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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.

Network55.152.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
55.152.0.0
Broadcast address
55.159.255.255
First usable
55.152.0.1
Last usable
55.159.255.254
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 37980000 · Integer 932708352 to 933232639
Reverse DNS zones
152.55.in-addr.arpa
153.55.in-addr.arpa
154.55.in-addr.arpa
155.55.in-addr.arpa
156.55.in-addr.arpa
157.55.in-addr.arpa
158.55.in-addr.arpa
159.55.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
Address00110111.10011000.00000000.0000000055.152.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00110111.10011000.00000000.0000000055.152.0.0
Broadcast00110111.10011111.11111111.1111111155.159.255.255
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)

55.152.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.152.0.0/2055.152.0.1 to 55.152.15.25455.152.15.2554,094
255.152.16.0/2055.152.16.1 to 55.152.31.25455.152.31.2554,094
355.152.32.0/2055.152.32.1 to 55.152.47.25455.152.47.2554,094
455.152.48.0/2055.152.48.1 to 55.152.63.25455.152.63.2554,094
555.152.64.0/2055.152.64.1 to 55.152.79.25455.152.79.2554,094
655.152.80.0/2055.152.80.1 to 55.152.95.25455.152.95.2554,094
755.152.96.0/2055.152.96.1 to 55.152.111.25455.152.111.2554,094
855.152.112.0/2055.152.112.1 to 55.152.127.25455.152.127.2554,094
955.152.128.0/2055.152.128.1 to 55.152.143.25455.152.143.2554,094
1055.152.144.0/2055.152.144.1 to 55.152.159.25455.152.159.2554,094
1155.152.160.0/2055.152.160.1 to 55.152.175.25455.152.175.2554,094
1255.152.176.0/2055.152.176.1 to 55.152.191.25455.152.191.2554,094
1355.152.192.0/2055.152.192.1 to 55.152.207.25455.152.207.2554,094
1455.152.208.0/2055.152.208.1 to 55.152.223.25455.152.223.2554,094
1555.152.224.0/2055.152.224.1 to 55.152.239.25455.152.239.2554,094
1655.152.240.0/2055.152.240.1 to 55.152.255.25455.152.255.2554,094
1755.153.0.0/2055.153.0.1 to 55.153.15.25455.153.15.2554,094
1855.153.16.0/2055.153.16.1 to 55.153.31.25455.153.31.2554,094
1955.153.32.0/2055.153.32.1 to 55.153.47.25455.153.47.2554,094
2055.153.48.0/2055.153.48.1 to 55.153.63.25455.153.63.2554,094
2155.153.64.0/2055.153.64.1 to 55.153.79.25455.153.79.2554,094
2255.153.80.0/2055.153.80.1 to 55.153.95.25455.153.95.2554,094
2355.153.96.0/2055.153.96.1 to 55.153.111.25455.153.111.2554,094
2455.153.112.0/2055.153.112.1 to 55.153.127.25455.153.127.2554,094
2555.153.128.0/2055.153.128.1 to 55.153.143.25455.153.143.2554,094
2655.153.144.0/2055.153.144.1 to 55.153.159.25455.153.159.2554,094
2755.153.160.0/2055.153.160.1 to 55.153.175.25455.153.175.2554,094
2855.153.176.0/2055.153.176.1 to 55.153.191.25455.153.191.2554,094
2955.153.192.0/2055.153.192.1 to 55.153.207.25455.153.207.2554,094
3055.153.208.0/2055.153.208.1 to 55.153.223.25455.153.223.2554,094
3155.153.224.0/2055.153.224.1 to 55.153.239.25455.153.239.2554,094
3255.153.240.0/2055.153.240.1 to 55.153.255.25455.153.255.2554,094
3355.154.0.0/2055.154.0.1 to 55.154.15.25455.154.15.2554,094
3455.154.16.0/2055.154.16.1 to 55.154.31.25455.154.31.2554,094
