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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.

Network50.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
50.0.0.0
Broadcast address
51.255.255.255
First usable
50.0.0.1
Last usable
51.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 32000000 · Integer 838860800 to 872415231
Reverse DNS zones
50.in-addr.arpa
51.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110010.00000000.00000000.0000000050.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00110010.00000000.00000000.0000000050.0.0.0
Broadcast00110011.11111111.11111111.1111111151.255.255.255
Split into smaller subnets/14
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

50.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
150.0.0.0/1450.0.0.1 to 50.3.255.25450.3.255.255262,142
250.4.0.0/1450.4.0.1 to 50.7.255.25450.7.255.255262,142
350.8.0.0/1450.8.0.1 to 50.11.255.25450.11.255.255262,142
450.12.0.0/1450.12.0.1 to 50.15.255.25450.15.255.255262,142
550.16.0.0/1450.16.0.1 to 50.19.255.25450.19.255.255262,142
650.20.0.0/1450.20.0.1 to 50.23.255.25450.23.255.255262,142
750.24.0.0/1450.24.0.1 to 50.27.255.25450.27.255.255262,142
850.28.0.0/1450.28.0.1 to 50.31.255.25450.31.255.255262,142
950.32.0.0/1450.32.0.1 to 50.35.255.25450.35.255.255262,142
1050.36.0.0/1450.36.0.1 to 50.39.255.25450.39.255.255262,142
1150.40.0.0/1450.40.0.1 to 50.43.255.25450.43.255.255262,142
1250.44.0.0/1450.44.0.1 to 50.47.255.25450.47.255.255262,142
1350.48.0.0/1450.48.0.1 to 50.51.255.25450.51.255.255262,142
1450.52.0.0/1450.52.0.1 to 50.55.255.25450.55.255.255262,142
1550.56.0.0/1450.56.0.1 to 50.59.255.25450.59.255.255262,142
1650.60.0.0/1450.60.0.1 to 50.63.255.25450.63.255.255262,142
1750.64.0.0/1450.64.0.1 to 50.67.255.25450.67.255.255262,142
1850.68.0.0/1450.68.0.1 to 50.71.255.25450.71.255.255262,142
1950.72.0.0/1450.72.0.1 to 50.75.255.25450.75.255.255262,142
2050.76.0.0/1450.76.0.1 to 50.79.255.25450.79.255.255262,142
2150.80.0.0/1450.80.0.1 to 50.83.255.25450.83.255.255262,142
2250.84.0.0/1450.84.0.1 to 50.87.255.25450.87.255.255262,142
2350.88.0.0/1450.88.0.1 to 50.91.255.25450.91.255.255262,142
2450.92.0.0/1450.92.0.1 to 50.95.255.25450.95.255.255262,142
2550.96.0.0/1450.96.0.1 to 50.99.255.25450.99.255.255262,142
2650.100.0.0/1450.100.0.1 to 50.103.255.25450.103.255.255262,142
2750.104.0.0/1450.104.0.1 to 50.107.255.25450.107.255.255262,142
2850.108.0.0/1450.108.0.1 to 50.111.255.25450.111.255.255262,142
2950.112.0.0/1450.112.0.1 to 50.115.255.25450.115.255.255262,142
3050.116.0.0/1450.116.0.1 to 50.119.255.25450.119.255.255262,142
3150.120.0.0/1450.120.0.1 to 50.123.255.25450.123.255.255262,142
3250.124.0.0/1450.124.0.1 to 50.127.255.25450.127.255.255262,142
3350.128.0.0/1450.128.0.1 to 50.131.255.25450.131.255.255262,142
3450.132.0.0/1450.132.0.1 to 50.135.255.25450.135.255.255262,142
3550.136.0.0/1450.136.0.1 to 50.139.255.25450.139.255.255262,142
3650.140.0.0/1450.140.0.1 to 50.143.255.25450.143.255.255262,142
