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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.

Network32.192.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
32.192.0.0
Broadcast address
32.199.255.255
First usable
32.192.0.1
Last usable
32.199.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 20C00000 · Integer 549453824 to 549978111
Reverse DNS zones
192.32.in-addr.arpa
193.32.in-addr.arpa
194.32.in-addr.arpa
195.32.in-addr.arpa
196.32.in-addr.arpa
197.32.in-addr.arpa
198.32.in-addr.arpa
199.32.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100000.11000000.00000000.0000000032.192.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00100000.11000000.00000000.0000000032.192.0.0
Broadcast00100000.11000111.11111111.1111111132.199.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

32.192.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
132.192.0.0/2032.192.0.1 to 32.192.15.25432.192.15.2554,094
232.192.16.0/2032.192.16.1 to 32.192.31.25432.192.31.2554,094
332.192.32.0/2032.192.32.1 to 32.192.47.25432.192.47.2554,094
432.192.48.0/2032.192.48.1 to 32.192.63.25432.192.63.2554,094
532.192.64.0/2032.192.64.1 to 32.192.79.25432.192.79.2554,094
632.192.80.0/2032.192.80.1 to 32.192.95.25432.192.95.2554,094
732.192.96.0/2032.192.96.1 to 32.192.111.25432.192.111.2554,094
832.192.112.0/2032.192.112.1 to 32.192.127.25432.192.127.2554,094
932.192.128.0/2032.192.128.1 to 32.192.143.25432.192.143.2554,094
1032.192.144.0/2032.192.144.1 to 32.192.159.25432.192.159.2554,094
1132.192.160.0/2032.192.160.1 to 32.192.175.25432.192.175.2554,094
1232.192.176.0/2032.192.176.1 to 32.192.191.25432.192.191.2554,094
1332.192.192.0/2032.192.192.1 to 32.192.207.25432.192.207.2554,094
1432.192.208.0/2032.192.208.1 to 32.192.223.25432.192.223.2554,094
1532.192.224.0/2032.192.224.1 to 32.192.239.25432.192.239.2554,094
1632.192.240.0/2032.192.240.1 to 32.192.255.25432.192.255.2554,094
1732.193.0.0/2032.193.0.1 to 32.193.15.25432.193.15.2554,094
1832.193.16.0/2032.193.16.1 to 32.193.31.25432.193.31.2554,094
1932.193.32.0/2032.193.32.1 to 32.193.47.25432.193.47.2554,094
2032.193.48.0/2032.193.48.1 to 32.193.63.25432.193.63.2554,094
2132.193.64.0/2032.193.64.1 to 32.193.79.25432.193.79.2554,094
2232.193.80.0/2032.193.80.1 to 32.193.95.25432.193.95.2554,094
2332.193.96.0/2032.193.96.1 to 32.193.111.25432.193.111.2554,094
2432.193.112.0/2032.193.112.1 to 32.193.127.25432.193.127.2554,094
2532.193.128.0/2032.193.128.1 to 32.193.143.25432.193.143.2554,094
2632.193.144.0/2032.193.144.1 to 32.193.159.25432.193.159.2554,094
2732.193.160.0/2032.193.160.1 to 32.193.175.25432.193.175.2554,094
2832.193.176.0/2032.193.176.1 to 32.193.191.25432.193.191.2554,094
2932.193.192.0/2032.193.192.1 to 32.193.207.25432.193.207.2554,094
3032.193.208.0/2032.193.208.1 to 32.193.223.25432.193.223.2554,094
3132.193.224.0/2032.193.224.1 to 32.193.239.25432.193.239.2554,094
3232.193.240.0/2032.193.240.1 to 32.193.255.25432.193.255.2554,094
3332.194.0.0/2032.194.0.1 to 32.194.15.25432.194.15.2554,094
3432.194.16.0/2032.194.16.1 to 32.194.31.25432.194.31.2554,094