3555.154.32.0/2055.154.32.1 to 55.154.47.25455.154.47.2554,094
3655.154.48.0/2055.154.48.1 to 55.154.63.25455.154.63.2554,094
3755.154.64.0/2055.154.64.1 to 55.154.79.25455.154.79.2554,094
3855.154.80.0/2055.154.80.1 to 55.154.95.25455.154.95.2554,094
3955.154.96.0/2055.154.96.1 to 55.154.111.25455.154.111.2554,094
4055.154.112.0/2055.154.112.1 to 55.154.127.25455.154.127.2554,094
4155.154.128.0/2055.154.128.1 to 55.154.143.25455.154.143.2554,094
4255.154.144.0/2055.154.144.1 to 55.154.159.25455.154.159.2554,094
4355.154.160.0/2055.154.160.1 to 55.154.175.25455.154.175.2554,094
4455.154.176.0/2055.154.176.1 to 55.154.191.25455.154.191.2554,094
4555.154.192.0/2055.154.192.1 to 55.154.207.25455.154.207.2554,094
4655.154.208.0/2055.154.208.1 to 55.154.223.25455.154.223.2554,094
4755.154.224.0/2055.154.224.1 to 55.154.239.25455.154.239.2554,094
4855.154.240.0/2055.154.240.1 to 55.154.255.25455.154.255.2554,094
4955.155.0.0/2055.155.0.1 to 55.155.15.25455.155.15.2554,094
5055.155.16.0/2055.155.16.1 to 55.155.31.25455.155.31.2554,094
5155.155.32.0/2055.155.32.1 to 55.155.47.25455.155.47.2554,094
5255.155.48.0/2055.155.48.1 to 55.155.63.25455.155.63.2554,094
5355.155.64.0/2055.155.64.1 to 55.155.79.25455.155.79.2554,094
5455.155.80.0/2055.155.80.1 to 55.155.95.25455.155.95.2554,094
5555.155.96.0/2055.155.96.1 to 55.155.111.25455.155.111.2554,094
5655.155.112.0/2055.155.112.1 to 55.155.127.25455.155.127.2554,094
5755.155.128.0/2055.155.128.1 to 55.155.143.25455.155.143.2554,094
5855.155.144.0/2055.155.144.1 to 55.155.159.25455.155.159.2554,094
5955.155.160.0/2055.155.160.1 to 55.155.175.25455.155.175.2554,094
6055.155.176.0/2055.155.176.1 to 55.155.191.25455.155.191.2554,094
6155.155.192.0/2055.155.192.1 to 55.155.207.25455.155.207.2554,094
6255.155.208.0/2055.155.208.1 to 55.155.223.25455.155.223.2554,094
6355.155.224.0/2055.155.224.1 to 55.155.239.25455.155.239.2554,094
6455.155.240.0/2055.155.240.1 to 55.155.255.25455.155.255.2554,094
6555.156.0.0/2055.156.0.1 to 55.156.15.25455.156.15.2554,094
6655.156.16.0/2055.156.16.1 to 55.156.31.25455.156.31.2554,094
6755.156.32.0/2055.156.32.1 to 55.156.47.25455.156.47.2554,094
6855.156.48.0/2055.156.48.1 to 55.156.63.25455.156.63.2554,094
6955.156.64.0/2055.156.64.1 to 55.156.79.25455.156.79.2554,094
7055.156.80.0/2055.156.80.1 to 55.156.95.25455.156.95.2554,094
7155.156.96.0/2055.156.96.1 to 55.156.111.25455.156.111.2554,094
7255.156.112.0/2055.156.112.1 to 55.156.127.25455.156.127.2554,094
7355.156.128.0/2055.156.128.1 to 55.156.143.25455.156.143.2554,094
7455.156.144.0/2055.156.144.1 to 55.156.159.25455.156.159.2554,094
7555.156.160.0/2055.156.160.1 to 55.156.175.25455.156.175.2554,094
7655.156.176.0/2055.156.176.1 to 55.156.191.25455.156.191.2554,094
7755.156.192.0/2055.156.192.1 to 55.156.207.25455.156.207.2554,094
7855.156.208.0/2055.156.208.1 to 55.156.223.25455.156.223.2554,094
7955.156.224.0/2055.156.224.1 to 55.156.239.25455.156.239.2554,094
8055.156.240.0/2055.156.240.1 to 55.156.255.25455.156.255.2554,094
8155.157.0.0/2055.157.0.1 to 55.157.15.25455.157.15.2554,094
8255.157.16.0/2055.157.16.1 to 55.157.31.25455.157.31.2554,094