3750.144.0.0/1450.144.0.1 to 50.147.255.25450.147.255.255262,142
3850.148.0.0/1450.148.0.1 to 50.151.255.25450.151.255.255262,142
3950.152.0.0/1450.152.0.1 to 50.155.255.25450.155.255.255262,142
4050.156.0.0/1450.156.0.1 to 50.159.255.25450.159.255.255262,142
4150.160.0.0/1450.160.0.1 to 50.163.255.25450.163.255.255262,142
4250.164.0.0/1450.164.0.1 to 50.167.255.25450.167.255.255262,142
4350.168.0.0/1450.168.0.1 to 50.171.255.25450.171.255.255262,142
4450.172.0.0/1450.172.0.1 to 50.175.255.25450.175.255.255262,142
4550.176.0.0/1450.176.0.1 to 50.179.255.25450.179.255.255262,142
4650.180.0.0/1450.180.0.1 to 50.183.255.25450.183.255.255262,142
4750.184.0.0/1450.184.0.1 to 50.187.255.25450.187.255.255262,142
4850.188.0.0/1450.188.0.1 to 50.191.255.25450.191.255.255262,142
4950.192.0.0/1450.192.0.1 to 50.195.255.25450.195.255.255262,142
5050.196.0.0/1450.196.0.1 to 50.199.255.25450.199.255.255262,142
5150.200.0.0/1450.200.0.1 to 50.203.255.25450.203.255.255262,142
5250.204.0.0/1450.204.0.1 to 50.207.255.25450.207.255.255262,142
5350.208.0.0/1450.208.0.1 to 50.211.255.25450.211.255.255262,142
5450.212.0.0/1450.212.0.1 to 50.215.255.25450.215.255.255262,142
5550.216.0.0/1450.216.0.1 to 50.219.255.25450.219.255.255262,142
5650.220.0.0/1450.220.0.1 to 50.223.255.25450.223.255.255262,142
5750.224.0.0/1450.224.0.1 to 50.227.255.25450.227.255.255262,142
5850.228.0.0/1450.228.0.1 to 50.231.255.25450.231.255.255262,142
5950.232.0.0/1450.232.0.1 to 50.235.255.25450.235.255.255262,142
6050.236.0.0/1450.236.0.1 to 50.239.255.25450.239.255.255262,142
6150.240.0.0/1450.240.0.1 to 50.243.255.25450.243.255.255262,142
6250.244.0.0/1450.244.0.1 to 50.247.255.25450.247.255.255262,142
6350.248.0.0/1450.248.0.1 to 50.251.255.25450.251.255.255262,142
6450.252.0.0/1450.252.0.1 to 50.255.255.25450.255.255.255262,142
6551.0.0.0/1451.0.0.1 to 51.3.255.25451.3.255.255262,142
6651.4.0.0/1451.4.0.1 to 51.7.255.25451.7.255.255262,142
6751.8.0.0/1451.8.0.1 to 51.11.255.25451.11.255.255262,142
6851.12.0.0/1451.12.0.1 to 51.15.255.25451.15.255.255262,142
6951.16.0.0/1451.16.0.1 to 51.19.255.25451.19.255.255262,142
7051.20.0.0/1451.20.0.1 to 51.23.255.25451.23.255.255262,142
7151.24.0.0/1451.24.0.1 to 51.27.255.25451.27.255.255262,142
7251.28.0.0/1451.28.0.1 to 51.31.255.25451.31.255.255262,142
7351.32.0.0/1451.32.0.1 to 51.35.255.25451.35.255.255262,142
7451.36.0.0/1451.36.0.1 to 51.39.255.25451.39.255.255262,142
7551.40.0.0/1451.40.0.1 to 51.43.255.25451.43.255.255262,142
7651.44.0.0/1451.44.0.1 to 51.47.255.25451.47.255.255262,142
7751.48.0.0/1451.48.0.1 to 51.51.255.25451.51.255.255262,142
7851.52.0.0/1451.52.0.1 to 51.55.255.25451.55.255.255262,142
7951.56.0.0/1451.56.0.1 to 51.59.255.25451.59.255.255262,142
8051.60.0.0/1451.60.0.1 to 51.63.255.25451.63.255.255262,142
8151.64.0.0/1451.64.0.1 to 51.67.255.25451.67.255.255262,142
8251.68.0.0/1451.68.0.1 to 51.71.255.25451.71.255.255262,142
8351.72.0.0/1451.72.0.1 to 51.75.255.25451.75.255.255262,142