3532.194.32.0/2032.194.32.1 to 32.194.47.25432.194.47.2554,094
3632.194.48.0/2032.194.48.1 to 32.194.63.25432.194.63.2554,094
3732.194.64.0/2032.194.64.1 to 32.194.79.25432.194.79.2554,094
3832.194.80.0/2032.194.80.1 to 32.194.95.25432.194.95.2554,094
3932.194.96.0/2032.194.96.1 to 32.194.111.25432.194.111.2554,094
4032.194.112.0/2032.194.112.1 to 32.194.127.25432.194.127.2554,094
4132.194.128.0/2032.194.128.1 to 32.194.143.25432.194.143.2554,094
4232.194.144.0/2032.194.144.1 to 32.194.159.25432.194.159.2554,094
4332.194.160.0/2032.194.160.1 to 32.194.175.25432.194.175.2554,094
4432.194.176.0/2032.194.176.1 to 32.194.191.25432.194.191.2554,094
4532.194.192.0/2032.194.192.1 to 32.194.207.25432.194.207.2554,094
4632.194.208.0/2032.194.208.1 to 32.194.223.25432.194.223.2554,094
4732.194.224.0/2032.194.224.1 to 32.194.239.25432.194.239.2554,094
4832.194.240.0/2032.194.240.1 to 32.194.255.25432.194.255.2554,094
4932.195.0.0/2032.195.0.1 to 32.195.15.25432.195.15.2554,094
5032.195.16.0/2032.195.16.1 to 32.195.31.25432.195.31.2554,094
5132.195.32.0/2032.195.32.1 to 32.195.47.25432.195.47.2554,094
5232.195.48.0/2032.195.48.1 to 32.195.63.25432.195.63.2554,094
5332.195.64.0/2032.195.64.1 to 32.195.79.25432.195.79.2554,094
5432.195.80.0/2032.195.80.1 to 32.195.95.25432.195.95.2554,094
5532.195.96.0/2032.195.96.1 to 32.195.111.25432.195.111.2554,094
5632.195.112.0/2032.195.112.1 to 32.195.127.25432.195.127.2554,094
5732.195.128.0/2032.195.128.1 to 32.195.143.25432.195.143.2554,094
5832.195.144.0/2032.195.144.1 to 32.195.159.25432.195.159.2554,094
5932.195.160.0/2032.195.160.1 to 32.195.175.25432.195.175.2554,094
6032.195.176.0/2032.195.176.1 to 32.195.191.25432.195.191.2554,094
6132.195.192.0/2032.195.192.1 to 32.195.207.25432.195.207.2554,094
6232.195.208.0/2032.195.208.1 to 32.195.223.25432.195.223.2554,094
6332.195.224.0/2032.195.224.1 to 32.195.239.25432.195.239.2554,094
6432.195.240.0/2032.195.240.1 to 32.195.255.25432.195.255.2554,094
6532.196.0.0/2032.196.0.1 to 32.196.15.25432.196.15.2554,094
6632.196.16.0/2032.196.16.1 to 32.196.31.25432.196.31.2554,094
6732.196.32.0/2032.196.32.1 to 32.196.47.25432.196.47.2554,094
6832.196.48.0/2032.196.48.1 to 32.196.63.25432.196.63.2554,094
6932.196.64.0/2032.196.64.1 to 32.196.79.25432.196.79.2554,094
7032.196.80.0/2032.196.80.1 to 32.196.95.25432.196.95.2554,094
7132.196.96.0/2032.196.96.1 to 32.196.111.25432.196.111.2554,094
7232.196.112.0/2032.196.112.1 to 32.196.127.25432.196.127.2554,094
7332.196.128.0/2032.196.128.1 to 32.196.143.25432.196.143.2554,094
7432.196.144.0/2032.196.144.1 to 32.196.159.25432.196.159.2554,094
7532.196.160.0/2032.196.160.1 to 32.196.175.25432.196.175.2554,094
7632.196.176.0/2032.196.176.1 to 32.196.191.25432.196.191.2554,094
7732.196.192.0/2032.196.192.1 to 32.196.207.25432.196.207.2554,094
7832.196.208.0/2032.196.208.1 to 32.196.223.25432.196.223.2554,094
7932.196.224.0/2032.196.224.1 to 32.196.239.25432.196.239.2554,094
8032.196.240.0/2032.196.240.1 to 32.196.255.25432.196.255.2554,094
8132.197.0.0/2032.197.0.1 to 32.197.15.25432.197.15.2554,094
8232.197.16.0/2032.197.16.1 to 32.197.31.25432.197.31.2554,094