8355.157.32.0/2055.157.32.1 to 55.157.47.25455.157.47.2554,094
8455.157.48.0/2055.157.48.1 to 55.157.63.25455.157.63.2554,094
8555.157.64.0/2055.157.64.1 to 55.157.79.25455.157.79.2554,094
8655.157.80.0/2055.157.80.1 to 55.157.95.25455.157.95.2554,094
8755.157.96.0/2055.157.96.1 to 55.157.111.25455.157.111.2554,094
8855.157.112.0/2055.157.112.1 to 55.157.127.25455.157.127.2554,094
8955.157.128.0/2055.157.128.1 to 55.157.143.25455.157.143.2554,094
9055.157.144.0/2055.157.144.1 to 55.157.159.25455.157.159.2554,094
9155.157.160.0/2055.157.160.1 to 55.157.175.25455.157.175.2554,094
9255.157.176.0/2055.157.176.1 to 55.157.191.25455.157.191.2554,094
9355.157.192.0/2055.157.192.1 to 55.157.207.25455.157.207.2554,094
9455.157.208.0/2055.157.208.1 to 55.157.223.25455.157.223.2554,094
9555.157.224.0/2055.157.224.1 to 55.157.239.25455.157.239.2554,094
9655.157.240.0/2055.157.240.1 to 55.157.255.25455.157.255.2554,094
9755.158.0.0/2055.158.0.1 to 55.158.15.25455.158.15.2554,094
9855.158.16.0/2055.158.16.1 to 55.158.31.25455.158.31.2554,094
9955.158.32.0/2055.158.32.1 to 55.158.47.25455.158.47.2554,094
10055.158.48.0/2055.158.48.1 to 55.158.63.25455.158.63.2554,094
10155.158.64.0/2055.158.64.1 to 55.158.79.25455.158.79.2554,094
10255.158.80.0/2055.158.80.1 to 55.158.95.25455.158.95.2554,094
10355.158.96.0/2055.158.96.1 to 55.158.111.25455.158.111.2554,094
10455.158.112.0/2055.158.112.1 to 55.158.127.25455.158.127.2554,094
10555.158.128.0/2055.158.128.1 to 55.158.143.25455.158.143.2554,094
10655.158.144.0/2055.158.144.1 to 55.158.159.25455.158.159.2554,094
10755.158.160.0/2055.158.160.1 to 55.158.175.25455.158.175.2554,094
10855.158.176.0/2055.158.176.1 to 55.158.191.25455.158.191.2554,094
10955.158.192.0/2055.158.192.1 to 55.158.207.25455.158.207.2554,094
11055.158.208.0/2055.158.208.1 to 55.158.223.25455.158.223.2554,094
11155.158.224.0/2055.158.224.1 to 55.158.239.25455.158.239.2554,094
11255.158.240.0/2055.158.240.1 to 55.158.255.25455.158.255.2554,094
11355.159.0.0/2055.159.0.1 to 55.159.15.25455.159.15.2554,094
11455.159.16.0/2055.159.16.1 to 55.159.31.25455.159.31.2554,094
11555.159.32.0/2055.159.32.1 to 55.159.47.25455.159.47.2554,094
11655.159.48.0/2055.159.48.1 to 55.159.63.25455.159.63.2554,094
11755.159.64.0/2055.159.64.1 to 55.159.79.25455.159.79.2554,094
11855.159.80.0/2055.159.80.1 to 55.159.95.25455.159.95.2554,094
11955.159.96.0/2055.159.96.1 to 55.159.111.25455.159.111.2554,094
12055.159.112.0/2055.159.112.1 to 55.159.127.25455.159.127.2554,094
12155.159.128.0/2055.159.128.1 to 55.159.143.25455.159.143.2554,094
12255.159.144.0/2055.159.144.1 to 55.159.159.25455.159.159.2554,094
12355.159.160.0/2055.159.160.1 to 55.159.175.25455.159.175.2554,094
12455.159.176.0/2055.159.176.1 to 55.159.191.25455.159.191.2554,094
12555.159.192.0/2055.159.192.1 to 55.159.207.25455.159.207.2554,094
12655.159.208.0/2055.159.208.1 to 55.159.223.25455.159.223.2554,094
12755.159.224.0/2055.159.224.1 to 55.159.239.25455.159.239.2554,094
12855.159.240.0/2055.159.240.1 to 55.159.255.25455.159.255.2554,094

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.