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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.

Network224.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
224.0.0.0
Broadcast address
224.255.255.255
First usable
224.0.0.1
Last usable
224.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E0000000 · Integer 3758096384 to 3774873599
Reverse DNS zone
224.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100000..00000000.00000000.00000000224.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11100000..00000000.00000000.00000000224.0.0.0
Broadcast11100000..11111111.11111111.11111111224.255.255.255
Split into smaller subnets/14
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

224.0.0.0/8 makes 64 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1224.0.0.0/14224.0.0.1 to 224.3.255.254224.3.255.255262,142
2224.4.0.0/14224.4.0.1 to 224.7.255.254224.7.255.255262,142
3224.8.0.0/14224.8.0.1 to 224.11.255.254224.11.255.255262,142
4224.12.0.0/14224.12.0.1 to 224.15.255.254224.15.255.255262,142
5224.16.0.0/14224.16.0.1 to 224.19.255.254224.19.255.255262,142
6224.20.0.0/14224.20.0.1 to 224.23.255.254224.23.255.255262,142
7224.24.0.0/14224.24.0.1 to 224.27.255.254224.27.255.255262,142
8224.28.0.0/14224.28.0.1 to 224.31.255.254224.31.255.255262,142
9224.32.0.0/14224.32.0.1 to 224.35.255.254224.35.255.255262,142
10224.36.0.0/14224.36.0.1 to 224.39.255.254224.39.255.255262,142
11224.40.0.0/14224.40.0.1 to 224.43.255.254224.43.255.255262,142
12224.44.0.0/14224.44.0.1 to 224.47.255.254224.47.255.255262,142
13224.48.0.0/14224.48.0.1 to 224.51.255.254224.51.255.255262,142
14224.52.0.0/14224.52.0.1 to 224.55.255.254224.55.255.255262,142
15224.56.0.0/14224.56.0.1 to 224.59.255.254224.59.255.255262,142
16224.60.0.0/14224.60.0.1 to 224.63.255.254224.63.255.255262,142
17224.64.0.0/14224.64.0.1 to 224.67.255.254224.67.255.255262,142
18224.68.0.0/14224.68.0.1 to 224.71.255.254224.71.255.255262,142
19224.72.0.0/14224.72.0.1 to 224.75.255.254224.75.255.255262,142
20224.76.0.0/14224.76.0.1 to 224.79.255.254224.79.255.255262,142
21224.80.0.0/14224.80.0.1 to 224.83.255.254224.83.255.255262,142
22224.84.0.0/14224.84.0.1 to 224.87.255.254224.87.255.255262,142
23224.88.0.0/14224.88.0.1 to 224.91.255.254224.91.255.255262,142
24224.92.0.0/14224.92.0.1 to 224.95.255.254224.95.255.255262,142
25224.96.0.0/14224.96.0.1 to 224.99.255.254224.99.255.255262,142
26224.100.0.0/14224.100.0.1 to 224.103.255.254224.103.255.255262,142
27224.104.0.0/14224.104.0.1 to 224.107.255.254224.107.255.255262,142
28224.108.0.0/14224.108.0.1 to 224.111.255.254224.111.255.255262,142
29224.112.0.0/14224.112.0.1 to 224.115.255.254224.115.255.255262,142
30224.116.0.0/14224.116.0.1 to 224.119.255.254224.119.255.255262,142
31224.120.0.0/14224.120.0.1 to 224.123.255.254224.123.255.255262,142
32224.124.0.0/14224.124.0.1 to 224.127.255.254224.127.255.255262,142
33224.128.0.0/14224.128.0.1 to 224.131.255.254224.131.255.255262,142
34224.132.0.0/14224.132.0.1 to 224.135.255.254224.135.255.255262,142
35224.136.0.0/14224.136.0.1 to 224.139.255.254224.139.255.255262,142
36224.140.0.0/14224.140.0.1 to 224.143.255.254224.143.255.255262,142
37224.144.0.0/14224.144.0.1 to 224.147.255.254224.147.255.255262,142
38224.148.0.0/14224.148.0.1 to 224.151.255.254224.151.255.255262,142
39224.152.0.0/14224.152.0.1 to 224.155.255.254224.155.255.255262,142
40224.156.0.0/14224.156.0.1 to 224.159.255.254224.159.255.255262,142
41224.160.0.0/14224.160.0.1 to 224.163.255.254224.163.255.255262,142
42224.164.0.0/14224.164.0.1 to 224.167.255.254224.167.255.255262,142
43224.168.0.0/14224.168.0.1 to 224.171.255.254224.171.255.255262,142
44224.172.0.0/14224.172.0.1 to 224.175.255.254224.175.255.255262,142
45224.176.0.0/14224.176.0.1 to 224.179.255.254224.179.255.255262,142
46224.180.0.0/14224.180.0.1 to 224.183.255.254224.183.255.255262,142
47224.184.0.0/14224.184.0.1 to 224.187.255.254224.187.255.255262,142
48224.188.0.0/14224.188.0.1 to 224.191.255.254224.191.255.255262,142
49224.192.0.0/14224.192.0.1 to 224.195.255.254224.195.255.255262,142
50224.196.0.0/14224.196.0.1 to 224.199.255.254224.199.255.255262,142
51224.200.0.0/14224.200.0.1 to 224.203.255.254224.203.255.255262,142
52224.204.0.0/14224.204.0.1 to 224.207.255.254224.207.255.255262,142
53224.208.0.0/14224.208.0.1 to 224.211.255.254224.211.255.255262,142
54224.212.0.0/14224.212.0.1 to 224.215.255.254224.215.255.255262,142
55224.216.0.0/14224.216.0.1 to 224.219.255.254224.219.255.255262,142
56224.220.0.0/14224.220.0.1 to 224.223.255.254224.223.255.255262,142
57224.224.0.0/14224.224.0.1 to 224.227.255.254224.227.255.255262,142
58224.228.0.0/14224.228.0.1 to 224.231.255.254224.231.255.255262,142
59224.232.0.0/14224.232.0.1 to 224.235.255.254224.235.255.255262,142
60224.236.0.0/14224.236.0.1 to 224.239.255.254224.239.255.255262,142
61224.240.0.0/14224.240.0.1 to 224.243.255.254224.243.255.255262,142
62224.244.0.0/14224.244.0.1 to 224.247.255.254224.247.255.255262,142
63224.248.0.0/14224.248.0.1 to 224.251.255.254224.251.255.255262,142
64224.252.0.0/14224.252.0.1 to 224.255.255.254224.255.255.255262,142

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.