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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.

Network219.4.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
219.4.0.0
Broadcast address
219.7.255.255
First usable
219.4.0.1
Last usable
219.7.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
C (default /24)
As numbers
Hex DB040000 · Integer 3674472448 to 3674734591
Reverse DNS zones
4.219.in-addr.arpa
5.219.in-addr.arpa
6.219.in-addr.arpa
7.219.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011011.00000100.00000000.00000000219.4.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11011011.00000100.00000000.00000000219.4.0.0
Broadcast11011011.00000111.11111111.11111111219.7.255.255
Split into smaller subnets/20
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

219.4.0.0/14 makes 64 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1219.4.0.0/20219.4.0.1 to 219.4.15.254219.4.15.2554,094
2219.4.16.0/20219.4.16.1 to 219.4.31.254219.4.31.2554,094
3219.4.32.0/20219.4.32.1 to 219.4.47.254219.4.47.2554,094
4219.4.48.0/20219.4.48.1 to 219.4.63.254219.4.63.2554,094
5219.4.64.0/20219.4.64.1 to 219.4.79.254219.4.79.2554,094
6219.4.80.0/20219.4.80.1 to 219.4.95.254219.4.95.2554,094
7219.4.96.0/20219.4.96.1 to 219.4.111.254219.4.111.2554,094
8219.4.112.0/20219.4.112.1 to 219.4.127.254219.4.127.2554,094
9219.4.128.0/20219.4.128.1 to 219.4.143.254219.4.143.2554,094
10219.4.144.0/20219.4.144.1 to 219.4.159.254219.4.159.2554,094
11219.4.160.0/20219.4.160.1 to 219.4.175.254219.4.175.2554,094
12219.4.176.0/20219.4.176.1 to 219.4.191.254219.4.191.2554,094
13219.4.192.0/20219.4.192.1 to 219.4.207.254219.4.207.2554,094
14219.4.208.0/20219.4.208.1 to 219.4.223.254219.4.223.2554,094
15219.4.224.0/20219.4.224.1 to 219.4.239.254219.4.239.2554,094
16219.4.240.0/20219.4.240.1 to 219.4.255.254219.4.255.2554,094
17219.5.0.0/20219.5.0.1 to 219.5.15.254219.5.15.2554,094
18219.5.16.0/20219.5.16.1 to 219.5.31.254219.5.31.2554,094
19219.5.32.0/20219.5.32.1 to 219.5.47.254219.5.47.2554,094
20219.5.48.0/20219.5.48.1 to 219.5.63.254219.5.63.2554,094
21219.5.64.0/20219.5.64.1 to 219.5.79.254219.5.79.2554,094
22219.5.80.0/20219.5.80.1 to 219.5.95.254219.5.95.2554,094
23219.5.96.0/20219.5.96.1 to 219.5.111.254219.5.111.2554,094
24219.5.112.0/20219.5.112.1 to 219.5.127.254219.5.127.2554,094
25219.5.128.0/20219.5.128.1 to 219.5.143.254219.5.143.2554,094
26219.5.144.0/20219.5.144.1 to 219.5.159.254219.5.159.2554,094
27219.5.160.0/20219.5.160.1 to 219.5.175.254219.5.175.2554,094
28219.5.176.0/20219.5.176.1 to 219.5.191.254219.5.191.2554,094
29219.5.192.0/20219.5.192.1 to 219.5.207.254219.5.207.2554,094
30219.5.208.0/20219.5.208.1 to 219.5.223.254219.5.223.2554,094
31219.5.224.0/20219.5.224.1 to 219.5.239.254219.5.239.2554,094
32219.5.240.0/20219.5.240.1 to 219.5.255.254219.5.255.2554,094
33219.6.0.0/20219.6.0.1 to 219.6.15.254219.6.15.2554,094
34219.6.16.0/20219.6.16.1 to 219.6.31.254219.6.31.2554,094
35219.6.32.0/20219.6.32.1 to 219.6.47.254219.6.47.2554,094
36219.6.48.0/20219.6.48.1 to 219.6.63.254219.6.63.2554,094
37219.6.64.0/20219.6.64.1 to 219.6.79.254219.6.79.2554,094
38219.6.80.0/20219.6.80.1 to 219.6.95.254219.6.95.2554,094
39219.6.96.0/20219.6.96.1 to 219.6.111.254219.6.111.2554,094
40219.6.112.0/20219.6.112.1 to 219.6.127.254219.6.127.2554,094
41219.6.128.0/20219.6.128.1 to 219.6.143.254219.6.143.2554,094
42219.6.144.0/20219.6.144.1 to 219.6.159.254219.6.159.2554,094
43219.6.160.0/20219.6.160.1 to 219.6.175.254219.6.175.2554,094
44219.6.176.0/20219.6.176.1 to 219.6.191.254219.6.191.2554,094
45219.6.192.0/20219.6.192.1 to 219.6.207.254219.6.207.2554,094
46219.6.208.0/20219.6.208.1 to 219.6.223.254219.6.223.2554,094
47219.6.224.0/20219.6.224.1 to 219.6.239.254219.6.239.2554,094
48219.6.240.0/20219.6.240.1 to 219.6.255.254219.6.255.2554,094
49219.7.0.0/20219.7.0.1 to 219.7.15.254219.7.15.2554,094
50219.7.16.0/20219.7.16.1 to 219.7.31.254219.7.31.2554,094
51219.7.32.0/20219.7.32.1 to 219.7.47.254219.7.47.2554,094
52219.7.48.0/20219.7.48.1 to 219.7.63.254219.7.63.2554,094
53219.7.64.0/20219.7.64.1 to 219.7.79.254219.7.79.2554,094
54219.7.80.0/20219.7.80.1 to 219.7.95.254219.7.95.2554,094
55219.7.96.0/20219.7.96.1 to 219.7.111.254219.7.111.2554,094
56219.7.112.0/20219.7.112.1 to 219.7.127.254219.7.127.2554,094
57219.7.128.0/20219.7.128.1 to 219.7.143.254219.7.143.2554,094
58219.7.144.0/20219.7.144.1 to 219.7.159.254219.7.159.2554,094
59219.7.160.0/20219.7.160.1 to 219.7.175.254219.7.175.2554,094
60219.7.176.0/20219.7.176.1 to 219.7.191.254219.7.191.2554,094
61219.7.192.0/20219.7.192.1 to 219.7.207.254219.7.207.2554,094
62219.7.208.0/20219.7.208.1 to 219.7.223.254219.7.223.2554,094
63219.7.224.0/20219.7.224.1 to 219.7.239.254219.7.239.2554,094
64219.7.240.0/20219.7.240.1 to 219.7.255.254219.7.255.2554,094

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.