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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.

Network16.7.32.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
16.7.32.0
Broadcast address
16.7.63.255
First usable
16.7.32.1
Last usable
16.7.63.254
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 10072000 · Integer 268902400 to 268910591
Reverse DNS zones
32.7.16.in-addr.arpa
33.7.16.in-addr.arpa
34.7.16.in-addr.arpa
35.7.16.in-addr.arpa
36.7.16.in-addr.arpa
37.7.16.in-addr.arpa
38.7.16.in-addr.arpa
39.7.16.in-addr.arpa
40.7.16.in-addr.arpa
41.7.16.in-addr.arpa
42.7.16.in-addr.arpa
43.7.16.in-addr.arpa
44.7.16.in-addr.arpa
45.7.16.in-addr.arpa
46.7.16.in-addr.arpa
47.7.16.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
Address00010000.00000111.00100000.0000000016.7.32.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00010000.00000111.00100000.0000000016.7.32.0
Broadcast00010000.00000111.00111111.1111111116.7.63.255
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)

16.7.32.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.7.32.0/2616.7.32.1 to 16.7.32.6216.7.32.6362
216.7.32.64/2616.7.32.65 to 16.7.32.12616.7.32.12762
316.7.32.128/2616.7.32.129 to 16.7.32.19016.7.32.19162
416.7.32.192/2616.7.32.193 to 16.7.32.25416.7.32.25562
516.7.33.0/2616.7.33.1 to 16.7.33.6216.7.33.6362
616.7.33.64/2616.7.33.65 to 16.7.33.12616.7.33.12762
716.7.33.128/2616.7.33.129 to 16.7.33.19016.7.33.19162
816.7.33.192/2616.7.33.193 to 16.7.33.25416.7.33.25562
916.7.34.0/2616.7.34.1 to 16.7.34.6216.7.34.6362
1016.7.34.64/2616.7.34.65 to 16.7.34.12616.7.34.12762
1116.7.34.128/2616.7.34.129 to 16.7.34.19016.7.34.19162
1216.7.34.192/2616.7.34.193 to 16.7.34.25416.7.34.25562
1316.7.35.0/2616.7.35.1 to 16.7.35.6216.7.35.6362
1416.7.35.64/2616.7.35.65 to 16.7.35.12616.7.35.12762
1516.7.35.128/2616.7.35.129 to 16.7.35.19016.7.35.19162
1616.7.35.192/2616.7.35.193 to 16.7.35.25416.7.35.25562
1716.7.36.0/2616.7.36.1 to 16.7.36.6216.7.36.6362
1816.7.36.64/2616.7.36.65 to 16.7.36.12616.7.36.12762
1916.7.36.128/2616.7.36.129 to 16.7.36.19016.7.36.19162
2016.7.36.192/2616.7.36.193 to 16.7.36.25416.7.36.25562
2116.7.37.0/2616.7.37.1 to 16.7.37.6216.7.37.6362
2216.7.37.64/2616.7.37.65 to 16.7.37.12616.7.37.12762
2316.7.37.128/2616.7.37.129 to 16.7.37.19016.7.37.19162
2416.7.37.192/2616.7.37.193 to 16.7.37.25416.7.37.25562
2516.7.38.0/2616.7.38.1 to 16.7.38.6216.7.38.6362
2616.7.38.64/2616.7.38.65 to 16.7.38.12616.7.38.12762
2716.7.38.128/2616.7.38.129 to 16.7.38.19016.7.38.19162
2816.7.38.192/2616.7.38.193 to 16.7.38.25416.7.38.25562
2916.7.39.0/2616.7.39.1 to 16.7.39.6216.7.39.6362
3016.7.39.64/2616.7.39.65 to 16.7.39.12616.7.39.12762