8451.76.0.0/1451.76.0.1 to 51.79.255.25451.79.255.255262,142
8551.80.0.0/1451.80.0.1 to 51.83.255.25451.83.255.255262,142
8651.84.0.0/1451.84.0.1 to 51.87.255.25451.87.255.255262,142
8751.88.0.0/1451.88.0.1 to 51.91.255.25451.91.255.255262,142
8851.92.0.0/1451.92.0.1 to 51.95.255.25451.95.255.255262,142
8951.96.0.0/1451.96.0.1 to 51.99.255.25451.99.255.255262,142
9051.100.0.0/1451.100.0.1 to 51.103.255.25451.103.255.255262,142
9151.104.0.0/1451.104.0.1 to 51.107.255.25451.107.255.255262,142
9251.108.0.0/1451.108.0.1 to 51.111.255.25451.111.255.255262,142
9351.112.0.0/1451.112.0.1 to 51.115.255.25451.115.255.255262,142
9451.116.0.0/1451.116.0.1 to 51.119.255.25451.119.255.255262,142
9551.120.0.0/1451.120.0.1 to 51.123.255.25451.123.255.255262,142
9651.124.0.0/1451.124.0.1 to 51.127.255.25451.127.255.255262,142
9751.128.0.0/1451.128.0.1 to 51.131.255.25451.131.255.255262,142
9851.132.0.0/1451.132.0.1 to 51.135.255.25451.135.255.255262,142
9951.136.0.0/1451.136.0.1 to 51.139.255.25451.139.255.255262,142
10051.140.0.0/1451.140.0.1 to 51.143.255.25451.143.255.255262,142
10151.144.0.0/1451.144.0.1 to 51.147.255.25451.147.255.255262,142
10251.148.0.0/1451.148.0.1 to 51.151.255.25451.151.255.255262,142
10351.152.0.0/1451.152.0.1 to 51.155.255.25451.155.255.255262,142
10451.156.0.0/1451.156.0.1 to 51.159.255.25451.159.255.255262,142
10551.160.0.0/1451.160.0.1 to 51.163.255.25451.163.255.255262,142
10651.164.0.0/1451.164.0.1 to 51.167.255.25451.167.255.255262,142
10751.168.0.0/1451.168.0.1 to 51.171.255.25451.171.255.255262,142
10851.172.0.0/1451.172.0.1 to 51.175.255.25451.175.255.255262,142
10951.176.0.0/1451.176.0.1 to 51.179.255.25451.179.255.255262,142
11051.180.0.0/1451.180.0.1 to 51.183.255.25451.183.255.255262,142
11151.184.0.0/1451.184.0.1 to 51.187.255.25451.187.255.255262,142
11251.188.0.0/1451.188.0.1 to 51.191.255.25451.191.255.255262,142
11351.192.0.0/1451.192.0.1 to 51.195.255.25451.195.255.255262,142
11451.196.0.0/1451.196.0.1 to 51.199.255.25451.199.255.255262,142
11551.200.0.0/1451.200.0.1 to 51.203.255.25451.203.255.255262,142
11651.204.0.0/1451.204.0.1 to 51.207.255.25451.207.255.255262,142
11751.208.0.0/1451.208.0.1 to 51.211.255.25451.211.255.255262,142
11851.212.0.0/1451.212.0.1 to 51.215.255.25451.215.255.255262,142
11951.216.0.0/1451.216.0.1 to 51.219.255.25451.219.255.255262,142
12051.220.0.0/1451.220.0.1 to 51.223.255.25451.223.255.255262,142
12151.224.0.0/1451.224.0.1 to 51.227.255.25451.227.255.255262,142
12251.228.0.0/1451.228.0.1 to 51.231.255.25451.231.255.255262,142
12351.232.0.0/1451.232.0.1 to 51.235.255.25451.235.255.255262,142
12451.236.0.0/1451.236.0.1 to 51.239.255.25451.239.255.255262,142
12551.240.0.0/1451.240.0.1 to 51.243.255.25451.243.255.255262,142
12651.244.0.0/1451.244.0.1 to 51.247.255.25451.247.255.255262,142
12751.248.0.0/1451.248.0.1 to 51.251.255.25451.251.255.255262,142
12851.252.0.0/1451.252.0.1 to 51.255.255.25451.255.255.255262,142

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.