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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.

Network80.7.32.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
80.7.32.0
Broadcast address
80.7.63.255
First usable
80.7.32.1
Last usable
80.7.63.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 50072000 · Integer 1342644224 to 1342652415
Reverse DNS zones
32.7.80.in-addr.arpa
33.7.80.in-addr.arpa
34.7.80.in-addr.arpa
35.7.80.in-addr.arpa
36.7.80.in-addr.arpa
37.7.80.in-addr.arpa
38.7.80.in-addr.arpa
39.7.80.in-addr.arpa
40.7.80.in-addr.arpa
41.7.80.in-addr.arpa
42.7.80.in-addr.arpa
43.7.80.in-addr.arpa
44.7.80.in-addr.arpa
45.7.80.in-addr.arpa
46.7.80.in-addr.arpa
47.7.80.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010000.00000111.00100000.0000000080.7.32.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01010000.00000111.00100000.0000000080.7.32.0
Broadcast01010000.00000111.00111111.1111111180.7.63.255
Split into smaller subnets/26
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

80.7.32.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.7.32.0/2680.7.32.1 to 80.7.32.6280.7.32.6362
280.7.32.64/2680.7.32.65 to 80.7.32.12680.7.32.12762
380.7.32.128/2680.7.32.129 to 80.7.32.19080.7.32.19162
480.7.32.192/2680.7.32.193 to 80.7.32.25480.7.32.25562
580.7.33.0/2680.7.33.1 to 80.7.33.6280.7.33.6362
680.7.33.64/2680.7.33.65 to 80.7.33.12680.7.33.12762
780.7.33.128/2680.7.33.129 to 80.7.33.19080.7.33.19162
880.7.33.192/2680.7.33.193 to 80.7.33.25480.7.33.25562
980.7.34.0/2680.7.34.1 to 80.7.34.6280.7.34.6362
1080.7.34.64/2680.7.34.65 to 80.7.34.12680.7.34.12762
1180.7.34.128/2680.7.34.129 to 80.7.34.19080.7.34.19162
1280.7.34.192/2680.7.34.193 to 80.7.34.25480.7.34.25562
1380.7.35.0/2680.7.35.1 to 80.7.35.6280.7.35.6362
1480.7.35.64/2680.7.35.65 to 80.7.35.12680.7.35.12762
1580.7.35.128/2680.7.35.129 to 80.7.35.19080.7.35.19162
1680.7.35.192/2680.7.35.193 to 80.7.35.25480.7.35.25562
1780.7.36.0/2680.7.36.1 to 80.7.36.6280.7.36.6362
1880.7.36.64/2680.7.36.65 to 80.7.36.12680.7.36.12762
1980.7.36.128/2680.7.36.129 to 80.7.36.19080.7.36.19162
2080.7.36.192/2680.7.36.193 to 80.7.36.25480.7.36.25562
2180.7.37.0/2680.7.37.1 to 80.7.37.6280.7.37.6362
2280.7.37.64/2680.7.37.65 to 80.7.37.12680.7.37.12762
2380.7.37.128/2680.7.37.129 to 80.7.37.19080.7.37.19162
2480.7.37.192/2680.7.37.193 to 80.7.37.25480.7.37.25562
2580.7.38.0/2680.7.38.1 to 80.7.38.6280.7.38.6362
2680.7.38.64/2680.7.38.65 to 80.7.38.12680.7.38.12762
2780.7.38.128/2680.7.38.129 to 80.7.38.19080.7.38.19162
2880.7.38.192/2680.7.38.193 to 80.7.38.25480.7.38.25562
2980.7.39.0/2680.7.39.1 to 80.7.39.6280.7.39.6362
3080.7.39.64/2680.7.39.65 to 80.7.39.12680.7.39.12762