3116.7.39.128/2616.7.39.129 to 16.7.39.19016.7.39.19162
3216.7.39.192/2616.7.39.193 to 16.7.39.25416.7.39.25562
3316.7.40.0/2616.7.40.1 to 16.7.40.6216.7.40.6362
3416.7.40.64/2616.7.40.65 to 16.7.40.12616.7.40.12762
3516.7.40.128/2616.7.40.129 to 16.7.40.19016.7.40.19162
3616.7.40.192/2616.7.40.193 to 16.7.40.25416.7.40.25562
3716.7.41.0/2616.7.41.1 to 16.7.41.6216.7.41.6362
3816.7.41.64/2616.7.41.65 to 16.7.41.12616.7.41.12762
3916.7.41.128/2616.7.41.129 to 16.7.41.19016.7.41.19162
4016.7.41.192/2616.7.41.193 to 16.7.41.25416.7.41.25562
4116.7.42.0/2616.7.42.1 to 16.7.42.6216.7.42.6362
4216.7.42.64/2616.7.42.65 to 16.7.42.12616.7.42.12762
4316.7.42.128/2616.7.42.129 to 16.7.42.19016.7.42.19162
4416.7.42.192/2616.7.42.193 to 16.7.42.25416.7.42.25562
4516.7.43.0/2616.7.43.1 to 16.7.43.6216.7.43.6362
4616.7.43.64/2616.7.43.65 to 16.7.43.12616.7.43.12762
4716.7.43.128/2616.7.43.129 to 16.7.43.19016.7.43.19162
4816.7.43.192/2616.7.43.193 to 16.7.43.25416.7.43.25562
4916.7.44.0/2616.7.44.1 to 16.7.44.6216.7.44.6362
5016.7.44.64/2616.7.44.65 to 16.7.44.12616.7.44.12762
5116.7.44.128/2616.7.44.129 to 16.7.44.19016.7.44.19162
5216.7.44.192/2616.7.44.193 to 16.7.44.25416.7.44.25562
5316.7.45.0/2616.7.45.1 to 16.7.45.6216.7.45.6362
5416.7.45.64/2616.7.45.65 to 16.7.45.12616.7.45.12762
5516.7.45.128/2616.7.45.129 to 16.7.45.19016.7.45.19162
5616.7.45.192/2616.7.45.193 to 16.7.45.25416.7.45.25562
5716.7.46.0/2616.7.46.1 to 16.7.46.6216.7.46.6362
5816.7.46.64/2616.7.46.65 to 16.7.46.12616.7.46.12762
5916.7.46.128/2616.7.46.129 to 16.7.46.19016.7.46.19162
6016.7.46.192/2616.7.46.193 to 16.7.46.25416.7.46.25562
6116.7.47.0/2616.7.47.1 to 16.7.47.6216.7.47.6362
6216.7.47.64/2616.7.47.65 to 16.7.47.12616.7.47.12762
6316.7.47.128/2616.7.47.129 to 16.7.47.19016.7.47.19162
6416.7.47.192/2616.7.47.193 to 16.7.47.25416.7.47.25562
6516.7.48.0/2616.7.48.1 to 16.7.48.6216.7.48.6362
6616.7.48.64/2616.7.48.65 to 16.7.48.12616.7.48.12762
6716.7.48.128/2616.7.48.129 to 16.7.48.19016.7.48.19162
6816.7.48.192/2616.7.48.193 to 16.7.48.25416.7.48.25562
6916.7.49.0/2616.7.49.1 to 16.7.49.6216.7.49.6362
7016.7.49.64/2616.7.49.65 to 16.7.49.12616.7.49.12762
7116.7.49.128/2616.7.49.129 to 16.7.49.19016.7.49.19162
7216.7.49.192/2616.7.49.193 to 16.7.49.25416.7.49.25562
7316.7.50.0/2616.7.50.1 to 16.7.50.6216.7.50.6362
7416.7.50.64/2616.7.50.65 to 16.7.50.12616.7.50.12762
7516.7.50.128/2616.7.50.129 to 16.7.50.19016.7.50.19162
7616.7.50.192/2616.7.50.193 to 16.7.50.25416.7.50.25562
7716.7.51.0/2616.7.51.1 to 16.7.51.6216.7.51.6362
7816.7.51.64/2616.7.51.65 to 16.7.51.12616.7.51.12762
7916.7.51.128/2616.7.51.129 to 16.7.51.19016.7.51.19162
8016.7.51.192/2616.7.51.193 to 16.7.51.25416.7.51.25562
