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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.

Network229.72.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
229.72.0.0
Broadcast address
229.79.255.255
First usable
229.72.0.1
Last usable
229.79.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E5480000 · Integer 3846701056 to 3847225343
Reverse DNS zones
72.229.in-addr.arpa
73.229.in-addr.arpa
74.229.in-addr.arpa
75.229.in-addr.arpa
76.229.in-addr.arpa
77.229.in-addr.arpa
78.229.in-addr.arpa
79.229.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
Address11100101.01001000.00000000.00000000229.72.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11100101.01001000.00000000.00000000229.72.0.0
Broadcast11100101.01001111.11111111.11111111229.79.255.255
Split into smaller subnets/19
/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)

229.72.0.0/13 makes 64 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1229.72.0.0/19229.72.0.1 to 229.72.31.254229.72.31.2558,190
2229.72.32.0/19229.72.32.1 to 229.72.63.254229.72.63.2558,190
3229.72.64.0/19229.72.64.1 to 229.72.95.254229.72.95.2558,190
4229.72.96.0/19229.72.96.1 to 229.72.127.254229.72.127.2558,190
5229.72.128.0/19229.72.128.1 to 229.72.159.254229.72.159.2558,190
6229.72.160.0/19229.72.160.1 to 229.72.191.254229.72.191.2558,190
7229.72.192.0/19229.72.192.1 to 229.72.223.254229.72.223.2558,190
8229.72.224.0/19229.72.224.1 to 229.72.255.254229.72.255.2558,190
9229.73.0.0/19229.73.0.1 to 229.73.31.254229.73.31.2558,190
10229.73.32.0/19229.73.32.1 to 229.73.63.254229.73.63.2558,190
11229.73.64.0/19229.73.64.1 to 229.73.95.254229.73.95.2558,190
12229.73.96.0/19229.73.96.1 to 229.73.127.254229.73.127.2558,190
13229.73.128.0/19229.73.128.1 to 229.73.159.254229.73.159.2558,190
14229.73.160.0/19229.73.160.1 to 229.73.191.254229.73.191.2558,190
15229.73.192.0/19229.73.192.1 to 229.73.223.254229.73.223.2558,190
16229.73.224.0/19229.73.224.1 to 229.73.255.254229.73.255.2558,190
17229.74.0.0/19229.74.0.1 to 229.74.31.254229.74.31.2558,190
18229.74.32.0/19229.74.32.1 to 229.74.63.254229.74.63.2558,190
19229.74.64.0/19229.74.64.1 to 229.74.95.254229.74.95.2558,190
20229.74.96.0/19229.74.96.1 to 229.74.127.254229.74.127.2558,190
21229.74.128.0/19229.74.128.1 to 229.74.159.254229.74.159.2558,190
22229.74.160.0/19229.74.160.1 to 229.74.191.254229.74.191.2558,190
23229.74.192.0/19229.74.192.1 to 229.74.223.254229.74.223.2558,190
24229.74.224.0/19229.74.224.1 to 229.74.255.254229.74.255.2558,190
25229.75.0.0/19229.75.0.1 to 229.75.31.254229.75.31.2558,190
26229.75.32.0/19229.75.32.1 to 229.75.63.254229.75.63.2558,190
27229.75.64.0/19229.75.64.1 to 229.75.95.254229.75.95.2558,190
28229.75.96.0/19229.75.96.1 to 229.75.127.254229.75.127.2558,190
29229.75.128.0/19229.75.128.1 to 229.75.159.254229.75.159.2558,190
30229.75.160.0/19229.75.160.1 to 229.75.191.254229.75.191.2558,190
31229.75.192.0/19229.75.192.1 to 229.75.223.254229.75.223.2558,190
32229.75.224.0/19229.75.224.1 to 229.75.255.254229.75.255.2558,190
33229.76.0.0/19229.76.0.1 to 229.76.31.254229.76.31.2558,190
34229.76.32.0/19229.76.32.1 to 229.76.63.254229.76.63.2558,190
35229.76.64.0/19229.76.64.1 to 229.76.95.254229.76.95.2558,190
36229.76.96.0/19229.76.96.1 to 229.76.127.254229.76.127.2558,190
37229.76.128.0/19229.76.128.1 to 229.76.159.254229.76.159.2558,190
38229.76.160.0/19229.76.160.1 to 229.76.191.254229.76.191.2558,190
39229.76.192.0/19229.76.192.1 to 229.76.223.254229.76.223.2558,190
40229.76.224.0/19229.76.224.1 to 229.76.255.254229.76.255.2558,190
41229.77.0.0/19229.77.0.1 to 229.77.31.254229.77.31.2558,190
42229.77.32.0/19229.77.32.1 to 229.77.63.254229.77.63.2558,190
43229.77.64.0/19229.77.64.1 to 229.77.95.254229.77.95.2558,190
44229.77.96.0/19229.77.96.1 to 229.77.127.254229.77.127.2558,190
45229.77.128.0/19229.77.128.1 to 229.77.159.254229.77.159.2558,190
46229.77.160.0/19229.77.160.1 to 229.77.191.254229.77.191.2558,190
47229.77.192.0/19229.77.192.1 to 229.77.223.254229.77.223.2558,190
48229.77.224.0/19229.77.224.1 to 229.77.255.254229.77.255.2558,190
49229.78.0.0/19229.78.0.1 to 229.78.31.254229.78.31.2558,190
50229.78.32.0/19229.78.32.1 to 229.78.63.254229.78.63.2558,190
51229.78.64.0/19229.78.64.1 to 229.78.95.254229.78.95.2558,190
52229.78.96.0/19229.78.96.1 to 229.78.127.254229.78.127.2558,190
53229.78.128.0/19229.78.128.1 to 229.78.159.254229.78.159.2558,190
54229.78.160.0/19229.78.160.1 to 229.78.191.254229.78.191.2558,190
55229.78.192.0/19229.78.192.1 to 229.78.223.254229.78.223.2558,190
56229.78.224.0/19229.78.224.1 to 229.78.255.254229.78.255.2558,190
57229.79.0.0/19229.79.0.1 to 229.79.31.254229.79.31.2558,190
58229.79.32.0/19229.79.32.1 to 229.79.63.254229.79.63.2558,190
59229.79.64.0/19229.79.64.1 to 229.79.95.254229.79.95.2558,190
60229.79.96.0/19229.79.96.1 to 229.79.127.254229.79.127.2558,190
61229.79.128.0/19229.79.128.1 to 229.79.159.254229.79.159.2558,190
62229.79.160.0/19229.79.160.1 to 229.79.191.254229.79.191.2558,190
63229.79.192.0/19229.79.192.1 to 229.79.223.254229.79.223.2558,190
64229.79.224.0/19229.79.224.1 to 229.79.255.254229.79.255.2558,190

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.