3180.7.39.128/2680.7.39.129 to 80.7.39.19080.7.39.19162
3280.7.39.192/2680.7.39.193 to 80.7.39.25480.7.39.25562
3380.7.40.0/2680.7.40.1 to 80.7.40.6280.7.40.6362
3480.7.40.64/2680.7.40.65 to 80.7.40.12680.7.40.12762
3580.7.40.128/2680.7.40.129 to 80.7.40.19080.7.40.19162
3680.7.40.192/2680.7.40.193 to 80.7.40.25480.7.40.25562
3780.7.41.0/2680.7.41.1 to 80.7.41.6280.7.41.6362
3880.7.41.64/2680.7.41.65 to 80.7.41.12680.7.41.12762
3980.7.41.128/2680.7.41.129 to 80.7.41.19080.7.41.19162
4080.7.41.192/2680.7.41.193 to 80.7.41.25480.7.41.25562
4180.7.42.0/2680.7.42.1 to 80.7.42.6280.7.42.6362
4280.7.42.64/2680.7.42.65 to 80.7.42.12680.7.42.12762
4380.7.42.128/2680.7.42.129 to 80.7.42.19080.7.42.19162
4480.7.42.192/2680.7.42.193 to 80.7.42.25480.7.42.25562
4580.7.43.0/2680.7.43.1 to 80.7.43.6280.7.43.6362
4680.7.43.64/2680.7.43.65 to 80.7.43.12680.7.43.12762
4780.7.43.128/2680.7.43.129 to 80.7.43.19080.7.43.19162
4880.7.43.192/2680.7.43.193 to 80.7.43.25480.7.43.25562
4980.7.44.0/2680.7.44.1 to 80.7.44.6280.7.44.6362
5080.7.44.64/2680.7.44.65 to 80.7.44.12680.7.44.12762
5180.7.44.128/2680.7.44.129 to 80.7.44.19080.7.44.19162
5280.7.44.192/2680.7.44.193 to 80.7.44.25480.7.44.25562
5380.7.45.0/2680.7.45.1 to 80.7.45.6280.7.45.6362
5480.7.45.64/2680.7.45.65 to 80.7.45.12680.7.45.12762
5580.7.45.128/2680.7.45.129 to 80.7.45.19080.7.45.19162
5680.7.45.192/2680.7.45.193 to 80.7.45.25480.7.45.25562
5780.7.46.0/2680.7.46.1 to 80.7.46.6280.7.46.6362
5880.7.46.64/2680.7.46.65 to 80.7.46.12680.7.46.12762
5980.7.46.128/2680.7.46.129 to 80.7.46.19080.7.46.19162
6080.7.46.192/2680.7.46.193 to 80.7.46.25480.7.46.25562
6180.7.47.0/2680.7.47.1 to 80.7.47.6280.7.47.6362
6280.7.47.64/2680.7.47.65 to 80.7.47.12680.7.47.12762
6380.7.47.128/2680.7.47.129 to 80.7.47.19080.7.47.19162
6480.7.47.192/2680.7.47.193 to 80.7.47.25480.7.47.25562
6580.7.48.0/2680.7.48.1 to 80.7.48.6280.7.48.6362
6680.7.48.64/2680.7.48.65 to 80.7.48.12680.7.48.12762
6780.7.48.128/2680.7.48.129 to 80.7.48.19080.7.48.19162
6880.7.48.192/2680.7.48.193 to 80.7.48.25480.7.48.25562
6980.7.49.0/2680.7.49.1 to 80.7.49.6280.7.49.6362
7080.7.49.64/2680.7.49.65 to 80.7.49.12680.7.49.12762
7180.7.49.128/2680.7.49.129 to 80.7.49.19080.7.49.19162
7280.7.49.192/2680.7.49.193 to 80.7.49.25480.7.49.25562
7380.7.50.0/2680.7.50.1 to 80.7.50.6280.7.50.6362
7480.7.50.64/2680.7.50.65 to 80.7.50.12680.7.50.12762
7580.7.50.128/2680.7.50.129 to 80.7.50.19080.7.50.19162
7680.7.50.192/2680.7.50.193 to 80.7.50.25480.7.50.25562
7780.7.51.0/2680.7.51.1 to 80.7.51.6280.7.51.6362
7880.7.51.64/2680.7.51.65 to 80.7.51.12680.7.51.12762
7980.7.51.128/2680.7.51.129 to 80.7.51.19080.7.51.19162
8080.7.51.192/2680.7.51.193 to 80.7.51.25480.7.51.25562