8116.7.52.0/2616.7.52.1 to 16.7.52.6216.7.52.6362
8216.7.52.64/2616.7.52.65 to 16.7.52.12616.7.52.12762
8316.7.52.128/2616.7.52.129 to 16.7.52.19016.7.52.19162
8416.7.52.192/2616.7.52.193 to 16.7.52.25416.7.52.25562
8516.7.53.0/2616.7.53.1 to 16.7.53.6216.7.53.6362
8616.7.53.64/2616.7.53.65 to 16.7.53.12616.7.53.12762
8716.7.53.128/2616.7.53.129 to 16.7.53.19016.7.53.19162
8816.7.53.192/2616.7.53.193 to 16.7.53.25416.7.53.25562
8916.7.54.0/2616.7.54.1 to 16.7.54.6216.7.54.6362
9016.7.54.64/2616.7.54.65 to 16.7.54.12616.7.54.12762
9116.7.54.128/2616.7.54.129 to 16.7.54.19016.7.54.19162
9216.7.54.192/2616.7.54.193 to 16.7.54.25416.7.54.25562
9316.7.55.0/2616.7.55.1 to 16.7.55.6216.7.55.6362
9416.7.55.64/2616.7.55.65 to 16.7.55.12616.7.55.12762
9516.7.55.128/2616.7.55.129 to 16.7.55.19016.7.55.19162
9616.7.55.192/2616.7.55.193 to 16.7.55.25416.7.55.25562
9716.7.56.0/2616.7.56.1 to 16.7.56.6216.7.56.6362
9816.7.56.64/2616.7.56.65 to 16.7.56.12616.7.56.12762
9916.7.56.128/2616.7.56.129 to 16.7.56.19016.7.56.19162
10016.7.56.192/2616.7.56.193 to 16.7.56.25416.7.56.25562
10116.7.57.0/2616.7.57.1 to 16.7.57.6216.7.57.6362
10216.7.57.64/2616.7.57.65 to 16.7.57.12616.7.57.12762
10316.7.57.128/2616.7.57.129 to 16.7.57.19016.7.57.19162
10416.7.57.192/2616.7.57.193 to 16.7.57.25416.7.57.25562
10516.7.58.0/2616.7.58.1 to 16.7.58.6216.7.58.6362
10616.7.58.64/2616.7.58.65 to 16.7.58.12616.7.58.12762
10716.7.58.128/2616.7.58.129 to 16.7.58.19016.7.58.19162
10816.7.58.192/2616.7.58.193 to 16.7.58.25416.7.58.25562
10916.7.59.0/2616.7.59.1 to 16.7.59.6216.7.59.6362
11016.7.59.64/2616.7.59.65 to 16.7.59.12616.7.59.12762
11116.7.59.128/2616.7.59.129 to 16.7.59.19016.7.59.19162
11216.7.59.192/2616.7.59.193 to 16.7.59.25416.7.59.25562
11316.7.60.0/2616.7.60.1 to 16.7.60.6216.7.60.6362
11416.7.60.64/2616.7.60.65 to 16.7.60.12616.7.60.12762
11516.7.60.128/2616.7.60.129 to 16.7.60.19016.7.60.19162
11616.7.60.192/2616.7.60.193 to 16.7.60.25416.7.60.25562
11716.7.61.0/2616.7.61.1 to 16.7.61.6216.7.61.6362
11816.7.61.64/2616.7.61.65 to 16.7.61.12616.7.61.12762
11916.7.61.128/2616.7.61.129 to 16.7.61.19016.7.61.19162
12016.7.61.192/2616.7.61.193 to 16.7.61.25416.7.61.25562
12116.7.62.0/2616.7.62.1 to 16.7.62.6216.7.62.6362
12216.7.62.64/2616.7.62.65 to 16.7.62.12616.7.62.12762
12316.7.62.128/2616.7.62.129 to 16.7.62.19016.7.62.19162
12416.7.62.192/2616.7.62.193 to 16.7.62.25416.7.62.25562
12516.7.63.0/2616.7.63.1 to 16.7.63.6216.7.63.6362
12616.7.63.64/2616.7.63.65 to 16.7.63.12616.7.63.12762
12716.7.63.128/2616.7.63.129 to 16.7.63.19016.7.63.19162
12816.7.63.192/2616.7.63.193 to 16.7.63.25416.7.63.25562

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.