8332.197.32.0/2032.197.32.1 to 32.197.47.25432.197.47.2554,094
8432.197.48.0/2032.197.48.1 to 32.197.63.25432.197.63.2554,094
8532.197.64.0/2032.197.64.1 to 32.197.79.25432.197.79.2554,094
8632.197.80.0/2032.197.80.1 to 32.197.95.25432.197.95.2554,094
8732.197.96.0/2032.197.96.1 to 32.197.111.25432.197.111.2554,094
8832.197.112.0/2032.197.112.1 to 32.197.127.25432.197.127.2554,094
8932.197.128.0/2032.197.128.1 to 32.197.143.25432.197.143.2554,094
9032.197.144.0/2032.197.144.1 to 32.197.159.25432.197.159.2554,094
9132.197.160.0/2032.197.160.1 to 32.197.175.25432.197.175.2554,094
9232.197.176.0/2032.197.176.1 to 32.197.191.25432.197.191.2554,094
9332.197.192.0/2032.197.192.1 to 32.197.207.25432.197.207.2554,094
9432.197.208.0/2032.197.208.1 to 32.197.223.25432.197.223.2554,094
9532.197.224.0/2032.197.224.1 to 32.197.239.25432.197.239.2554,094
9632.197.240.0/2032.197.240.1 to 32.197.255.25432.197.255.2554,094
9732.198.0.0/2032.198.0.1 to 32.198.15.25432.198.15.2554,094
9832.198.16.0/2032.198.16.1 to 32.198.31.25432.198.31.2554,094
9932.198.32.0/2032.198.32.1 to 32.198.47.25432.198.47.2554,094
10032.198.48.0/2032.198.48.1 to 32.198.63.25432.198.63.2554,094
10132.198.64.0/2032.198.64.1 to 32.198.79.25432.198.79.2554,094
10232.198.80.0/2032.198.80.1 to 32.198.95.25432.198.95.2554,094
10332.198.96.0/2032.198.96.1 to 32.198.111.25432.198.111.2554,094
10432.198.112.0/2032.198.112.1 to 32.198.127.25432.198.127.2554,094
10532.198.128.0/2032.198.128.1 to 32.198.143.25432.198.143.2554,094
10632.198.144.0/2032.198.144.1 to 32.198.159.25432.198.159.2554,094
10732.198.160.0/2032.198.160.1 to 32.198.175.25432.198.175.2554,094
10832.198.176.0/2032.198.176.1 to 32.198.191.25432.198.191.2554,094
10932.198.192.0/2032.198.192.1 to 32.198.207.25432.198.207.2554,094
11032.198.208.0/2032.198.208.1 to 32.198.223.25432.198.223.2554,094
11132.198.224.0/2032.198.224.1 to 32.198.239.25432.198.239.2554,094
11232.198.240.0/2032.198.240.1 to 32.198.255.25432.198.255.2554,094
11332.199.0.0/2032.199.0.1 to 32.199.15.25432.199.15.2554,094
11432.199.16.0/2032.199.16.1 to 32.199.31.25432.199.31.2554,094
11532.199.32.0/2032.199.32.1 to 32.199.47.25432.199.47.2554,094
11632.199.48.0/2032.199.48.1 to 32.199.63.25432.199.63.2554,094
11732.199.64.0/2032.199.64.1 to 32.199.79.25432.199.79.2554,094
11832.199.80.0/2032.199.80.1 to 32.199.95.25432.199.95.2554,094
11932.199.96.0/2032.199.96.1 to 32.199.111.25432.199.111.2554,094
12032.199.112.0/2032.199.112.1 to 32.199.127.25432.199.127.2554,094
12132.199.128.0/2032.199.128.1 to 32.199.143.25432.199.143.2554,094
12232.199.144.0/2032.199.144.1 to 32.199.159.25432.199.159.2554,094
12332.199.160.0/2032.199.160.1 to 32.199.175.25432.199.175.2554,094
12432.199.176.0/2032.199.176.1 to 32.199.191.25432.199.191.2554,094
12532.199.192.0/2032.199.192.1 to 32.199.207.25432.199.207.2554,094
12632.199.208.0/2032.199.208.1 to 32.199.223.25432.199.223.2554,094
12732.199.224.0/2032.199.224.1 to 32.199.239.25432.199.239.2554,094
12832.199.240.0/2032.199.240.1 to 32.199.255.25432.199.255.2554,094

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.