8180.7.52.0/2680.7.52.1 to 80.7.52.6280.7.52.6362
8280.7.52.64/2680.7.52.65 to 80.7.52.12680.7.52.12762
8380.7.52.128/2680.7.52.129 to 80.7.52.19080.7.52.19162
8480.7.52.192/2680.7.52.193 to 80.7.52.25480.7.52.25562
8580.7.53.0/2680.7.53.1 to 80.7.53.6280.7.53.6362
8680.7.53.64/2680.7.53.65 to 80.7.53.12680.7.53.12762
8780.7.53.128/2680.7.53.129 to 80.7.53.19080.7.53.19162
8880.7.53.192/2680.7.53.193 to 80.7.53.25480.7.53.25562
8980.7.54.0/2680.7.54.1 to 80.7.54.6280.7.54.6362
9080.7.54.64/2680.7.54.65 to 80.7.54.12680.7.54.12762
9180.7.54.128/2680.7.54.129 to 80.7.54.19080.7.54.19162
9280.7.54.192/2680.7.54.193 to 80.7.54.25480.7.54.25562
9380.7.55.0/2680.7.55.1 to 80.7.55.6280.7.55.6362
9480.7.55.64/2680.7.55.65 to 80.7.55.12680.7.55.12762
9580.7.55.128/2680.7.55.129 to 80.7.55.19080.7.55.19162
9680.7.55.192/2680.7.55.193 to 80.7.55.25480.7.55.25562
9780.7.56.0/2680.7.56.1 to 80.7.56.6280.7.56.6362
9880.7.56.64/2680.7.56.65 to 80.7.56.12680.7.56.12762
9980.7.56.128/2680.7.56.129 to 80.7.56.19080.7.56.19162
10080.7.56.192/2680.7.56.193 to 80.7.56.25480.7.56.25562
10180.7.57.0/2680.7.57.1 to 80.7.57.6280.7.57.6362
10280.7.57.64/2680.7.57.65 to 80.7.57.12680.7.57.12762
10380.7.57.128/2680.7.57.129 to 80.7.57.19080.7.57.19162
10480.7.57.192/2680.7.57.193 to 80.7.57.25480.7.57.25562
10580.7.58.0/2680.7.58.1 to 80.7.58.6280.7.58.6362
10680.7.58.64/2680.7.58.65 to 80.7.58.12680.7.58.12762
10780.7.58.128/2680.7.58.129 to 80.7.58.19080.7.58.19162
10880.7.58.192/2680.7.58.193 to 80.7.58.25480.7.58.25562
10980.7.59.0/2680.7.59.1 to 80.7.59.6280.7.59.6362
11080.7.59.64/2680.7.59.65 to 80.7.59.12680.7.59.12762
11180.7.59.128/2680.7.59.129 to 80.7.59.19080.7.59.19162
11280.7.59.192/2680.7.59.193 to 80.7.59.25480.7.59.25562
11380.7.60.0/2680.7.60.1 to 80.7.60.6280.7.60.6362
11480.7.60.64/2680.7.60.65 to 80.7.60.12680.7.60.12762
11580.7.60.128/2680.7.60.129 to 80.7.60.19080.7.60.19162
11680.7.60.192/2680.7.60.193 to 80.7.60.25480.7.60.25562
11780.7.61.0/2680.7.61.1 to 80.7.61.6280.7.61.6362
11880.7.61.64/2680.7.61.65 to 80.7.61.12680.7.61.12762
11980.7.61.128/2680.7.61.129 to 80.7.61.19080.7.61.19162
12080.7.61.192/2680.7.61.193 to 80.7.61.25480.7.61.25562
12180.7.62.0/2680.7.62.1 to 80.7.62.6280.7.62.6362
12280.7.62.64/2680.7.62.65 to 80.7.62.12680.7.62.12762
12380.7.62.128/2680.7.62.129 to 80.7.62.19080.7.62.19162
12480.7.62.192/2680.7.62.193 to 80.7.62.25480.7.62.25562
12580.7.63.0/2680.7.63.1 to 80.7.63.6280.7.63.6362
12680.7.63.64/2680.7.63.65 to 80.7.63.12680.7.63.12762
12780.7.63.128/2680.7.63.129 to 80.7.63.19080.7.63.19162
12880.7.63.192/2680.7.63.193 to 80.7.63.25480.7.63.25562

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.