.189.255.255131,070
9676.190.0.0/1576.190.0.1 to 76.191.255.25476.191.255.255131,070
9776.192.0.0/1576.192.0.1 to 76.193.255.25476.193.255.255131,070
9876.194.0.0/1576.194.0.1 to 76.195.255.25476.195.255.255131,070
9976.196.0.0/1576.196.0.1 to 76.197.255.25476.197.255.255131,070
10076.198.0.0/1576.198.0.1 to 76.199.255.25476.199.255.255131,070
10176.200.0.0/1576.200.0.1 to 76.201.255.25476.201.255.255131,070
10276.202.0.0/1576.202.0.1 to 76.203.255.25476.203.255.255131,070
10376.204.0.0/1576.204.0.1 to 76.205.255.25476.205.255.255131,070
10476.206.0.0/1576.206.0.1 to 76.207.255.25476.207.255.255131,070
10576.208.0.0/1576.208.0.1 to 76.209.255.25476.209.255.255131,070
10676.210.0.0/1576.210.0.1 to 76.211.255.25476.211.255.255131,070
10776.212.0.0/1576.212.0.1 to 76.213.255.25476.213.255.255131,070
10876.214.0.0/1576.214.0.1 to 76.215.255.25476.215.255.255131,070
10976.216.0.0/1576.216.0.1 to 76.217.255.25476.217.255.255131,070
11076.218.0.0/1576.218.0.1 to 76.219.255.25476.219.255.255131,070
11176.220.0.0/1576.220.0.1 to 76.221.255.25476.221.255.255131,070
11276.222.0.0/1576.222.0.1 to 76.223.255.25476.223.255.255131,070
11376.224.0.0/1576.224.0.1 to 76.225.255.25476.225.255.255131,070
11476.226.0.0/1576.226.0.1 to 76.227.255.25476.227.255.255131,070
11576.228.0.0/1576.228.0.1 to 76.229.255.25476.229.255.255131,070
11676.230.0.0/1576.230.0.1 to 76.231.255.25476.231.255.255131,070
11776.232.0.0/1576.232.0.1 to 76.233.255.25476.233.255.255131,070
11876.234.0.0/1576.234.0.1 to 76.235.255.25476.235.255.255131,070
11976.236.0.0/1576.236.0.1 to 76.237.255.25476.237.255.255131,070
12076.238.0.0/1576.238.0.1 to 76.239.255.25476.239.255.255131,070
12176.240.0.0/1576.240.0.1 to 76.241.255.25476.241.255.255131,070
12276.242.0.0/1576.242.0.1 to 76.243.255.25476.243.255.255131,070
12376.244.0.0/1576.244.0.1 to 76.245.255.25476.245.255.255131,070
12476.246.0.0/1576.246.0.1 to 76.247.255.25476.247.255.255131,070
12576.248.0.0/1576.248.0.1 to 76.249.255.25476.249.255.255131,070
12676.250.0.0/1576.250.0.1 to 76.251.255.25476.251.255.255131,070
12776.252.0.0/1576.252.0.1 to 76.253.255.25476.253.255.255131,070
12876.254.0.0/1576.254.0.1 to 76.255.255.25476.255.255.255131,070

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.